JPH02291505A - Light signal distribution system - Google Patents
Light signal distribution systemInfo
- Publication number
- JPH02291505A JPH02291505A JP1111819A JP11181989A JPH02291505A JP H02291505 A JPH02291505 A JP H02291505A JP 1111819 A JP1111819 A JP 1111819A JP 11181989 A JP11181989 A JP 11181989A JP H02291505 A JPH02291505 A JP H02291505A
- Authority
- JP
- Japan
- Prior art keywords
- optical
- optical fiber
- optical signal
- light signal
- light
- 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.)
- Pending
Links
- 238000009826 distribution Methods 0.000 title claims abstract description 20
- 230000003287 optical effect Effects 0.000 claims abstract description 152
- 239000013307 optical fiber Substances 0.000 claims abstract description 98
- 230000010287 polarization Effects 0.000 claims abstract description 16
- 230000000644 propagated effect Effects 0.000 claims abstract description 16
- 229910052761 rare earth metal Inorganic materials 0.000 claims abstract description 15
- 230000001902 propagating effect Effects 0.000 claims abstract description 7
- 230000005284 excitation Effects 0.000 claims description 18
- 150000002910 rare earth metals Chemical class 0.000 claims description 11
- 238000000034 method Methods 0.000 claims description 2
- 230000001419 dependent effect Effects 0.000 claims 2
- 230000005540 biological transmission Effects 0.000 abstract description 22
- 238000005086 pumping Methods 0.000 description 18
- 238000010586 diagram Methods 0.000 description 5
- 239000004065 semiconductor Substances 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 230000005281 excited state Effects 0.000 description 4
- 230000003321 amplification Effects 0.000 description 3
- 238000003199 nucleic acid amplification method Methods 0.000 description 3
- 239000006185 dispersion Substances 0.000 description 2
- 230000010355 oscillation Effects 0.000 description 2
- 229910052691 Erbium Inorganic materials 0.000 description 1
- 235000018747 Typha elephantina Nutrition 0.000 description 1
- 244000177175 Typha elephantina Species 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- UYAHIZSMUZPPFV-UHFFFAOYSA-N erbium Chemical compound [Er] UYAHIZSMUZPPFV-UHFFFAOYSA-N 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- -1 for example Inorganic materials 0.000 description 1
- 230000006903 response to temperature Effects 0.000 description 1
Landscapes
- Light Guides In General And Applications Therefor (AREA)
- Optical Communication System (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は、光ファイバを用いる種々のシステムにおいて
、光ファイバ中を伝搬する光信号を分配する光信号分配
方式に関するものである。DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an optical signal distribution system for distributing optical signals propagating through optical fibers in various systems using optical fibers.
（従来の技術）
第２図は、従来の光信号分配方式を採用した光ファイバ
伝送系の基本構成を示す図である。第２図において、１
は光送信器、２は複数のボートに配置され、光信号の一
部を分岐する光分岐回路、３は各ボートに配置された光
受信器、４は伝送路用光ファイバ、５は光分岐回路２で
分岐された一方の分岐光信号を光受信器３に入射させる
光ファイバである。(Prior Art) FIG. 2 is a diagram showing the basic configuration of an optical fiber transmission system employing a conventional optical signal distribution system. In Figure 2, 1
is an optical transmitter, 2 is an optical branching circuit placed on multiple boats and branches a part of the optical signal, 3 is an optical receiver placed on each boat, 4 is an optical fiber for transmission line, and 5 is an optical branching circuit. This is an optical fiber that allows one of the branched optical signals branched by the circuit 2 to enter the optical receiver 3.
このような構成においては、光送信器１から送出された
光信号は、光ファイバ４を伝搬し、各ボートにおける光
分岐回路２を通過する毎に、その一部が分岐される。分
岐された光信号は、光ファイバ５を伝搬した後、光受信
器３にて受信される。In such a configuration, the optical signal transmitted from the optical transmitter 1 propagates through the optical fiber 4, and a portion of the optical signal is branched each time it passes through the optical branching circuit 2 in each boat. After propagating through the optical fiber 5, the branched optical signal is received by the optical receiver 3.
このように、光分岐回路２を、伝送路用先ファイバ４の
途中に多段に接続することにより、光信号の分配を行な
うことができる。In this way, by connecting the optical branch circuits 2 in multiple stages in the middle of the destination fiber 4 for transmission line, it is possible to distribute optical signals.
しかし、この構成では、光分岐回路２を通過する毎に、
主光信号電力より光受信器３の受光レベル相当分が失わ
れるために、分配できるボート数に著しい制限が生じる
。However, in this configuration, each time the optical branch circuit 2 is passed through,
Since an amount equivalent to the light reception level of the optical receiver 3 is lost from the main optical signal power, the number of ports that can be distributed is significantly limited.
この問題を解決し、分配可能なポート数を増大させるた
めに、光分岐回路２で受けた光損失を補償する方法を挙
げることができる。この光分岐回路２による光損失を補
償する良好な手段は、光分岐回路２の分岐光出射側に光
増幅器を配置することである。この光増幅器の代表的な
ものとしては、半導体レーザを用いた光増幅器がある。In order to solve this problem and increase the number of ports that can be distributed, there is a method of compensating for the optical loss suffered by the optical branch circuit 2. A good means for compensating for the optical loss caused by the optical branching circuit 2 is to arrange an optical amplifier on the branched light output side of the optical branching circuit 2. A typical example of this optical amplifier is an optical amplifier using a semiconductor laser.
（発明が解決しようとする課題）
しかしながら、上記半導体レーザを用いた光増幅器は、
■増幅特性が入射光の偏波状態に依存する、■温度変動
に対して特性の変動が大きい、という欠点を有している
。(Problems to be Solved by the Invention) However, optical amplifiers using the above-mentioned semiconductor lasers have the disadvantages that: (1) the amplification characteristics depend on the polarization state of the incident light; and (2) the characteristics fluctuate greatly in response to temperature fluctuations. have.
特に、現在の光通信システムでは、主に伝送路に偏波依
存性のない１．３μｍ零分散単一モード光ファイバ（カ
ットオフ波長１．１μｍ以上）もしくは１．５μｍ零分
散単一モード光ファイバ（カットオフ波長０．８μｍ以
上）が用いられており、半導体レーザ型の光増幅器にお
いては、上記■の欠点のために、伝送路中に挿入するこ
とは困難であった。In particular, in current optical communication systems, the transmission path is mainly a 1.3 μm zero-dispersion single mode optical fiber (cutoff wavelength 1.1 μm or more) or a 1.5 μm zero dispersion single mode optical fiber without polarization dependence. (cutoff wavelength of 0.8 μm or more), and in semiconductor laser type optical amplifiers, it has been difficult to insert them into the transmission line due to the drawback (2) above.
本発明は、かかる事情に鑑みてなされたものであり、そ
の目的は、伝送路中への挿入を容易に行なえ、しかも光
分岐回路にて受ける光損失を補償でき、分配数を増大さ
せることのできる光信号分配方式を提供することにある
。The present invention has been made in view of the above circumstances, and its purpose is to easily insert it into a transmission line, compensate for optical loss suffered in an optical branch circuit, and increase the number of distributions. The purpose of this invention is to provide an optical signal distribution system that allows for efficient optical signal distribution.
（課題を解決するための手段）
上記目的を達成するため、請求項（１）では、光ファイ
バを伝搬する光信号を光分岐回路にて分岐し、前記光分
岐回路にて分岐された少なくとも一の分岐光信号を、カ
ットオフ波長が０．６μｍ以上の偏波依存性のない単一
モード光ファイバにて伝搬させた後、希土類元素添加光
ファイバ増幅器にて、入射される励起光強度に応じて増
幅するようにした。(Means for Solving the Problem) In order to achieve the above object, in claim (1), an optical signal propagating through an optical fiber is branched by an optical branching circuit, and at least one branched by the optical branching circuit is provided. The branched optical signal is propagated through a polarization-independent single mode optical fiber with a cutoff wavelength of 0.6 μm or more, and then transmitted to a rare earth element-doped optical fiber amplifier according to the intensity of the incident pump light. and amplified it.
また、請求項（２）では、光信号と励起光とを波長多重
して光ファイバを伝搬させるようにした。Moreover, in claim (2), the optical signal and the pumping light are wavelength-multiplexed and propagated through the optical fiber.
（作 用）
請求項（１）によれば、光ファイバを伝搬された光信号
は、光分岐回路に到達する。光分岐回路は、入射した光
信号を所定の分岐比をもって分岐する。(Function) According to claim (1), the optical signal propagated through the optical fiber reaches the optical branch circuit. The optical branching circuit branches an incident optical signal at a predetermined branching ratio.
光分岐回路による一の分岐光信号は、カットオフ波長が
０．６μｍ以上の偏波依存性のない光ファイバを伝搬さ
れて、希土類元素添加光ファイバ増幅器に入射される。One branched optical signal from the optical branching circuit is propagated through a polarization-independent optical fiber with a cutoff wavelength of 0.6 μm or more, and inputted into a rare earth element-doped optical fiber amplifier.
希土類元素添加光ファイバ増幅器には、励起光が入射さ
れて励起状態となり、これにより、エルルギ一の一部が
入射された光信号に変換され、光信号は所定の利得をも
って増幅される。Pumping light is incident on the rare earth element-doped optical fiber amplifier to bring it into an excited state, whereby a part of the energy is converted into an incident optical signal, and the optical signal is amplified with a predetermined gain.
この増幅作用を受けた光信号は、分配先の光受信器ある
いは次段の伝送路用光ファイバに送出される。The amplified optical signal is sent to a distribution destination optical receiver or to an optical fiber for the next stage transmission line.
また、請求項（２）によれば、光信号に励起光が波長多
重され、この波長多重光が光ファイバを伝搬され、光分
岐回路に到達する。光分岐回路は入射した光信号を所定
の分岐比をもって分岐する。Further, according to claim (2), excitation light is wavelength-multiplexed on the optical signal, and this wavelength-multiplexed light is propagated through an optical fiber and reaches the optical branch circuit. The optical branching circuit branches the incident optical signal at a predetermined branching ratio.
光分岐回路による一の分岐波長多重光は、カットオフ波
長が０．６μｍ以上の偏波依存性のない光ファイバを伝
搬されて、希土類元素添加光ファイバ増幅器に入射され
る。希土類元素添加光ファイバ増幅器９は、入射した分
岐波長多重光のうち、励起光の入射に伴い励起状態とな
り、これにより、エルルギ一の一部が光信号に変換され
、光信号は所定の利得をもって増幅される。One branched wavelength-multiplexed light from the optical branching circuit is propagated through a polarization-independent optical fiber with a cutoff wavelength of 0.6 μm or more, and is input to a rare earth element-doped optical fiber amplifier. The rare earth element-doped optical fiber amplifier 9 enters an excited state due to the input of the pumping light among the input branched wavelength multiplexed light, whereby a part of the energy is converted into an optical signal, and the optical signal is converted into an optical signal with a predetermined gain. amplified.
この増幅作用を受けた光信号は、分配先の先受信器ある
いは次段の伝送路用光ファイバに送出される。The optical signal subjected to this amplification effect is sent to a destination receiver or an optical fiber for the next stage transmission line.
（実施例）
第１図は、本発明に係る光信号分配方式を採用した光フ
ァイバ伝送系の第１の実施例を示す構成図であって、基
本構成を示す第２図と同一構成部分は同一符号をもって
表す。即ち、１は光送信器で、例えば、発振波長１．５
５μｍの半導体レーザーを備え、光信号を後記する伝送
路用光ファイバ４に送出する。２は光分岐回路で、複数
の各ポートに配置され、光信号の一部を分岐する。３は
各ボートに配置された光受信器、４は伝送路用光ファイ
バで、例えば偏波依存性がな＜、シかもカットオフ波長
が０．６μｍ以上で波長１．５μｍ近傍に零分散波長を
有する単一モード光ファイバからなる。(Embodiment) FIG. 1 is a block diagram showing a first embodiment of an optical fiber transmission system employing the optical signal distribution system according to the present invention, and the same components as in FIG. 2 showing the basic configuration are as follows. Represented by the same symbol. That is, 1 is an optical transmitter, for example, the oscillation wavelength is 1.5
It is equipped with a 5 μm semiconductor laser and sends an optical signal to a transmission line optical fiber 4, which will be described later. Reference numeral 2 denotes an optical branching circuit, which is arranged at each of a plurality of ports and branches a part of the optical signal. 3 is an optical receiver placed on each boat, and 4 is an optical fiber for a transmission line. It consists of a single mode optical fiber with a
５ （ａ，ｂ）は光ファイバで、光分岐回路２で分岐さ
れ、後記する希土類元素添加光ファイバ９で増幅された
光信号を光受信器３に入射させる。5 (a, b) are optical fibers, which are branched by an optical branching circuit 2 and amplified by a rare earth element-doped optical fiber 9 (to be described later), and input an optical signal into an optical receiver 3.
６は励起光源で、例えば発振波長１．４８μｍの半導体
レーザからなり、励起光を所定の強度で出射する。Reference numeral 6 denotes an excitation light source, which is made of, for example, a semiconductor laser with an oscillation wavelength of 1.48 μm, and emits excitation light at a predetermined intensity.
７は励起先用光ファイバで、励起光源６から出射された
励起光が伝搬される。Reference numeral 7 denotes a pumping destination optical fiber through which the pumping light emitted from the pumping light source 6 is propagated.
８は光結合器で、光分岐回路２にて分岐された一の分岐
光信号と励起光源６による励起光とを合波する。Reference numeral 8 denotes an optical coupler, which combines one branched optical signal branched by the optical branching circuit 2 and the pumping light from the pumping light source 6.
９は希土類元素添加光ファイバ増幅器（以下、光ファイ
バ増幅器と０う）で、光ファイバに希土類元素、例えば
エルビウム（Ｅｒ３”）を所定の濃度で添加して構成さ
れている。Reference numeral 9 denotes a rare earth element-doped optical fiber amplifier (hereinafter referred to as an optical fiber amplifier), which is constructed by doping an optical fiber with a rare earth element, for example, erbium (Er3'') at a predetermined concentration.
この光ファイバ増幅器９は、入力端が光結合器８の合波
光出射側に後記する光ファイバ１０ｂを介して接続され
、出力端が光ファイバ５ａの一端に接続されており、励
起光が所定の強度で入射されていると、光信号を所定の
利得（〜２ ５ ｄ Ｂ）をもって増幅する。その増幅
特性は、入射光の偏波状態に依存せず、かつ、温度変動
に対して特性が安定している。また、その長さは１００
ｍ以下（数ｍ〜数十ｍ）に設定される。This optical fiber amplifier 9 has an input end connected to the multiplexed light output side of the optical coupler 8 via an optical fiber 10b, which will be described later, and an output end connected to one end of an optical fiber 5a, so that the pumping light is When the optical signal is incident at a high intensity, the optical signal is amplified with a predetermined gain (~25 dB). Its amplification characteristics do not depend on the polarization state of incident light and are stable against temperature fluctuations. Also, its length is 100
m or less (several meters to several tens of meters).
なお、利得のある波長或は、光ファイバに添加した希土
類元素がＥｒ３＋の場合、光信号の波長は１．５３〜１
．５６μｍ（励起光の波長は、〜１．４８μｍ）に制限
される（文献： Ｋ．Ｈａｇｌａ＋ｏｔｏ． ｅｔ．
ａｌ． “Ａ ２１２ ｋｍ Ｎｏｎ−
ｒｅｐｅａｔｅｄ Ｔｒａｎｓｍｉｓｓ１ｏｎ Ｅ
ｘｐｅｒｉｍｅｎｔ ａｔ ｌ．８Ｇｂ／ｓ ｕ
ｓｉｎｇ ＬＤ ＰｕｍｐｅｄＥｒ”−Ｄｏｐｅｄ
Ｆｉｂｅｒ Ａ＋＊ｐｌｌｒ１ｅｒｓ Ｉｎ ａｎ
ＩＭ／Ｄｌｒｅｃｔ一Ｄｅｔｅｃｔｌｏｎ Ｓｙｓｔｅ
ｍ ．ＯＦＣ’ ８９．Ｐｏｓｔ Ｄｅａｄｌｌｎ
ｅ Ｐａｐｅｒ． Ｈｏｕｓｔｏｎ． Ｆｅｂ．１９８
９、参照）。In addition, when the wavelength has a gain or the rare earth element added to the optical fiber is Er3+, the wavelength of the optical signal is 1.53 to 1.
．． 56 μm (the wavelength of the excitation light is ~1.48 μm) (Reference: K. Hagla+oto. et.
al. “A 212 km Non-
repeated Transmission1onE
experiment at l. 8Gb/s u
sing LD PumpedEr”-Doped
Fiber A+*pllr1ers In an
IM/Dlrect-Detectlon System
m. OFC' 89. Post Deadlln
e Paper. Houston. Feb. 198
9, see).
１０ （ａ，ｂ）は光ファイバで、前記伝送路用光ファ
イバ４と同様に、例えば、偏波依存性がな＜、シかもカ
ットオフ波長が０．８μｍ以上で波長１．５μｍ近傍に
零分散波長を有する単一モード光ファイバからなる。光
ファイバ１０ａは、光分岐回路２の一方の分岐光信号出
射側と光結合器８の一の入射端とを、光ファイバ１０ｂ
は、光結合器８の合波光出射側と光ファイバ増幅器９の
入力側とをそれぞれ接続している。10 (a, b) are optical fibers, which, like the transmission line optical fiber 4, have, for example, no polarization dependence, and a cutoff wavelength of 0.8 μm or more and a zero near the wavelength of 1.5 μm. It consists of a single mode optical fiber with dispersive wavelengths. The optical fiber 10a connects one branch optical signal output side of the optical branch circuit 2 and one input end of the optical coupler 8 to the optical fiber 10b.
connect the multiplexed light output side of the optical coupler 8 and the input side of the optical fiber amplifier 9, respectively.
１１は励起光除去用光フィルタで、光ファイバ５ａと５
ｂ間に挿入されており、光ファイバ増幅器９の出力光の
うち、光信号は透過させ、励起光は遮断する。11 is an optical filter for removing excitation light, which connects optical fibers 5a and 5.
b, and among the output light of the optical fiber amplifier 9, the optical signal is transmitted and the pumping light is blocked.
次に、上記構成による動作を説明する。Next, the operation of the above configuration will be explained.
光送信器１から送出された光信号は、光ファイバ４を伝
搬され、光分岐回路２に到達する。光分岐回路２は入射
した光信号を所定の分岐比をもって２分岐し、次段の光
ファイバ４及び光ファイバ１０ａにそれぞれ出射する。The optical signal sent out from the optical transmitter 1 is propagated through the optical fiber 4 and reaches the optical branch circuit 2 . The optical branching circuit 2 branches the incident optical signal into two at a predetermined branching ratio, and outputs them to the next stage optical fiber 4 and optical fiber 10a, respectively.
光ファイバ１０ａに出射された分岐光信号は、光ファイ
バ１０ａを伝搬されて光結合器８の一の入射端に入射さ
れる。また、光結合器８の他の入射端には、励起光源６
による励起光が光ファイバ７を介して入射され、分岐光
信号と励起光とが合波される。次いで、この合波光は、
光ファイバ１０ｂを介して光ファイバ増幅器９に入射さ
れる。The branched optical signal outputted to the optical fiber 10a is propagated through the optical fiber 10a and inputted into one input end of the optical coupler 8. Further, an excitation light source 6 is provided at the other input end of the optical coupler 8.
The excitation light is input through the optical fiber 7, and the branched optical signal and the excitation light are combined. Next, this combined light is
The light is input to the optical fiber amplifier 9 via the optical fiber 10b.
光ファイバ増幅器９は、入射された合波光のうち、励起
光の入射に伴い励起状態となる。これにより、エルルギ
一の一部が光信号に変換され、光信号は所定の利得をも
って増幅される。The optical fiber amplifier 9 enters an excited state as the pumping light of the multiplexed light enters the optical fiber amplifier 9 . As a result, a part of the energy is converted into an optical signal, and the optical signal is amplified with a predetermined gain.
次に、増幅作用を受けた光信号並びに励起光は、光ファ
イバ５ａを介して光フィルタ１１に入射される。光フィ
ルタ１１は、光信号はそのまま透過され、励起光は遮断
する。光フィルタ１１を透過した光信号は、光ファイバ
５ｂを介して光受信器３にて受信される。Next, the amplified optical signal and excitation light are input to the optical filter 11 via the optical fiber 5a. The optical filter 11 allows the optical signal to pass through as it is and blocks the excitation light. The optical signal transmitted through the optical filter 11 is received by the optical receiver 3 via the optical fiber 5b.
一方、光ファイバ４に出射された主光信号は、光ファイ
バ４を伝搬された後、次段の光分岐回路２に入射され、
上記したと同様の作用を受ける。On the other hand, the main optical signal emitted to the optical fiber 4 is propagated through the optical fiber 4 and then input to the next stage optical branch circuit 2.
It receives the same effect as described above.
このようにして、各ボートにおいて光信号の分配が行な
われる。In this way, optical signals are distributed in each boat.
以上のように、本第１の実施例によれば、先分岐回路２
にて分岐された光信号を、偏波依存性のない光ファイバ
１０ａ，１０ｂを伝搬させ、かつ、分岐光信号に励起光
を合波させた後、この合波光を励起光の入射により励起
状態となる希土類元素添加光ファイバ増幅器９に入射さ
せて、分岐光信号を増幅してから光受信器３にて受信す
るようにしたので、光分岐回路２による光分岐損失を補
償することができる。従って、光分岐回路２の分岐比を
適切に設定（光ファイバ４側に多くの電力を分岐）する
ことにより、主光信号の分岐損失の小さい光ファイバ伝
送系を実現できる。その結果、分配可能なボート数の増
大を図ることができる。As described above, according to the first embodiment, the destination branch circuit 2
After propagating the branched optical signal through optical fibers 10a and 10b without polarization dependence and combining the branched optical signal with excitation light, the combined light is brought into an excited state by the incidence of the excitation light. Since the branched optical signal is made incident on the rare earth element-doped optical fiber amplifier 9 and amplified before being received by the optical receiver 3, the optical branching loss caused by the optical branching circuit 2 can be compensated. Therefore, by appropriately setting the branching ratio of the optical branching circuit 2 (branching a large amount of power to the optical fiber 4 side), an optical fiber transmission system with small branching loss of the main optical signal can be realized. As a result, it is possible to increase the number of boats that can be distributed.
なお、光ファイバ増幅器９の出力側の光ファイバ５ａ，
５ｂは、増幅された光信号を光受信器３に導くものであ
り、入力側の光ファイバ１０ａ，１０ｂと構造パラメー
タが異なったり、偏波依存性を有するものであっても良
い。Note that the optical fibers 5a on the output side of the optical fiber amplifier 9,
5b guides the amplified optical signal to the optical receiver 3, and may have different structural parameters from the optical fibers 10a and 10b on the input side, or may have polarization dependence.
第３図は、本発明に係る光信号分配方式を採用した光フ
ァイバ伝送系の第２の実施例を示す構成図である。本第
２の実施例と前記第１の実施例の異なる点は、第１の実
施例では、光ファイバ増幅器９を光信号の分配側に配置
したのに対して、本第２の実施例においては、主光信号
の伝送路用光ファイバ４に挿入したことにある。また、
これに伴い、前記第１の実施例と同様に、光ファイバ増
幅器９の入力側には、光結合器８及び励起光源６と光フ
ァイバ７を配置し、出力側には光信号のみを透過させる
励起光除去用光フィルタ１１を配置している。FIG. 3 is a block diagram showing a second embodiment of an optical fiber transmission system employing the optical signal distribution system according to the present invention. The difference between the second embodiment and the first embodiment is that in the first embodiment, the optical fiber amplifier 9 is placed on the optical signal distribution side, whereas in the second embodiment, the optical fiber amplifier 9 is disposed on the optical signal distribution side. This is because the main optical signal is inserted into the optical fiber 4 for transmission line. Also,
Accordingly, as in the first embodiment, an optical coupler 8, a pumping light source 6, and an optical fiber 7 are arranged on the input side of the optical fiber amplifier 9, and only optical signals are transmitted on the output side. An optical filter 11 for removing excitation light is arranged.
本第２の実施例において、光分岐回路２は光信号の分配
側に多くの電力が分岐されるように設計される。このよ
うな構成においても、前記第１の実施例と同様の効果を
得ることができる。In the second embodiment, the optical branching circuit 2 is designed so that a large amount of power is branched to the optical signal distribution side. Even in such a configuration, the same effects as in the first embodiment can be obtained.
また、前記第１及び第２の実施例において、励起光源を
、光ファイバ増幅器９の数に対応した数だけ配置するこ
となく、別の場所に配置し、光信号と波長多重して伝送
させてもよい。この場合、励起光源６、光結合器８並び
に励起光用光ファイバ７の数を削減できる利点がある。Furthermore, in the first and second embodiments, the pumping light sources are not arranged in a number corresponding to the number of optical fiber amplifiers 9, but are arranged in different locations, and are wavelength-multiplexed with the optical signal and transmitted. Good too. In this case, there is an advantage that the number of excitation light sources 6, optical couplers 8, and excitation light optical fibers 7 can be reduced.
但し、励起光が伝送路用光ファイバ４や光分岐回路２並
びに光ファイバ増幅器９にて光損失を受けるため、光フ
ァイバ増幅器９の数に制約を受ける。However, the number of optical fiber amplifiers 9 is limited because the pumping light undergoes optical loss in the transmission line optical fiber 4, the optical branch circuit 2, and the optical fiber amplifier 9.
（発明の効果）
以上説明したように、請求項（１）によれば、光ファイ
バを伝搬する光信号を光分岐回路にて分岐し、前記光分
岐回路にて分岐された少なくとも一の分岐光信号を、カ
ットオフ波長が０．６μｍ以上の偏波依存性のない単一
モード光ファイバにて伝搬させた後、希土類元素添加光
ファイバ増幅器にて、入射される励起光強度に応じて増
幅するようにし、また、請求項（２）では、光信号と励
起光とを波長多重して光ファイバを伝搬させるようにし
たので、光分岐回路で生じた光損失を補償できる。(Effects of the Invention) As explained above, according to claim (1), an optical signal propagating through an optical fiber is branched by an optical branching circuit, and at least one branched light branched by the optical branching circuit is After the signal is propagated through a polarization-independent single mode optical fiber with a cutoff wavelength of 0.6 μm or more, it is amplified using a rare earth element-doped optical fiber amplifier according to the intensity of the incident pumping light. Furthermore, in claim (2), since the optical signal and the pumping light are wavelength-multiplexed and propagated through the optical fiber, it is possible to compensate for optical loss occurring in the optical branch circuit.
従って、分配可能なボート数の増大を図れる光信号分配
方式を提供できる利点がある。Therefore, it is advantageous to provide an optical signal distribution system that can increase the number of ports that can be distributed.
第１図は本発明に係る光信号分配方式を採用した光ファ
イバ伝送系の第１の実施例を示す構成図、第２図は従来
の光信号分配方式を採用した光ファイバ伝送系の基本構
成を示す図、第３図は本発明に係る光信号分配方式を採
用した光ファイバ伝送系の第２の実施例を示す構成図で
ある。
図中、１・・・光送信器、２・・・光分岐回路、３・・
・光受信器、４・・・偏波依存性のない伝送路用光ファ
イバ、６・・・励起光源、７・・・励起光用光ファイバ
、８・・・光結合器、９・・・希土類元素添加光ファイ
バ増幅器、１０・・・偏波依存性のない単一モード光フ
ァイバ、１１・・・励起光除去用光フィルタ。
特許出願人 日本電信電話株式会社Fig. 1 is a configuration diagram showing a first embodiment of an optical fiber transmission system using the optical signal distribution system according to the present invention, and Fig. 2 is a basic configuration of an optical fiber transmission system using the conventional optical signal distribution system. FIG. 3 is a configuration diagram showing a second embodiment of an optical fiber transmission system employing the optical signal distribution system according to the present invention. In the figure, 1... optical transmitter, 2... optical branch circuit, 3...
- Optical receiver, 4... Optical fiber for transmission line without polarization dependence, 6... Pumping light source, 7... Optical fiber for pumping light, 8... Optical coupler, 9... Rare earth element-doped optical fiber amplifier, 10... Single mode optical fiber without polarization dependence, 11... Optical filter for removing excitation light. Patent applicant Nippon Telegraph and Telephone Corporation
Claims (2)
岐し、 前記光分岐回路にて分岐された少なくとも一の分岐光信
号を、カットオフ波長が０．６μｍ以上の偏波依存性の
ない単一モード光ファイバにて伝搬させた後、 希土類元素添加光ファイバ増幅器にて、入射される励起
光強度に応じて増幅するようにしたことを特徴とする光
信号分配方式。(1) An optical signal propagating through an optical fiber is branched by an optical branching circuit, and at least one branched optical signal branched by the optical branching circuit is divided into polarization-dependent polarization-dependent signals having a cutoff wavelength of 0.6 μm or more. An optical signal distribution method characterized in that the optical signal is propagated through a single-mode optical fiber without any excitation light, and then amplified in accordance with the intensity of the incident excitation light using a rare-earth element-doped optical fiber amplifier.
搬させるようにした請求項（１）記載の光信号分配方式
。(2) The optical signal distribution system according to claim (1), wherein the optical signal and the pump light are wavelength-multiplexed and propagated through an optical fiber.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1111819A JPH02291505A (en) | 1989-04-28 | 1989-04-28 | Light signal distribution system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1111819A JPH02291505A (en) | 1989-04-28 | 1989-04-28 | Light signal distribution system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH02291505A true JPH02291505A (en) | 1990-12-03 |
Family
ID=14570956
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1111819A Pending JPH02291505A (en) | 1989-04-28 | 1989-04-28 | Light signal distribution system |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02291505A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06292038A (en) * | 1992-05-08 | 1994-10-18 | Matsushita Electric Ind Co Ltd | Video image distributer in passenger moving |
-
1989
- 1989-04-28 JP JP1111819A patent/JPH02291505A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06292038A (en) * | 1992-05-08 | 1994-10-18 | Matsushita Electric Ind Co Ltd | Video image distributer in passenger moving |
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