JPH05327663A - Optical wavelength division multiplex system - Google Patents
Optical wavelength division multiplex systemInfo
- Publication number
- JPH05327663A JPH05327663A JP4126963A JP12696392A JPH05327663A JP H05327663 A JPH05327663 A JP H05327663A JP 4126963 A JP4126963 A JP 4126963A JP 12696392 A JP12696392 A JP 12696392A JP H05327663 A JPH05327663 A JP H05327663A
- Authority
- JP
- Japan
- Prior art keywords
- optical
- output
- signal
- sine wave
- voltage
- 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.)
- Granted
Links
Landscapes
- Lasers (AREA)
- Optical Communication System (AREA)
Abstract
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 multiplexing system in the field of optical communication, and more particularly to an optical wavelength division multiplexing 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。Referring to FIG. 3, in the conventional optical wavelength division multiplexing system, optical transmitters 1 and 2 for converting two input electric signals into two kinds of optical signals having different wavelengths, respectively,
An optical multiplexer 3 that combines the optical outputs of the optical transmitters 1 and 2 and an optical fiber amplifier 4 that amplifies the optical signal combined by the optical multiplexer 3 are provided.
A part of the output of the optical fiber amplifier 4 is distributed by the optical demultiplexer 5, the optical output power average value is monitored by the photodiode 6, and the output of the optical fiber amplifier 4 is stabilized by the negative feedback circuit by the operational amplifier 14. I'm thinking.
【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。In this conventional optical wavelength division multiplexing system, as shown in FIG. 3, when the optical output of one of the two waves of the optical transmission board is lowered due to some factor, , If the gain of the optical fiber amplifier has wavelength sensitivity, the output of the optical fiber amplifier can be kept constant,
Considering each wavelength, there is a problem in 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。The optical wavelength division multiplexing system of the present invention receives an electric signal as an input, and applies a unique low-frequency sine wave to a constant modulation degree with respect to the amplitude of a digital optical signal having a different wavelength. A plurality of optical transmitters that are amplitude-modulated and output, an optical multiplexer that multiplexes the optical output signals of the optical transmitters, an optical fiber amplifier that amplifies the output of the multiplexer, and the optical fiber An optical demultiplexer that demultiplexes a part of the optical signal output to the transmission line at the output of the amplifier, a photodiode that converts the optical signal demultiplexed by the optical demultiplexer into an output electrical signal, and the photo diode. 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 according to the 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。DESCRIPTION OF THE PREFERRED EMBODIMENTS 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 the present embodiment. FIG. 1A shows an example of an optical output waveform of the optical transmission board 1. FIG. 1B is a diagram showing an example of the 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 the amplitude of a low frequency sine wave peculiar to each of the amplitudes of the digital optical signals having different wavelengths is amplitude-modulated with a constant modulation degree and output. Transmitters 1 and 2, and optical transmitters 1 and 2
An optical multiplexer 3 that multiplexes the respective optical output signals, an optical fiber amplifier 4 that amplifies the output of the optical 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,
Bandpass filters 8 and 9 for extracting a low-frequency sine wave superimposed on a digital optical signal from an output electric signal of the photodiode 6, and a DC voltage corresponding to each output sine wave of the bandpass filters 8 and 9 Of the peak value detecting circuits 10 and 11 for converting into the following, and the operational amplifier 12 for controlling the optical transmission boards 1 and 2 so that the output current voltage of the peak value detecting circuits 10 and 11 is compared with the reference voltage and the voltage difference is minimized. , 13
And an operational amplifier 14 that negatively feeds 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 to the optical signal amplitude (an example of the output waveform is shown in FIG. 2). (A) and (B)), and the output light amplitude can be arbitrarily changed by a control signal from the outside.
【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 frequencies of the sinusoidal waves to be superimposed are different between the optical transmission boards 1 and 2, and are 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 respective outputs from the optical transmitters 1 and 2 are combined by the optical multiplexer 3 and are collectively amplified by the 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 demultiplexer 5. In the optical demultiplexer 5, a part of the light 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 optical signal is converted into an electric signal by the photodiode 6 and divided into three. One of the three distributed 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 band-pass filters 8 and 9 for f 1 and f 2 are input and converted into sine waves. Transformed sine wave f 1 , f
2 is input to the peak value detection circuits 10 and 11, respectively,
Converted to a DC signal according to the peak value, and operational amplifier 1
Negative feedback is performed via 2 and 13 so as to control the output levels of the optical transmission boards 1 and 2.
【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, the present invention superimposes a low-frequency sine wave on each optical signal output from a plurality of transmission boards at a certain ratio with respect to the amplitude of the optical signal. By using different frequencies for the superimposed sine wave for each optical transmission board, and by monitoring the peak value of the superimposed sine wave when monitoring a part of the output of the optical fiber amplifier, Even if the signal component of the wavelength is lowered, the negative feedback is provided, so that the optical transmission level can be stabilized.
【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 an 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 optical output signal waveforms of the optical transmission board in the present embodiment, FIG. 2A is a diagram showing an example of optical output signal waveforms of the optical transmission board 1, and FIG. 2B is an optical output signal of the optical transmission board 2. It is a figure which shows 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 board 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 transmitters, each of which receives an electric signal as an input and amplitude-modulates a unique low-frequency sine wave with a constant modulation degree with respect to the amplitude of a digital optical signal having a different wavelength, and a plurality of optical transmitters. An optical multiplexer that multiplexes the respective optical output signals of the optical transmission board, an optical fiber amplifier that amplifies the output of the optical multiplexer, and one of the optical signals that are output to the transmission line at the output of the optical fiber amplifier. An optical demultiplexer for demultiplexing a unit, 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 is 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 according to the 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 quasi 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 true JPH05327663A (en) | 1993-12-10 |
| JP2797834B2 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) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0794628A2 (en) * | 1996-03-08 | 1997-09-10 | Nec Corporation | Optical receiving apparatus |
| JPH10154961A (en) * | 1996-11-22 | 1998-06-09 | Nec Corp | Optical transmitter and 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
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0794628A2 (en) * | 1996-03-08 | 1997-09-10 | Nec Corporation | Optical receiving apparatus |
| US6008919A (en) * | 1996-03-08 | 1999-12-28 | Nec Corporation | Optical receiving apparatus |
| EP0794628A3 (en) * | 1996-03-08 | 2000-04-05 | Nec Corporation | Optical receiving apparatus |
| JPH10154961A (en) * | 1996-11-22 | 1998-06-09 | Nec Corp | Optical transmitter and 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 |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2797834B2 (en) | 1998-09-17 |
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