JPH0591201A - Optical relay transmitter - Google Patents
Optical relay transmitterInfo
- Publication number
- JPH0591201A JPH0591201A JP3251442A JP25144291A JPH0591201A JP H0591201 A JPH0591201 A JP H0591201A JP 3251442 A JP3251442 A JP 3251442A JP 25144291 A JP25144291 A JP 25144291A JP H0591201 A JPH0591201 A JP H0591201A
- Authority
- JP
- Japan
- Prior art keywords
- signal
- level
- optical
- input
- avalanche photodiode
- 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.)
- Withdrawn
Links
Landscapes
- Interconnected Communication Systems, Intercoms, And Interphones (AREA)
- Optical Communication System (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明は伝送媒体である光信号が
伝送中に減衰のほかに雑音とひずみの影響を受け、これ
をひずみのない送出信号と同じ信号に再生するために伝
送路に決められた間隔で配置された光中継伝送装置に関
する。特に本発明ではアバランシェフォトダイオードへ
の光入力が低くなったときに不安定領域に入りアバラン
シェフォトダイオードが間欠的なノイズを発生するのを
防止することを目的とする。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical signal, which is a transmission medium, which is affected by noise and distortion in addition to being attenuated during transmission, and is reproduced in a transmission line in order to reproduce the same signal as a transmission signal without distortion. The present invention relates to an optical repeater transmission device arranged at fixed intervals. Particularly, it is an object of the present invention to prevent the avalanche photodiode from generating intermittent noise when it enters an unstable region when the light input to the avalanche photodiode becomes low.
【0002】[0002]
【従来の技術】図3は従来の光中継伝送装置を示す図で
ある。本図に示す該光中継伝送装置は3R系を用いたも
のであって減衰を受けひずんだ受信波形を増幅、整形し
信号対雑音比(S/N)のよい等化波形にする等化増幅
部1と、送出パルスを正しい時間間隔で送出するため受
信信号から位相情報を再生するタイミング再生部2と、
該等化増幅部1からの等化波形から2進情報を識別しこ
れに対応するパルスを再生する識別再生部3とを含む。2. Description of the Related Art FIG. 3 is a diagram showing a conventional optical repeater transmission apparatus. The optical repeater transmission apparatus shown in this figure uses a 3R system and amplifies and shapes the received waveform that is distorted and distorted to form an equalized waveform with a good signal-to-noise ratio (S / N). And a timing reproducing section 2 for reproducing phase information from a received signal in order to transmit a transmission pulse at correct time intervals,
An identification / reproduction unit 3 for identifying binary information from the equalized waveform from the equalization amplification unit 1 and reproducing a pulse corresponding to the binary information.
【0003】該等化増幅部1は有信号状態のマーク信号
と無信号状態のスペース信号からなる光信号Pinを受
光するアバランシェフォトダイオード(APD)11
と、該APD11の前置増幅器(PREAMP)12
と、信号の出力特性の振幅を該PREAMP12の信号
からの入力におけるその特性のある範囲にわたっての変
化に無関係に本質的に一定に保つように自動的操作をす
る自動利得制御増幅器(AGCAMP)13と、該AG
CAMP13の出力信号を複数の目的に応じて分配する
分配器(DIS)14と、該DIS14からのスペース
信号で直流成分を検出して該PREAMP12にフィー
ドバックをかけてオフセット除去するための直流フィー
ドバック部(DCFB)15と、該DIS14からのス
ペース信号のピークレベルを検出してフィードバック信
号を形成する自動利得制御フィードバック部(AGCF
B)16と、該AGCFB16の出力レベルが基準電圧
Vref1より高い場合には該AGCAMP13に該出
力レベルを本図に示すように電気AGCFB信号として
供給するスイッチ17と、該スイッチ17で該AGCF
B16の出力レベルが基準電圧Vref1より低い場合
には該出力レベルが本図に示すように光AGCFB信号
として供給され該APD11に増倍率を変化させるべく
バイアス電圧を供給する直流/直流変換器(D/D c
onverter)18とを含む。The equalizing and amplifying section 1 receives an optical signal Pin consisting of a mark signal in a signal state and a space signal in a non-signal state, and an avalanche photodiode (APD) 11
And a preamplifier (PREAMP) 12 of the APD 11
And an automatic gain control amplifier (AGCAMP) 13 which operates automatically to keep the amplitude of the output characteristic of the signal essentially constant irrespective of the change in its characteristic at the input from the signal of the PREAMP 12. , The AG
A distributor (DIS) 14 that distributes the output signal of the CAMP 13 according to a plurality of purposes, and a DC feedback unit that detects a DC component from a space signal from the DIS 14 and feeds it back to the PREAMP 12 to remove an offset ( DCFB) 15 and an automatic gain control feedback unit (AGCF) for detecting the peak level of the space signal from the DIS 14 and forming a feedback signal.
B) 16, a switch 17 that supplies the output level to the AGCAMP 13 as an electric AGCFB signal as shown in the figure when the output level of the AGCFB 16 is higher than the reference voltage Vref1, and the switch 17
When the output level of B16 is lower than the reference voltage Vref1, the output level is supplied as an optical AGCFB signal as shown in the figure and a DC / DC converter (D) for supplying a bias voltage to the APD 11 to change the multiplication factor is supplied. / D c
18).
【0004】なお受光素子としては通常のフォトダイオ
ードを用いるものもあるが本発明では光電増倍作用があ
るAPDを前提とす。該タイミング再生部2は例えばS
AWフィルタからなり該DIS14からの出力信号より
クロック信号を非線形抽出するためのクロック抽出回路
21と、該クロック抽出回路21の出力信号を基準電圧
Vref2と比較して基準電圧よりも小さいときには出
力阻止信号を送出する入力断検出部22とを含む。Although some of the light receiving elements use ordinary photodiodes, the present invention is premised on the APD having a photoelectric multiplication function. The timing reproducing unit 2 is, for example, S
A clock extraction circuit 21 configured by an AW filter for nonlinearly extracting a clock signal from the output signal from the DIS 14, and an output blocking signal when the output signal of the clock extraction circuit 21 is smaller than a reference voltage Vref2. And an input disconnection detection unit 22 for transmitting
【0005】該識別再生部3は該DIS14からの出力
信号を基準電圧Vref3と比較してレベルが1かまた
は0かを判定するための比較器31と、該比較器31の
出力信号と該クロック抽出回路21の再生クロック信号
とによって信号を再生するフリっプフロップ32と、該
参フリっプフロップ32の出力信号を該入力断検出部2
2の出力信号で阻止する比較器33と、該比較器33の
出力に接続されるレーザダイオード駆動装置34と、該
レーザダイオード駆動装置34によって光出力Poを送
出するレーザダイオード35とを含む。The identification reproduction section 3 compares the output signal from the DIS 14 with a reference voltage Vref3 to determine whether the level is 1 or 0, the output signal of the comparator 31 and the clock. The flip-flop 32 that reproduces a signal according to the reproduction clock signal of the extraction circuit 21 and the output signal of the reference flip-flop 32 are input to the input disconnection detection unit 2
It includes a comparator 33 for blocking by the output signal of 2, a laser diode driving device 34 connected to the output of the comparator 33, and a laser diode 35 for sending an optical output Po by the laser diode driving device 34.
【0006】次に動作を説明する。正規の光の入力を該
APD11が受信している場合該DCFB15及び該A
GCFB16が正常に動作してクロックが抽出された後
再生されて電気/光変換され光出力が送出される。図4
は図3の等化増幅部の制御動作を説明する図である。本
図に示すように通常の光入力受信時、光入力の高いレベ
ルでは該APD11の増幅率(M)を1又は2に固定し
該AGCAMP13のゲイン可変により一定の出力振幅
を保つ。光入力の低いレベルでは該AGCAMP13の
ゲインを最大として該APD11の増幅率を可変にする
ことにより一定の出力振幅を保つ。さらに光入力が低く
なると図に示すように該APD11が不安定領域に入り
該APD11が間欠的なノイズを出すため制御動作が不
安定になる。従来この不安定動作を防ぐためクロック成
分があるしきい値レベル以下になると該入力断検出部2
2により信号断動作をさせ無信号時の光出力信号をOF
Fする機能を設けていた。Next, the operation will be described. When the APD 11 receives a normal light input, the DCFB 15 and the A
After the GCFB 16 operates normally and the clock is extracted, the clock is regenerated, converted to electrical / optical, and the optical output is transmitted. Figure 4
FIG. 4 is a diagram illustrating a control operation of the equalization amplification unit in FIG. 3. As shown in the figure, during normal optical input reception, at a high optical input level, the amplification factor (M) of the APD 11 is fixed to 1 or 2, and a constant output amplitude is maintained by changing the gain of the AGCAMP 13. At a low level of optical input, the gain of the AGCAMP 13 is maximized and the amplification factor of the APD 11 is made variable to maintain a constant output amplitude. When the light input further decreases, the APD 11 enters an unstable region as shown in the figure, and the APD 11 emits intermittent noise, so that the control operation becomes unstable. Conventionally, in order to prevent this unstable operation, when the clock component falls below a certain threshold level, the input disconnection detection unit 2
2 to disconnect the signal and output the optical output signal when there is no signal
There was a function to do F.
【0007】[0007]
【発明が解決しようとする課題】しかしながら従来の光
中継伝送装置では主信号の伝送速度が上がるにつれてす
なわち高周波になるに従いクロック成分を検出するのが
難しくなり該入力断検出部22自身が不安定となりさら
に該比較器33を介して光中継伝送装置の出力が不安定
になるため該入力断検出部22を削除した回路構成をと
るシステムが増えているがこれでは無入力時にもノイズ
を中継する構成となり光入力が低くなったとき該APD
11が間欠的なノイズを発生することを防止できなくな
るという問題がある。However, in the conventional optical repeater transmission apparatus, it becomes difficult to detect the clock component as the transmission speed of the main signal increases, that is, as the frequency becomes higher, and the input break detection unit 22 itself becomes unstable. Further, since the output of the optical repeater transmission device becomes unstable via the comparator 33, the number of systems having a circuit configuration in which the input disconnection detection unit 22 is deleted is increasing. However, in this configuration, noise is relayed even when there is no input. When the optical input becomes low, the APD
There is a problem in that it is impossible to prevent the noise from being generated intermittently by 11.
【0008】したがって本発明は上記問題点に鑑みて光
入力が低いときに等化増幅部の不安定動作を防ぎかつ伝
送速度の上昇に対して安定性を確保するための光中継伝
送装置を提供することを目的とする。Therefore, in view of the above problems, the present invention provides an optical repeater transmission device for preventing an unstable operation of the equalization amplification section and ensuring stability against an increase in transmission speed when the optical input is low. The purpose is to do.
【0009】[0009]
【課題を解決するための手段】本発明は前記問題点を解
決するために、光信号を受信して有信号状態のマーク信
号の出力特性の振幅を一定に保たせるために光信号のレ
ベルが所定以上の場合に動作する自動利得制御増幅器
と、光信号のレベルが所定以下の場合に増倍率を変化さ
せるアバランシェフォトダイオードを有する光中継伝送
装置において、該アバランシェフォトダイオードの一方
へ入力する光信号のレベルより低いホワイトノイズの光
入力を他方へ加えて供給をする。SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a method for controlling the level of an optical signal in order to keep the amplitude of the output characteristic of a mark signal in a signal state by receiving an optical signal. In an optical repeater transmission device having an automatic gain control amplifier that operates when the optical signal level is above a predetermined level and an avalanche photodiode that changes the multiplication factor when the level of the optical signal is below a predetermined level, the optical signal input to one of the avalanche photodiodes. An optical input with white noise lower than the level of is supplied to the other.
【0010】[0010]
【作用】本発明の光中継伝送装置によれば、該アバラン
シェフォトダイオードの一方へ入力する光信号のレベル
より低いホワイトノイズの光入力を他方へ加えて供給を
することによって光信号のレベルが低くても該アバラン
シェフォトダイオードの不安定領域に入り該アバランシ
ェフォトダイオードが間欠的なノイズを出すため制御動
作が不安定になることを防止できる。さらに該入力断検
出部が不要になり伝送速度の上昇に対して安定性を確保
できるようになる。According to the optical repeater transmitter of the present invention, the level of the optical signal is lowered by adding the optical input of white noise lower than the level of the optical signal input to one of the avalanche photodiodes to the other and supplying it. However, it is possible to prevent the control operation from becoming unstable because the avalanche photodiode emits intermittent noise when it enters the unstable region of the avalanche photodiode. Further, the input disconnection detecting section is not required, and the stability can be secured against the increase of the transmission rate.
【0011】[0011]
【実施例】以下、本発明の実施例ついて図面を参照して
説明する。図1は本発明の実施例の光中継伝送装置の係
る等化増幅部の構成を示す図である。本図において図3
の等化増幅部の構成と異なるものは2入力用のAPD4
1と、該APD41の光入力Pinに対して他方の入力
に一定の低い雑音の光信号を供給する発光ダイオード4
2と、該発光ダイオード42駆動するための供給電源4
3である。Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of an equalizing / amplifying unit in an optical repeater transmission apparatus according to an embodiment of the present invention. In this figure, FIG.
The difference from the configuration of the equalizing / amplifying unit is the APD4 for two inputs
1 and a light emitting diode 4 for supplying a constant low noise optical signal to the other input with respect to the optical input Pin of the APD 41.
2 and a power supply 4 for driving the light emitting diode 42
It is 3.
【0012】図2は本実施例に係る受光素子の動作を説
明する図である。本図に示すように該発光ダイオード4
2よりホワイトノイズ成分Pin2が該APD41に常
に入力する。該APD41への入力信号成分Pin1が
小さくなって該APD41が間欠ノイズを発生させる最
小受光レベルPminより十分低いレベル(12〜15
dB位)のホワイトノイズを該発光ダイオード42より
入力せられるのでこれにより不安定動作範囲に入らなく
なり間欠ノイズの発生を防止できる。したがって図3に
示す該入力断検出部22が不要になり伝送速度の上昇に
対しても光中継伝送装置の出力の安定性を確保できるこ
とにもなる。FIG. 2 is a diagram for explaining the operation of the light receiving element according to this embodiment. As shown in this figure, the light emitting diode 4
2, the white noise component Pin2 is always input to the APD 41. The input signal component Pin1 to the APD 41 is reduced to a level (12 to 15) sufficiently lower than the minimum light receiving level Pmin at which the APD 41 generates intermittent noise.
Since white noise of about dB) can be input from the light emitting diode 42, it is possible to prevent the occurrence of intermittent noise because the white noise does not enter the unstable operation range. Therefore, the input break detection unit 22 shown in FIG. 3 is not required, and the stability of the output of the optical repeater transmission apparatus can be secured even when the transmission speed increases.
【0013】[0013]
【発明の効果】以上説明したように、本発明によればA
PDの一方の光入力に対して他方から十分低いレベルの
ホワイトノイズを入力するようにしたのでAPDへの光
入力レベルが低くなっても不安定動作に入って間欠ノイ
ズを発生するのを防止し等化増幅部を安定に動作させる
ことができる。As described above, according to the present invention, A
Since white noise of a sufficiently low level is input to one optical input of the PD from the other, it is possible to prevent intermittent noise from occurring due to unstable operation even when the optical input level to the APD becomes low. The equalizing and amplifying unit can be operated stably.
【図1】本発明の実施例の光中継伝送装置の係る等化増
幅部の構成を示す図である。FIG. 1 is a diagram showing a configuration of an equalization amplification unit in an optical repeater transmission apparatus according to an exemplary embodiment of the present invention.
【図2】本実施例に係る受光素子の動作を説明する図で
ある。FIG. 2 is a diagram for explaining the operation of the light receiving element according to the present embodiment.
【図3】従来の光中継伝送装置を示す図である。FIG. 3 is a diagram showing a conventional optical repeater transmission device.
【図4】図3の等化増幅部の制御動作を説明する図であ
る。FIG. 4 is a diagram illustrating a control operation of the equalization amplification unit in FIG.
1…等化増幅部 2…タイミング再生部 3…識別再生部 11、41…APD 42…発光ダイオード 43…供給電源 12…前置増幅器 13…自動利得制御増幅器 14…分配器 15…直流フィードバック部 16…自動利得制御フィードバック部 17…スイッチ 18…直流/直流変換器 DESCRIPTION OF SYMBOLS 1 ... Equalization amplification part 2 ... Timing reproduction part 3 ... Identification reproduction part 11, 41 ... APD 42 ... Light emitting diode 43 ... Supply power supply 12 ... Preamplifier 13 ... Automatic gain control amplifier 14 ... Distributor 15 ... DC feedback part 16 ... Automatic gain control feedback unit 17 ... Switch 18 ... DC / DC converter
Claims (1)
号の出力特性の振幅を一定に保たせるために光信号のレ
ベルが所定以上の場合に動作する自動利得制御増幅器
と、光信号のレベルが所定以下の場合に増倍率を変化さ
せるアバランシェフォトダイオードを有する光中継伝送
装置において、 該アバランシェフォトダイオードの一方へ入力する光信
号のレベルより低いホワイトノイズの光入力を他方へ加
えて供給をすることを特徴とする光中継伝送装置。1. An automatic gain control amplifier which operates when a level of an optical signal is equal to or higher than a predetermined level in order to keep an amplitude of an output characteristic of a mark signal in a signal state by receiving the optical signal, and an optical gain control amplifier for the optical signal. In an optical repeater transmission device having an avalanche photodiode that changes the multiplication factor when the level is below a predetermined level, an optical input of white noise lower than the level of the optical signal input to one of the avalanche photodiodes is added to the other to supply. An optical repeater transmission device characterized by:
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3251442A JPH0591201A (en) | 1991-09-30 | 1991-09-30 | Optical relay transmitter |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3251442A JPH0591201A (en) | 1991-09-30 | 1991-09-30 | Optical relay transmitter |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH0591201A true JPH0591201A (en) | 1993-04-09 |
Family
ID=17222896
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP3251442A Withdrawn JPH0591201A (en) | 1991-09-30 | 1991-09-30 | Optical relay transmitter |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH0591201A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2009060203A (en) * | 2007-08-30 | 2009-03-19 | Nec Corp | Optical receiving signal interruption detection circuit and optical receiving signal interruption detection method |
-
1991
- 1991-09-30 JP JP3251442A patent/JPH0591201A/en not_active Withdrawn
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2009060203A (en) * | 2007-08-30 | 2009-03-19 | Nec Corp | Optical receiving signal interruption detection circuit and optical receiving signal interruption detection method |
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Legal Events
Date | Code | Title | Description |
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A300 | Withdrawal of application because of no request for examination |
Free format text: JAPANESE INTERMEDIATE CODE: A300 Effective date: 19981203 |