JP2797834B2 - Optical wavelength division multiplexing system - Google Patents
Optical wavelength division multiplexing systemInfo
- Publication number
- JP2797834B2 JP2797834B2 JP4126963A JP12696392A JP2797834B2 JP 2797834 B2 JP2797834 B2 JP 2797834B2 JP 4126963 A JP4126963 A JP 4126963A JP 12696392 A JP12696392 A JP 12696392A JP 2797834 B2 JP2797834 B2 JP 2797834B2
- Authority
- JP
- Japan
- Prior art keywords
- optical
- output
- signal
- amplitude
- sine wave
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Landscapes
- Lasers (AREA)
- Optical Communication System (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、光通信分野における光
波長分割多重システムに関し、特に光ファイバ増幅器を
用いた光波長分割多重システムに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical wavelength division multiplex system in the field of optical communication, and more particularly to an optical wavelength division multiplex system using an optical fiber amplifier.
【０００２】[0002]
【従来の技術】従来の光波長分割多重システムについて
図面を参照して説明する。2. Description of the Related Art A conventional optical wavelength division multiplexing system will be described with reference to the drawings.
【０００３】図３は従来の光波長分割多重システムの一
例を示すブロック図である。FIG. 3 is a block diagram showing an example of a conventional optical wavelength division multiplexing system.
【０００４】図３において、従来の光波長分割多重シス
テムにおいては、入力の二つの電気信号をそれぞれ波長
の異なる２種類の光信号に変換する光送信盤１，２と、
この光送信盤１，２のそれぞれの光出力を合成する光合
波器３と、この光合波器３で合成された光信号を増幅す
る光ファイバ増幅器４とを有する構成であり、さらに、
光ファイバ増幅器４の出力の一部を光分波器５で分配
し、フォトダイオード６で光出力パワー平均値の監視を
行い、オペアンプ１４による負帰還回路により光ファイ
バ増幅器４の出力の安定化をはかっている。In FIG. 3, in a conventional optical wavelength division multiplexing system, optical transmitters 1 and 2 for converting two input electric signals into two types of optical signals having different wavelengths, respectively;
An optical multiplexer 3 for combining the optical outputs of the optical transmitters 1 and 2 and an optical fiber amplifier 4 for amplifying the optical signal combined by the optical multiplexer 3 are further provided.
A part of the output of the optical fiber amplifier 4 is distributed by the optical splitter 5, the average output power of the optical fiber is monitored by the photodiode 6, and the output of the optical fiber amplifier 4 is stabilized by the negative feedback circuit of the operational amplifier 14. I am wearing it.
【０００５】[0005]
【発明が解決しようとする課題】この従来の光波長分割
多重システムは、図３に示すように、２波の内の一方の
光送信盤の光出力が何かの要因により、低下した場合
や、光ファイバ増幅器の利得に波長感度が存在する場合
に、光ファイバ増幅器の出力を一定に保たれるものの、
それぞれの波長で考えると、光送信盤の低下に相当する
分、又は光ファイバ増幅器の波長感度分だけ低下してし
まうという問題があった。As shown in FIG. 3, this conventional optical wavelength division multiplexing system is used when the optical output of one of the two optical transmitters is reduced due to some factor. However, if the gain of the optical fiber amplifier has wavelength sensitivity, the output of the optical fiber amplifier is kept constant,
Considering each wavelength, there is a problem that the wavelength is reduced by the amount corresponding to the reduction of the optical transmission board or the wavelength sensitivity of the optical fiber amplifier.
【０００６】[0006]
【課題を解決するための手段】本発明の光波長分配多重
システムは、電気信号を入力とし、それぞれ波長の異な
るデジタル光信号の振幅に対し、それぞれ固有の低周波
の正弦波を一定の変調度で振幅変調して出力する複数の
光送信盤と、前記光送信盤のそれぞれの光出力信号を合
波する光合波器と、前記合波器の出力を増幅する光ファ
イバ増幅器と、前記光ファイバ増幅器の出力で伝送路へ
出力される光信号の一部を分波する光分波器と、前記光
分波器により分波された光信号を出力電気信号に変換す
るフォトダイオードと、前記フォトダイオードの前記出
力電気信号から前記デジタル光信号に重畳されている前
記低周波の正弦波を抽出する複数のフィルタと、前記複
数のフィルタの各出力正弦波を振幅に応じた直流電圧に
変換するピーク値検出回路と、前記ピーク値検出回路の
出力電流電圧を基準電圧と比較してこの電圧差が最小と
なるように前記複数の光送信盤を制御する負帰還回路と
を有している。SUMMARY OF THE INVENTION An optical wavelength division multiplexing system according to the present invention receives an electric signal as an input, and modulates a specific low frequency sine wave at a constant modulation degree with respect to the amplitude of a digital optical signal having a different wavelength. A plurality of optical transmitters that output by amplitude-modulating the optical transmitter, an optical multiplexer that multiplexes the respective optical output signals of the optical transmitter, an optical fiber amplifier that amplifies the output of the multiplexer, and the optical fiber An optical demultiplexer for demultiplexing a part of the optical signal output to the transmission line at the output of the amplifier, a photodiode for converting the optical signal demultiplexed by the optical demultiplexer into an output electric signal, A plurality of filters for extracting the low-frequency sine wave superimposed on the digital optical signal from the output electric signal of the diode; and a peak for converting each output sine wave of the plurality of filters into a DC voltage corresponding to an amplitude. value A circuit output, and a negative feedback circuit for the voltage difference is compared with a reference voltage the output current voltage of the peak value detecting circuit controls the plurality of light transmitting plate so as to minimize.
【０００７】[0007]
【実施例】次に、本発明について図面を参照して説明す
る。Next, the present invention will be described with reference to the drawings.
【０００８】図１は本発明の一実施例を示すブロック
図、図２は本実施例における光送信盤の光出力信号波形
を示し（ａ）は光送信盤１の光出力波形の一例を示す
図、（ｂ）は光送信盤２の光出力信号波形の一例を示す
図である。FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 shows an optical output signal waveform of an optical transmission board in this embodiment. FIG. 3B is a diagram illustrating an example of an optical output signal waveform of the optical transmission board 2.
【０００９】図１において、本実施例は電気信号を入力
とし、それぞれ波長の異なるディタル光信号の振幅に対
し、それぞれ固有の低周波の正弦波を一定の変調度で振
幅変調して出力する光送信盤１，２と、光送信盤１，２
それぞれの光出力信号を合波する光合波器３と、合波器
３の出力を増幅する光ファイバ増幅器４と、光ファイバ
増幅器４の出力で、伝送路へ出力される光信号の一部を
分波する光分波器５と、光分波器５により分波された光
信号を出力電気信号に変換するフォトダイオード６と、
フォトダイオード６の出力電気信号からデジタル光信号
に重畳されている低周波の正弦波を抽出するバンドパス
フィルタ８，９と、バンドパスフィルタ８，９の各出力
正弦波を振幅に応じた直流電圧に変換するピーク値検出
回路１０，１１と、ピーク値検出回路１０，１１の出力
電流電圧を基準電圧と比較してこの電圧差が最小となる
ように光送信盤１，２を制御するオペアンプ１２，１３
と、フォトダイオード６の出力電気信号を光ファイバ増
幅器４へ負帰還するオペアンプ１４とを有して構成して
いる。In FIG. 1, in this embodiment, an electric signal is input, and a specific sine wave of a low frequency is amplitude-modulated at a constant modulation degree with respect to the amplitude of a digital optical signal having a different wavelength. Transmitters 1 and 2 and optical transmitters 1 and 2
An optical multiplexer 3 for multiplexing the respective optical output signals, an optical fiber amplifier 4 for amplifying the output of the multiplexer 3, and a part of the optical signal output to the transmission line by the output of the optical fiber amplifier 4 An optical demultiplexer 5 for demultiplexing, a photodiode 6 for converting an optical signal demultiplexed by the optical demultiplexer 5 into an output electric signal,
Band-pass filters 8 and 9 for extracting low-frequency sine waves superimposed on a digital optical signal from an output electric signal of the photodiode 6, and a DC voltage corresponding to the amplitude of each output sine wave of the band-pass filters 8 and 9. And an operational amplifier 12 that compares the output current voltage of the peak value detection circuits 10 and 11 with a reference voltage and controls the optical transmitters 1 and 2 so that this voltage difference is minimized. , 13
And an operational amplifier 14 for negatively feeding back the output electric signal of the photodiode 6 to the optical fiber amplifier 4.
【００１０】次に、本実施例の動作について、図１，図
２を併用して説明する。Next, the operation of this embodiment will be described with reference to FIGS.
【００１１】光送信盤１，２から出力される光信号に
は、光信号振幅に対し、ある一定の割り合にて低周波数
の正弦波が重畳されており（出力波形の一例を図２の
（ａ），（ｂ）に示す）、また外部からの制御信号によ
り、出力光振幅を任意に可変できる。A low frequency sine wave is superimposed on the optical signals output from the optical transmitters 1 and 2 at a certain ratio with respect to the amplitude of the optical signal (an example of an output waveform is shown in FIG. 2). (Shown in (a) and (b)) and the amplitude of the output light can be arbitrarily varied by an external control signal.
【００１２】さらに、重畳される正弦波の周波数は、光
送信盤１，２にて異なりそれぞれｆ1 ，ｆ2 とする。Further, the frequency of the sine wave to be superimposed differs between the optical transmitters 1 and 2 and is f 1 and f 2 , respectively.
【００１３】光送信盤１，２からのそれぞれの出力は光
合波器３にて合波され、光ファイバ増幅器４により一括
して増幅される。The outputs from the optical transmitters 1 and 2 are multiplexed by an optical multiplexer 3 and are collectively amplified by an optical fiber amplifier 4.
【００１４】光ファイバ増幅器４から、出力された光信
号は光分波器５を介し、伝送路へ出力される。光分波器
５では一部が分配され、さらに、フォトダイオード６に
入力される。The optical signal output from the optical fiber amplifier 4 is output to the transmission line via the optical splitter 5. In the optical demultiplexer 5, a part is distributed and further input to the photodiode 6.
【００１５】フォトダイオード６により光信号は電気信
号に変換されて三分配される。三分配されたうちの１つ
の信号は光ファイバ増幅器４から出力された光信号の平
均値が一定になるように、光ファイバ増幅器４へオペア
ンプ１４を介し負帰還される。The light signal is converted into an electric signal by the photodiode 6 and is divided into three. One of the three signals is negatively fed back to the optical fiber amplifier 4 via the operational amplifier 14 so that the average value of the optical signal output from the optical fiber amplifier 4 becomes constant.
【００１６】三分配されたうちの残りの２つの信号は、
それぞれｆ1 ，ｆ2 のバンドパスフィルタ８，９に入力
され、正弦波に変換される。変換された正弦波ｆ1 ，ｆ
2 はそれぞれピーク値検出回路１０，１１に入力され、
ピーク値に応じた直流信号に変換され、オペアンプ１
２，１３を介し、光送信盤１，２の出力レベルを制御す
るよう負帰還される。The remaining two signals of the three distributions are:
The signals are input to bandpass filters 8 and 9 of f 1 and f 2 , respectively, and are converted into sine waves. Converted sine waves f 1 , f
2 are input to the peak value detection circuits 10 and 11, respectively.
It is converted into a DC signal corresponding to the peak value, and the operational amplifier 1
Negative feedback is provided to control the output levels of the optical transmitters 1 and 2 via the optical transmitters 2 and 13.
【００１７】[0017]
【発明の効果】以上説明したように本発明は、複数の送
信盤から出力されるそれぞれの光信号に、光信号の振幅
に対し、ある一定の割り合で低周波正弦波を重畳し、こ
の重畳される正弦波の周波数を光送信盤ごとに別々の周
波数を用い、光ファイバ増幅器の出力の一部をモニタす
る際に、重畳される正弦波のピーク値を監視することに
より、ある一つの波長の信号成分が、低下した場合にお
いても負帰還をほどこすことにより光送信レベルの安定
化をはかることができる効果がある。As described above, according to the present invention, a low-frequency sine wave is superimposed on each optical signal output from a plurality of transmitters at a certain ratio with respect to the amplitude of the optical signal. By monitoring the peak value of the superimposed sine wave when monitoring a part of the output of the optical fiber amplifier by using the frequency of the superimposed sine wave at a different frequency for each optical transmission board, one certain Even if the signal component of the wavelength is reduced, there is an effect that the optical transmission level can be stabilized by applying negative feedback.
【図面の簡単な説明】[Brief description of the drawings]
【図１】本発明の一実施例を示すブロック図である。FIG. 1 is a block diagram showing one embodiment of the present invention.
【図２】本実施例における光送信盤の光出力信号波形を
示し、（ａ）は光送信盤１の光出力信号波形の一例を示
す図、（ｂ）は光送信盤２の光出力信号波形の一例を示
す図である。2A and 2B show an optical output signal waveform of an optical transmission board in the present embodiment, FIG. 2A shows an example of an optical output signal waveform of an optical transmission board 1, and FIG. It is a figure showing an example of a waveform.
【図３】従来の光波形分割多重システムの一例を示すブ
ロック図である。FIG. 3 is a block diagram showing an example of a conventional optical waveform division multiplexing system.
１，２ 光送信盤 ３ 光合波器 ４ 光ファイバ増幅器 ５ 光分波器 ６ フォトダイオード ７ 抵抗器 ８，９ バンドパスフィルタ １０，１１ ピーク値検出回路 １２，１３，１４ オペアンプ 1, 2 optical transmitter 3 optical multiplexer 4 optical fiber amplifier 5 optical demultiplexer 6 photodiode 7 resistor 8, 9 bandpass filter 10, 11 peak value detection circuit 12, 13, 14 operational amplifier
Claims (1)
なるデジタル光信号の振幅に対し、それぞれ固有の低周
波の正弦波を一定の変調度で振幅変調して出力する複数
の光送信盤と、前記光送信盤のそれぞれの光出力信号を
合波する光合波器と、前記合波器の出力を増幅する光フ
ァイバ増幅器と、前記光ファイバ増幅器の出力で伝送路
へ出力される光信号の一部を分波する光分波器と、前記
光分波器により分波された光信号を出力電気信号に変換
するフォトダイオードと、前記フォトダイオードの前記
出力電気信号から前記デジタル光信号に重畳されている
前記低周波の正弦波を抽出する複数のフィルタと、前記
複数のフィルタの各出力正弦波を振幅に応じた直流電圧
に変換するピーク値検出回路と、前記ピーク値検出回路
の出力電流電圧を基準電圧と比較してこの電圧差が最小
となるように前記複数の光送信盤を制御する負帰還回路
とを有することを特徴とする光波長分割多重システム。1. A plurality of optical transmission boards which receive an electric signal as input, and amplitude-modulate a unique low-frequency sine wave with a constant modulation degree for the amplitude of a digital optical signal having a different wavelength, and output the same. An optical multiplexer for multiplexing the respective optical output signals of the optical transmitter, an optical fiber amplifier for amplifying the output of the multiplexer, and an optical signal output to the transmission line at the output of the optical fiber amplifier. An optical demultiplexer for demultiplexing a portion, a photodiode for converting an optical signal demultiplexed by the optical demultiplexer into an output electric signal, and the output electric signal of the photodiode superimposed on the digital optical signal. A plurality of filters for extracting the low frequency sine wave, a peak value detection circuit for converting each output sine wave of the plurality of filters into a DC voltage corresponding to an amplitude, and an output current voltage of the peak value detection circuit Based on An optical wavelength division multiplexing system comprising: a negative feedback circuit that controls the plurality of optical transmitters so that the voltage difference is minimized as compared with a reference voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4126963A JP2797834B2 (en) | 1992-05-20 | 1992-05-20 | Optical wavelength division multiplexing system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4126963A JP2797834B2 (en) | 1992-05-20 | 1992-05-20 | Optical wavelength division multiplexing system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05327663A JPH05327663A (en) | 1993-12-10 |
| JP2797834B2 true JP2797834B2 (en) | 1998-09-17 |
Family
ID=14948233
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4126963A Expired - Lifetime JP2797834B2 (en) | 1992-05-20 | 1992-05-20 | Optical wavelength division multiplexing system |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2797834B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2976874B2 (en) * | 1996-03-08 | 1999-11-10 | 日本電気株式会社 | Optical receiver |
| JP3006519B2 (en) * | 1996-11-22 | 2000-02-07 | 日本電気株式会社 | Optical communication system |
| JP2011217165A (en) * | 2010-03-31 | 2011-10-27 | Opnext Japan Inc | Optical transmitter, optical transmission component and method for controlling optical transmitter |
-
1992
- 1992-05-20 JP JP4126963A patent/JP2797834B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH05327663A (en) | 1993-12-10 |
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Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 19980602 |