JPS6114697B2 - - Google Patents
Info
- Publication number
- JPS6114697B2 JPS6114697B2 JP55151810A JP15181080A JPS6114697B2 JP S6114697 B2 JPS6114697 B2 JP S6114697B2 JP 55151810 A JP55151810 A JP 55151810A JP 15181080 A JP15181080 A JP 15181080A JP S6114697 B2 JPS6114697 B2 JP S6114697B2
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- agc
- optical
- pilot signal
- signal
- 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
Links
- 230000005540 biological transmission Effects 0.000 claims description 20
- 230000003287 optical effect Effects 0.000 claims description 14
- 238000004891 communication Methods 0.000 claims description 10
- 239000013307 optical fiber Substances 0.000 claims description 8
- 230000002159 abnormal effect Effects 0.000 claims description 4
- 238000006243 chemical reaction Methods 0.000 description 9
- 238000010586 diagram Methods 0.000 description 5
- 230000003321 amplification Effects 0.000 description 3
- 238000001514 detection method Methods 0.000 description 3
- 238000003199 nucleic acid amplification method Methods 0.000 description 3
- 238000013139 quantization Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 230000005856 abnormality Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/60—Receivers
- H04B10/66—Non-coherent receivers, e.g. using direct detection
- H04B10/69—Electrical arrangements in the receiver
- H04B10/691—Arrangements for optimizing the photodetector in the receiver
- H04B10/6911—Photodiode bias control, e.g. for compensating temperature variations
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Optical Communication System (AREA)
- Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
Description
【発明の詳細な説明】
本発明は、光フアイバーを伝送路とする光通信
伝送路に用いられる光通信受信回路のAGC回路
に改良を加えた光通信方式に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical communication system in which an AGC circuit of an optical communication receiving circuit used in an optical communication transmission line using an optical fiber as a transmission line is improved.
光フアイバーを伝送路に用いる光通信方式の受
信回路におけるAGCとして、従来は第１図に示
すように、送信側において入力端１よりの伝送信
号にパイロツト信号発生器２４によるパイロツト
信号を重畳した後、電気−光変換回路２で光信号
に変換し、光フアイバー３に光パワーとして送出
し、受信側において第２図に示すように、光フア
イバー３１からのパワーを受光ダイオード３２に
より電気変換した後、電気増幅器３３により正規
信号に増幅し、中間中継器の場合は電気−光変換
器３４により電気−光変換を行つた後、光フアイ
バー３５に光パワーを伝送し、受信端局において
は電気増幅器３３の出力より出力信号を取り出し
ている。またAGC用として電気増幅器３３の出
力を分岐し、帯域波器３６によりパイロツト信
号の抽出を行い、増幅整流回路３７により直流制
御信号を得て、それを発光ダイオード３２のバイ
アスを制御し、その量子化効率を可変し、AGC
動作を行わせている。 Conventionally, as AGC in a receiving circuit of an optical communication system using an optical fiber as a transmission path, as shown in Fig. 1, after superimposing a pilot signal from a pilot signal generator 24 on the transmission signal from the input end 1 on the transmitting side. , it is converted into an optical signal by the electric-optical conversion circuit 2, and sent as optical power to the optical fiber 3. On the receiving side, as shown in FIG. , amplified into a regular signal by an electric amplifier 33, and in the case of an intermediate repeater, subjected to electric-to-optical conversion by an electric-to-optical converter 34, the optical power is transmitted to an optical fiber 35, and an electric amplifier is used at the receiving terminal station. The output signal is extracted from the output of 33. In addition, the output of the electric amplifier 33 is branched for AGC, a pilot signal is extracted by the bandpass filter 36, a DC control signal is obtained by the amplification rectifier circuit 37, and the bias of the light emitting diode 32 is controlled, and the quantum AGC
It makes the action take place.
一方、別のAGC回路としては第３図に示すよ
うな回路も用いられる。この回路は受光ダイオー
ド３２の受光パワーの平均値を増幅回路４６によ
り検出し、その直流出力により受光ダイオード３
２の量子化効率を制御するものである。 On the other hand, as another AGC circuit, a circuit as shown in FIG. 3 may also be used. This circuit detects the average value of the light receiving power of the light receiving diode 32 by the amplifier circuit 46, and uses the DC output to detect the average value of the light receiving power of the light receiving diode 32.
This controls the quantization efficiency of 2.
受光ダイオードとしてアパランシエフオトダイ
オードを用いた場合、降伏電圧の制御によりこの
量子化効率は広い範囲で可変できるため、AGC
動作に非常に適している。 When an apparantee photodiode is used as a photodiode, the quantization efficiency can be varied over a wide range by controlling the breakdown voltage.
very suitable for operation.
受光パワー平均値AGCは回路が簡単である
が、送信側の変調度の変化等により光パワーとそ
の中に含まれる電気信号との対応は必ずしも一定
でないため、電気信号の安定性が余りよくないと
いう欠点があつた。 The average received power value AGC has a simple circuit, but the correspondence between the optical power and the electrical signal contained therein is not necessarily constant due to changes in the modulation degree on the transmitting side, so the stability of the electrical signal is not very good. There was a drawback.
また、パイロツトAGCは精度がよく、伝送路
を多段に接続した場合も伝送信号の安定性が非常
により反面、パイロツト信号の異常時、特にパイ
ロツト信号が断となつた場合、受光ダイオードよ
り発生する雑音が大きく、多段接続した場合、雑
音が多大となり、次段に接続される機器に悪影響
を与える場合があつた。また、伝送路の障害復旧
時に第１図の入力端１に伝送信号があつた場合、
第２図の受光ダイオードの量子化効率が非常によ
つており、増幅器３３の出力は伝送信号により飽
和して重畳されているパイロツト信号の抽出が不
能となり、AGC動作が復旧しなくなる場合があ
つた。 In addition, pilot AGC has good accuracy and the transmission signal is very stable even when the transmission line is connected in multiple stages.However, when the pilot signal is abnormal, especially when the pilot signal is disconnected, noise generated by the photodetector diode is large, and when connected in multiple stages, the noise becomes large and may have an adverse effect on the equipment connected to the next stage. Also, if a transmission signal is applied to input terminal 1 in Fig. 1 when the transmission path is restored from a fault,
The quantization efficiency of the photodetector diode shown in Fig. 2 was extremely low, and the output of the amplifier 33 was saturated by the transmission signal, making it impossible to extract the superimposed pilot signal, and in some cases AGC operation could not be restored. .
本発明の目的は従来のAGC動作の欠点を除
き、伝送路復旧時の回線の回復を容易することお
よび従続接続時には障害伝送路以外を正常動作に
近い状態とする事により、障害部分の探索を容易
とすることのできる光通信方式を提供することに
ある。 The purpose of the present invention is to eliminate the drawbacks of conventional AGC operation, to facilitate line recovery when the transmission line is restored, and to search for the faulty part by bringing the transmission line other than the faulty transmission line into a state close to normal operation during continuous connection. The object of the present invention is to provide an optical communication system that can facilitate the communication.
本発明の光通信方式は、光フアイバーを伝送路
とし、伝送信号に重畳したパイロツト信号が正常
のときはこのパイロツト信号がほぼ一定レベルと
なるようなAGC動作を行わせ、該パイロツト信
号が異常のときは受光パワーがほぼ一定となるよ
うな受光パワー平均値AGC動作を行わせる事を
特徴とする。 The optical communication system of the present invention uses an optical fiber as a transmission path, performs AGC operation such that when the pilot signal superimposed on the transmission signal is normal, this pilot signal remains at a nearly constant level, and when the pilot signal is abnormal, The present invention is characterized in that the received light power average value AGC operation is performed so that the received light power is approximately constant.
以下、本発明を第４図の実施例をもとに説明す
る。受光ダイオード３２の出力の電気信号を増幅
器３３により増幅し、パイロツト抽出帯域波器
５６によりパイロツト信号を抽出し、増幅整流回
路５７により直流制御信号を得ている。一方、平
均受光パワー検出増幅回路５８により直流制御信
号を得ている。このとき増幅整流回路５７の内部
にある異常状態検出回路によりパイロツト信号の
状態を常時監視しており、正常のときはスイツチ
５９によりパイロツト信号によるAGC回路の動
作を行わせ、パイロツト信号の異常があるとき
は、スイツチ５９を平均受光パワーによるAGC
回路を動作する側に切替えてAGC動作を行わせ
るものである。 The present invention will be explained below based on the embodiment shown in FIG. The electrical signal output from the light receiving diode 32 is amplified by the amplifier 33, the pilot signal is extracted by the pilot extracting bandpass filter 56, and the DC control signal is obtained by the amplifying rectifier circuit 57. On the other hand, the average received light power detection amplification circuit 58 obtains a DC control signal. At this time, the state of the pilot signal is constantly monitored by the abnormal state detection circuit inside the amplification and rectification circuit 57, and when it is normal, the switch 59 operates the AGC circuit by the pilot signal, and if there is an abnormality in the pilot signal, At this time, switch 59 is set to AGC based on the average received light power.
This switches the circuit to the active side and performs AGC operation.
第５図に示すように、光伝送路が縦続に接続さ
れている場合に本発明の効果は顕著に現われる。
以下その特徴を述べる。第５図のフアイバー３に
断線があつたとすると、光−電気変換回路４の利
得（光−電気変換利得）は上昇する。もし、光−
電気変換回路７と１０がパイロツトAGCのみと
すると、その利得はともに上昇し、出力端１１に
現われる雑音は多大のものとなる。また、このと
き、電気−光変換回路５と８の入力を切離し、信
号の挿入を行い、伝送特性の試験を行おうとして
も、正常な測定はできず、障害の切分けは困難と
なる。もし、このような状態のとき、光−電気変
換回路７と１０のAGC動作を本発明の平均受光
パワーによる方法に切替えれば、変換回路５より
変換回路１０までの間の伝送特性はほぼ正常とな
つており、上記切分作業は容易となる。また、パ
イロツト信号が正常である場合は、精度の高いパ
イロツトAGC回路を使用しており、伝送路は高
品質である事は言うまでもない。 As shown in FIG. 5, the effects of the present invention are particularly apparent when optical transmission lines are connected in series.
Its characteristics are described below. If the fiber 3 in FIG. 5 is broken, the gain of the optical-to-electrical conversion circuit 4 (optical-to-electrical conversion gain) increases. If light-
If the electrical conversion circuits 7 and 10 are only pilot AGC, the gains of both will increase and the noise appearing at the output terminal 11 will become large. Further, at this time, even if an attempt is made to test the transmission characteristics by disconnecting the inputs of the electro-optical conversion circuits 5 and 8 and inserting signals, normal measurements cannot be made and it becomes difficult to isolate the fault. If, in such a state, the AGC operation of the optical-to-electrical conversion circuits 7 and 10 is switched to the method using the average received light power of the present invention, the transmission characteristics from the conversion circuit 5 to the conversion circuit 10 will be almost normal. Therefore, the above-mentioned cutting operation becomes easy. Furthermore, if the pilot signal is normal, it goes without saying that a highly accurate pilot AGC circuit is used and the transmission line is of high quality.
第１図は従来の光通信方式の送信端局を示すブ
ロツク図、第２図はパイロツトAGCを採用した
従来の中間中継器を示すブロツク図、第３図は平
均受光パワーAGCを採用した従来の中間中継器
を示すブロツク図、第４図は本発明の実施例に用
いる中間中継器を示すブロツク図、第５図は一般
の光通信方式を示すブロツク図である。
３１……光フアイバー、３２……受光ダイオー
ド、３３……電気増幅器、３４……発光ダイオー
ド、３５……光フアイバー、５６……帯域波
器、５７……増幅整流回路、５８……平均受光パ
ワー検出増幅回路、５９……切替スイツチ。
Figure 1 is a block diagram showing a transmitting terminal station in a conventional optical communication system, Figure 2 is a block diagram showing a conventional intermediate repeater that uses pilot AGC, and Figure 3 is a block diagram that shows a conventional intermediate repeater that uses average received power AGC. FIG. 4 is a block diagram showing an intermediate repeater used in an embodiment of the present invention, and FIG. 5 is a block diagram showing a general optical communication system. 31... Optical fiber, 32... Light receiving diode, 33... Electrical amplifier, 34... Light emitting diode, 35... Optical fiber, 56... Bandwidth wave generator, 57... Amplifying and rectifying circuit, 58... Average received light power Detection amplifier circuit, 59... changeover switch.
Claims (1)
したパイロツト信号が正常のときはこのパイロツ
ト信号がほぼ一定レベルとなるようなAGC動作
を行わせ、該パイロツト信号が異常のときは受光
パワーがほぼ一定となるような受光パワー平均値
AGC動作を行なわせる事を特徴とする光通信方
式。1 Using an optical fiber as a transmission path, when the pilot signal superimposed on the transmission signal is normal, the AGC operation is performed so that the pilot signal is at a nearly constant level, and when the pilot signal is abnormal, the received light power is almost constant. The average value of received light power such that
An optical communication system characterized by AGC operation.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP55151810A JPS5775042A (en) | 1980-10-29 | 1980-10-29 | Optical communication system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP55151810A JPS5775042A (en) | 1980-10-29 | 1980-10-29 | Optical communication system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5775042A JPS5775042A (en) | 1982-05-11 |
| JPS6114697B2 true JPS6114697B2 (en) | 1986-04-19 |
Family
ID=15526799
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP55151810A Granted JPS5775042A (en) | 1980-10-29 | 1980-10-29 | Optical communication system |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5775042A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6084034A (en) * | 1983-06-02 | 1985-05-13 | Nec Corp | Optical agc system |
| JPS62116029A (en) * | 1985-11-15 | 1987-05-27 | Fujitsu Ltd | Detecting system for cut off of optical signal |
| US7630631B2 (en) * | 2004-04-14 | 2009-12-08 | Finisar Corporation | Out-of-band data communication between network transceivers |
-
1980
- 1980-10-29 JP JP55151810A patent/JPS5775042A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5775042A (en) | 1982-05-11 |
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