JP4703303B2 - Optical transmitter and frequency shift type high density optical frequency multiplex transmission system - Google Patents

Optical transmitter and frequency shift type high density optical frequency multiplex transmission system Download PDF

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JP4703303B2
JP4703303B2 JP2005213206A JP2005213206A JP4703303B2 JP 4703303 B2 JP4703303 B2 JP 4703303B2 JP 2005213206 A JP2005213206 A JP 2005213206A JP 2005213206 A JP2005213206 A JP 2005213206A JP 4703303 B2 JP4703303 B2 JP 4703303B2
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達也 島田
広明 三条
聖 成川
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Nippon Telegraph and Telephone Corp
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本発明は、光通信に係り、特に高密度光周波数多重伝送システムに好適に用いられる光送信器およびその構成に関する。   The present invention relates to optical communication, and more particularly to an optical transmitter suitably used in a high-density optical frequency multiplex transmission system and a configuration thereof.

図１５は、非特許文献１を参考とした光周波数多重伝送システムの従来例を示す図である。   FIG. 15 is a diagram illustrating a conventional example of an optical frequency multiplex transmission system with reference to Non-Patent Document 1.

アクセスネットワークの大容量化・柔軟性の向上等を目的として、ＷＤＭ（Ｗａｖｅｌｅｎｇｔｈ Ｄｉｖｉｓｉｏｎ Ｍｕｌｔｉｐｌｅｘｉｎｇ：波長分割多重）技術を用いた、ＷＤＭアクセスネットワークの研究開発が活発に行われている。一般にＷＤＭアクセスネットワークでは、波長フィルタや波長分波器により波長選択が行われている。しかし、高密度波長多重〈波長間隔：２５ＧＨｚ，１２．５ＧＨｚ・・・等〉になればなるほど、波長フィルタや波長分波器の実現は難しくなる。こうした問題の解決策の１つとして、コヒーレント光受信技術を用いた、光ＦＤＭ（Ｆｒｅｑｕｅｎｃｙ Ｄｉｖｉｓｉｏｎ Ｍｕｌｔｉｐｌｅｘｉｎｇ：周波数分割多重）アクセスネットワークがある。これは、高密度の波長多重伝送による周波数利用効率の向上が実現できるほか、高感度受信ができるため、アクセスネットワーク、とりわけ、光送信器と光受信器の間に光カプラを設け、１台の光送信器と複数の光受信器を接続する、いわゆるＰＯＮ（Ｐａｓｓｉｖｅ Ｏｐｔｉｃａｌ Ｎｅｔｗｏｒｋ）構成のアクセスネットワークにおいて、信号多重数、ユーザ数、伝送距離を大幅に拡大することが可能となる。   Research and development of a WDM access network using a WDM (Wavelength Division Multiplexing) technique has been actively conducted for the purpose of increasing the capacity and flexibility of the access network. Generally, in a WDM access network, wavelength selection is performed by a wavelength filter or a wavelength demultiplexer. However, the higher the density wavelength multiplexing (wavelength interval: 25 GHz, 12.5 GHz, etc.), the more difficult it becomes to realize a wavelength filter or wavelength demultiplexer. One solution to this problem is an optical FDM (Frequency Division Multiplexing) access network using coherent optical reception technology. This is because frequency utilization efficiency can be improved by high-density wavelength division multiplexing transmission and high-sensitivity reception is possible. Therefore, an optical coupler is provided between the access network, in particular, the optical transmitter and the optical receiver. In an access network having a so-called PON (Passive Optical Network) configuration in which an optical transmitter and a plurality of optical receivers are connected, the number of multiplexed signals, the number of users, and the transmission distance can be greatly increased.

図１５の従来例は、前述した光ＦＤＭアクセスネットワークを実現するための、光周波数多重伝送システムの一例である。図１５の従来例は、周波数ｆ１の光信号を送信する光源１０１−１と、光源１０１−１からの光信号の偏波を調整する偏波制御器１０２−１と、周波数ｆ２の光信号を送信する光源１０１−２と、光源１０１−２からの光信号の偏波を調整する偏波制御器１０２−２と、偏波制御器１０２−１からの光信号と偏波制御器１０２−２からの光信号を合波する光カプラ１０３と、光カプラ１０３で合波した光信号を変調する光変調器１０４からなる光送信器１０と、光送信器１０と光ファイバ２０を介して接続され、光送信器１０からの光信号をコヒーレント光検波する光受信器３０を備えた光周波数多重伝送システムである。 The conventional example of FIG. 15 is an example of an optical frequency multiplex transmission system for realizing the optical FDM access network described above. Conventional example of FIG. 15 includes a light source 101-1 for transmitting an optical signal of frequency f 1, a polarization controller 102-1 for adjusting the polarization of the optical signal from the light source 101-1, a frequency f 2 light A light source 101-2 that transmits a signal, a polarization controller 102-2 that adjusts the polarization of the optical signal from the light source 101-2, an optical signal from the polarization controller 102-1 and the polarization controller 102 -2 that combines the optical signal from -2, the optical transmitter 10 that includes the optical modulator 104 that modulates the optical signal combined by the optical coupler 103, the optical transmitter 10 and the optical fiber 20 The optical frequency multiplex transmission system includes an optical receiver 30 that is connected and detects optical signals from the optical transmitter 10 coherently.

ここで偏波制御器１０２−１と偏波制御器１０２−２は、周波数ｆ１の光信号と周波数ｆ２の光信号の偏波が互いに直交するように、それぞれ制御する。このように制御することにより、光受信器３０では、伝送路中の偏波状態に依存しないコヒーレント光受信を行うことができる。 Here polarization controller 102-1 and polarization controller 102-2, as the polarization of the optical signal and the frequency f 2 of the optical signal of frequency f 1 are perpendicular to each other, and controls, respectively. By controlling in this way, the optical receiver 30 can perform coherent light reception independent of the polarization state in the transmission path.

図１５では、光送信器は１台であるが、同様な光送信器を複数台配置し、それぞれの光送信器からの光信号を合波し光受信器へ伝送することで、多波長の高密度波長多重システムを実現することもできる。この場合、光受信器では任意の波長を選択受信する構成にすることが可能である。また、ＰＯＮ構成にし、光送信器と光ファイバを複数の光受信器で共有することもできる。
成川 聖、外３名、“光ＦＤＭアクセスにおける送信側偏波ダイバーシティ方式”、電子情報通信学会総合大会、Ｂ−１０−９５、２００５年 In FIG. 15, there is one optical transmitter, but a plurality of similar optical transmitters are arranged, and optical signals from the respective optical transmitters are combined and transmitted to the optical receiver. A high-density wavelength multiplexing system can also be realized. In this case, the optical receiver can be configured to selectively receive an arbitrary wavelength. Further, a PON configuration can be used, and an optical transmitter and an optical fiber can be shared by a plurality of optical receivers.
Sei Narukawa, 3 others, “Transmission-side polarization diversity method in optical FDM access”, IEICE General Conference, B-10-95, 2005

光ＦＤＭアクセスネットワークでは、波長間隔が高密度であるので、周波数の安定した光源が必要となる。図１５の従来システムでは、図に示すとおり、２台の周波数の安定した光源が必要となる。Ｎ台の光送信器の光信号を多重する場合は、光源は２Ｎ台必要となる。そのため周波数の多重数が増えれば増えるほど、多数の周波数の安定した光源を準備する必要があり、光源の品種が増えてしまうという問題が生じる。   In the optical FDM access network, since the wavelength interval is high density, a light source having a stable frequency is required. The conventional system of FIG. 15 requires two light sources having stable frequencies as shown in the figure. When multiplexing optical signals from N optical transmitters, 2N light sources are required. Therefore, as the number of multiplexed frequencies increases, it is necessary to prepare a stable light source having a large number of frequencies, resulting in an increase in the types of light sources.

本発明は、このような背景で行われたものであり、本発明の目的は、２台の光源を準備する代わりに、１台の光源と１台あるいは２台の光周波数シフタを用いることにより、光源の品種数を減らすことのできる周波数シフト型高密度光周波数多重伝送システムを提供することにある。   The present invention has been made in this background, and the object of the present invention is to use one light source and one or two optical frequency shifters instead of preparing two light sources. Another object of the present invention is to provide a frequency shift type high density optical frequency multiplex transmission system capable of reducing the number of types of light sources.

上述したように本発明は、光送信器に光周波数シフタを備え、光周波数シフタにより、１台の光源で２つの周波数の光信号を周波数多重伝送できるようにして、周波数多重伝送に必要な、周波数の安定した光源の品種数の削減を実現するものである。   As described above, the present invention includes an optical frequency shifter in an optical transmitter, and the optical frequency shifter can perform frequency multiplexing transmission of optical signals of two frequencies with one light source, and is necessary for frequency multiplexing transmission. This is to reduce the number of light sources with stable frequency.

第１の発明は、１台の光源と、前記光源に接続された光周波数シフタと、光周波数シフタの一方のポートに接続された第１の偏波制御器と、光周波数シフタの他方のポートに接続された第２の偏波制御器と、第１の偏波制御器および第２の偏波制御器により偏波状態が互いに直交するように制御された前記２つのポートからの光信号を合波する光カプラと、合波した光信号を変調する光変調器からなる光送信器において、光周波数シフタは、出力側に方向性結合器が配置され、前記方向性結合器の一方の入力に第１のマッハツェンダ回路が接続され、前記方向性結合器の他方の入力に第２のマッハツェンダ回路が接続され、前記第１のマッハツェンダ回路の入力と前記周波数シフタの入力が接続され、前記第２のマッハツェンダ回路の入力と前記周波数シフタの入力が接続され、前記周波数シフタの入力に前記光源が接続され、前記方向性結合器の一方の出力に前記第１の偏波制御器が接続され、前記方向性結合器の他方の出力に前記第２の偏波制御器が接続された構成であり、前記第１のマッハツェンダ回路は、第１のＲＦ信号電極と各導波路の光位相差を調整する第２のＤＣ電極とが直列に接続され、さらに直列に接続された前記第１のＲＦ信号電極および前記第２のＤＣ電極と、第２のＲＦ信号電極とが並列に接続された構成であり、前記第２のマッハツェンダ回路は、第３のＲＦ信号電極と各導波路の光位相差を調整する第３のＤＣ電極とが直列に接続され、さらに直列に接続された前記第３のＲＦ信号電極および前記第３のＤＣ電極と、第４のＲＦ信号電極とが並列に接続された構成であり、前記光周波数シフタが、前記第１の偏波制御器に前記光源からの光信号の周波数を低周波シフトさせた光信号を出力し、前記第２の偏波制御器に前記光源からの光信号の周波数を高周波シフトさせた光信号を出力し、１台の光源で２つの周波数の光信号を周波数多重伝送できるようにしたことを特徴とする光送信器である。 The first invention includes one light source, an optical frequency shifter connected to the light source, a first polarization controller connected to one port of the optical frequency shifter, and the other port of the optical frequency shifter. Optical signals from the two ports controlled by the second polarization controller connected to the first polarization controller and the first polarization controller and the second polarization controller so that the polarization states are orthogonal to each other. In an optical transmitter comprising an optical coupler for multiplexing and an optical modulator for modulating the combined optical signal, the optical frequency shifter has a directional coupler disposed on the output side, and one input of the directional coupler The first Mach-Zehnder circuit is connected to the other input of the directional coupler, the second Mach-Zehnder circuit is connected to the other input of the directional coupler, the input of the first Mach-Zehnder circuit and the input of the frequency shifter are connected, and the second The input of the Mach-Zehnder circuit The input of the frequency shifter is connected, the light source is connected to the input of the frequency shifter, the first polarization controller is connected to one output of the directional coupler, and the other of the directional coupler is connected The second polarization controller is connected to the output of the first Mach-Zehnder circuit, and the first Mach-Zehnder circuit includes a first DC signal electrode and a second DC electrode that adjusts an optical phase difference between the waveguides. Are connected in series, and the first RF signal electrode and the second DC electrode connected in series, and the second RF signal electrode are connected in parallel, and the second Mach-Zehnder In the circuit, a third RF signal electrode and a third DC electrode for adjusting the optical phase difference of each waveguide are connected in series, and the third RF signal electrode and the third DC electrode connected in series are connected. The DC electrode and the fourth RF signal electrode are connected in parallel. A configurations, the optical frequency shifter, and outputs an optical signal the frequency of the optical signal obtained by low-frequency shift from said light source to said first polarization controller, the second polarization controller An optical transmitter characterized in that an optical signal obtained by shifting the frequency of an optical signal from the light source by a high frequency is outputted so that optical signals of two frequencies can be frequency-multiplexed and transmitted by a single light source.

第２の発明は、１台の光源と、前記光源に接続された光周波数シフタと、光周波数シフタの一方のポートに接続された第１の偏波制御器と、光周波数シフタの他方のポートに接続された第２の偏波制御器と、第１の偏波制御器および第２の偏波制御器により偏波状態が互いに直交するように制御された前記２つのポートからの光信号を合波する光カプラと、合波した光信号を変調する光変調器からなる光送信器と、前記光送信器と光ファイバを介して接続され、前記光送信器からの光信号をコヒーレント光検波する光受信器からなる光周波数多重伝送システムにおいて、光周波数シフタは、出力側に方向性結合器が配置され、前記方向性結合器の一方の入力に第１のマッハツェンダ回路が接続され、前記方向性結合器の他方の入力に第２のマッハツェンダ回路が接続され、前記第１のマッハツェンダ回路の入力と前記周波数シフタの入力が接続され、前記第２のマッハツェンダ回路の入力と前記周波数シフタの入力が接続され、前記周波数シフタの入力に前記光源が接続され、前記方向性結合器の一方の出力に前記第１の偏波制御器が接続され、前記方向性結合器の他方の出力に前記第２の偏波制御器が接続された構成であり、前記第１のマッハツェンダ回路は、第１のＲＦ信号電極と各導波路の光位相差を調整する第２のＤＣ電極とが直列に接続され、さらに直列に接続された前記第１のＲＦ信号電極および前記第２のＤＣ電極と、第２のＲＦ信号電極とが並列に接続された構成であり、前記第２のマッハツェンダ回路は、第３のＲＦ信号電極と各導波路の光位相差を調整する第３のＤＣ電極とが直列に接続され、さらに直列に接続された前記第３のＲＦ信号電極および前記第３のＤＣ電極と、第４のＲＦ信号電極とが並列に接続された構成であり、前記光周波数シフタが、前記第１の偏波制御器に前記光源からの光信号の周波数を低周波シフトさせた光信号を出力し、前記第２の偏波制御器に前記光源からの光信号の周波数を高周波シフトさせた光信号を出力し、１台の光源で２つの周波数の光信号を周波数多重伝送できるようにしたことを特徴とする周波数シフト型高密度光周波数多重伝送システムである。 According to a second aspect of the present invention, there is provided one light source, an optical frequency shifter connected to the light source, a first polarization controller connected to one port of the optical frequency shifter, and the other port of the optical frequency shifter. Optical signals from the two ports controlled by the second polarization controller connected to the first polarization controller and the first polarization controller and the second polarization controller so that the polarization states are orthogonal to each other. An optical transmitter comprising an optical coupler for multiplexing, an optical modulator for modulating the combined optical signal, and the optical transmitter connected via an optical fiber, and coherent optical detection of the optical signal from the optical transmitter In the optical frequency multiplex transmission system comprising the optical receiver, the optical frequency shifter has a directional coupler disposed on the output side, and a first Mach-Zehnder circuit is connected to one input of the directional coupler, and the direction The second input to the other input of the sex coupler A Hazender circuit is connected, an input of the first Mach-Zehnder circuit and an input of the frequency shifter are connected, an input of the second Mach-Zehnder circuit and an input of the frequency shifter are connected, and the light source is connected to the input of the frequency shifter Is connected, the first polarization controller is connected to one output of the directional coupler, and the second polarization controller is connected to the other output of the directional coupler. In the first Mach-Zehnder circuit, the first RF signal electrode and the second DC electrode for adjusting the optical phase difference of each waveguide are connected in series, and the first RF signal electrode is further connected in series. The signal electrode, the second DC electrode, and the second RF signal electrode are connected in parallel, and the second Mach-Zehnder circuit includes an optical phase difference between the third RF signal electrode and each waveguide. Adjust the second And DC electrodes are connected in series, further said serially connected third RF signal electrode and the third DC electrode, a configuration in which the fourth RF signal electrodes are connected in parallel, the An optical frequency shifter outputs an optical signal obtained by shifting the frequency of the optical signal from the light source to the first polarization controller, and outputs an optical signal from the light source to the second polarization controller. A frequency shift type high density optical frequency multiplex transmission system characterized in that an optical signal having a frequency shifted by a high frequency is output so that optical signals of two frequencies can be frequency multiplex transmitted by one light source.

第３の発明は、１台の光源と、前記光源に接続された光周波数シフタと、光周波数シフタの一方のポートに接続された第１の偏波制御器と、光周波数シフタの他方のポートに接続された第２の偏波制御器と、第１の偏波制御器および第２の偏波制御器により偏波状態が互いに直交するように制御された前記２つのポートからの光信号を合波する第１の光カプラと、合波した光信号を変調する光変調器からなる光送信器Ｎ台と、Ｎ台の各光送信器からの光信号を合波する第２の光カプラと、前記第２の光カプラと光ファイバを介して接続され、前記光送信器からの光信号をコヒーレント光検波する光受信器からなる光周波数多重伝送システムにおいて、光周波数シフタは、出力側に方向性結合器が配置され、前記方向性結合器の一方の入力に第１のマッハツェンダ回路が接続され、前記方向性結合器の他方の入力に第２のマッハツェンダ回路が接続され、前記第１のマッハツェンダ回路の入力と前記周波数シフタの入力が接続され、前記第２のマッハツェンダ回路の入力と前記周波数シフタの入力が接続され、前記周波数シフタの入力に前記光源が接続され、前記方向性結合器の一方の出力に前記第１の偏波制御器が接続され、前記方向性結合器の他方の出力に前記第２の偏波制御器が接続された構成であり、前記第１のマッハツェンダ回路は、第１のＲＦ信号電極と各導波路の光位相差を調整する第２のＤＣ電極とが直列に接続され、さらに直列に接続された前記第１のＲＦ信号電極および前記第２のＤＣ電極と、第２のＲＦ信号電極とが並列に接続された構成であり、前記第２のマッハツェンダ回路は、第３のＲＦ信号電極と各導波路の光位相差を調整する第３のＤＣ電極とが直列に接続され、さらに直列に接続された前記第３のＲＦ信号電極および前記第３のＤＣ電極と、第４のＲＦ信号電極とが並列に接続された構成であり、前記光周波数シフタが、前記第１の偏波制御器に前記光源からの光信号の周波数を低周波シフトさせた光信号を出力し、前記第２の偏波制御器に前記光源からの光信号の周波数を高周波シフトさせた光信号を出力し、１台の光源で２つの周波数の光信号を周波数多重伝送できるようにしたことを特徴とする周波数シフト型高密度光周波数多重伝送システムである。 According to a third aspect of the present invention, there is provided one light source, an optical frequency shifter connected to the light source, a first polarization controller connected to one port of the optical frequency shifter, and the other port of the optical frequency shifter. Optical signals from the two ports controlled by the second polarization controller connected to the first polarization controller and the first polarization controller and the second polarization controller so that the polarization states are orthogonal to each other. A first optical coupler for multiplexing, N optical transmitters comprising optical modulators for modulating the combined optical signals, and a second optical coupler for multiplexing optical signals from each of the N optical transmitters. When the second is connected via an optical coupler and an optical fiber, the optical frequency division multiplexed transmission system the optical signal and an optical receiver for coherent optical detection from the optical transmitter, an optical frequency shifter, the output side A directional coupler is disposed and connected to one input of the directional coupler. The second Mach-Zehnder circuit is connected to the other input of the directional coupler, the input of the first Mach-Zehnder circuit and the input of the frequency shifter are connected, and the second Mach-Zehnder circuit is connected. And the input of the frequency shifter are connected, the light source is connected to the input of the frequency shifter, the first polarization controller is connected to one output of the directional coupler, and the directional coupling The second polarization controller is connected to the other output of the detector, and the first Mach-Zehnder circuit adjusts the optical phase difference between the first RF signal electrode and each waveguide. A DC electrode is connected in series, and the first RF signal electrode and the second DC electrode connected in series, and a second RF signal electrode are connected in parallel; 2 In the Cach-Zehnder circuit, a third RF signal electrode and a third DC electrode for adjusting an optical phase difference of each waveguide are connected in series, and the third RF signal electrode and the third RF electrode connected in series are connected. The DC electrode and the fourth RF signal electrode are connected in parallel, and the optical frequency shifter causes the first polarization controller to shift the frequency of the optical signal from the light source by a low frequency. Output an optical signal, output an optical signal obtained by shifting the frequency of the optical signal from the light source to the second polarization controller, and frequency-multiplexed transmission of the optical signal of two frequencies with one light source. This is a frequency shift type high density optical frequency multiplex transmission system characterized in that it is made possible.

第４の発明は、それぞれ周波数の異なるＮ台の光源と、前記Ｎ台の光源からの光信号を合波する第１の光カプラと、第１の光カプラに接続された光周波数シフタと、光周波数シフタの一方のポートに接続された第１の偏波制御器と、光周波数シフタの他方のポートに接続された第２の偏波制御器と、第１の偏波制御器および第２の偏波制御器により偏波状態が互いに直交するように制御された前記２つのポートからの光信号を合波する第２の光カプラと、合波した光信号を変調する光変調器からなる光送信器において、光周波数シフタは、出力側に方向性結合器が配置され、前記方向性結合器の一方の入力に第１のマッハツェンダ回路が接続され、前記方向性結合器の他方の入力に第２のマッハツェンダ回路が接続され、前記第１のマッハツェンダ回路の入力と前記周波数シフタの入力が接続され、前記第２のマッハツェンダ回路の入力と前記周波数シフタの入力が接続され、前記周波数シフタの入力に前記光源が接続され、前記方向性結合器の一方の出力に前記第１の偏波制御器が接続され、前記方向性結合器の他方の出力に前記第２の偏波制御器が接続された構成であり、前記第１のマッハツェンダ回路は、第１のＲＦ信号電極と各導波路の光位相差を調整する第２のＤＣ電極とが直列に接続され、さらに直列に接続された前記第１のＲＦ信号電極および前記第２のＤＣ電極と、第２のＲＦ信号電極とが並列に接続された構成であり、前記第２のマッハツェンダ回路は、第３のＲＦ信号電極と各導波路の光位相差を調整する第３のＤＣ電極とが直列に接続され、さらに直列に接続された前記第３のＲＦ信号電極および前記第３のＤＣ電極と、第４のＲＦ信号電極とが並列に接続された構成であり、前記光周波数シフタが、前記第１の偏波制御器に前記Ｎ台の光源からの光信号の周波数を一括で低周波シフトさせた光信号を出力し、前記第２の偏波制御器に前記Ｎ台の光源からの光信号の周波数を一括で高周波シフトさせた光信号を出力し、Ｎ台の光源で２Ｎの周波数の光信号を周波数多重伝送できるようにしたことを特徴とする光送信器である。 According to a fourth aspect of the present invention, there are N light sources having different frequencies, a first optical coupler for multiplexing optical signals from the N light sources, an optical frequency shifter connected to the first optical coupler, A first polarization controller connected to one port of the optical frequency shifter; a second polarization controller connected to the other port of the optical frequency shifter; a first polarization controller and a second A second optical coupler that multiplexes optical signals from the two ports whose polarization states are controlled to be orthogonal to each other by the polarization controller, and an optical modulator that modulates the combined optical signal. In the optical transmitter, the optical frequency shifter has a directional coupler disposed on the output side, a first Mach-Zehnder circuit is connected to one input of the directional coupler, and the other input of the directional coupler is A second Mach-Zehnder circuit is connected, and the first Mach-Zehnder circuit is connected. The input of the frequency shifter is connected to the input of the second shift circuit, the input of the frequency shifter is connected to the input of the frequency shifter, the light source is connected to the input of the frequency shifter, and the directional coupler The first polarization controller is connected to one output, and the second polarization controller is connected to the other output of the directional coupler, and the first Mach-Zehnder circuit is A first RF signal electrode and a second DC electrode that adjusts the optical phase difference of each waveguide are connected in series, and further, the first RF signal electrode and the second DC electrode connected in series, The second RF signal electrode is connected in parallel, and the second Mach-Zehnder circuit includes a third RF signal electrode and a third DC electrode that adjusts an optical phase difference between each waveguide. Connected in series and further connected in series Said third RF signal electrode and the third DC electrodes, and a fourth RF signal electrode is connected to each in parallel, the optical frequency shifter, the first polarization controller An optical signal obtained by collectively shifting the frequency of the optical signals from the N light sources is output, and the frequency of the optical signals from the N light sources is collectively shifted to the second polarization controller. An optical transmitter characterized in that an optical signal having a frequency of 2N can be frequency-multiplexed and transmitted by N light sources.

第５の発明は、それぞれ周波数の異なるＮ台の光源と、前記Ｎ台の光源からの光信号を合波する第１の光カプラと、第１の光カプラに接続された光周波数シフタと、光周波数シフタの一方のポートに接続された第１の偏波制御器と、光周波数シフタの他方のポートに接続された第２の偏波制御器と、第１の偏波制御器および第２の偏波制御器により偏波状態が互いに直交するように制御された前記２つのポートからの光信号を合波する第２の光カプラと、合波した光信号を変調する光変調器からなる光送信器と、前記光送信器と光ファイバを介して接続され、前記光送信器からの光信号をコヒーレント光検波する光受信器からなる光周波数多重伝送システムにおいて、光周波数シフタは、出力側に方向性結合器が配置され、前記方向性結合器の一方の入力に第１のマッハツェンダ回路が接続され、前記方向性結合器の他方の入力に第２のマッハツェンダ回路が接続され、前記第１のマッハツェンダ回路の入力と前記周波数シフタの入力が接続され、前記第２のマッハツェンダ回路の入力と前記周波数シフタの入力が接続され、前記周波数シフタの入力に前記光源が接続され、前記方向性結合器の一方の出力に前記第１の偏波制御器が接続され、前記方向性結合器の他方の出力に前記第２の偏波制御器が接続された構成であり、前記第１のマッハツェンダ回路は、第１のＲＦ信号電極と各導波路の光位相差を調整する第２のＤＣ電極とが直列に接続され、さらに直列に接続された前記第１のＲＦ信号電極および前記第２のＤＣ電極と、第２のＲＦ信号電極とが並列に接続された構成であり、前記第２のマッハツェンダ回路は、第３のＲＦ信号電極と各導波路の光位相差を調整する第３のＤＣ電極とが直列に接続され、さらに直列に接続された前記第３のＲＦ信号電極および前記第３のＤＣ電極と、第４のＲＦ信号電極とが並列に接続された構成であり、前記光周波数シフタが、前記第１の偏波制御器に前記Ｎ台の光源からの光信号の周波数を一括で低周波シフトさせた光信号を出力し、前記第２の偏波制御器に前記Ｎ台の光源からの光信号の周波数を一括で高周波シフトさせた光信号を出力し、Ｎ台の光源で２Ｎの周波数の光信号を周波数多重伝送できるようにしたことを特徴とする周波数シフト型高密度光周波数多重伝送システムである。 According to a fifth aspect of the invention, there are N light sources having different frequencies, a first optical coupler for multiplexing optical signals from the N light sources, an optical frequency shifter connected to the first optical coupler, A first polarization controller connected to one port of the optical frequency shifter; a second polarization controller connected to the other port of the optical frequency shifter; a first polarization controller and a second A second optical coupler that multiplexes optical signals from the two ports whose polarization states are controlled to be orthogonal to each other by the polarization controller, and an optical modulator that modulates the combined optical signal. In an optical frequency multiplex transmission system comprising an optical transmitter and an optical receiver connected to the optical transmitter via an optical fiber and detecting an optical signal from the optical transmitter, the optical frequency shifter is connected to the output side. A directional coupler is disposed on the directional coupler. A first Mach-Zehnder circuit is connected to one input; a second Mach-Zehnder circuit is connected to the other input of the directional coupler; an input of the first Mach-Zehnder circuit is connected to an input of the frequency shifter; The input of the second Mach-Zehnder circuit and the input of the frequency shifter are connected, the light source is connected to the input of the frequency shifter, and the first polarization controller is connected to one output of the directional coupler The second polarization controller is connected to the other output of the directional coupler, and the first Mach-Zehnder circuit has an optical phase difference between the first RF signal electrode and each waveguide. The second DC electrode for adjusting the voltage is connected in series, and the first RF signal electrode and the second DC electrode connected in series, and the second RF signal electrode are connected in parallel. In configuration In the second Mach-Zehnder circuit, the third RF signal electrode and the third DC electrode for adjusting the optical phase difference of each waveguide are connected in series, and further, the third RF signal electrode is connected in series. The signal electrode, the third DC electrode, and the fourth RF signal electrode are connected in parallel, and the optical frequency shifter is connected to the first polarization controller from the N light sources. An optical signal obtained by shifting the frequency of the optical signal collectively at a low frequency is output, and an optical signal obtained by collectively shifting the frequency of the optical signal from the N light sources is output to the second polarization controller. A frequency shift type high density optical frequency multiplex transmission system in which optical signals having a frequency of 2N can be frequency multiplex transmitted by N light sources.

第６の発明は、それぞれ周波数の異なるＮ台の光源と、それぞれの光源に接続されたＮ台の光変調器と、前記Ｎ台の光変調器からの光信号を合波する第１の光カプラと、第１の光カプラに接続された光周波数シフタと、光周波数シフタの一方のポートに接続された第１の偏波制御器と、光周波数シフタの他方のポートに接続された第２の偏波制御器と、第１の偏波制御器および第２の偏波制御器により偏波状態が互いに直交するように制御された前記２つのポートからの光信号を合波する第２の光カプラからなる光送信器において、光周波数シフタは、出力側に方向性結合器が配置され、前記方向性結合器の一方の入力に第１のマッハツェンダ回路が接続され、前記方向性結合器の他方の入力に第２のマッハツェンダ回路が接続され、前記第１のマッハツェンダ回路の入力と前記周波数シフタの入力が接続され、前記第２のマッハツェンダ回路の入力と前記周波数シフタの入力が接続され、前記周波数シフタの入力に前記光源が接続され、前記方向性結合器の一方の出力に前記第１の偏波制御器が接続され、前記方向性結合器の他方の出力に前記第２の偏波制御器が接続された構成であり、前記第１のマッハツェンダ回路は、第１のＲＦ信号電極と各導波路の光位相差を調整する第２のＤＣ電極とが直列に接続され、さらに直列に接続された前記第１のＲＦ信号電極および前記第２のＤＣ電極と、第２のＲＦ信号電極とが並列に接続された構成であり、前記第２のマッハツェンダ回路は、第３のＲＦ信号電極と各導波路の光位相差を調整する第３のＤＣ電極とが直列に接続され、さらに直列に接続された前記第３のＲＦ信号電極および前記第３のＤＣ電極と、第４のＲＦ信号電極とが並列に接続された構成であり、前記光周波数シフタが、前記第１の偏波制御器に前記Ｎ台の光源からの光信号の周波数を一括で低周波シフトさせた光信号を出力し、前記第２の偏波制御器に前記Ｎ台の光源からの光信号の周波数を一括で高周波シフトさせた光信号を出力し、Ｎ台の光源で２Ｎの周波数の光信号を周波数多重伝送できるようにしたことを特徴とする光送信器である。 According to a sixth aspect of the present invention, there are N light sources having different frequencies, N optical modulators connected to the respective light sources, and a first light that combines optical signals from the N optical modulators. A coupler, an optical frequency shifter connected to the first optical coupler, a first polarization controller connected to one port of the optical frequency shifter, and a second connected to the other port of the optical frequency shifter A second polarization controller that combines the optical signals from the two ports controlled by the first polarization controller and the second polarization controller so that the polarization states are orthogonal to each other. In the optical transmitter including the optical coupler, the optical frequency shifter includes a directional coupler disposed on an output side, a first Mach-Zehnder circuit is connected to one input of the directional coupler, and the directional coupler includes: A second Mach-Zehnder circuit is connected to the other input, and the second The input of the Mach-Zehnder circuit and the input of the frequency shifter are connected, the input of the second Mach-Zehnder circuit and the input of the frequency shifter are connected, the light source is connected to the input of the frequency shifter, and the directional coupler The first polarization controller is connected to one output of the second directional coupler, and the second polarization controller is connected to the other output of the directional coupler, and the first Mach-Zehnder circuit is The first RF signal electrode and the second DC electrode for adjusting the optical phase difference of each waveguide are connected in series, and the first RF signal electrode and the second DC electrode connected in series. And the second RF signal electrode are connected in parallel, and the second Mach-Zehnder circuit includes a third DC signal electrode and a third DC electrode that adjusts an optical phase difference between each waveguide. Are connected in series, To said serially connected third RF signal electrode and the third DC electrode, a configuration in which the fourth RF signal electrodes are connected in parallel, the optical frequency shifter, said first polarization An optical signal obtained by collectively shifting the frequency of the optical signals from the N light sources is output to the wave controller, and the frequency of the optical signals from the N light sources is output to the second polarization controller. An optical transmitter characterized in that an optical signal shifted in high frequency at a time is output, and an optical signal having a frequency of 2N can be frequency-multiplexed by N light sources.

第７の発明は、それぞれ周波数の異なるＮ台の光源と、それぞれの光源に接続されたＮ台の光変調器と、前記Ｎ台の光変調器からの光信号を合波する第１の光カプラと、第１の光カプラに接続された光周波数シフタと、光周波数シフタの一方のポートに接続された第１の偏波制御器と、光周波数シフタの他方のポートに接続された第２の偏波制御器と、第１の偏波制御器および第２の偏波制御器により偏波状態が互いに直交するように制御された前記２つのポートからの光信号を合波する第２の光カプラからなる光送信器と、前記光送信器と光ファイバを介して接続され、前記光送信器からの光信号をコヒーレント光検波する光受信器からなる光周波数多重伝送システムにおいて、光周波数シフタは、出力側に方向性結合器が配置され、前記方向性結合器の一方の入力に第１のマッハツェンダ回路が接続され、前記方向性結合器の他方の入力に第２のマッハツェンダ回路が接続され、前記第１のマッハツェンダ回路の入力と前記周波数シフタの入力が接続され、前記第２のマッハツェンダ回路の入力と前記周波数シフタの入力が接続され、前記周波数シフタの入力に前記光源が接続され、前記方向性結合器の一方の出力に前記第１の偏波制御器が接続され、前記方向性結合器の他方の出力に前記第２の偏波制御器が接続された構成であり、前記第１のマッハツェンダ回路は、第１のＲＦ信号電極と各導波路の光位相差を調整する第２のＤＣ電極とが直列に接続され、さらに直列に接続された前記第１のＲＦ信号電極および前記第２のＤＣ電極と、第２のＲＦ信号電極とが並列に接続された構成であり、前記第２のマッハツェンダ回路は、第３のＲＦ信号電極と各導波路の光位相差を調整する第３のＤＣ電極とが直列に接続され、さらに直列に接続された前記第３のＲＦ信号電極および前記第３のＤＣ電極と、第４のＲＦ信号電極とが並列に接続された構成であり、前記光周波数シフタが、前記第１の偏波制御器に前記Ｎ台の光源からの光信号の周波数を一括で低周波シフトさせた光信号を出力し、前記第２の偏波制御器に前記Ｎ台の光源からの光信号の周波数を一括で高周波シフトさせた光信号を出力し、Ｎ台の光源で２Ｎの周波数の光信号を周波数多重伝送できるようにしたことを特徴とする周波数シフト型高密度光周波数多重伝送システムである。
According to a seventh aspect of the present invention, there are N light sources having different frequencies, N optical modulators connected to the respective light sources, and a first light that combines optical signals from the N optical modulators. A coupler, an optical frequency shifter connected to the first optical coupler, a first polarization controller connected to one port of the optical frequency shifter, and a second connected to the other port of the optical frequency shifter A second polarization controller that combines the optical signals from the two ports controlled by the first polarization controller and the second polarization controller so that the polarization states are orthogonal to each other. an optical transmitter and an optical coupler, is connected through the optical transmitter and the optical fiber, the optical frequency division multiplexed transmission system the optical signal and an optical receiver for coherent optical detection from the optical transmitter, an optical frequency shifter Is provided with a directional coupler on the output side, A first Mach-Zehnder circuit is connected to one input of the directional coupler, a second Mach-Zehnder circuit is connected to the other input of the directional coupler, and the input of the first Mach-Zehnder circuit and the frequency shifter An input is connected, an input of the second Mach-Zehnder circuit and an input of the frequency shifter are connected, the light source is connected to an input of the frequency shifter, and the first bias is output to one output of the directional coupler. A wave controller is connected, and the second polarization controller is connected to the other output of the directional coupler, and the first Mach-Zehnder circuit includes a first RF signal electrode and each conductor. A second DC electrode for adjusting the optical phase difference of the waveguide is connected in series, and the first RF signal electrode and the second DC electrode connected in series are connected to the second RF signal electrode. Connect in parallel In the second Mach-Zehnder circuit, the third RF signal electrode and the third DC electrode for adjusting the optical phase difference of each waveguide are connected in series, and further connected in series. The third RF signal electrode, the third DC electrode, and the fourth RF signal electrode are connected in parallel, and the optical frequency shifter is connected to the first polarization controller by the N units. An optical signal obtained by shifting the frequency of the optical signal from the light source at a time to a low frequency is output, and the second polarization controller is configured to shift the frequency of the optical signal from the N light sources at a time to a high frequency. This is a frequency shift type high density optical frequency multiplex transmission system characterized in that a signal is output and an optical signal having a frequency of 2N can be frequency multiplexed by N light sources.

第８の発明は、１台の光源と、前記光源からの光信号を分岐する第１の光カプラと、第１の光カプラの一方のポートに接続された第１の光周波数シフタおよび第１の偏波制御器と、第１の光カプラの他方のポートに接続された第２の光周波数シフタおよび第２の偏波制御器と、第１の偏波制御器および第２の偏波制御器により偏波状態が互いに直交するように制御された前記２つのポートからの光信号を合波する第２の光カプラと、合波した光信号を変調する光変調器からなる光送信器において、前記第１の光周波数シフタが、前記第１の偏波制御器に前記光源からの光信号の周波数を低周波シフトさせた光信号を出力し、前記第２の光周波数シフタが、前記第２の偏波制御器に前記光源からの光信号の周波数を高周波シフトさせた光信号を出力し、１台の光源で２つの周波数の光信号を周波数多重伝送できるようにしたことを特徴とする光送信器である。   According to an eighth aspect of the present invention, there is provided a first light source, a first optical coupler that branches an optical signal from the light source, a first optical frequency shifter connected to one port of the first optical coupler, and a first optical coupler. Polarization controller, a second optical frequency shifter and a second polarization controller connected to the other port of the first optical coupler, a first polarization controller and a second polarization control An optical transmitter comprising: a second optical coupler that combines optical signals from the two ports, whose polarization states are controlled to be orthogonal to each other by an optical device; and an optical modulator that modulates the combined optical signal. The first optical frequency shifter outputs an optical signal obtained by shifting the frequency of the optical signal from the light source to the first polarization controller, and the second optical frequency shifter includes the first optical frequency shifter. An optical signal obtained by shifting the frequency of the optical signal from the light source to the polarization controller 2 And force, an optical transmitter, characterized in that to allow frequency division multiplexing the optical signals of the two frequencies in a single light source.

第９の発明は、１台の光源と、前記光源からの光信号を分岐する第１の光カプラと、第１の光カプラの一方のポートに接続された第１の光周波数シフタおよび第１の偏波制御器と、第１の光カプラの他方のポートに接続された第２の光周波数シフタおよび第２の偏波制御器と、第１の偏波制御器および第２の偏波制御器により偏波状態が互いに直交するように制御された前記２つのポートからの光信号を合波する第２の光カプラと、合波した光信号を変調する光変調器からなる光送信器と、前記光送信器と光ファイバを介して接続され、前記光送信器からの光信号をコヒーレント光検波する光受信器からなる光周波数多重伝送システムにおいて、前記第１の光周波数シフタが、前記第１の偏波制御器に前記光源からの光信号の周波数を低周波シフトさせた光信号を出力し、前記第２の光周波数シフタが、前記第２の偏波制御器に前記光源からの光信号の周波数を高周波シフトさせた光信号を出力し、１台の光源で２つの周波数の光信号を周波数多重伝送できるようにしたことを特徴とする周波数シフト型高密度光周波数多重伝送システムである。   According to a ninth aspect of the present invention, there is provided one light source, a first optical coupler that branches an optical signal from the light source, a first optical frequency shifter connected to one port of the first optical coupler, and a first optical coupler. Polarization controller, a second optical frequency shifter and a second polarization controller connected to the other port of the first optical coupler, a first polarization controller and a second polarization control A second optical coupler that combines the optical signals from the two ports, the polarization states of which are controlled so as to be orthogonal to each other, and an optical transmitter that includes an optical modulator that modulates the combined optical signals; In the optical frequency multiplex transmission system comprising an optical receiver connected to the optical transmitter via an optical fiber and coherently detecting an optical signal from the optical transmitter, the first optical frequency shifter includes the first optical frequency shifter. 1 polarization controller to set the frequency of the optical signal from the light source to a low frequency The second optical frequency shifter outputs an optical signal obtained by shifting the frequency of the optical signal from the light source to the second polarization controller, and outputs a single light source. The frequency shift type high density optical frequency multiplex transmission system is characterized in that optical signals of two frequencies can be frequency multiplex transmitted.

第１０の発明は、１台の光源と、前記光源からの光信号を分岐する第１の光カプラと、第１の光カプラの一方のポートに接続された第１の光周波数シフタおよび第１の偏波制御器と、第１の光カプラの他方のポートに接続された第２の光周波数シフタおよび第２の偏波制御器と、第１の偏波制御器および第２の偏波制御器により偏波状態が互いに直交するように制御された前記２つのポートからの光信号を合波する第２の光カプラと、合波した光信号を変調する光変調器からなる光送信器Ｎ台と、Ｎ台の各光送信器からの光信号を合波する第３の光カプラと、第３の光カプラと光ファイバを介して接続され、前記光送信器からの光信号をコヒーレント光検波する光受信器からなる光周波数多重伝送システムにおいて、前記第１の光周波数シフタが、前記第１の偏波制御器に前記光源からの光信号の周波数を低周波シフトさせた光信号を出力し、前記第２の光周波数シフタが、前記第２の偏波制御器に前記光源からの光信号の周波数を高周波シフトさせた光信号を出力し、１台の光源で２つの周波数の光信号を周波数多重伝送できるようにしたことを特徴とする周波数シフト型高密度光周波数多重伝送システムである。   According to a tenth aspect of the present invention, there is provided one light source, a first optical coupler for branching an optical signal from the light source, a first optical frequency shifter connected to one port of the first optical coupler, and a first optical coupler. Polarization controller, a second optical frequency shifter and a second polarization controller connected to the other port of the first optical coupler, a first polarization controller and a second polarization control An optical transmitter N composed of a second optical coupler for multiplexing optical signals from the two ports whose polarization states are controlled to be orthogonal to each other by an optical modulator, and an optical modulator for modulating the combined optical signal. And a third optical coupler that multiplexes the optical signals from the N optical transmitters, and the third optical coupler via an optical fiber, and the optical signals from the optical transmitters are coherent. In the optical frequency multiplex transmission system comprising an optical receiver for detection, the first optical frequency shift Outputs an optical signal obtained by shifting the frequency of the optical signal from the light source to the first polarization controller, and the second optical frequency shifter outputs the optical signal to the second polarization controller. An optical signal obtained by shifting the frequency of an optical signal from a light source by a high frequency is output, and an optical signal having two frequencies can be frequency-multiplexed and transmitted by a single light source. It is a transmission system.

第１１の発明は、それぞれ周波数の異なるＮ台の光源と、前記Ｎ台の光源からの光信号を合波する第１の光カプラと、合波した光信号を分岐する第２の光カプラと、第２の光カプラの一方のポートに接続された第１の光周波数シフタおよび第１の偏波制御器と、第２の光カプラの他方のポートに接続された第２の光周波数シフタおよび第２の偏波制御器と、第１の偏波制御器および第２の偏波制御器により偏波状態が互いに直交するように制御された前記２つのポートからの光信号を合波する第３の光カプラと、合波した光信号を変調する光変調器からなる光送信器において、前記第１の光周波数シフタが、前記第１の偏波制御器に前記Ｎ台の光源からの光信号の周波数を一括で低周波シフトさせた光信号を出力し、前記第２の光周波数シフタが、前記第２の偏波制御器に前記Ｎ台の光源からの光信号の周波数を一括で高周波シフトさせた光信号を出力し、Ｎ台の光源で２Ｎの周波数の光信号を周波数多重伝送できるようにしたことを特徴とする光送信器である。   An eleventh aspect of the invention includes N light sources having different frequencies, a first optical coupler that combines optical signals from the N light sources, and a second optical coupler that branches the combined optical signals, , A first optical frequency shifter and a first polarization controller connected to one port of the second optical coupler, a second optical frequency shifter connected to the other port of the second optical coupler, and A second polarization controller, a first polarization controller and a second polarization controller combine the optical signals from the two ports whose polarization states are controlled to be orthogonal to each other. 3, and an optical transmitter that modulates the combined optical signal, the first optical frequency shifter transmits light from the N light sources to the first polarization controller. An optical signal obtained by shifting the frequency of the signal collectively at a low frequency is output, and the second optical frequency shift is output. Outputs, to the second polarization controller, an optical signal obtained by shifting the frequency of the optical signals from the N light sources at once, and frequency multiplexed transmission of an optical signal having a frequency of 2N from the N light sources. An optical transmitter characterized in that it can be used.

第１２の発明は、それぞれ周波数の異なるＮ台の光源と、前記Ｎ台の光源からの光信号を合波する第１の光カプラと、合波した光信号を分岐する第２の光カプラと、第２の光カプラの一方のポートに接続された第１の光周波数シフタおよび第１の偏波制御器と、第２の光カプラの他方のポートに接続された第２の光周波数シフタおよび第２の偏波制御器と、第１の偏波制御器および第２の偏波制御器により偏波状態が互いに直交するように制御された前記２つのポートからの光信号を合波する第３の光カプラと、合波した光信号を変調する光変調器からなる光送信器と、前記光送信器と光ファイバを介して接続され、前記光送信器からの光信号をコヒーレント光検波する光受信器からなる光周波数多重伝送システムにおいて、前記第１の光周波数シフタが、前記第１の偏波制御器に前記Ｎ台の光源からの光信号の周波数を一括で低周波シフトさせた光信号を出力し、前記第２の光周波数シフタが、前記第２の偏波制御器に前記Ｎ台の光源からの光信号の周波数を一括で高周波シフトさせた光信号を出力し、Ｎ台の光源で２Ｎの周波数の光信号を周波数多重伝送できるようにしたことを特徴とする周波数シフト型高密度光周波数多重伝送システムである。   A twelfth aspect of the invention includes N light sources having different frequencies, a first optical coupler that combines optical signals from the N light sources, and a second optical coupler that branches the combined optical signals, , A first optical frequency shifter and a first polarization controller connected to one port of the second optical coupler, a second optical frequency shifter connected to the other port of the second optical coupler, and A second polarization controller, a first polarization controller and a second polarization controller combine the optical signals from the two ports whose polarization states are controlled to be orthogonal to each other. And an optical transmitter composed of an optical modulator that modulates the combined optical signal, and the optical transmitter connected via an optical fiber to detect the optical signal from the optical transmitter coherently. In the optical frequency multiplexing transmission system comprising an optical receiver, the first optical frequency A number shifter outputs an optical signal obtained by shifting the frequency of optical signals from the N light sources at a time to the first polarization controller, and the second optical frequency shifter outputs the second optical frequency shifter. An optical signal obtained by shifting the frequency of the optical signals from the N light sources at once is output to the polarization controller of the N light sources so that an optical signal having a frequency of 2N can be frequency-multiplexed with the N light sources. This is a frequency shift type high-density optical frequency multiplex transmission system.

第１３の発明は、それぞれ周波数の異なるＮ台の光源と、それぞれの光源に接続されたＮ台の光変調器と、前記Ｎ台の光変調器からの光信号を合波する第１の光カプラと、合波した光信号を分岐する第２の光カプラと、第２の光カプラの一方のポートに接続された第１の光周波数シフタおよび第１の偏波制御器と、第２の光カプラの他方のポートに接続された第２の光周波数シフタおよび第２の偏波制御器と、第１の偏波制御器および第２の偏波制御器により偏波状態が互いに直交するように制御された前記２つのポートからの光信号を合波する第３の光カプラからなる光送信器において、前記第１の光周波数シフタが、前記第１の偏波制御器に前記Ｎ台の光源からの光信号の周波数を一括で低周波シフトさせた光信号を出力し、前記第２の光周波数シフタが、前記第２の偏波制御器に前記Ｎ台の光源からの光信号の周波数を一括で高周波シフトさせた光信号を出力し、Ｎ台の光源で２Ｎの周波数の光信号を周波数多重伝送できるようにしたことを特徴とする光送信器である。   In a thirteenth aspect of the invention, N light sources having different frequencies, N optical modulators connected to the respective light sources, and a first light that multiplexes optical signals from the N optical modulators. A coupler, a second optical coupler for branching the combined optical signal, a first optical frequency shifter and a first polarization controller connected to one port of the second optical coupler, The polarization states are orthogonal to each other by the second optical frequency shifter and the second polarization controller connected to the other port of the optical coupler, and the first polarization controller and the second polarization controller. In the optical transmitter including the third optical coupler for multiplexing the optical signals from the two ports controlled by the first port, the first optical frequency shifter is connected to the first polarization controller by the N units. An optical signal obtained by shifting the frequency of the optical signal from the light source at a low frequency in a batch; A frequency shifter outputs an optical signal obtained by collectively shifting the frequency of the optical signals from the N light sources to the second polarization controller, and an optical signal having a frequency of 2N is output by the N light sources. An optical transmitter characterized in that multiplex transmission is possible.

第１４の発明は、それぞれ周波数の異なるＮ台の光源と、それぞれの光源に接続されたＮ台の光変調器と、前記Ｎ台の光変調器からの光信号を合波する第１の光カプラと、合波した光信号を分岐する第２の光カプラと、第２の光カプラの一方のポートに接続された第１の光周波数シフタおよび第１の偏波制御器と、第２の光カプラの他方のポートに接続された第２の光周波数シフタおよび第２の偏波制御器と、第１の偏波制御器および第２の偏波制御器により偏波状態が互いに直交するように制御された前記２つのポートからの光信号を合波する第３の光カプラからなる光送信器と、前記光送信器と光ファイバを介して接続され、前記光送信器からの光信号をコヒーレント光検波する光受信器からなる光周波数多重伝送システムにおいて、前記第１の光周波数シフタが、前記第１の偏波制御器に前記Ｎ台の光源からの光信号の周波数を一括で低周波シフトさせた光信号を出力し、前記第２の光周波数シフタが、前記第２の偏波制御器に前記Ｎ台の光源からの光信号の周波数を一括で高周波シフトさせた光信号を出力し、Ｎ台の光源で２Ｎの周波数の光信号を周波数多重伝送できるようにしたことを特徴とする周波数シフト型高密度光周波数多重伝送システムである。   In a fourteenth aspect of the invention, N light sources having different frequencies, N optical modulators connected to the respective light sources, and a first light that multiplexes optical signals from the N optical modulators. A coupler, a second optical coupler for branching the combined optical signal, a first optical frequency shifter and a first polarization controller connected to one port of the second optical coupler, The polarization states are orthogonal to each other by the second optical frequency shifter and the second polarization controller connected to the other port of the optical coupler, and the first polarization controller and the second polarization controller. An optical transmitter composed of a third optical coupler that multiplexes optical signals from the two ports controlled by the optical port, and the optical transmitter connected to the optical transmitter via an optical fiber. In an optical frequency multiplex transmission system comprising an optical receiver for coherent optical detection, The first optical frequency shifter outputs an optical signal obtained by shifting the frequency of the optical signals from the N light sources collectively to the first polarization controller, and the second optical frequency shifter The optical signal obtained by shifting the frequency of the optical signals from the N light sources at once is output to the second polarization controller, and an optical signal having a frequency of 2N can be frequency-multiplexed by the N light sources. This is a frequency shift type high-density optical frequency multiplex transmission system characterized as described above.

第１５の発明は、それぞれ周波数の異なるＮ台の光源と、前記Ｎ台の光源からの光信号を合波する第１の光カプラと、合波した光信号を分岐する第２の光カプラと、第２の光カプラの一方のポートに接続された第１の偏波制御器と、第２の光カプラの他方のポートに接続された光周波数シフタおよび第２の偏波制御器と、第１の偏波制御器および第２の偏波制御器により偏波状態が互いに直交するように制御された前記２つのポートからの光信号を合波する第３の光カプラと、合波した光信号を変調する光変調器からなる光送信器において、前記光周波数シフタが、前記第２の偏波制御器に前記Ｎ台の光源からの光信号の周波数を一括でシフトさせた光信号を出力し、Ｎ台の光源で２Ｎの周波数の光信号を周波数多重伝送できるようにしたことを特徴とする光送信器である。   According to a fifteenth aspect of the present invention, there are provided N light sources having different frequencies, a first optical coupler for combining optical signals from the N light sources, and a second optical coupler for branching the combined optical signals. A first polarization controller connected to one port of the second optical coupler, an optical frequency shifter and a second polarization controller connected to the other port of the second optical coupler, A third optical coupler that combines the optical signals from the two ports whose polarization states are controlled to be orthogonal to each other by the first polarization controller and the second polarization controller, and the combined light In an optical transmitter comprising an optical modulator that modulates a signal, the optical frequency shifter outputs an optical signal obtained by shifting the frequency of optical signals from the N light sources at a time to the second polarization controller. In addition, N light sources can be used for frequency multiplexing of 2N frequency optical signals. An optical transmitter according to claim.

第１６の発明は、それぞれ周波数の異なるＮ台の光源と、前記Ｎ台の光源からの光信号を合波する第１の光カプラと、合波した光信号を分岐する第２の光カプラと、第２の光カプラの一方のポートに接続された第１の偏波制御器と、第２の光カプラの他方のポートに接続された光周波数シフタおよび第２の偏波制御器と、第１の偏波制御器および第２の偏波制御器により偏波状態が互いに直交するように制御された前記２つのポートからの光信号を合波する第３の光カプラと、合波した光信号を変調する光変調器からなる光送信器と、前記光送信器と光ファイバを介して接続され、前記光送信器からの光信号をコヒーレント光検波する光受信器からなる光周波数多重伝送システムにおいて、前記光周波数シフタが、前記第２の偏波制御器に前記Ｎ台の光源からの光信号の周波数を一括でシフトさせた光信号を出力し、Ｎ台の光源で２Ｎの周波数の光信号を周波数多重伝送できるようにしたことを特徴とする周波数シフト型高密度光周波数多重伝送システムである。   According to a sixteenth aspect of the present invention, there are N light sources having different frequencies, a first optical coupler for combining optical signals from the N light sources, and a second optical coupler for branching the combined optical signals. A first polarization controller connected to one port of the second optical coupler, an optical frequency shifter and a second polarization controller connected to the other port of the second optical coupler, A third optical coupler that combines the optical signals from the two ports whose polarization states are controlled to be orthogonal to each other by the first polarization controller and the second polarization controller, and the combined light An optical frequency multiplex transmission system comprising an optical transmitter comprising an optical modulator for modulating a signal, and an optical receiver connected to the optical transmitter via an optical fiber and coherently detecting the optical signal from the optical transmitter. The optical frequency shifter in front of the second polarization controller. An optical signal obtained by shifting the frequency of optical signals from N light sources at once is output, and an optical signal having a frequency of 2N can be frequency-multiplexed and transmitted by N light sources. This is a density optical frequency multiplex transmission system.

第１７の発明は、それぞれ周波数の異なるＮ台の光源と、それぞれの光源に接続されたＮ台の光変調器と、前記Ｎ台の光変調器からの光信号を合波する第１の光カプラと、合波した光信号を分岐する第２の光カプラと、第２の光カプラの一方のポートに接続された第１の偏波制御器と、第２の光カプラの他方のポートに接続された光周波数シフタおよび第２の偏波制御器と、第１の偏波制御器および第２の偏波制御器により偏波状態が互いに直交するように制御された前記２つのポートからの光信号を合波する第３の光カプラからなる光送信器において、前記光周波数シフタが、前記第２の偏波制御器に前記Ｎ台の光源からの光信号の周波数を一括でシフトさせた光信号を出力し、Ｎ台の光源で２Ｎの周波数の光信号を周波数多重伝送できるようにしたことを特徴とする光送信器である。   In a seventeenth aspect of the present invention, N light sources having different frequencies, N optical modulators connected to the respective light sources, and a first light that multiplexes optical signals from the N optical modulators. A coupler, a second optical coupler for branching the combined optical signal, a first polarization controller connected to one port of the second optical coupler, and the other port of the second optical coupler. The connected optical frequency shifter and the second polarization controller, and the two polarization ports controlled by the first polarization controller and the second polarization controller so that the polarization states are orthogonal to each other. In the optical transmitter including the third optical coupler for multiplexing the optical signals, the optical frequency shifter shifts the frequencies of the optical signals from the N light sources collectively to the second polarization controller. Outputs optical signals and frequency multiplexed transmission of 2N frequency optical signals with N light sources An optical transmitter, wherein was Unishi.

第１８の発明は、それぞれ周波数の異なるＮ台の光源と、それぞれの光源に接続されたＮ台の光変調器と、前記Ｎ台の光変調器からの光信号を合波する第１の光カプラと、合波した光信号を分岐する第２の光カプラと、第２の光カプラの一方のポートに接続された第１の偏波制御器と、第２の光カプラの他方のポートに接続された光周波数シフタおよび第２の偏波制御器と、第１の偏波制御器および第２の偏波制御器により偏波状態が互いに直交するように制御された前記２つのポートからの光信号を合波する第３の光カプラからなる光送信器と、前記光送信器と光ファイバを介して接続され、前記光送信器からの光信号をコヒーレント光検波する光受信器からなる光周波数多重伝送システムにおいて、前記光周波数シフタが、前記第２の偏波制御器に前記Ｎ台の光源からの光信号の周波数を一括でシフトさせた光信号を出力し、Ｎ台の光源で２Ｎの周波数の光信号を周波数多重伝送できるようにしたことを特徴とする周波数シフト型高密度光周波数多重伝送システムである。   According to an eighteenth aspect of the present invention, N light sources having different frequencies, N optical modulators connected to the respective light sources, and a first light for multiplexing optical signals from the N optical modulators. A coupler, a second optical coupler for branching the combined optical signal, a first polarization controller connected to one port of the second optical coupler, and the other port of the second optical coupler. The connected optical frequency shifter and the second polarization controller, and the two polarization ports controlled by the first polarization controller and the second polarization controller so that the polarization states are orthogonal to each other. An optical transmitter composed of a third optical coupler for multiplexing optical signals and an optical receiver connected to the optical transmitter via an optical fiber and detecting optical signals from the optical transmitter for coherent optical detection In the frequency multiplex transmission system, the optical frequency shifter includes the second bias. An optical signal obtained by collectively shifting the frequency of the optical signals from the N light sources is output to the controller, and an optical signal having a frequency of 2N can be frequency-multiplexed and transmitted by the N light sources. This is a frequency shift type high-density optical frequency multiplex transmission system.

本発明は、光送信器に光周波数シフタを備え、光周波数シフタにより光源からの光信号の周波数をシフトさせ、１台の光源で２つの周波数の光信号を伝送できるようにすることにより、周波数多重伝送に必要な、周波数の安定した光源の品種数を削減することができる。   The present invention includes an optical frequency shifter in an optical transmitter, shifts the frequency of an optical signal from a light source by the optical frequency shifter, and allows an optical signal of two frequencies to be transmitted by a single light source. It is possible to reduce the number of types of light sources with stable frequencies required for multiplex transmission.

本発明の実施例の光周波数多重伝送システムを図１〜図１４を参照して説明する。図１は、第１の実施例の周波数シフト型高密度光周波数多重伝送システムの全体構成図である。図２は、第２の実施例の周波数シフト型高密度光周波数多重伝送システムの全体構成図である。図３は、第３の実施例の周波数シフト型高密度光周波数多重伝送システムの全体構成図である。図４は、第４の実施例の周波数シフト型高密度光周波数多重伝送システムの全体構成図である。図５は、第５の実施例の周波数シフト型高密度光周波数多重伝送システムの全体構成図である。図６は、第６の実施例の周波数シフト型高密度光周波数多重伝送システムの全体構成図である。図７は、第７の実施例の周波数シフト型高密度光周波数多重伝送システムの全体構成図である。図８は、第８の実施例の周波数シフト型高密度光周波数多重伝送システムの全体構成図である。図９は、図１〜図８に示す周波数シフト型高密度光周波数多重伝送システムにおける光周波数シフタの構成例を示す図である。図１０は、第９の実施例の周波数シフト型高密度光周波数多重伝送システムの全体構成図である。図１１は、第１０の実施例の周波数シフト型高密度光周波数多重伝送システムの全体構成図である。図１２は、第１１の実施例の周波数シフト型高密度光周波数多重伝送システムの全体構成図である。図１３は、第１２の実施例の周波数シフト型高密度光周波数多重伝送システムの全体構成図である。図１４は、図１０〜図１３に示す周波数シフト型高密度光周波数多重伝送システムにおける光周波数シフタの構成例を示す図である。   An optical frequency multiplexing transmission system according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an overall configuration diagram of a frequency shift type high-density optical frequency multiplex transmission system according to a first embodiment. FIG. 2 is an overall configuration diagram of the frequency shift type high-density optical frequency multiplex transmission system according to the second embodiment. FIG. 3 is an overall configuration diagram of a frequency shift type high-density optical frequency multiplex transmission system according to a third embodiment. FIG. 4 is an overall configuration diagram of a frequency shift type high-density optical frequency multiplex transmission system according to a fourth embodiment. FIG. 5 is an overall configuration diagram of a frequency shift type high-density optical frequency multiplex transmission system according to a fifth embodiment. FIG. 6 is an overall configuration diagram of a frequency shift type high-density optical frequency multiplex transmission system according to a sixth embodiment. FIG. 7 is an overall configuration diagram of a frequency shift type high-density optical frequency multiplex transmission system according to a seventh embodiment. FIG. 8 is an overall configuration diagram of a frequency shift type high-density optical frequency multiplex transmission system according to an eighth embodiment. FIG. 9 is a diagram illustrating a configuration example of an optical frequency shifter in the frequency shift type high-density optical frequency multiplex transmission system illustrated in FIGS. FIG. 10 is an overall configuration diagram of a frequency shift type high-density optical frequency multiplex transmission system according to a ninth embodiment. FIG. 11 is an overall configuration diagram of a frequency shift type high-density optical frequency multiplex transmission system according to a tenth embodiment. FIG. 12 is an overall configuration diagram of a frequency shift type high-density optical frequency multiplex transmission system according to an eleventh embodiment. FIG. 13 is an overall configuration diagram of a frequency shift type high-density optical frequency multiplex transmission system according to a twelfth embodiment. FIG. 14 is a diagram illustrating a configuration example of an optical frequency shifter in the frequency shift type high-density optical frequency multiplex transmission system illustrated in FIGS. 10 to 13.

本発明の第１の実施例の周波数シフト型高密度光周波数多重伝送システムは、図１に示すように、周波数ｆ１の光信号を送信する光源１１１と、光源１１１からの光信号を分岐する光カプラ１１２と、光カプラ１１２の一方のポートに接続された偏波制御器１１３１２と、光カプラ１１２の他方のポートに接続された光周波数シフタ１１３２１および偏波制御器１１３２２と、偏波制御器１１３１２と偏波制御器１１３２２により前記２つのポートからの光信号の偏波状態が互いに直交するように制御された、それら直交した２つのポートからの光信号を合波する光カプラ１１４と、合波した光信号を変調する光変調器１１５からなる光送信器１１と、光送信器１１と光ファイバ２１を介して接続され、光送信器１１からの光信号をコヒーレント光検波する光受信器３１からなる周波数シフト型高密度光周波数多重伝送システムである。 As shown in FIG. 1, the frequency-shifted high-density optical frequency multiplex transmission system of the first embodiment of the present invention branches a light source 111 that transmits an optical signal of frequency f 1 and an optical signal from the light source 111. Optical coupler 112, polarization controller 11312 connected to one port of optical coupler 112, optical frequency shifter 11321 and polarization controller 11322 connected to the other port of optical coupler 112, and polarization controller 11312 and a polarization controller 11322 are controlled so that the polarization states of the optical signals from the two ports are orthogonal to each other, and an optical coupler 114 for multiplexing the optical signals from the two orthogonal ports. An optical transmitter 11 including an optical modulator 115 that modulates a waved optical signal, and the optical transmitter 11 and the optical fiber 21 are connected to each other, and the optical signal from the optical transmitter 11 is cohered. This is a frequency shift type high-density optical frequency multiplex transmission system comprising an optical receiver 31 that detects the detected light.

ここで、光周波数シフタ１１３２１は、光源１１１から伝送されてくる周波数ｆ１の光信号をｆ１＋△ｆあるいはｆ１−△ｆのように周波数をシフトさせ、光送信器１１からｆ１とｆ１＋△ｆ、あるいはｆ１とｆ１−△ｆの２波長を送信する。これより、１台の光源で２つの周波数の光信号を周波数多重伝送することができる。 Here, the optical frequency shifter 11321 shifts the frequency of the optical signal having the frequency f 1 transmitted from the light source 111 as f 1 + Δf or f 1 −Δf, and the optical signal from the optical transmitter 11 is changed to f 1 . Two wavelengths of f 1 + Δf or f 1 and f 1 −Δf are transmitted. As a result, optical signals of two frequencies can be frequency-multiplexed with a single light source.

本発明の第２の実施例の周波数シフト型高密度光周波数多重伝送システムは、図２に示すように、周波数ｆ１の光信号を送信する光源１２１−１と、光源１２１−１からの光信号を分岐する光カプラ１２２−１と、光カプラ１２２−１の一方のポートに接続された偏波制御器１２３１２−１と、光カプラ１２２−１の他方のポートに接続された光周波数シフタ１２３２１−１および偏波制御器１２３２２−２と、偏波制御器１２３１２−１と偏波制御器１２３２２−１により前記２つのポートからの光信号の偏波状態が互いに直交するように制御された、それら直交した２つのポートからの光信号を合波する光カプラ１２４−１と、合波した光信号を変調する光変調器１２５−１からなる光送信器１２−１と、周波数ｆＮの光信号を送信する光源１２１−Ｎと、光源１２１−Ｎからの光信号を分岐する光カプラ１２２−Ｎと、光カプラ１２２−Ｎの一方のポートに接続された偏波制御器１２３１２−Ｎと、光カプラ１２２−Ｎの他方のポートに接続された光周波数シフタ１２３２１−Ｎおよび偏波制御器１２３２２−Ｎと、偏波制御器１２３１２−Ｎと偏波制御器１２３２２−Ｎにより前記２つのポートからの光信号の偏波状態が互いに直交するように制御された、それら直交した２つのポートからの光信号を合波する光カプラ１２４−Ｎと、合波した光信号を変調する光変調器１２５−Ｎからなる光送信器１２−Ｎと、これら合計Ｎ台の光送信器１２−１〜１２−Ｎからの光信号を合波する光カプラ４２と、光カプラ４２と光ファイバ２２を介して接続され、光送信器１２−１〜１２−Ｎからの光信号をコヒーレント光検波する光受信器３２からなる周波数シフト型高密度光周波数多重伝送システムである。 Second frequency-shifting a high-density optical frequency division multiplex transmission system of an embodiment of the present invention, as shown in FIG. 2, the light source 121-1 for transmitting an optical signal of frequency f 1, the light from the light source 121-1 An optical coupler 122-1 for branching the signal, a polarization controller 12312-1 connected to one port of the optical coupler 122-1, and an optical frequency shifter 12321 connected to the other port of the optical coupler 122-1. -1 and the polarization controller 12322-2, and the polarization controller 12312-1 and the polarization controller 12322-1 were controlled so that the polarization states of the optical signals from the two ports were orthogonal to each other, an optical coupler 124-1 for multiplexing the optical signals from two ports that they orthogonal to the optical transmitter 12-1 consisting of a light modulator 125-1 modulates the multiplexed optical signal, the optical frequency f N Send signal A light source 121-N, an optical coupler 122-N that branches an optical signal from the light source 121-N, a polarization controller 12312-N connected to one port of the optical coupler 122-N, and an optical coupler 122- The optical frequency shifter 12321-N and the polarization controller 12322-N connected to the other port of N, and the optical signals from the two ports by the polarization controller 12312-N and the polarization controller 12322-N An optical coupler 124-N that multiplexes optical signals from two orthogonal ports whose polarization states are controlled to be orthogonal to each other, and an optical modulator 125-N that modulates the combined optical signal. The optical transmitter 12 -N is connected to the optical coupler 42 that combines the optical signals from the total of N optical transmitters 12-1 to 12 -N, the optical coupler 42, and the optical fiber 22. Transmitter 12-1 ~ This is a frequency shift type high density optical frequency multiplex transmission system comprising an optical receiver 32 for coherently detecting an optical signal from 12-N.

ここで、光周波数シフタ１２３２１−１は、光源１２１−１から伝送されてくる周波数ｆ１の光信号をｆ１＋△ｆ１あるいはｆ１−△ｆ１のように周波数をシフトさせ、光送信器１２−１からｆ１とｆ１＋△ｆ１、あるいはｆ１とｆ１−△ｆ１の２波長を送信する。同様に、光周波数シフタ１２３２１−Ｎは、光源１２１−Ｎから伝送されてくる周波数ｆＮの光信号をｆＮ＋△ｆＮあるいはｆＮ−△ｆＮのように周波数をシフトさせ、光送信器１２−ＮからｆＮとｆＮ＋△ｆＮ、あるいはｆＮとｆＮ−△ｆＮの２波長を送信する。これより、１台の光源で２つの周波数の光信号を周波数多重伝送することができる。 Here, the optical frequency shifter 12321-1 shifts the frequency of the optical signal having the frequency f 1 transmitted from the light source 121-1 as f 1 + Δf 1 or f 1 −Δf 1 , and transmits the light. Two wavelengths of f 1 and f 1 + Δf 1 , or f 1 and f 1 −Δf 1 are transmitted from the device 12-1. Similarly, the optical frequency shifter 12321-N are optical signal of a frequency f N transmitted from the light source 121-N f N + △ f N or f N - shifts the frequency as △ f N, the light transmission vessel 12-N from f N and f N + △ f N or f N and f N, - transmits two wavelengths of △ f N. As a result, optical signals of two frequencies can be frequency-multiplexed with a single light source.

本発明の第３の実施例の周波数シフト型高密度光周波数多重伝送システムは、図３に示すように、周波数ｆ１の光信号を送信する光源１３１−１と、周波数ｆＮの光信号を送信する光源１３１−Ｎと、合計Ｎ台の光源からの光信号を合波する光カプラ１３２と、合波した光信号を分岐する光カプラ１３３と、光カプラ１３３の一方のポートに接続された偏波制御器１３４１２と、光カプラ１３３の他方のポートに接続された光周波数シフタ１３４２１および偏波制御器１３４２２と、偏波制御器１３４１２と偏波制御器１３４２２により前記２つのポートからの光信号の偏波状態が互いに直交するように制御された、それら直交した２つのポートからの光信号を合波する光カプラ１３５と、合波した光信号を変調する光変調器１３６からなる光送信器１３と、光送信器１３と光ファイバ２３を介して接続され、光送信器１３からの光信号をコヒーレント光検波する光受信器３３からなる周波数シフト型高密度光周波数多重伝送システムである。 Third frequency-shifted high-density optical frequency division multiplex transmission system of an embodiment of the present invention, as shown in FIG. 3, the light source 131-1 for transmitting an optical signal of frequency f 1, the optical signal of the frequency f N A light source 131-N for transmission, an optical coupler 132 for combining optical signals from a total of N light sources, an optical coupler 133 for branching the combined optical signals, and one port of the optical coupler 133 are connected. A polarization controller 13412, an optical frequency shifter 13421 and a polarization controller 13422 connected to the other port of the optical coupler 133, and an optical signal from the two ports by the polarization controller 13412 and the polarization controller 13422. Of the optical coupler 135 that combines the optical signals from the two orthogonal ports and the optical modulator 136 that modulates the combined optical signal. A frequency shift type high-density optical frequency multiplex transmission system comprising an optical transmitter 13 and an optical receiver 33 connected to the optical transmitter 13 via an optical fiber 23 and coherently detecting an optical signal from the optical transmitter 13. is there.

ここで、光周波数シフタ１３４２１は、光源１３１−１〜１３１−Ｎから伝送されてくる周波数ｆ１〜ｆＮの光信号をｆ１＋△ｆ，・・・，ｆＮ＋△ｆ、あるいはｆ１−△ｆ，・・・，ｆＮ−△ｆのように一括で周波数シフトさせ、光送信器１３から、ｆ１〜ｆＮとｆ１＋△ｆ〜ｆＮ＋△ｆ、あるいはｆ１〜ｆＮとｆ１−△ｆ〜ｆＮ−△ｆの２Ｎの波長を送信する。これより、Ｎ台の光源で２Ｎの周波数の光信号を周波数多重伝送することができる。 Here, the optical frequency shifter 13421 converts the optical signals of the frequencies f 1 to f N transmitted from the light sources 131-1 to 131-N to f 1 + Δf,..., F N + Δf, or f. 1 −Δf,..., F N −Δf, and the frequency is collectively shifted, and f 1 to f N and f 1 + Δf to f N + Δf or f 1 are transmitted from the optical transmitter 13. ~f N and f 1 - △ f~f N - △ transmits the wavelength of 2N of f. As a result, it is possible to multiplex-transmit an optical signal having a frequency of 2N with N light sources.

本発明の第４の実施例の周波数シフト型高密度光周波数多重伝送システムは、図４に示すように、周波数ｆ１の光信号を送信する光源１４１−１と、光源１４１−１からの光信号を変調する光変調器１４６−１と、周波数ｆＮの光信号を送信する光源１４１−Ｎと、光源１４１−Ｎからの光信号を変調する光変調器１４６−Ｎと、合計Ｎ台の光変調器からの光信号を合波する光カプラ１４２と、合波した光信号を分岐する光カプラ１４３と、光カプラ１４３の一方のポートに接続された偏波制御器１４４１２と、光カプラ１４３の他方のポートに接続された光周波数シフタ１４４２１および偏波制御器１４４２２と、偏波制御器１４４１２と偏波制御器１４４２２により前記２つのポートからの光信号の偏波状態が互いに直交するように制御された、それら直交した２つのポートからの光信号を合波する光カプラ１４５からなる光送信器１４と、光送信器１４と光ファイバ２４を介して接続され、光送信器１４からの光信号をコヒーレント光検波する光受信器３４からなる周波数シフト型高密度光周波数多重伝送システムである。 The fourth frequency-shifted high-density optical frequency division multiplex transmission system of an embodiment of the present invention, as shown in FIG. 4, a light source 141-1 for transmitting an optical signal of frequency f 1, the light from the light source 141-1 an optical modulator 146 - for modulating a signal, a light source 141-N for transmitting an optical signal of a frequency f N, and the optical modulator 146-N for modulating the light signal from the light source 141-N, a total of N number An optical coupler 142 that combines optical signals from the optical modulator, an optical coupler 143 that branches the combined optical signal, a polarization controller 14412 connected to one port of the optical coupler 143, and an optical coupler 143 The optical frequency shifter 14421 and the polarization controller 14422 connected to the other of the two ports, the polarization controller 14412 and the polarization controller 14422 so that the polarization states of the optical signals from the two ports are orthogonal to each other. System The optical transmitter 14 composed of the optical coupler 145 that combines the optical signals from the two orthogonal ports, and the optical transmitter 14 and the optical fiber 24 are connected to each other, and the optical signal from the optical transmitter 14 is connected. This is a frequency shift type high density optical frequency multiplex transmission system comprising an optical receiver 34 for coherent optical detection.

ここで、光周波数シフタ１４４２１は、光源１４１−１〜１４１−Ｎから伝送されてくる周波数ｆ１〜ｆＮの光信号をｆ１＋△ｆ，・・・，ｆＮ＋△ｆ、あるいはｆ１−△ｆ，・・・，ｆＮ−△ｆのように一括で周波数シフトさせ、光送信器１４から、ｆ１〜ｆＮとｆ１＋△ｆ〜ｆＮ＋△ｆ、あるいはｆ１〜ｆＮとｆ１−△ｆ〜ｆＮ−△ｆの２Ｎの波長を送信する。これより、Ｎ台の光源で２Ｎの周波数の光信号を周波数多重伝送することができる。 Here, the optical frequency shifter 14421 converts the optical signals of the frequencies f 1 to f N transmitted from the light sources 141-1 to 141-N into f 1 + Δf,..., F N + Δf, or f. 1 −Δf,..., F N −Δf, and the frequency is collectively shifted, and f 1 to f N and f 1 + Δf to f N + Δf or f 1 are transmitted from the optical transmitter 14. ~f N and f 1 - △ f~f N - △ transmits the wavelength of 2N of f. As a result, it is possible to multiplex-transmit an optical signal having a frequency of 2N with N light sources.

本発明の第５の実施例の周波数シフト型高密度光周波数多重伝送システムは、図５に示すように、周波数ｆ１の光信号を送信する光源１５１と、光源１５１からの光信号を分岐する光カプラ１５２と、光カプラ１５２の一方のポートに接続された光周波数シフタ１５３１１および偏波制御器１５３１２と、光カプラ１５２の他方のポートに接続された光周波数シフタ１５３２１および偏波制御器１５３２２と、偏波制御器１５３１２と偏波制御器１５３２２により前記２つのポートからの光信号の偏波状態が互いに直交するように制御された、それら直交した２つのポートからの光信号を合波する光カプラ１５４と、合波した光信号を変調する光変調器１５５からなる光送信器１５と、光送信器１５と光ファイバ２５を介して接続され、光送信器１５からの光信号をコヒーレント光検波する光受信器３５からなる周波数シフト型高密度光周波数多重伝送システムである。 As shown in FIG. 5, the frequency shift type high-density optical frequency multiplex transmission system of the fifth embodiment of the present invention branches a light source 151 for transmitting an optical signal of frequency f 1 and an optical signal from the light source 151. An optical coupler 152, an optical frequency shifter 15311 and a polarization controller 15312 connected to one port of the optical coupler 152, an optical frequency shifter 15321 and a polarization controller 15322 connected to the other port of the optical coupler 152, and The optical signals from the two ports orthogonal to each other are controlled so that the polarization states of the optical signals from the two ports are orthogonal to each other by the polarization controller 15312 and the polarization controller 15322 A coupler 154, an optical transmitter 15 including an optical modulator 155 that modulates the combined optical signal, and the optical transmitter 15 are connected to the optical fiber 25 via an optical fiber 25. This is a frequency shift type high density optical frequency multiplex transmission system comprising an optical receiver 35 for coherently detecting an optical signal from the transmitter 15.

ここで、光周波数シフタ１５３１１は、光源１５１から伝送されてくる周波数ｆ１の光信号をｆ１−△ｆのように低周波シフトさせ、光周波数シフタ１５３２１は、光源１５１から伝送されてくる周波数ｆ１の光信号をｆ１＋△ｆのように高周波シフトさせ、光送信器１５から、ｆ１−△ｆとｆ１＋△ｆの２波長を送信する。あるいは、光周波数シフタ１５３１１は、光源１５１から伝送されてくる周波数ｆ１の光信号をｆ１＋△ｆのように高周波シフトさせ、光周波数シフタ１５３２１は、光源１５１から伝送されてくる周波数ｆ１の光信号をｆ１−△ｆのように低周波シフトさせ、光送信器１５から、ｆ１−△ｆとｆ１＋△ｆの２波長を送信する。これより、１台の光源で２つの周波数の光信号を周波数多重伝送することができる。 Here, the optical frequency shifter 15311 shifts the optical signal of the frequency f 1 transmitted from the light source 151 by a low frequency as f 1 −Δf, and the optical frequency shifter 15321 transmits the frequency transmitted from the light source 151. the optical signal of f 1 to frequency shifts as f 1 + △ f, from the optical transmitter 15, f 1 - △ f and f 1 + △ transmits two wavelengths of f. Alternatively, the optical frequency shifter 15311 shifts the optical signal of the frequency f 1 transmitted from the light source 151 by a high frequency as f 1 + Δf, and the optical frequency shifter 15321 transmits the frequency f 1 transmitted from the light source 151. of the optical signal f 1 - △ is the low-frequency shifts as f, from the optical transmitter 15, f 1 - △ f and f 1 + △ transmits two wavelengths of f. As a result, optical signals of two frequencies can be frequency-multiplexed with a single light source.

本発明の第６の実施例の周波数シフト型高密度光周波数多重伝送システムは、図６に示すように、周波数ｆ１の光信号を送信する光源１６１−１と、光源１６１−１からの光信号を分岐する光カプラ１６２−１と、光カプラ１６２−１の一方のポートに接続された光周波数シフタ１６３１１−１および偏波制御器１６３１２−１と、光カプラ１６２−１の他方のポートに接続された光周波数シフタ１６３２１−１および偏波制御器１６３２２−１と、偏波制御器１６３１２−１と偏波制御器１６３２２−１により前記２つのポートからの光信号の偏波状態が互いに直交するように制御された、それら直交した２つのポートからの光信号を合波する光カプラ１６４−１と、合波した光信号を変調する光変調器１６５−１からなる光送信器１６−１と、周波数ｆＮの光信号を送信する光源１６１−Ｎと、光源１６１−Ｎからの光信号を分岐する光カプラ１６２−Ｎと、光カプラ１６２−Ｎの一方のポートに接続された光周波数シフタ１６３１１−Ｎおよび偏波制御器１６３１２−Ｎと、光カプラ１６２−Ｎの他方のポートに接続された光周波数シフタ１６３２１−Ｎおよび偏波制御器１６３２２−Ｎと、偏波制御器１６３１２−Ｎと偏波制御器１６３２２−Ｎにより前記２つのポートからの光信号の偏波状態が互いに直交するように制御された、それら直交した２つのポートからの光信号を合波する光カプラ１６４−Ｎと、合波した光信号を変調する光変調器１６５−Ｎからなる光送信器１６−Ｎと、これら合計Ｎ台の光送信器１６−１〜１６−Ｎからの光信号を合波する光カプラ４６と、光カプラ４６と光ファイバ２６を介して接続され、光送信器１６−１〜１６−Ｎからの光信号をコヒーレント光検波する光受信器３６からなる周波数シフト型高密度光周波数多重伝送システムである。 Sixth frequency-shifted high-density optical frequency division multiplex transmission system of an embodiment of the present invention, as shown in FIG. 6, a light source 161-1 for transmitting an optical signal of frequency f 1, the light from the light source 161-1 An optical coupler 162-1 that branches the signal, an optical frequency shifter 16311-1 and polarization controller 16312-1 connected to one port of the optical coupler 162-1, and the other port of the optical coupler 162-1 The polarization states of the optical signals from the two ports are orthogonal to each other by the connected optical frequency shifter 16321-1 and polarization controller 16322-1, and the polarization controller 16312-1 and polarization controller 16322-1. The optical transmitter 16-is composed of an optical coupler 164-1 that multiplexes optical signals from the two orthogonal ports and an optical modulator 165-1 that modulates the combined optical signal. 1, a light source 161 -N that transmits an optical signal having a frequency f N , an optical coupler 162 -N that branches an optical signal from the light source 161 -N, and light connected to one port of the optical coupler 162 -N Frequency shifter 16311-N and polarization controller 16312-N, optical frequency shifter 16321-N and polarization controller 16322-N connected to the other port of the optical coupler 162-N, and polarization controller 16312- N and the polarization controller 16322-N are controlled so that the polarization states of the optical signals from the two ports are orthogonal to each other, and an optical coupler 164 that combines the optical signals from the two orthogonal ports N and an optical transmitter 16-N including an optical modulator 165-N that modulates the combined optical signal, and optical signals from a total of N optical transmitters 16-1 to 16-N are combined. Optical coupler 46 And a frequency shift type high-density optical frequency multiplex transmission system comprising an optical receiver 36 connected to the optical coupler 46 via the optical fiber 26 and coherently detecting optical signals from the optical transmitters 16-1 to 16-N. It is.

ここで、光周波数シフタ１６３１１−１は、光源１６１−１から伝送されてくる周波数ｆ１の光信号をｆ１−△ｆ１のように低周波シフトあるいはｆ１＋△ｆ１のように高周波シフトさせ、光周波数シフタ１６３２１−１は、光源１６１−１から伝送されてくる周波数ｆ１の光信号をｆ１＋△ｆ１のように高周波シフトあるいはｆ１−△ｆ１のように低周波シフトさせ、光送信器１６−１から、ｆ１−△ｆ１とｆ１＋△ｆ１の２波長を送信する。同様に、光周波数シフタ１６３１１−Ｎは、光源１６１−Ｎから伝送されてくる周波数ｆＮの光信号をｆＮ−△ｆＮのように低周波シフトあるいはｆＮ＋△ｆＮのように高周波シフトさせ、光周波数シフタ１６３２１−Ｎは、光源１６１−Ｎから伝送されてくる周波数ｆＮの光信号をｆＮ＋△ｆＮのように高周波シフトあるいはｆＮ−△ｆＮのように低周波シフトさせ、光送信器１６−Ｎから、ｆＮ−△ｆＮとｆＮ＋△ｆＮの２波長を送信する。これより、１台の光源で２つの周波数の光信号を周波数多重伝送することができる。 Here, the optical frequency shifter 16311-1 is an optical signal of a frequency f 1 that is transmitted from the light source 161-1 f 1 - high frequency as △ low-frequency shift as f 1 or f 1 + △ f 1 is shifted, the optical frequency shifter 16321-1 is frequency shift or f 1 as the optical signal of a frequency f 1 that is transmitted from the light source 161-1 f 1 + △ f 1 - △ low frequency as f 1 is shifted from the optical transmitter 16-1, f 1 - △ transmits two wavelengths of f 1 and f 1 + △ f 1. Similarly, the optical frequency shifter 16311-N are optical signal of a frequency f N transmitted from the light source 161-N f N - high frequency as △ f lower frequency shift or f as N N + △ f N is shifted, the optical frequency shifter 16 321-N are radio frequency shift or f N as the optical signal of a frequency f N transmitted from the light source 161-N f N + △ f N - △ low frequency as f N It is shifted from the optical transmitters 16-N, f N - transmits two wavelengths of △ f N and f N + △ f N. As a result, optical signals of two frequencies can be frequency-multiplexed with a single light source.

本発明の第７の実施例の周波数シフト型高密度光周波数多重伝送システムは、図７に示すように、周波数ｆ１の光信号を送信する光源１７１−１と、周波数ｆＮの光信号を送信する光源１７１−Ｎと、合計Ｎ台の光源１７１−１〜１７１−Ｎからの光信号を合波する光カプラ１７２と、合波した光信号を分岐する光カプラ１７３と、光カプラ１７３の一方のポートに接続された光周波数シフタ１７４１１および偏波制御器１７４１２と、光カプラ１７３の他方のポートに接続された光周波数シフタ１７４２１および偏波制御器１７４２２と、偏波制御器１７４１２と偏波制御器１７４２２により前記２つのポートからの光信号の偏波状態が互いに直交するように制御された、それら直交した２つのポートからの光信号を合波する光カプラ１７５と、合波した光信号を変調する光変調器１７６からなる光送信器１７と、光送信器１７と光ファイバ２７を介して接続され、光送信器１７からの光信号をコヒーレント光検波する光受信器３７からなる周波数シフト型高密度光周波数多重伝送システムである。 As shown in FIG. 7, the frequency shift type high-density optical frequency multiplex transmission system of the seventh embodiment of the present invention includes a light source 171-1 that transmits an optical signal of frequency f 1 and an optical signal of frequency f N. A light source 171 -N for transmission, an optical coupler 172 for combining optical signals from a total of N light sources 171-1 to 171 -N, an optical coupler 173 for branching the combined optical signals, and an optical coupler 173. Optical frequency shifter 17411 and polarization controller 17412 connected to one port, optical frequency shifter 17421 and polarization controller 17422 connected to the other port of optical coupler 173, polarization controller 17412 and polarization controller An optical coupler 1 that combines the optical signals from the two orthogonal ports controlled by the controller 17422 so that the polarization states of the optical signals from the two ports are orthogonal to each other. 5 and an optical transmitter 17 composed of an optical modulator 176 that modulates the combined optical signal, and the optical transmitter 17 and the optical fiber 27 are connected, and the optical signal from the optical transmitter 17 is coherently detected. This is a frequency shift type high-density optical frequency multiplex transmission system comprising an optical receiver 37.

ここで、光周波数シフタ１７４１１は、光源１７１−１〜１７１−Ｎから伝送されてくる周波数ｆ１〜ｆＮの光信号をｆ１−△ｆ，・・・，ｆＮ−△ｆのように一括で低周波シフトあるいはｆ１＋△ｆ，・・・，ｆＮ＋△ｆのように一括で高周波シフトさせ、光周波数シフタ１７４２１は、光源１７１−１〜１７１−Ｎから伝送されてくる周波数ｆ１〜ｆＮの光信号をｆ１＋△ｆ，・・・，ｆＮ＋△ｆのように一括で高周波シフトあるいはｆ１−△ｆ，・・・，ｆＮ−△ｆのように一括で低周波シフトさせ、光送信器１７からｆ１−△ｆ〜ｆＮ−△ｆとｆ１＋△ｆ〜ｆＮ＋△ｆの２Ｎ波長を送信する。これより、Ｎ台の光源で２Ｎの周波数の光信号を周波数多重伝送することができる。 Here, the optical frequency shifter 17 411 is an optical signal of frequency f 1 ~f N transmitted from the light source 171-1~171-N f 1 - △ f , ···, f N - as △ f The low frequency shift at once or the high frequency shift at once like f 1 + Δf,..., F N + Δf, and the optical frequency shifter 17421 is a frequency transmitted from the light sources 171-1 to 171-N. f 1 ~f optical signals N f 1 + △ f, ··· , f N + △ frequency shift or f 1 collectively as f - △ f, ···, f N - as △ f collectively to low frequency shift, f 1 from an optical transmitter 17 - △ f~f N - △ f and f 1 + △ f~f N + △ transmits a 2N wavelength of f. As a result, it is possible to multiplex-transmit an optical signal having a frequency of 2N with N light sources.

本発明の第８の実施例の周波数シフト型高密度光周波数多重伝送システムは、図８に示すように、周波数ｆ１の光信号を送信する光源１８１−１と、光源１８１−１からの光信号を変調する光変調器１８６−１と、周波数ｆＮの光信号を送信する光源１８１−Ｎと、光源１８１−Ｎからの光信号を変調する光変調器１８６−Ｎと、合計Ｎ台の光変調器１８６−１〜１８６−Ｎからの光信号を合波する光カプラ１８２と、合波した光信号を分岐する光カプラ１８３と、光カプラ１８３の一方のポートに接続された光周波数シフタ１８４１１および偏波制御器１８４１２と、光カプラ１８３の他方のポートに接続された光周波数シフタ１８４２１および偏波制御器１８４２２と、偏波制御器１８４１２と偏波制御器１８４２２により前記２つのポートからの光信号の偏波状態が互いに直交するように制御された、それら直交した２つのポートからの光信号を合波する光カプラ１８５からなる光送信器１８と、光送信器１８と光ファイバ２８を介して接続され、光送信器１８からの光信号をコヒーレント光検波する光受信器３８からなる周波数シフト型高密度光周波数多重伝送システムである。 Eighth frequency-shifted high-density optical frequency division multiplex transmission system of an embodiment of the present invention, as shown in FIG. 8, the light source 181-1 for transmitting an optical signal of frequency f 1, the light from the light source 181-1 a light modulator 186-1 which modulates the signals, a light source 181-N for transmitting an optical signal of a frequency f N, and the optical modulator 186-N for modulating the light signal from the light source 181-N, a total of N number An optical coupler 182 that combines optical signals from the optical modulators 186-1 to 186-N, an optical coupler 183 that branches the combined optical signal, and an optical frequency shifter connected to one port of the optical coupler 183 18411 and the polarization controller 18412; the optical frequency shifter 18421 and the polarization controller 18422 connected to the other port of the optical coupler 183; the polarization controller 18412 and the polarization controller 18422 An optical transmitter 18 comprising an optical coupler 185 for multiplexing the optical signals from the two orthogonal ports, the polarization states of which are controlled so as to be orthogonal to each other; This is a frequency shift type high density optical frequency multiplex transmission system comprising an optical receiver 38 connected through an optical fiber 28 and coherently detecting an optical signal from the optical transmitter 18.

ここで、光周波数シフタ１８４１１は、光源１８１−１〜１８１−Ｎから伝送されてくる周波数ｆ１〜ｆＮの光信号をｆ１−△ｆ，・・・，ｆＮ−△ｆのように一括で低周波シフトあるいはｆ１＋△ｆ，・・・，ｆＮ＋△ｆのように一括で高周波シフトさせ、光周波数シフタ１８４２１は、光源１８１−１〜１８１−Ｎから伝送されてくる周波数ｆ１〜ｆＮの光信号をｆ１＋△ｆ，・・・，ｆＮ＋△ｆのように一括で高周波シフトあるいはｆ１−△ｆ，・・・，ｆＮ−△ｆのように一括で低周波シフトさせ、光送信器１８から、ｆ１−△ｆ〜ｆＮ−△ｆとｆ１＋△ｆ〜ｆＮ＋△ｆの２Ｎ波長を送信する。これより、Ｎ台の光源で２Ｎの周波数の光信号を周波数多重伝送することができる。 Here, the optical frequency shifter 18 411 is an optical signal of frequency f 1 ~f N transmitted from the light source 181-1~181-N f 1 - △ f , ···, f N - as △ f The low frequency shift at once or the high frequency shift at once like f 1 + Δf,..., F N + Δf, and the optical frequency shifter 18421 is a frequency transmitted from the light sources 181-1 to 181-N. f 1 ~f optical signals N f 1 + △ f, ··· , f N + △ frequency shift or f 1 collectively as f - △ f, ···, f N - as △ f is low frequency shifts in bulk, from the optical transmitter 18, f 1 - △ f~f N - △ f and f 1 + △ f~f N + △ transmits a 2N wavelength of f. As a result, it is possible to multiplex-transmit an optical signal having a frequency of 2N with N light sources.

以上、第１〜第８の実施例に示すように光送信器を構成することにより、周波数の安定した光源の品種数を減らすことができる。   As described above, by configuring the optical transmitter as shown in the first to eighth embodiments, the number of types of light sources with stable frequencies can be reduced.

図９には、本発明の第１〜第８の実施例に示す周波数シフト型高密度光周波数多重伝送システムの光周波数シフタの構成例を示す。図９の光周波数シフタは、単側波帯（ｓｉｎｇｌｅ ｓｉｄｅｂａｎｄ：ＳＳＢ）光変調器と呼ばれるものである。その構成は、マッハツェンダ回路１９のそれぞれの導波路にマッハツェンダ回路１９１、１９２を配置した構成である。マッハツェンダ回路１９１には、ＲＦ信号電極１９１１１、１９１２１と各導波路の光位相差を調整するＤＣ電極１９１２２が設けられ、マッハツェンダ回路１９２には、ＲＦ信号電極１９２１１、１９２２１と各導波路の光位相差を調整するＤＣ電極１９２２２が設けられ、マッハツェンダ回路１９１には、光位相差を調整するＤＣ電極１９３が設けられている。   FIG. 9 shows a configuration example of the optical frequency shifter of the frequency shift type high-density optical frequency multiplex transmission system shown in the first to eighth embodiments of the present invention. The optical frequency shifter of FIG. 9 is called a single sideband (SSB) optical modulator. The configuration is such that the Mach-Zehnder circuits 191 and 192 are arranged in the respective waveguides of the Mach-Zehnder circuit 19. The Mach-Zehnder circuit 191 is provided with a DC electrode 19122 for adjusting the optical phase difference between the RF signal electrodes 19111 and 19121 and the respective waveguides. The DC electrode 19222 for adjusting the optical phase difference is provided, and the Mach-Zehnder circuit 191 is provided with the DC electrode 193 for adjusting the optical phase difference.

各ＲＦ信号電極における変調度をφ、時間をｔ、搬送波をｃｏｓωＣｔとし、ＲＦ信号電極１９１１１にはφｃｏｓωＳｔ、ＲＦ信号電極１９１２１には−φｃｏｓωＳｔ、ＲＦ信号電極１９２１１にはφｓｉｎωＳｔ、ＲＦ信号電極１９２２１には−φｓｉｎωＳｔを印加する。また、ＤＣ電極１９１２２、１９２２２には、それぞれの導波路の位相差がπとなるようＤＣバイアスを印加する。さらに、ＤＣ電極１９３は、マッハツェンダ回路１９１、１９２からの光信号の位相差がπ／２となるようにＤＣバイアスを印加する。このように動作させると、ｍを整数とすると、マッハツェンダ回路１９１から出力される光信号Ｅ１９１は、

Figure 0004703303

となる。マッハツェンダ回路１９２から出力される光信号Ｅ１９２は、
Figure 0004703303
となる。そして、マッハツェンダ回路１９からの出力される光信号Ｅ１９は、
Figure 0004703303
となる。以上より、マッハツェンダ回路１９は、角周波数ωＳ低周波シフトした光信号を出力することができる。同様に、ＤＣ電極１９３に、マッハツェンダ回路１９１、１９２からの光信号の位相差が−π／２となるようにＤＣバイアスを印加すると、マッハツェンダ回路１９からの出力される光信号Ｅ１９は、
Figure 0004703303
となる。以上より、マッハツェンダ回路１９は、角周波数ωＳ高周波シフトした光信号を出力することができる。 The degree of modulation of each RF signal electrodes phi, and the time t, the carrier wave cosω C t, φcosω the RF signal electrode 19111 S t, the RF signal electrode 19121 -φcosω S t, φsinω the RF signal electrode 19211 S t, the RF signal electrode 19221 to apply a -φsinω S t. Further, a DC bias is applied to the DC electrodes 19122 and 19222 so that the phase difference between the respective waveguides becomes π. Further, the DC electrode 193 applies a DC bias so that the phase difference of the optical signals from the Mach-Zehnder circuits 191 and 192 becomes π / 2. When operated in this way, if m is an integer, the optical signal E 191 output from the Mach-Zehnder circuit 191 is
Figure 0004703303
It becomes. The optical signal E 192 output from the Mach-Zehnder circuit 192 is
Figure 0004703303
It becomes. The optical signal E 19 output from the Mach-Zehnder circuit 19 is
Figure 0004703303
It becomes. As described above, the Mach-Zehnder circuit 19 can output the optical signal shifted by the angular frequency ω S and the low frequency. Similarly, when a DC bias is applied to the DC electrode 193 so that the phase difference of the optical signals from the Mach-Zehnder circuits 191 and 192 is −π / 2, the optical signal E 19 output from the Mach-Zehnder circuit 19 is
Figure 0004703303
It becomes. Thus, the Mach-Zehnder circuit 19 can output an optical signal angular frequency omega S frequency shift.

本発明の第９の実施例の周波数シフト型高密度光周波数多重伝送システムは、図１０に示すように、周波数ｆ１の光信号を送信する光源４５１と、光源４５１に接続された光周波数シフタ４５２と、光周波数シフタ４５２の一方のポートに接続された偏波制御器４５３１と、光周波数シフタ４５２の他方のポートに接続された偏波制御器４５３２と、偏波制御器４５３１と偏波制御器４５３２により前記２つのポートからの光信号の偏波状態が互いに直交するように制御された、それら直交した２つのポートからの光信号を合波する光カプラ４５４と、合波した光信号を変調する光変調器４５５からなる光送信器４５と、光送信器４５と光ファイバ５５を介して接続され、光送信器４５からの光信号をコヒーレント光検波する光受信器６５からなる周波数シフト型高密度光周波数多重伝送システムである。 As shown in FIG. 10, a frequency shift type high-density optical frequency multiplex transmission system according to a ninth embodiment of the present invention includes a light source 451 that transmits an optical signal having a frequency f 1 and an optical frequency shifter connected to the light source 451. 452, a polarization controller 4531 connected to one port of the optical frequency shifter 452, a polarization controller 4532 connected to the other port of the optical frequency shifter 452, and a polarization controller 4531 and polarization control The optical coupler 454 for controlling the polarization states of the optical signals from the two ports to be orthogonal to each other by the optical device 4532, and the optical coupler 454 for multiplexing the optical signals from the two orthogonal ports, An optical transmitter 45 composed of an optical modulator 455 to be modulated, and an optical receiver 65 connected to the optical transmitter 45 via an optical fiber 55 to detect an optical signal from the optical transmitter 45 coherently. This is a frequency shift type high-density optical frequency multiplex transmission system.

ここで、光周波数シフタ４５２は、光源４５１から伝送されてくる周波数ｆ１の光信号を、ｆ１−△ｆのように低周波シフトさせた光信号を一方のポートへ、ｆ１＋△ｆのように高周波シフトさせた光信号を他方のポートに出力し、光送信器４５から、ｆ１−△ｆとｆ１＋△ｆの２波長を送信する。これより、１台の光源で２つの周波数の光信号を周波数多重伝送することができる。 Here, the optical frequency shifter 452 sends an optical signal obtained by shifting the optical signal of the frequency f 1 transmitted from the light source 451 by a low frequency like f 1 −Δf to one port, f 1 + Δf. the optical signal obtained by frequency shifted output to the other port as, from the optical transmitter 45, f 1 - △ f and f 1 + △ transmits two wavelengths of f. As a result, optical signals of two frequencies can be frequency-multiplexed with a single light source.

本発明の第１０の実施例の周波数シフト型高密度光周波数多重伝送システムは、図１１に示すように、周波数ｆ１の光信号を送信する光源４６１−１と、光源４６１−１に接続された光周波数シフタ４６２−１と、光周波数シフタ４６２−１の一方のポートに接続された偏波制御器４６３１−１と、光周波数シフタ４６２−１の他方のポートに接続された偏波制御器４６３２−１と、偏波制御器４６３１−ｌと偏波制御器４６３２−１により前記２つのポートからの光信号の偏波状態が互いに直交するように制御された、それら直交した２つのポートからの光信号を合波する光カプラ４６４−１と、合波した光信号を変調する光変調器４６５−１からなる光送信器４６−１と、周波数ｆＮの光信号を送信する光源４６１−Ｎと、光源４６１−Ｎに接続された光周波数シフタ４６２−Ｎと、光周波数シフタ４６２−Ｎの一方のポートに接続された偏波制御器４６３１−Ｎと、光周波数シフタ４６２−Ｎの他方のポートに接続された偏波制御器４６３２−Ｎと、偏波制御器４６３１−Ｎと偏波制御器４６３２−Ｎにより前記２つのポートからの光信号の偏波状態が互いに直交するように制御された、それら直交した２つのポートからの光信号を合波する光カプラ４６４−Ｎと、合波した光信号を変調する光変調器４６５−Ｎからなる光送信器４６−Ｎと、これら合計Ｎ台の光送信器４６−１〜４６−Ｎからの光信号を合波する光カプラ７６と、光カプラ７６と光ファイバ５６を介して接続され、光送信器４６−１〜４６−Ｎからの光信号をコヒーレント光検波する光受信器６６からなる周波数シフト型高密度光周波数多重伝送システムである。 10 frequency-shifted high-density optical frequency division multiplex transmission system of an embodiment of the present invention, as shown in FIG. 11, a light source 461-1 for transmitting an optical signal of frequency f 1, is connected to the light source 461-1 The optical frequency shifter 462-1, the polarization controller 4631-1 connected to one port of the optical frequency shifter 462-1, and the polarization controller connected to the other port of the optical frequency shifter 462-1 463-1, the polarization controller 4631-1, and the polarization controller 4632-1 controlled so that the polarization states of the optical signals from the two ports are orthogonal to each other. a light source for the transmitted optical coupler 464-1 for multiplexing the optical signal, the optical transmitter 46-1 consisting of a light modulator 465-1 which modulates the multiplexed optical signal, the optical signal of the frequency f N 461- N and light source 461 Optical frequency shifter 462-N connected to N, polarization controller 4631-N connected to one port of optical frequency shifter 462-N, and connected to the other port of optical frequency shifter 462-N The polarization controller 4632-N, the polarization controller 4631-N, and the polarization controller 4632-N are controlled so that the polarization states of the optical signals from the two ports are orthogonal to each other. An optical coupler 464-N that combines optical signals from two ports, an optical transmitter 46-N that includes an optical modulator 465-N that modulates the combined optical signal, and a total of N optical transmitters An optical coupler 76 that multiplexes optical signals from 46-1 to 46-N, and an optical coupler 76 that is connected to the optical coupler 56 via an optical fiber 56. The optical signals from the optical transmitters 46-1 to 46-N are coherent light. It consists of an optical receiver 66 for detection. This is a frequency shift type high-density optical frequency multiplex transmission system.

ここで、光周波数シフタ４６２−１は、光源４６１−１から伝送されてくる周波数ｆ１の光信号を、ｆ１−△ｆ１のように低周波シフトさせた光信号を一方のポートへ、ｆ１＋△ｆ１のように高周波シフトさせた光信号を他方のポートに出力し、光送信器４６−１から、ｆ１−△ｆ１とｆ１＋△ｆ１の２波長を送信する。同様に光周波数シフタ４６２−Ｎは、光源４６１−Ｎから伝送されてくる周波数ｆＮの光信号を、ｆＮ−△ｆＮのように低周波シフトさせた光信号を一方のポートへ、ｆＮ＋△ｆＮのように高周波シフトさせた光信号を他方のポートに出力し、光送信器４６−Ｎから、ｆＮ−△ｆＮとｆＮ＋△ｆＮの２波長を送信する。これより、１台の光源で２つの周波数の光信号を周波数多重伝送することができる。 Here, the optical frequency shifter 462-1 is an optical signal of a frequency f 1 that is transmitted from the light source 461-1, f 1 - a light signal obtained by low-frequency shifts as △ f 1 to one port, the optical signal obtained by frequency shifting as f 1 + △ f 1 is output to the other ports, the optical transmitter 46-1, f 1 - sending △ two wavelengths f 1 and f 1 + △ f 1 . Similarly optical frequency shifter 462-N is an optical signal of a frequency f N transmitted from the light source 461-N, f N - △ optical signal obtained by low-frequency shifts as f N to one port, f the optical signal obtained by frequency shifting as N + △ f N is output to the other port, from the optical transmitter 46-N, f N - it transmits two wavelengths of △ f N and f N + △ f N. As a result, optical signals of two frequencies can be frequency-multiplexed with a single light source.

本発明の第１１の実施例の周波数シフト型高密度光周波数多重伝送システムは、図１２に示すように、周波数ｆ１の光信号を送信する光源４７１−１と、周波数ｆＮの光信号を送信する光源４７１−Ｎと、合計Ｎ台の光源４７１−１〜４７１−Ｎからの光信号を合波する光カプラ４７２と、光カプラ４７２に接続された光周波数シフタ４７３と、光周波数シフタ４７３の一方のポートに接続された偏波制御器４７４１と、光周波数シフタ４７３の他方のポートに接続された偏波制御器４７４２と、偏波制御器４７４１と偏波制御器４７４２により前記２つのポートからの光信号の偏波状態が互いに直交するように制御された、それら直交した２つのポートからの光信号を合波する光カプラ４７５と、合波した光信号を変調する光変調器４７６からなる光送信器４７と、光送信器４７と光ファイバ５７を介して接続され、光送信器４７からの光信号をコヒーレント光検波する光受信器６７からなる周波数シフト型高密度光周波数多重伝送システムである。 As shown in FIG. 12, the frequency shift type high-density optical frequency multiplex transmission system of the eleventh embodiment of the present invention includes a light source 471-1 that transmits an optical signal of frequency f 1 and an optical signal of frequency f N. A light source 471-N for transmission, an optical coupler 472 for combining optical signals from a total of N light sources 471-1 to 471-N, an optical frequency shifter 473 connected to the optical coupler 472, and an optical frequency shifter 473 The polarization controller 4741 connected to one of the ports, the polarization controller 4742 connected to the other port of the optical frequency shifter 473, and the two ports by the polarization controller 4741 and the polarization controller 4742. Are controlled so that the polarization states of the optical signals from each other are orthogonal to each other, an optical coupler 475 that combines the optical signals from the two orthogonal ports, and an optical modulator 47 that modulates the combined optical signal. A frequency shift type high-density optical frequency multiplex transmission comprising an optical transmitter 47 comprising: an optical receiver 47 connected to the optical transmitter 47 via an optical fiber 57 and coherently detecting an optical signal from the optical transmitter 47. System.

ここで、光周波数シフタ４７３は、光源４７１−１〜４７１−Ｎから伝送されてくる周波数ｆ１〜ｆＮの光信号をｆ１−△ｆ，・・・，ｆＮ−△ｆのように一括で低周波シフトさせた光信号を一方のポートへ、ｆ１＋△ｆ，・・・，ｆＮ＋△ｆのように一括で高周波シフトさせた光信号を他方のポートに出力し、光送信器４７からｆ１−△ｆ〜ｆＮ−△ｆと、ｆ１＋△ｆ〜ｆＮ＋△ｆの２Ｎ波長を送信する。これより、Ｎ台の光源で２Ｎの周波数の光信号を周波数多重伝送することができる。 Here, the optical frequency shifter 473, the optical signal of frequency f 1 ~f N transmitted from the light source 471-1~471-N f 1 - △ f , ···, f N - as △ f The optical signal shifted at a low frequency in a lump is output to one port, and the optical signal shifted in a lump at a high frequency as f 1 + Δf,..., F N + Δf is output to the other port. the transmitter 47 from f 1 - △ f~f N - and △ f, transmits a 2N wavelengths f 1 + △ f~f N + △ f. As a result, it is possible to multiplex-transmit an optical signal having a frequency of 2N with N light sources.

本発明の第１２の実施例の周波数シフト型高密度光周波数多重伝送システムは、図１３に示すように、周波数ｆ１の光信号を送信する光源４８１−１と、光源４８１−１からの光信号を変調する光変調器４８６−１と、周波数ｆＮの光信号を送信する光源４８１−Ｎと、光源４８１−Ｎからの光信号を変調する光変調器４８６−Ｎと、合計Ｎ台の光変調器４８６−１〜４８６−Ｎからの光信号を合波する光カプラ４８２と、光カプラ４８２に接続された光周波数シフタ４８３と、光周波数シフタ４８３の一方のポートに接続された偏波制御器４８４１と、光周波数シフタ４８３の他方のポートに接続された偏波制御器４８４２と、偏波制御器４８４１と偏波制御器４８４２により前記２つのポートからの光信号の偏波状態が互いに直交するように制御された、それら直交した２つのポートからの光信号を合波する光カプラ４８５からなる光送信器４８と、光送信器４８と光ファイバ５８を介して接続され、光送信器４８からの光信号をコトーレント光検波する光受信器６８からなる周波数シフト型高密度光周波数多重伝送システムである。 12 frequency-shifted high-density optical frequency division multiplex transmission system of an embodiment of the present invention, as shown in FIG. 13, a light source 481-1 for transmitting an optical signal of frequency f 1, the light from the light source 481-1 a light modulator 486-1 which modulates the signals, a light source 481-N for transmitting an optical signal of a frequency f N, and the optical modulator 486-N for modulating the light signal from the light source 481-N, a total of N number Optical coupler 482 that multiplexes optical signals from optical modulators 486-1 to 486-N, optical frequency shifter 483 connected to optical coupler 482, and polarization connected to one port of optical frequency shifter 483 The controller 4841, the polarization controller 4842 connected to the other port of the optical frequency shifter 483, and the polarization states of the optical signals from the two ports are mutually controlled by the polarization controller 4841 and the polarization controller 4842. Orthogonal The optical transmitter 48 is composed of an optical coupler 485 that multiplexes optical signals from the two orthogonal ports, and is connected to the optical transmitter 48 via an optical fiber 58. This is a frequency shift type high-density optical frequency multiplex transmission system comprising an optical receiver 68 for detecting a torrent optical signal.

ここで、光周波数シフタ４８３は、光源４８１−１〜４８１−Ｎから伝送されてくる周波数ｆ１〜ｆＮの光信号をｆ１−△ｆ，・・・，ｆＮ−△ｆのように一括で低周波シフトさせた光信号を一方のポートへ、ｆ１＋△ｆ，・・・，ｆＮ＋△ｆのように一括で高周波シフトさせた光信号を他方のポートに出力し、光送信器４８からｆ１−△ｆ〜ｆＮ−△ｆとｆ１＋△ｆ〜ｆＮ＋△ｆの２Ｎ波長を送信する。これより、Ｎ台の光源で２Ｎの周波数の光信号を周波数多重伝送することができる。 Here, the optical frequency shifter 483, the optical signal of frequency f 1 ~f N transmitted from the light source 481-1~481-N f 1 - △ f , ···, f N - as △ f The optical signal shifted at a low frequency in a lump is output to one port, and the optical signal shifted in a lump at a high frequency as f 1 + Δf,..., F N + Δf is output to the other port. from the transmitter 48 f 1 - △ f~f N - △ f and f 1 + △ f~f N + △ transmits a 2N wavelength of f. As a result, it is possible to multiplex-transmit an optical signal having a frequency of 2N with N light sources.

以上、第９〜第１２の実施例に示すように光送信器を構成することにより、周波数の安定した光源の品種数を減らすことができる。   As described above, by configuring the optical transmitter as shown in the ninth to twelfth embodiments, the number of types of light sources with stable frequencies can be reduced.

図１４は、本発明の第９〜第１２の実施例に示す周波数シフト型高密度光周波数多重伝送システムの光周波数シフタの構成例を示す。図１４の光周波数シフタは、図９の単側波帯（ｓｉｎｇｌｅ ｓｉｄｅｂａｎｄ：ＳＳＢ）光変調器の出力側を方向性結合器型にしたものである。その構成は、マッハツェンダ回路４９のそれぞれの導波路にマッハツェンダ回路４９１、４９２を配置した構成である。マッハツェンダ回路４９１には、ＲＦ信号電極４９１１１、４９１２１と各導波路の光位相差を調整するＤＣ電極４９１２２が設けられ、マッハツェンダ回路４９２には、ＲＦ信号電極４９２１１、４９２２１と各導波路の光位相差を調整するＤＣ電極４９２２２が設けられ、マッハツェンダ回路４９の出力は、方向性結合器４９３により構成される。   FIG. 14 shows a configuration example of an optical frequency shifter of the frequency shift type high density optical frequency multiplex transmission system shown in the ninth to twelfth embodiments of the present invention. The optical frequency shifter of FIG. 14 is a directional coupler type on the output side of the single sideband (SSB) optical modulator of FIG. The configuration is such that Mach-Zehnder circuits 491 and 492 are arranged in the respective waveguides of the Mach-Zehnder circuit 49. The Mach-Zehnder circuit 491 is provided with DC electrodes 49122 for adjusting the optical phase difference between the RF signal electrodes 49111 and 49121 and the respective waveguides. DC electrode 49222 is provided, and the output of the Mach-Zehnder circuit 49 is constituted by a directional coupler 493.

各ＲＦ信号電極における変調度をφ、時間をｔ、搬送波をｃｏｓωＣｔとし、ＲＦ信号電極４９１１１にはφｃｏｓωＳｔ、ＲＦ信号電極４９１２１には−φｃｏｓωＳｔ、ＲＦ信号電極４９２１１にはφｓｉｎωＳｔ、ＲＦ信号電極４９２２１には−φｓｉｎωＳｔを印加する。また、ＤＣ電極４９１２２、４９２２２には、それぞれの導波路の位相差がπとなるようＤＣバイアスを印加する。このように動作させると、ｍを整数とすると、マッハツェンダ回路４９１から出力される光信号Ｅ４９１は、

Figure 0004703303

となる。マッハツェンダ回路４９２から出力される光信号Ｅ４９２は、
Figure 0004703303
となる。そして、出力５９−１から出力される光信号Ｅ５９−１は、
Figure 0004703303
出力５９−２から出力される光信号Ｅ５９−２は、
Figure 0004703303
となる。以上より、マッハツェンダ回路４９は、角周波数ωＳ低周波シフトした光信号と、角周波数ωＳ高周波シフトした光信号を出力することができる。 The degree of modulation of each RF signal electrodes phi, and the time t, the carrier wave cosω C t, φcosω the RF signal electrode 49 111 S t, the RF signal electrode 49121 -φcosω S t, φsinω the RF signal electrode forty-nine thousand two hundred and eleven S t, the RF signal electrode 49221 to apply a -φsinω S t. Further, a DC bias is applied to the DC electrodes 49122 and 49222 so that the phase difference between the respective waveguides becomes π. When operated in this way, if m is an integer, the optical signal E 491 output from the Mach-Zehnder circuit 491 is
Figure 0004703303
It becomes. The optical signal E 492 output from the Mach-Zehnder circuit 492 is
Figure 0004703303
It becomes. The optical signal E 59-1 output from the output 59-1 is
Figure 0004703303
The optical signal E 59-2 output from the output 59-2 is
Figure 0004703303
It becomes. Thus, the Mach-Zehnder circuit 49 can output the optical signal angular frequency omega S low frequency shift, an optical signal angular frequency omega S frequency shift.

以下では、第１〜第１２の実施例における周波数シフト型高密度光周波数多重伝送システムの、応用的な構成を述べる。   Hereinafter, an applied configuration of the frequency shift type high-density optical frequency multiplex transmission system in the first to twelfth embodiments will be described.

第１の応用として、第１〜第１２の実施例における周波数シフト型高密度光周波数多重伝送システムは、光送信器と光受信器は１本の光ファイバを介して接続されているが、光送信器と光受信器の間に光カプラを設け、１台の光送信器と複数の光受信器を接続する、いわゆるＰＯＮ（Ｐａｓｓｉｖｅ Ｏｐｔｉｃａｌ Ｎｅｔｗｏｒｋ）構成にして、光送信器と光ファイバを複数の光受信器で共有する構成にすることが可能である。   As a first application, in the frequency shift type high-density optical frequency multiplex transmission system in the first to twelfth embodiments, the optical transmitter and the optical receiver are connected through one optical fiber. An optical coupler is provided between the transmitter and the optical receiver, and a so-called PON (Passive Optical Network) configuration in which one optical transmitter and a plurality of optical receivers are connected to each other. It is possible to adopt a configuration shared by the optical receiver.

第２の応用として、第１〜第４の実施例における周波数シフト型高蜜度光周波数多重伝送システムの光送信器は、光カプラ１１２、１２２−１〜１２２−Ｎ、１３３、１４３の一方のポートは光周波数シフタを有するため、他方のポートに比べ、光損失が大きいと考えることができる。光カプラ１１４、１２４−１〜１２４−Ｎ、１３５、１４５の出力において、各周波数の光出力レベルを同一にするために、光周波数シフタを有するポートに光増幅器を設けることが可能である。あるいは、各周波数の光出力レベルを同一にするために、光カプラ１１２、１２２−１〜１２２−Ｎ、１３３、１４３の光出力レベルの分岐比率を非等分岐として、光周波数シフタを有するポートに高強度の光出力レベルを送る構成にすることも可能である。   As a second application, the optical transmitter of the frequency shift type high optical frequency multiplexing transmission system in the first to fourth embodiments is one of the optical couplers 112, 122-1 to 122 -N, 133, and 143. Since the port has an optical frequency shifter, it can be considered that the optical loss is larger than that of the other port. In order to make the optical output level of each frequency the same at the outputs of the optical couplers 114, 124-1 to 124-N, 135, and 145, an optical amplifier can be provided at the port having the optical frequency shifter. Alternatively, in order to make the optical output level of each frequency the same, the branch ratio of the optical output levels of the optical couplers 112, 122-1 to 122-N, 133, and 143 is set as an unequal branch, and the port having the optical frequency shifter is used. It is also possible to send a high intensity light output level.

第３の応用として、第２および第６の実施例における周波数シフト型高密度光周波数多重伝送システムおける光周波数シフタに、図９に示す単側波帯光変調器を用いるとき、各送信器における周波数シフト量が同じである場合、単側波帯光変調器を動作させるＲＦ信号やＤＣバイアスを各送信器で共有することができる。すなわち、光周波数シフタの制御回路を共有して使用することができるので、周波数シフト型高密度光周波数多重伝送システム全体のコストを抑えることが可能となる。   As a third application, when the single sideband optical modulator shown in FIG. 9 is used for the optical frequency shifter in the frequency shift type high-density optical frequency multiplex transmission system in the second and sixth embodiments, When the frequency shift amount is the same, each transmitter can share the RF signal and DC bias for operating the single sideband optical modulator. That is, since the control circuit of the optical frequency shifter can be shared and used, the cost of the entire frequency shift type high density optical frequency multiplex transmission system can be suppressed.

第４の応用として、光周波数シフタとして、図９に示す単側波帯光変調器を用いる代わりに、擬似位相整合導波路を用いた波長変換器を用いることもできる。これは、２次の非線形効果を用いたもので、信号光の角周波数をωＳ、励起光の角周波数をωＰとし、信号光と励起光を擬似位相整合導波路に入射させることにより、変換光ωＣ＝ωＰ−ωＳを得ることができる。本波長変換器は、第３、第４、第７、第８の実施例に示すような、一括ですべての周波数をシフトする光周波数シフタとしても利用することが可能である。 As a fourth application, a wavelength converter using a quasi phase matching waveguide can be used as the optical frequency shifter instead of the single sideband optical modulator shown in FIG. This uses a second-order nonlinear effect, where the angular frequency of the signal light is ω S , the angular frequency of the excitation light is ω P , and the signal light and the excitation light are incident on the quasi-phase matching waveguide, Converted light ω C = ω P −ω S can be obtained. This wavelength converter can also be used as an optical frequency shifter that shifts all frequencies at once as shown in the third, fourth, seventh, and eighth embodiments.

第５の応用として、第１〜第１２の実施例における周波数シフト型高密度光周波数多重伝送システムの光送信器は、偏波制御器を２台有するが、どちらか１台の偏波制御器だけ有する周波数シフト型高密度光周波数多重伝送システムとすることができる。例えば、偏波状態に依存しないコヒーレント光受信を行うために、偏波制御器２台からの出力の偏波状態を互いに直交するようにそれぞれの偏波制御器を制御する場合は、２台の偏波制御器のうちどちらか１台の偏波制御器だけを配置し、この偏波制御器を、偏波制御器を有する方の偏波状態を他方の偏波状態と直交するように制御すればよい。これより、本発明の第１〜第１２の実施例における偏波制御器は、どちらか一方の１台でもよい。   As a fifth application, the optical transmitter of the frequency shift type high-density optical frequency multiplex transmission system in the first to twelfth embodiments has two polarization controllers, but one of the polarization controllers. The frequency shift type high density optical frequency multiplex transmission system can be provided. For example, in order to perform coherent light reception independent of the polarization state, when controlling each polarization controller so that the polarization states of the outputs from the two polarization controllers are orthogonal to each other, Only one of the polarization controllers is arranged, and this polarization controller is controlled so that the polarization state having the polarization controller is orthogonal to the other polarization state. do it. Thus, either one of the polarization controllers in the first to twelfth embodiments of the present invention may be used.

第１〜第４および第９〜第１２の実施例では、光送信器１台あたりの光周波数シフタの台数は１台であるが、第５〜第８の実施例では、光送信器１台あたりの光周波数シフタの台数は２台である。以下では、光周波数シフタの台数の差分の効果を述べる。   In the first to fourth and ninth to twelfth embodiments, the number of optical frequency shifters per optical transmitter is one, but in the fifth to eighth embodiments, one optical transmitter. The number of optical frequency shifters per unit is two. Hereinafter, the effect of the difference in the number of optical frequency shifters will be described.

第１〜第８の実施例において、光周波数シフタとして図９の単側波帯光変調器を用いる場合、第１〜第４の実施例では、角周波数ω ｓ に相当するＲＦ信号発生器が必要となるが、第５〜第８の実施例では、角周波数ω ｓ ／２に相当するＲＦ信号発生器を準備し、一方の光周波数シフタを−ω ｓ ／２、他方の光周波数シフタをω ｓ ／２にシフトさせることで、角周波数ω ｓ 分のシフト量を実現することができる。一般にＲＦ信号発生器は、高周波になるほど高価になるので、第５〜第８の実施例では、２台の光周波数シフタが必要となるが、周波数シフトのためのＲＦ信号発生器は安価にできるという利点を有する。 In the first to eighth embodiments, when the single sideband optical modulator of FIG. 9 is used as the optical frequency shifter, in the first to fourth embodiments, an RF signal generator corresponding to the angular frequency ω s is provided. Although necessary, in the fifth to eighth embodiments, an RF signal generator corresponding to the angular frequency ω s / 2 is prepared, one optical frequency shifter is −ω s / 2, and the other optical frequency shifter is By shifting to ω s / 2, a shift amount corresponding to the angular frequency ω s can be realized. In general, since the RF signal generator becomes more expensive as the frequency becomes higher, in the fifth to eighth embodiments, two optical frequency shifters are required, but the RF signal generator for frequency shift can be made inexpensive. Has the advantage.

さらに、第９〜第１２の実施例においては、光周波数シフタとして図１２の単側波帯光変調器を用い、角周波数ω ｓ ／２に相当するＲＦ信号発生器を準備することで、一方の出力の光信号をω ｓ ／２シフト、他方の出力の光信号を−ω ｓ ／２シフトすることができるので、１台の光周波数シフタで、かつＲＦ信号発生器は安価にできるという利点を有する。 Furthermore, in the ninth to twelfth embodiments, by using the single sideband optical modulator of FIG. 12 as an optical frequency shifter and preparing an RF signal generator corresponding to the angular frequency ω s / 2, Since the output optical signal can be shifted by ω s / 2 and the other output optical signal can be shifted by −ω s / 2, the advantage is that the RF signal generator can be made inexpensively with a single optical frequency shifter. Have

第３、第７、第１１の実施例と第４、第８、第１２の実施例を比較すると、光変調器の配置箇所が異なる。以下では、その違いによる用途の差異を述べる。   When the third, seventh, and eleventh embodiments are compared with the fourth, eighth, and twelfth embodiments, the arrangement locations of the optical modulators are different. Below, the difference of the use by the difference is described.

第３、第７、第１１の実施例では、光変調器は、光周波数シフタの後段にあるので、光源から送信される全ての光信号は、同じ変調信号により変調され、全ての波長が同じ信号を伝送する。この場合、光受信器では、伝送されてくるどの波長を選択しても同じ信号を受信できるので、例えば信号光と局発光を混合させて受信するヘテロダイン受信の場合、局発光用の光源は、任意の固定波長光源でよい。一方で、第４、第８、第１２の実施例では、光変調器は、各光源の後段にあるので、光源から送信される光信号はそれぞれ異なる変調信号により変調され、全ての波長が異なる信号を伝送する。この場合、光受信器では、例えば信号光と局発光を混合させて受信するへテロダイン受信の場合、局発光用の光源を選択波長光源とすることにより、所望の波長を選択して受信することができる。   In the third, seventh, and eleventh embodiments, since the optical modulator is located after the optical frequency shifter, all the optical signals transmitted from the light source are modulated by the same modulation signal, and all the wavelengths are the same. Transmit the signal. In this case, the optical receiver can receive the same signal regardless of which wavelength is transmitted.For example, in the case of heterodyne reception in which signal light and local light are mixed and received, the light source for local light is Any fixed wavelength light source may be used. On the other hand, in the fourth, eighth, and twelfth embodiments, since the optical modulator is in the subsequent stage of each light source, the optical signals transmitted from the light sources are modulated by different modulation signals, and all wavelengths are different. Transmit the signal. In this case, in the optical receiver, for example, in the case of heterodyne reception in which signal light and local light are mixed and received, a desired wavelength is selected and received by using a local light source as a selective wavelength light source. Can do.

以上説明したように、本発明は、光送信器に光周波数シフタを備え、光周波数シフタにより、１台の光源で２つの周波数の光信号を周波数多重伝送できるようにすることにより、周波数多重伝送に必要な、周波数の安定した光源の品種数を削減することができる。例えば、図１に示す周波数シフト型高密度光周波数多重伝送システムと図１５に示す従来の光周波数多重伝送システムを比較してみると、光源の種類の合計は、図１５では２であるのに対して図２では１となり、半分となる。   As described above, according to the present invention, the optical transmitter includes the optical frequency shifter, and the optical frequency shifter enables frequency multiplexing transmission of optical signals of two frequencies with one light source. It is possible to reduce the number of types of light sources having a stable frequency that are necessary for the above. For example, comparing the frequency shift type high-density optical frequency multiplex transmission system shown in FIG. 1 with the conventional optical frequency multiplex transmission system shown in FIG. 15, the total number of light sources is 2 in FIG. On the other hand, it becomes 1 in FIG.

第１の実施例の周波数シフト型高密度光周波数多重伝送システムの全体構成図である。1 is an overall configuration diagram of a frequency shift type high-density optical frequency multiplex transmission system according to a first embodiment. 第２の実施例の周波数シフト型高密度光周波数多重伝送システムの全体構成図である。It is a whole block diagram of the frequency shift type high-density optical frequency multiplexing transmission system of a 2nd Example. 第３の実施例の周波数シフト型高密度光周波数多重伝送システムの全体構成図である。It is a whole block diagram of the frequency shift type high-density optical frequency multiplexing transmission system of a 3rd Example. 第４の実施例の周波数シフト型高密度光周波数多重伝送システムの全体構成図である。It is a whole block diagram of the frequency shift type high-density optical frequency multiplexing transmission system of a 4th Example. 第５の実施例の周波数シフト型高密度光周波数多重伝送システムの全体構成図である。It is a whole block diagram of the frequency shift type high-density optical frequency multiplexing transmission system of a 5th Example. 第６の実施例の周波数シフト型高密度光周波数多重伝送システムの全体構成図である。It is a whole block diagram of the frequency shift type high-density optical frequency multiplexing transmission system of a 6th Example. 第７の実施例の周波数シフト型高密度光周波数多重伝送システムの全体構成図である。It is a whole block diagram of the frequency shift type high-density optical frequency multiplexing transmission system of a 7th Example. 第８の実施例の周波数シフト型高密度光周波数多重伝送システムの全体構成図である。It is a whole block diagram of the frequency shift type high-density optical frequency multiplexing transmission system of an 8th Example. 第１〜第８の実施例の周波数シフト型高密度光周波数多重伝送システムにおける光周波数シフタの構成例を示す図である。It is a figure which shows the structural example of the optical frequency shifter in the frequency shift type high-density optical frequency multiplexing transmission system of the 1st-8th Example. 第９の実施例の周波数シフト型高密度光周波数多重伝送システムの全体構成図である。It is a whole block diagram of the frequency shift type high-density optical frequency multiplexing transmission system of a 9th Example. 第１０の実施例の周波数シフト型高密度光周波数多重伝送システムの全体構成図である。It is a whole block diagram of the frequency shift type high-density optical frequency multiplexing transmission system of a 10th Example. 第１１の実施例の周波数シフト型高密度光周波数多重伝送システムの全体構成図である。It is a whole block diagram of the frequency shift type high-density optical frequency multiplexing transmission system of an 11th Example. 第１２の実施例の周波数シフト型高密度光周波数多重伝送システムの全体構成図である。It is a whole block diagram of the frequency shift type high-density optical frequency multiplexing transmission system of the 12th embodiment. 第９〜第１２の実施例の周波数シフト型高密度光周波数多重伝送システムにおける光周波数シフタの構成例を示す図である。It is a figure which shows the structural example of the optical frequency shifter in the frequency shift type high-density optical frequency multiplexing transmission system of the 9th-12th Example. 従来の光周波数多重伝送システムの全体構成図である。It is a whole block diagram of the conventional optical frequency multiplexing transmission system.

符号の説明Explanation of symbols

１０，１１，１２−１〜１２−Ｎ，１３，１４，１５，１６−１〜１６−Ｎ，１７，１８，４５，４６−１〜４６−Ｎ，４７，４８ 光送信器
１０１−１〜１０１−２，１１１，１２１−１〜１２１−Ｎ，１３１−１〜１３１−Ｎ，１４１−１〜１４１−Ｎ，１５１，１６１−１〜１６１−Ｎ，１７１−１〜１７１−Ｎ，１８１−１〜１８１−Ｎ，４５１，４６１−１〜４６１−Ｎ，４７１−１〜４７１−Ｎ，４８１−１〜４８１−Ｎ 光源
４２，４６，７６，１０３，１１２，１１４，１２２−１〜１２２−Ｎ，１２４−１〜１２４−Ｎ，１３２，１３３，１３５，１４２，１４３，１４５，１５２，１５４，１６２−１〜１６２−Ｎ，１６４−１〜１６４−Ｎ，１７２，１７３，１７５，１８２，１８３，１８５，４５４，４６４−１〜４６４−Ｎ，４７２，４７５，４８２，４８５ 光カプラ
１０２−１〜１０２−２，４５３１，４５３２，４６３１−１〜４６３１−Ｎ，４６３２−１〜４６３２−Ｎ，４７４１，４７４２，４８４１，４８４２，１１３１２，１１３２２，１２３１２−１〜１２３１２−Ｎ，１２３２２−１，１２３２２−Ｎ，１３４１２，１３４２２，１４４１２，１４４２２，１５３１２，１５３２２，１６３１２−１〜１６３１２−Ｎ，１６３２２−１〜１６３２２−Ｎ，１７４１２，１７４２２，１８４１２，１８４２２ 偏波制御器
４５２，４６２−１〜４６２−Ｎ，４７３，４８３，１１３２１，１２３２１−１〜１２３２１−Ｎ，１３４２１，１４４２１，１５３１１，１５３２１，１６３１１−１〜１６３１１−Ｎ，１６３２１−１〜１６３２１−Ｎ，１７４１１，１７４２１，１８４１１，１８４２１ 光周波数シフタ
１０４，１１５，１２５−１〜１２５−Ｎ，１３６，１４６−１〜１４６−Ｎ，１５５，１６５−１〜１６５−Ｎ，１７６，１８６−１〜１８６−Ｎ，４５５，４６５−１〜４６５−Ｎ，４７６，４８６−１〜４８６−Ｎ 光変調器
２０，２１，２２，２３，２４，２５，２６，２７，２８，５５，５６，５７，５８ 光ファイバ
３０，３１，３２，３３，３４，３５，３６，３７，３８，６５，６６，６７，６８， 光受信器
１９，４９，１９１，１９２，４９１，４９２ マッハツェンダ回路
１９１１１，１９１２１，１９２１１，１９２２１，４９１１１，４９１２１，４９２１１，４９２２１ ＲＦ電極
１９３，１９１２２，１９２２２，４９１２２，４９２２２ ＤＣ電極
４９３ 方向性結合器
５９−１，５９−２ 出力 10, 11, 12-1 to 12-N, 13, 14, 15, 16-1 to 16-N, 17, 18, 45, 46-1 to 46-N, 47, 48 Optical transmitter 101-1 to 101-2, 111, 121-1 to 121-N, 131-1 to 131-N, 141-1 to 141-N, 151, 161-1 to 161-N, 171-1 to 171-N, 181- 1-181-N, 451, 461-1 to 461-N, 471-1 to 471-N, 481-1 to 481-N Light source 42, 46, 76, 103, 112, 114, 122-1 to 122- N, 124-1 to 124-N, 132, 133, 135, 142, 143, 145, 152, 154, 162-1 to 162-N, 164-1 to 164-N, 172, 173, 175, 182 183, 185, 454, 464-1-4 64-N, 472, 475, 482, 485 Optical couplers 102-1 to 102-2, 4531, 4532, 4631-1 to 4631-N, 4632-1 to 4632-N, 4741, 4742, 4841, 4842, 11312 , 11322, 12312-1 to 12312-N, 12322-1, 12322-N, 13412, 13422, 14412, 14422, 15312, 15322, 16312-1 to 16312-1, 16322-1 to 16322-N, 174112, 17422 , 18412, 18422 Polarization controller 452, 462-1 to 462-N, 473, 483, 11321, 123211-1 to 12321-N, 13421, 14421, 15311, 15321, 16311-1 to 163111-N, 16321 1-1632 1-N, 17411, 17421, 18411, 18421 Optical frequency shifter 104, 115, 125-1 to 125-N, 136, 146-1 to 146-N, 155, 165-1 to 165-N, 176, 186 1-186-N, 455, 465-1 to 465-N, 476, 486-1 to 486-N optical modulators 20, 21, 22, 23, 24, 25, 26, 27, 28, 55, 56, 57, 58 optical fibers 30, 31, 32, 33, 34, 35, 36, 37, 38, 65, 66, 67, 68, optical receivers 19, 49, 191, 192, 491, 492 Mach-Zehnder circuits 19111, 19121 , 19211, 19221, 49111, 49121, 49211, 49221 RF electrode 193, 19122, 19222, 49122, 492 2 DC electrode 493 directional coupler 59-1,59-2 output

Claims (7)

１台の光源と、前記光源に接続された光周波数シフタと、光周波数シフタの一方のポートに接続された第１の偏波制御器と、光周波数シフタの他方のポートに接続された第２の偏波制御器と、第１の偏波制御器および第２の偏波制御器により偏波状態が互いに直交するように制御された前記２つのポートからの光信号を合波する光カプラと、合波した光信号を変調する光変調器からなる光送信器において、
光周波数シフタは、出力側に方向性結合器が配置され、前記方向性結合器の一方の入力に第１のマッハツェンダ回路が接続され、前記方向性結合器の他方の入力に第２のマッハツェンダ回路が接続され、前記第１のマッハツェンダ回路の入力と前記周波数シフタの入力が接続され、前記第２のマッハツェンダ回路の入力と前記周波数シフタの入力が接続され、前記周波数シフタの入力に前記光源が接続され、前記方向性結合器の一方の出力に前記第１の偏波制御器が接続され、前記方向性結合器の他方の出力に前記第２の偏波制御器が接続された構成であり、
前記第１のマッハツェンダ回路は、第１のＲＦ信号電極と各導波路の光位相差を調整する第２のＤＣ電極とが直列に接続され、さらに直列に接続された前記第１のＲＦ信号電極および前記第２のＤＣ電極と、第２のＲＦ信号電極とが並列に接続された構成であり、前記第２のマッハツェンダ回路は、第３のＲＦ信号電極と各導波路の光位相差を調整する第３のＤＣ電極とが直列に接続され、さらに直列に接続された前記第３のＲＦ信号電極および前記第３のＤＣ電極と、第４のＲＦ信号電極とが並列に接続された構成であり、
前記光周波数シフタは、前記第１の偏波制御器に前記光源からの光信号の周波数を低周波シフトさせた光信号を出力し、前記第２の偏波制御器に前記光源からの光信号の周波数を高周波シフトさせた光信号を出力し、１台の光源で２つの周波数の光信号を周波数多重伝送できるようにしたことを特徴とする光送信器。 One light source, an optical frequency shifter connected to the light source, a first polarization controller connected to one port of the optical frequency shifter, and a second connected to the other port of the optical frequency shifter A polarization controller, and an optical coupler for multiplexing the optical signals from the two ports whose polarization states are controlled to be orthogonal to each other by the first polarization controller and the second polarization controller In an optical transmitter comprising an optical modulator that modulates a combined optical signal,
In the optical frequency shifter, a directional coupler is arranged on the output side, a first Mach-Zehnder circuit is connected to one input of the directional coupler, and a second Mach-Zehnder circuit is connected to the other input of the directional coupler. Are connected, the input of the first Mach-Zehnder circuit and the input of the frequency shifter are connected, the input of the second Mach-Zehnder circuit and the input of the frequency shifter are connected, and the light source is connected to the input of the frequency shifter The first polarization controller is connected to one output of the directional coupler, and the second polarization controller is connected to the other output of the directional coupler,
In the first Mach-Zehnder circuit, a first RF signal electrode and a second DC electrode that adjusts an optical phase difference of each waveguide are connected in series, and the first RF signal electrode is further connected in series. And the second DC electrode and the second RF signal electrode are connected in parallel, and the second Mach-Zehnder circuit adjusts the optical phase difference between the third RF signal electrode and each waveguide. The third DC electrode is connected in series, and the third RF signal electrode and the third DC electrode connected in series and the fourth RF signal electrode are connected in parallel. Yes,
The optical frequency shifter outputs an optical signal obtained by shifting the frequency of the optical signal from the light source to the first polarization controller, and the optical signal from the light source to the second polarization controller. An optical transmitter characterized in that an optical signal obtained by shifting the frequency of the signal is output so that optical signals of two frequencies can be frequency-multiplexed with a single light source. １台の光源と、前記光源に接続された光周波数シフタと、光周波数シフタの一方のポートに接続された第１の偏波制御器と、光周波数シフタの他方のポートに接続された第２の偏波制御器と、第１の偏波制御器および第２の偏波制御器により偏波状態が互いに直交するように制御された前記２つのポートからの光信号を合波する光カプラと、合波した光信号を変調する光変調器からなる光送信器と、前記光送信器と光ファイバを介して接続され、前記光送信器からの光信号をコヒーレント光検波する光受信器からなる光周波数多重伝送システムにおいて、
光周波数シフタは、出力側に方向性結合器が配置され、前記方向性結合器の一方の入力に第１のマッハツェンダ回路が接続され、前記方向性結合器の他方の入力に第２のマッハツェンダ回路が接続され、前記第１のマッハツェンダ回路の入力と前記周波数シフタの入力が接続され、前記第２のマッハツェンダ回路の入力と前記周波数シフタの入力が接続され、前記周波数シフタの入力に前記光源が接続され、前記方向性結合器の一方の出力に前記第１の偏波制御器が接続され、前記方向性結合器の他方の出力に前記第２の偏波制御器が接続された構成であり、
前記第１のマッハツェンダ回路は、第１のＲＦ信号電極と各導波路の光位相差を調整する第２のＤＣ電極とが直列に接続され、さらに直列に接続された前記第１のＲＦ信号電極および前記第２のＤＣ電極と、第２のＲＦ信号電極とが並列に接続された構成であり、前記第２のマッハツェンダ回路は、第３のＲＦ信号電極と各導波路の光位相差を調整する第３のＤＣ電極とが直列に接続され、さらに直列に接続された前記第３のＲＦ信号電極および前記第３のＤＣ電極と、第４のＲＦ信号電極とが並列に接続された構成であり、
前記光周波数シフタは、前記第１の偏波制御器に前記光源からの光信号の周波数を低周波シフトさせた光信号を出力し、前記第２の偏波制御器に前記光源からの光信号の周波数を高周波シフトさせた光信号を出力し、１台の光源で２つの周波数の光信号を周波数多重伝送できるようにしたことを特徴とする周波数シフト型高密度光周波数多重伝送システム。 One light source, an optical frequency shifter connected to the light source, a first polarization controller connected to one port of the optical frequency shifter, and a second connected to the other port of the optical frequency shifter A polarization controller, and an optical coupler for multiplexing the optical signals from the two ports whose polarization states are controlled to be orthogonal to each other by the first polarization controller and the second polarization controller An optical transmitter composed of an optical modulator for modulating the combined optical signal, and an optical receiver connected to the optical transmitter via an optical fiber and detecting the optical signal from the optical transmitter coherently. In an optical frequency multiplex transmission system,
In the optical frequency shifter, a directional coupler is arranged on the output side, a first Mach-Zehnder circuit is connected to one input of the directional coupler, and a second Mach-Zehnder circuit is connected to the other input of the directional coupler. Are connected, the input of the first Mach-Zehnder circuit and the input of the frequency shifter are connected, the input of the second Mach-Zehnder circuit and the input of the frequency shifter are connected, and the light source is connected to the input of the frequency shifter The first polarization controller is connected to one output of the directional coupler, and the second polarization controller is connected to the other output of the directional coupler,
In the first Mach-Zehnder circuit, a first RF signal electrode and a second DC electrode that adjusts an optical phase difference of each waveguide are connected in series, and the first RF signal electrode is further connected in series. And the second DC electrode and the second RF signal electrode are connected in parallel, and the second Mach-Zehnder circuit adjusts the optical phase difference between the third RF signal electrode and each waveguide. The third DC electrode is connected in series, and the third RF signal electrode and the third DC electrode connected in series and the fourth RF signal electrode are connected in parallel. Yes,
The optical frequency shifter outputs an optical signal obtained by shifting the frequency of the optical signal from the light source to the first polarization controller, and the optical signal from the light source to the second polarization controller. A frequency-shifted high-density optical frequency multiplex transmission system that outputs an optical signal obtained by shifting the frequency of the optical frequency by two, and enables a single light source to multiplex-transmit an optical signal of two frequencies. １台の光源と、前記光源に接続された光周波数シフタと、光周波数シフタの一方のポートに接続された第１の偏波制御器と、光周波数シフタの他方のポートに接続された第２の偏波制御器と、第１の偏波制御器および第２の偏波制御器により偏波状態が互いに直交するように制御された前記２つのポートからの光信号を合波する第１の光カプラと、合波した光信号を変調する光変調器からなる光送信器Ｎ台と、Ｎ台の各光送信器からの光信号を合波する第２の光カプラと、前記第２の光カプラと光ファイバを介して接続され、前記光送信器からの光信号をコヒーレント光検波する光受信器からなる光周波数多重伝送システムにおいて、
光周波数シフタは、出力側に方向性結合器が配置され、前記方向性結合器の一方の入力に第１のマッハツェンダ回路が接続され、前記方向性結合器の他方の入力に第２のマッハツェンダ回路が接続され、前記第１のマッハツェンダ回路の入力と前記周波数シフタの入力が接続され、前記第２のマッハツェンダ回路の入力と前記周波数シフタの入力が接続され、前記周波数シフタの入力に前記光源が接続され、前記方向性結合器の一方の出力に前記第１の偏波制御器が接続され、前記方向性結合器の他方の出力に前記第２の偏波制御器が接続された構成であり、
前記第１のマッハツェンダ回路は、第１のＲＦ信号電極と各導波路の光位相差を調整する第２のＤＣ電極とが直列に接続され、さらに直列に接続された前記第１のＲＦ信号電極および前記第２のＤＣ電極と、第２のＲＦ信号電極とが並列に接続された構成であり、前記第２のマッハツェンダ回路は、第３のＲＦ信号電極と各導波路の光位相差を調整する第３のＤＣ電極とが直列に接続され、さらに直列に接続された前記第３のＲＦ信号電極および前記第３のＤＣ電極と、第４のＲＦ信号電極とが並列に接続された構成であり、
前記光周波数シフタは、前記第１の偏波制御器に前記光源からの光信号の周波数を低周波シフトさせた光信号を出力し、前記第２の偏波制御器に前記光源からの光信号の周波数を高周波シフトさせた光信号を出力し、１台の光源で２つの周波数の光信号を周波数多重伝送できるようにしたことを特徴とする周波数シフト型高密度光周波数多重伝送システム。 One light source, an optical frequency shifter connected to the light source, a first polarization controller connected to one port of the optical frequency shifter, and a second connected to the other port of the optical frequency shifter The first polarization controller, the first polarization controller, and the second polarization controller to multiplex the optical signals from the two ports whose polarization states are controlled to be orthogonal to each other. An optical coupler, N optical transmitters composed of optical modulators that modulate the combined optical signals, a second optical coupler that combines optical signals from the N optical transmitters, In an optical frequency multiplex transmission system comprising an optical receiver connected via an optical coupler and an optical fiber and detecting a coherent optical signal from the optical transmitter,
In the optical frequency shifter, a directional coupler is arranged on the output side, a first Mach-Zehnder circuit is connected to one input of the directional coupler, and a second Mach-Zehnder circuit is connected to the other input of the directional coupler. Are connected, the input of the first Mach-Zehnder circuit and the input of the frequency shifter are connected, the input of the second Mach-Zehnder circuit and the input of the frequency shifter are connected, and the light source is connected to the input of the frequency shifter The first polarization controller is connected to one output of the directional coupler, and the second polarization controller is connected to the other output of the directional coupler,
In the first Mach-Zehnder circuit, a first RF signal electrode and a second DC electrode that adjusts an optical phase difference of each waveguide are connected in series, and the first RF signal electrode is further connected in series. And the second DC electrode and the second RF signal electrode are connected in parallel, and the second Mach-Zehnder circuit adjusts the optical phase difference between the third RF signal electrode and each waveguide. The third DC electrode is connected in series, and the third RF signal electrode and the third DC electrode connected in series and the fourth RF signal electrode are connected in parallel. Yes,
The optical frequency shifter outputs an optical signal obtained by shifting the frequency of the optical signal from the light source to the first polarization controller, and the optical signal from the light source to the second polarization controller. A frequency-shifted high-density optical frequency multiplex transmission system that outputs an optical signal obtained by shifting the frequency of the optical frequency by two, and enables a single light source to multiplex-transmit an optical signal of two frequencies. それぞれ周波数の異なるＮ台の光源と、前記Ｎ台の光源からの光信号を合波する第１の光カプラと、第１の光カプラに接続された光周波数シフタと、光周波数シフタの一方のポートに接続された第１の偏波制御器と、光周波数シフタの他方のポートに接続された第２の偏波制御器と、第１の偏波制御器および第２の偏波制御器により偏波状態が互いに直交するように制御された前記２つのポートからの光信号を合波する第２の光カプラと、合波した光信号を変調する光変調器からなる光送信器において、
光周波数シフタは、出力側に方向性結合器が配置され、前記方向性結合器の一方の入力に第１のマッハツェンダ回路が接続され、前記方向性結合器の他方の入力に第２のマッハツェンダ回路が接続され、前記第１のマッハツェンダ回路の入力と前記周波数シフタの入力が接続され、前記第２のマッハツェンダ回路の入力と前記周波数シフタの入力が接続され、前記周波数シフタの入力に前記光源が接続され、前記方向性結合器の一方の出力に前記第１の偏波制御器が接続され、前記方向性結合器の他方の出力に前記第２の偏波制御器が接続された構成であり、
前記第１のマッハツェンダ回路は、第１のＲＦ信号電極と各導波路の光位相差を調整する第２のＤＣ電極とが直列に接続され、さらに直列に接続された前記第１のＲＦ信号電極および前記第２のＤＣ電極と、第２のＲＦ信号電極とが並列に接続された構成であり、前記第２のマッハツェンダ回路は、第３のＲＦ信号電極と各導波路の光位相差を調整する第３のＤＣ電極とが直列に接続され、さらに直列に接続された前記第３のＲＦ信号電極および前記第３のＤＣ電極と、第４のＲＦ信号電極とが並列に接続された構成であり、
前記光周波数シフタは、前記第１の偏波制御器に前記Ｎ台の光源からの光信号の周波数を一括で低周波シフトさせた光信号を出力し、前記第２の偏波制御器に前記Ｎ台の光源からの光信号の周波数を一括で高周波シフトさせた光信号を出力し、Ｎ台の光源で２Ｎの周波数の光信号を周波数多重伝送できるようにしたことを特徴とする光送信器。 One of N light sources having different frequencies, a first optical coupler for multiplexing optical signals from the N light sources, an optical frequency shifter connected to the first optical coupler, and one of the optical frequency shifters A first polarization controller connected to the port; a second polarization controller connected to the other port of the optical frequency shifter; and the first polarization controller and the second polarization controller. In an optical transmitter comprising a second optical coupler for combining optical signals from the two ports controlled so that their polarization states are orthogonal to each other, and an optical modulator for modulating the combined optical signal,
In the optical frequency shifter, a directional coupler is arranged on the output side, a first Mach-Zehnder circuit is connected to one input of the directional coupler, and a second Mach-Zehnder circuit is connected to the other input of the directional coupler. Are connected, the input of the first Mach-Zehnder circuit and the input of the frequency shifter are connected, the input of the second Mach-Zehnder circuit and the input of the frequency shifter are connected, and the light source is connected to the input of the frequency shifter The first polarization controller is connected to one output of the directional coupler, and the second polarization controller is connected to the other output of the directional coupler,
In the first Mach-Zehnder circuit, a first RF signal electrode and a second DC electrode that adjusts an optical phase difference of each waveguide are connected in series, and the first RF signal electrode is further connected in series. And the second DC electrode and the second RF signal electrode are connected in parallel, and the second Mach-Zehnder circuit adjusts the optical phase difference between the third RF signal electrode and each waveguide. The third DC electrode is connected in series, and the third RF signal electrode and the third DC electrode connected in series and the fourth RF signal electrode are connected in parallel. Yes,
The optical frequency shifter outputs an optical signal obtained by shifting the frequency of optical signals from the N light sources collectively to the first polarization controller, and outputs the optical signal to the second polarization controller. An optical transmitter characterized in that an optical signal obtained by shifting the frequency of optical signals from N light sources at once is output in a lump so that an optical signal having a frequency of 2N can be frequency-multiplexed by the N light sources. . それぞれ周波数の異なるＮ台の光源と、前記Ｎ台の光源からの光信号を合波する第１の光カプラと、第１の光カプラに接続された光周波数シフタと、光周波数シフタの一方のポートに接続された第１の偏波制御器と、光周波数シフタの他方のポートに接続された第２の偏波制御器と、第１の偏波制御器および第２の偏波制御器により偏波状態が互いに直交するように制御された前記２つのポートからの光信号を合波する第２の光カプラと、合波した光信号を変調する光変調器からなる光送信器と、前記光送信器と光ファイバを介して接続され、前記光送信器からの光信号をコヒーレント光検波する光受信器からなる光周波数多重伝送システムにおいて、
光周波数シフタは、出力側に方向性結合器が配置され、前記方向性結合器の一方の入力に第１のマッハツェンダ回路が接続され、前記方向性結合器の他方の入力に第２のマッハツェンダ回路が接続され、前記第１のマッハツェンダ回路の入力と前記周波数シフタの入力が接続され、前記第２のマッハツェンダ回路の入力と前記周波数シフタの入力が接続され、前記周波数シフタの入力に前記光源が接続され、前記方向性結合器の一方の出力に前記第１の偏波制御器が接続され、前記方向性結合器の他方の出力に前記第２の偏波制御器が接続された構成であり、
前記第１のマッハツェンダ回路は、第１のＲＦ信号電極と各導波路の光位相差を調整する第２のＤＣ電極とが直列に接続され、さらに直列に接続された前記第１のＲＦ信号電極および前記第２のＤＣ電極と、第２のＲＦ信号電極とが並列に接続された構成であり、前記第２のマッハツェンダ回路は、第３のＲＦ信号電極と各導波路の光位相差を調整する第３のＤＣ電極とが直列に接続され、さらに直列に接続された前記第３のＲＦ信号電極および前記第３のＤＣ電極と、第４のＲＦ信号電極とが並列に接続された構成であり、
前記光周波数シフタは、前記第１の偏波制御器に前記Ｎ台の光源からの光信号の周波数を一括で低周波シフトさせた光信号を出力し、前記第２の偏波制御器に前記Ｎ台の光源からの光信号の周波数を一括で高周波シフトさせた光信号を出力し、Ｎ台の光源で２Ｎの周波数の光信号を周波数多重伝送できるようにしたことを特徴とする周波数シフト型高密度光周波数多重伝送システム。 One of N light sources having different frequencies, a first optical coupler for multiplexing optical signals from the N light sources, an optical frequency shifter connected to the first optical coupler, and one of the optical frequency shifters A first polarization controller connected to the port; a second polarization controller connected to the other port of the optical frequency shifter; and the first polarization controller and the second polarization controller. A second optical coupler that combines the optical signals from the two ports whose polarization states are controlled to be orthogonal to each other; an optical transmitter that includes an optical modulator that modulates the combined optical signal; and In an optical frequency multiplex transmission system comprising an optical receiver connected to an optical transmitter via an optical fiber and detecting an optical signal from the optical transmitter coherently,
In the optical frequency shifter, a directional coupler is arranged on the output side, a first Mach-Zehnder circuit is connected to one input of the directional coupler, and a second Mach-Zehnder circuit is connected to the other input of the directional coupler. Are connected, the input of the first Mach-Zehnder circuit and the input of the frequency shifter are connected, the input of the second Mach-Zehnder circuit and the input of the frequency shifter are connected, and the light source is connected to the input of the frequency shifter The first polarization controller is connected to one output of the directional coupler, and the second polarization controller is connected to the other output of the directional coupler,
In the first Mach-Zehnder circuit, a first RF signal electrode and a second DC electrode that adjusts an optical phase difference of each waveguide are connected in series, and the first RF signal electrode is further connected in series. And the second DC electrode and the second RF signal electrode are connected in parallel, and the second Mach-Zehnder circuit adjusts the optical phase difference between the third RF signal electrode and each waveguide. The third DC electrode is connected in series, and the third RF signal electrode and the third DC electrode connected in series and the fourth RF signal electrode are connected in parallel. Yes,
The optical frequency shifter outputs an optical signal obtained by shifting the frequency of optical signals from the N light sources collectively to the first polarization controller, and outputs the optical signal to the second polarization controller. A frequency shift type characterized in that optical signals obtained by shifting the frequency of optical signals from N light sources at once are output in a lump so that optical signals having a frequency of 2N can be frequency-multiplexed with the N light sources. High density optical frequency multiplex transmission system. それぞれ周波数の異なるＮ台の光源と、それぞれの光源に接続されたＮ台の光変調器と、前記Ｎ台の光変調器からの光信号を合波する第１の光カプラと、第１の光カプラに接続された光周波数シフタと、光周波数シフタの一方のポートに接続された第１の偏波制御器と、光周波数シフタの他方のポートに接続された第２の偏波制御器と、第１の偏波制御器および第２の偏波制御器により偏波状態が互いに直交するように制御された前記２つのポートからの光信号を合波する第２の光カプラからなる光送信器において、
光周波数シフタは、出力側に方向性結合器が配置され、前記方向性結合器の一方の入力に第１のマッハツェンダ回路が接続され、前記方向性結合器の他方の入力に第２のマッハツェンダ回路が接続され、前記第１のマッハツェンダ回路の入力と前記周波数シフタの入力が接続され、前記第２のマッハツェンダ回路の入力と前記周波数シフタの入力が接続され、前記周波数シフタの入力に前記光源が接続され、前記方向性結合器の一方の出力に前記第１の偏波制御器が接続され、前記方向性結合器の他方の出力に前記第２の偏波制御器が接続された構成であり、
前記第１のマッハツェンダ回路は、第１のＲＦ信号電極と各導波路の光位相差を調整する第２のＤＣ電極とが直列に接続され、さらに直列に接続された前記第１のＲＦ信号電極および前記第２のＤＣ電極と、第２のＲＦ信号電極とが並列に接続された構成であり、前記第２のマッハツェンダ回路は、第３のＲＦ信号電極と各導波路の光位相差を調整する第３のＤＣ電極とが直列に接続され、さらに直列に接続された前記第３のＲＦ信号電極および前記第３のＤＣ電極と、第４のＲＦ信号電極とが並列に接続された構成であり、
前記光周波数シフタは、前記第１の偏波制御器に前記Ｎ台の光源からの光信号の周波数を一括で低周波シフトさせた光信号を出力し、前記第２の偏波制御器に前記Ｎ台の光源からの光信号の周波数を一括で高周波シフトさせた光信号を出力し、Ｎ台の光源で２Ｎの周波数の光信号を周波数多重伝送できるようにしたことを特徴とする光送信器。 N light sources having different frequencies, N optical modulators connected to the respective light sources, a first optical coupler for multiplexing optical signals from the N optical modulators, An optical frequency shifter connected to the optical coupler, a first polarization controller connected to one port of the optical frequency shifter, and a second polarization controller connected to the other port of the optical frequency shifter; , An optical transmission comprising a second optical coupler for multiplexing optical signals from the two ports whose polarization states are controlled to be orthogonal to each other by the first polarization controller and the second polarization controller In the vessel
In the optical frequency shifter, a directional coupler is arranged on the output side, a first Mach-Zehnder circuit is connected to one input of the directional coupler, and a second Mach-Zehnder circuit is connected to the other input of the directional coupler. Are connected, the input of the first Mach-Zehnder circuit and the input of the frequency shifter are connected, the input of the second Mach-Zehnder circuit and the input of the frequency shifter are connected, and the light source is connected to the input of the frequency shifter The first polarization controller is connected to one output of the directional coupler, and the second polarization controller is connected to the other output of the directional coupler,
In the first Mach-Zehnder circuit, a first RF signal electrode and a second DC electrode that adjusts an optical phase difference of each waveguide are connected in series, and the first RF signal electrode is further connected in series. And the second DC electrode and the second RF signal electrode are connected in parallel, and the second Mach-Zehnder circuit adjusts the optical phase difference between the third RF signal electrode and each waveguide. The third DC electrode is connected in series, and the third RF signal electrode and the third DC electrode connected in series and the fourth RF signal electrode are connected in parallel. Yes,
The optical frequency shifter outputs an optical signal obtained by shifting the frequency of optical signals from the N light sources collectively to the first polarization controller, and outputs the optical signal to the second polarization controller. An optical transmitter characterized in that an optical signal obtained by shifting the frequency of optical signals from N light sources at once is output in a lump so that an optical signal having a frequency of 2N can be frequency-multiplexed by the N light sources. . それぞれ周波数の異なるＮ台の光源と、それぞれの光源に接続されたＮ台の光変調器と、前記Ｎ台の光変調器からの光信号を合波する第１の光カプラと、第１の光カプラに接続された光周波数シフタと、光周波数シフタの一方のポートに接続された第１の偏波制御器と、光周波数シフタの他方のポートに接続された第２の偏波制御器と、第１の偏波制御器および第２の偏波制御器により偏波状態が互いに直交するように制御された前記２つのポートからの光信号を合波する第２の光カプラからなる光送信器と、前記光送信器と光ファイバを介して接続され、前記光送信器からの光信号をコヒーレント光検波する光受信器からなる光周波数多重伝送システムにおいて、
光周波数シフタは、出力側に方向性結合器が配置され、前記方向性結合器の一方の入力に第１のマッハツェンダ回路が接続され、前記方向性結合器の他方の入力に第２のマッハツェンダ回路が接続され、前記第１のマッハツェンダ回路の入力と前記周波数シフタの入力が接続され、前記第２のマッハツェンダ回路の入力と前記周波数シフタの入力が接続され、前記周波数シフタの入力に前記光源が接続され、前記方向性結合器の一方の出力に前記第１の偏波制御器が接続され、前記方向性結合器の他方の出力に前記第２の偏波制御器が接続された構成であり、
前記第１のマッハツェンダ回路は、第１のＲＦ信号電極と各導波路の光位相差を調整する第２のＤＣ電極とが直列に接続され、さらに直列に接続された前記第１のＲＦ信号電極および前記第２のＤＣ電極と、第２のＲＦ信号電極とが並列に接続された構成であり、前記第２のマッハツェンダ回路は、第３のＲＦ信号電極と各導波路の光位相差を調整する第３のＤＣ電極とが直列に接続され、さらに直列に接続された前記第３のＲＦ信号電極および前記第３のＤＣ電極と、第４のＲＦ信号電極とが並列に接続された構成であり、
前記光周波数シフタは、前記第１の偏波制御器に前記Ｎ台の光源からの光信号の周波数を一括で低周波シフトさせた光信号を出力し、前記第２の偏波制御器に前記Ｎ台の光源からの光信号の周波数を一括で高周波シフトさせた光信号を出力し、Ｎ台の光源で２Ｎの周波数の光信号を周波数多重伝送できるようにしたことを特徴とする周波数シフト型高密度光周波数多重伝送システム。 N light sources having different frequencies, N optical modulators connected to the respective light sources, a first optical coupler for multiplexing optical signals from the N optical modulators, An optical frequency shifter connected to the optical coupler, a first polarization controller connected to one port of the optical frequency shifter, and a second polarization controller connected to the other port of the optical frequency shifter; , An optical transmission comprising a second optical coupler for multiplexing optical signals from the two ports whose polarization states are controlled to be orthogonal to each other by the first polarization controller and the second polarization controller And an optical frequency multiplex transmission system comprising an optical receiver connected to the optical transmitter via an optical fiber and coherently detecting an optical signal from the optical transmitter,
In the optical frequency shifter, a directional coupler is arranged on the output side, a first Mach-Zehnder circuit is connected to one input of the directional coupler, and a second Mach-Zehnder circuit is connected to the other input of the directional coupler. Are connected, the input of the first Mach-Zehnder circuit and the input of the frequency shifter are connected, the input of the second Mach-Zehnder circuit and the input of the frequency shifter are connected, and the light source is connected to the input of the frequency shifter The first polarization controller is connected to one output of the directional coupler, and the second polarization controller is connected to the other output of the directional coupler,
In the first Mach-Zehnder circuit, a first RF signal electrode and a second DC electrode that adjusts an optical phase difference of each waveguide are connected in series, and the first RF signal electrode is further connected in series. And the second DC electrode and the second RF signal electrode are connected in parallel, and the second Mach-Zehnder circuit adjusts the optical phase difference between the third RF signal electrode and each waveguide. The third DC electrode is connected in series, and the third RF signal electrode and the third DC electrode connected in series and the fourth RF signal electrode are connected in parallel. Yes,
The optical frequency shifter outputs an optical signal obtained by shifting the frequency of optical signals from the N light sources collectively to the first polarization controller, and outputs the optical signal to the second polarization controller. A frequency shift type characterized in that optical signals obtained by shifting the frequency of optical signals from N light sources at once are output in a lump so that optical signals having a frequency of 2N can be frequency-multiplexed with the N light sources. High density optical frequency multiplex transmission system.
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