JPH02266245A - Optical transmission system monitoring method - Google Patents
Optical transmission system monitoring methodInfo
- Publication number
- JPH02266245A JPH02266245A JP1086936A JP8693689A JPH02266245A JP H02266245 A JPH02266245 A JP H02266245A JP 1086936 A JP1086936 A JP 1086936A JP 8693689 A JP8693689 A JP 8693689A JP H02266245 A JPH02266245 A JP H02266245A
- Authority
- JP
- Japan
- Prior art keywords
- light
- pulse pattern
- optical
- transmission line
- circuit
- 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
- 230000005540 biological transmission Effects 0.000 title claims abstract description 38
- 230000003287 optical effect Effects 0.000 title claims abstract description 38
- 238000000034 method Methods 0.000 title abstract description 9
- 238000012544 monitoring process Methods 0.000 title description 14
- 239000013307 optical fiber Substances 0.000 claims abstract description 18
- 238000005086 pumping Methods 0.000 claims description 7
- 230000003321 amplification Effects 0.000 claims description 6
- 238000003199 nucleic acid amplification method Methods 0.000 claims description 6
- 229910052761 rare earth metal Inorganic materials 0.000 claims description 6
- 239000000969 carrier Substances 0.000 claims description 3
- 238000004891 communication Methods 0.000 claims description 2
- 239000000835 fiber Substances 0.000 abstract description 8
- 238000010408 sweeping Methods 0.000 abstract description 2
- 230000004936 stimulating effect Effects 0.000 abstract 3
- 230000005284 excitation Effects 0.000 description 14
- 238000010586 diagram Methods 0.000 description 5
- 238000012360 testing method Methods 0.000 description 5
- 238000000253 optical time-domain reflectometry Methods 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 230000002269 spontaneous effect Effects 0.000 description 2
- 229910052691 Erbium Inorganic materials 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000002596 correlated effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- UYAHIZSMUZPPFV-UHFFFAOYSA-N erbium Chemical compound [Er] UYAHIZSMUZPPFV-UHFFFAOYSA-N 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000001902 propagating effect Effects 0.000 description 1
Landscapes
- Arrangements For Transmission Of Measured Signals (AREA)
- Testing Of Optical Devices Or Fibers (AREA)
- 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、光伝送システムの簡易な監視方法に関する。[Detailed description of the invention] (Industrial application field) The present invention relates to a simple monitoring method for an optical transmission system.
（従来の技術）
従来、光伝送システムにおいて、伝送線路を監視する方
法として、伝送線路の一部に監視用の光パルスを入射し
その後方散乱光を検出するために設けた光分岐素子を通
して、伝送路の光損失及び破断位置等を測定していた。(Prior Art) Conventionally, in an optical transmission system, as a method of monitoring a transmission line, a monitoring optical pulse is incident on a part of the transmission line, and the backscattered light is detected through an optical branching element. The optical loss and breakage position of the transmission line were measured.
しかしこの方法によると、伝送線路の監視のためには、
新たな監視用の光源が必要になり装置構成が複雑になる
という欠点があった。However, according to this method, for monitoring transmission lines,
This has the disadvantage that a new monitoring light source is required and the device configuration becomes complicated.
第３図は従来技術による監視方法を前述のＥｒドープフ
ァイバを光増幅器として用いた光伝送システムにおける
伝送線路監視システムの構成を示す。図で１−８は伝送
システムを構成する装置であり、９−１０は伝送線路を
監視するために新たに必要となる装置である。すなわち
、１は伝送すべき電気信号源、２は電気信号源１で半導
体レーザ３を駆動するための回路、４は、駆動回路３で
駆動された励起光源６の光出力をＥｒドープファイバ７
に入射するための光合分岐回路である。また８は、伝送
線路である。信号光の波長は１．５２−１．５５μｍ、
励起光の波長は１．４６−１．４８μｍに設定される。FIG. 3 shows the configuration of a transmission line monitoring system in an optical transmission system using the conventional monitoring method using the Er-doped fiber as an optical amplifier. In the figure, 1-8 is a device constituting the transmission system, and 9-10 is a device newly required to monitor the transmission line. That is, 1 is an electric signal source to be transmitted, 2 is a circuit for driving the semiconductor laser 3 with the electric signal source 1, and 4 is an Er-doped fiber 7 for transmitting the optical output of the excitation light source 6 driven by the drive circuit 3.
This is an optical multiplexing/branching circuit for inputting light into the optical system. Further, 8 is a transmission line. The wavelength of the signal light is 1.52-1.55μm,
The wavelength of the excitation light is set to 1.46-1.48 μm.
このため、受信部に伝搬する励起光及び自然放出光を遮
断しシステムのＳ／Ｎを向上するために、受信部に、信
号光の波長（１，５２−１，５５μｍ ）に通過帯域を
有する波長フィルタを挿入する。９は通常の光パルス試
験器（ＯＴＤＲ） 、１０はパルス試験光を伝送線路に
入射するための光合分岐器である。Therefore, in order to block the excitation light and spontaneous emission light propagating to the receiver and improve the S/N of the system, the receiver has a passband at the wavelength of the signal light (1,52-1,55 μm). Insert wavelength filter. 9 is an ordinary optical pulse tester (OTDR), and 10 is an optical multiplexer/brancher for inputting pulse test light into the transmission line.
（発明が解決しようとする課題）
図から分かるようにこの方法によると、Ｅｒドープ光フ
ァイバを増幅器として用いた伝送線路を監視するために
は光パルス試験器を新たに備える必要がある。さらに光
パルス試験器の光源の波長を励起光のそれと同一に選定
するか、受信部で光パルス試験器の監視光を遮断するフ
ィルタを設ける必要があるという欠点があった。(Problems to be Solved by the Invention) As can be seen from the figure, according to this method, it is necessary to newly provide an optical pulse tester in order to monitor a transmission line using an Er-doped optical fiber as an amplifier. Another disadvantage is that it is necessary to select the wavelength of the light source of the optical pulse tester to be the same as that of the excitation light, or to provide a filter to block the monitoring light of the optical pulse tester in the receiving section.
本発明はこれらの欠点を改善し簡易な光伝送路監視方法
を提供することを目的とする。An object of the present invention is to improve these drawbacks and provide a simple optical transmission line monitoring method.
（課題を解決するための手段）
この目的を達成するための本発明の特徴は、光通信シス
テムにおける伝送可能距離を拡大するために、伝送路と
して使用する光ファイバの送信部あるいは受信部側の端
部に希土類原素をドープした光ファイバを備え、これに
励起光を入射することにより信号光の増幅機能を付与し
た光伝送システムにおいて、励起光を励起されたキャリ
アの緩和時間より短い周期のパルスパターンで変調して
、希土類原素をドープした光ファイバに入射して信号光
を増幅するための励起光とし、前記パルスパターンと、
該パルスパターンによる光ファイバ伝送路からの後方散
乱光との時間相関を求め、該時間相関に従って光ファイ
バ伝送路の光損失及び破断位置の少なくとも一方を測定
する光伝送システム監視方法にある。(Means for Solving the Problems) A feature of the present invention for achieving this object is that, in order to expand the possible transmission distance in an optical communication system, In an optical transmission system that has an optical fiber doped with a rare earth element at the end and provides a signal light amplification function by injecting pump light into the fiber, the pump light is used to transmit a signal with a period shorter than the relaxation time of the excited carriers. Pumping light is modulated with a pulse pattern and input into an optical fiber doped with a rare earth element to amplify the signal light, and the pulse pattern and
The present invention provides an optical transmission system monitoring method that obtains a time correlation between the pulse pattern and backscattered light from an optical fiber transmission line, and measures at least one of optical loss and breakage position of the optical fiber transmission line according to the time correlation.
（作用）
本発明は、希土類原素をドープした光ファイバに増幅機
能をもたすための励起光源を所定のパルスパターンで変
調し、かつパルスパターンの繰り返し周期を励起光によ
り励起されたキャリアの緩和時間と比較して充分短く設
定するとゲインの時間変動は無視できるという事実に着
目し、励起光を伝送線路の光損失測定用並びに障害点探
索にも使用することにより、簡易な伝送線路監視システ
ムの実現を可能とする。(Function) The present invention modulates a pumping light source with a predetermined pulse pattern to provide an amplification function to an optical fiber doped with rare earth elements, and adjusts the repetition period of the pulse pattern to the carriers excited by the pumping light. By focusing on the fact that the time fluctuation of the gain can be ignored if it is set sufficiently short compared to the relaxation time, and by using the excitation light to measure the optical loss of the transmission line and also to search for fault points, we have developed a simple transmission line monitoring system. This makes it possible to realize the following.
上記希土類元素としてはＥｒ （エルビウム）の使用
が代表的である。As the rare earth element, Er (erbium) is typically used.
励起光をパルスパターンで変調しても、Ｅｒドープ光フ
ァイバによる増幅度は従来の直流の励起光の場合と同じ
である。したがって該パルスパターンと、光ファイバ伝
送路からの後方散乱光との時間相関を取ることにより、
光損失及び障害点探索が簡易に行なわれる。Even if the excitation light is modulated with a pulse pattern, the amplification degree by the Er-doped optical fiber is the same as in the case of conventional DC excitation light. Therefore, by taking the time correlation between the pulse pattern and the backscattered light from the optical fiber transmission line,
Optical loss and failure point search can be easily performed.
従来必要であった試験用光パルスは不要となり、かつ、
受信側で該試験用光パルスを除去するためのフィルタも
不要となる。The test light pulses that were previously required are no longer necessary, and
A filter for removing the test optical pulse on the receiving side is also not required.
（実施例）
第１図は、本発明の第１の実施例を示す図である。１−
４は前項で説明したものと同様である。(Example) FIG. 1 is a diagram showing a first example of the present invention. 1-
4 is the same as that explained in the previous section.
５は励起光源の駆動回路で、従来提案されている伝送シ
ステムでは、直流電流で駆動するが、本発明では、擬似
ランダムパルスパターン発生器１２により駆動する。１
１は方向性結合器で、ハーフミラ−あるいは、ファイバ
カブラで構成する。１３は光信号を電気信号に変換する
ための受光器、１４は相関器、１５は遅延回路である。Reference numeral 5 denotes a drive circuit for an excitation light source, which is driven by a direct current in conventionally proposed transmission systems, but is driven by a pseudo-random pulse pattern generator 12 in the present invention. 1
Reference numeral 1 denotes a directional coupler, which is composed of a half mirror or a fiber coupler. 13 is a photoreceiver for converting an optical signal into an electrical signal, 14 is a correlator, and 15 is a delay circuit.
次に本実施例の動作原理について述べる。Ｅｒファイバ
に入射した励起光は、 Ｉ ｌ ３／２とＩＩＳ／□の
間に反転分布を形成する。’Ｉ＋３／□の準位に励起さ
れた電子の緩和時間は、１０ｍ５ｅｃ以上なので、励起
光は直流でも、緩和時間より繰り返しの早いパルスでも
実効上は、時間的に一定の光増幅度が達成される。第４
図及び第５図にこの原理を示す。Next, the operating principle of this embodiment will be described. The excitation light incident on the Er fiber forms a population inversion between I l 3/2 and IIS/□. 'The relaxation time of an electron excited to the I+3/□ level is 10 m5ec or more, so even if the excitation light is a direct current or a pulse whose repetition is faster than the relaxation time, effectively a temporally constant optical amplification degree can be achieved. Ru. Fourth
This principle is shown in FIG.
本実施例のシステムの動作について詳細に説明する。前
述したように、励起光源６をパルスパターン発生器１２
により例えば８ビツトのランダムパルスパターンにより
変調する。この励起光を方向性結合器１１、合分波回路
４を介し信号光とともにＥｒ ドープ光ファイバに入射
する。ランダムパルスパターンによるファイバ各点から
の後方散乱光は、合分波回路４、方向性結合器１１を通
って、受光器１３に入射する。受光器１３で電気信号に
変換された信号は、相関器に入力され、遅延回路を介し
てランダムパルスパターンと相関をとる。遅延回路の遅
延時間を掃引することにより、後方散乱波形が得られる
。これにより伝送路の損失並びに障害点の探索が可能と
なる。以上の構成をとることにより、伝送システムを構
成する光源を使用することにより伝送路の監視が可能と
なり、さらにシステムがポンプ光ならびにＥｒの自然放
出光を遮断するフィルタを備えているため、試験光を遮
断するフィルタ等は不要となり、システム構成が簡易に
なるという大きな利点がある。The operation of the system of this embodiment will be explained in detail. As mentioned above, the excitation light source 6 is connected to the pulse pattern generator 12.
The signal is modulated by, for example, an 8-bit random pulse pattern. This excitation light is input into an Er doped optical fiber together with the signal light via the directional coupler 11 and the multiplexing/demultiplexing circuit 4. Backscattered light from each point of the fiber according to the random pulse pattern passes through the multiplexing/demultiplexing circuit 4 and the directional coupler 11 and enters the light receiver 13 . The signal converted into an electrical signal by the photoreceiver 13 is input to a correlator, and is correlated with a random pulse pattern via a delay circuit. A backscattered waveform is obtained by sweeping the delay time of the delay circuit. This makes it possible to search for transmission path losses and failure points. With the above configuration, it is possible to monitor the transmission line by using the light sources that make up the transmission system, and since the system is equipped with a filter that blocks pump light and Er spontaneous emission light, the test light There is no need for a filter or the like to block out the noise, which has the great advantage of simplifying the system configuration.
第２図は本発明の第２の実施例である。先の実施例では
、Ｅｒドープ光ファイバにおいて、励起光の損失は避け
られないという欠点があった。そのため、本実施例では
励起光の一部をハーフミラ−１１により、Ｅｒ ドープ
光ファイバを介さずに伝送路に入射する。これにより測
定系のダイナミックレンジの拡大が可能となる。FIG. 2 shows a second embodiment of the invention. The previous embodiments had a drawback in that the loss of pumping light was unavoidable in the Er-doped optical fiber. Therefore, in this embodiment, a part of the excitation light is made incident on the transmission path through the half mirror 11 without passing through the Er-doped optical fiber. This makes it possible to expand the dynamic range of the measurement system.
（発明の効果）
以上説明したように本発明の監視システムは、監視用の
光源を具備する必要がなく、また試験光の入射によるＳ
／Ｎの劣化を避けることができるという効果がある。(Effects of the Invention) As explained above, the monitoring system of the present invention does not need to be equipped with a light source for monitoring, and the
/N deterioration can be avoided.
第１図は本発明の実施例の構成図、
第２図は本発明の別の実施例を示す図、第３図は従来の
技術の説明図、
第４図と第５図は時間的に一定の光増幅度が得られるこ
とを示す説明図である。
１；伝送すべき電気信号源、
２；半導体レーザ３を駆動するための回路、４；駆動回
路５で駆動された励起光源６の光出力をＥｒドープファ
イバ７に入射するための光合分岐器、 ８；伝送線路
、
９；通常の光パルス試験器（ＯＴＤＲ）、１０；パルス
試験光を伝送線路に入射するための光合分岐器、 １１
；方向性結合器、
１２；擬似ランダムパルスパターン発生器、１３；光信
号を電気信号に変換するための受光器、１４；相関器、
１５；遅延回路、
１６；データ処理装置及び表示装置である。Fig. 1 is a block diagram of an embodiment of the present invention, Fig. 2 is a diagram showing another embodiment of the invention, Fig. 3 is an explanatory diagram of a conventional technique, and Figs. 4 and 5 are chronologically shown. FIG. 3 is an explanatory diagram showing that a constant optical amplification degree can be obtained. 1; an electric signal source to be transmitted; 2; a circuit for driving the semiconductor laser 3; 4; an optical multiplexer/brancher for inputting the optical output of the excitation light source 6 driven by the driving circuit 5 into the Er-doped fiber 7; 8; Transmission line, 9; Ordinary optical pulse tester (OTDR), 10; Optical multiplexer/brancher for inputting pulse test light into the transmission line, 11
; Directional coupler; 12; Pseudo-random pulse pattern generator; 13; Optical receiver for converting an optical signal into an electrical signal; 14; Correlator;
15; delay circuit; 16; data processing device and display device.
Claims (1)
、伝送路として使用する光ファイバの送信部あるいは受
信部側の端部に希土類原素をドープした光ファイバを備
え、これに励起光を入射することにより信号光の増幅機
能を付与した光伝送システムにおいて、 励起光を励起されたキャリアの緩和時間より短い周期の
パルスパターンで変調して、希土類原素をドープした光
ファイバに入射して信号光を増幅するための励起光とし
、 前記パルスパターンと、該パルスパターンによる光ファ
イバ伝送路からの後方散乱光との時間相関を求め、 該時間相関に従って光ファイバ伝送路の光損失及び破断
位置の少なくとも一方を測定することを特徴とする光伝
送システム監視方法。[Claims] In order to expand the possible transmission distance in an optical communication system, an optical fiber used as a transmission line is provided with an optical fiber doped with a rare earth element at the end on the transmitter or receiver side. In an optical transmission system that provides a signal light amplification function by inputting pumping light, the pumping light is modulated with a pulse pattern with a period shorter than the relaxation time of the excited carriers, and the optical fiber is doped with rare earth elements. Enter the pumping light to amplify the signal light, find the time correlation between the pulse pattern and the backscattered light from the optical fiber transmission line due to the pulse pattern, and calculate the optical loss of the optical fiber transmission line according to the time correlation. and a fracture position.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1086936A JPH02266245A (en) | 1989-04-07 | 1989-04-07 | Optical transmission system monitoring method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1086936A JPH02266245A (en) | 1989-04-07 | 1989-04-07 | Optical transmission system monitoring method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH02266245A true JPH02266245A (en) | 1990-10-31 |
Family
ID=13900755
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1086936A Pending JPH02266245A (en) | 1989-04-07 | 1989-04-07 | Optical transmission system monitoring method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02266245A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5668658A (en) * | 1995-02-28 | 1997-09-16 | Nec Corporation | Transfer of repeater information signals in in-line optical amplifier repeater system |
| US6266169B1 (en) | 1992-04-08 | 2001-07-24 | Hitachi, Ltd. | Optical transmission equipment which transmits an amplified optical data signal and an optical surveillance signal |
| CN117154535A (en) * | 2023-08-25 | 2023-12-01 | 密尔医疗科技(深圳)有限公司 | Waveform shaping circuit of laser driving circuit, laser driving circuit and laser |
-
1989
- 1989-04-07 JP JP1086936A patent/JPH02266245A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6266169B1 (en) | 1992-04-08 | 2001-07-24 | Hitachi, Ltd. | Optical transmission equipment which transmits an amplified optical data signal and an optical surveillance signal |
| US6728489B2 (en) | 1992-04-08 | 2004-04-27 | Hitachi, Ltd. | Optical transmission system constructing method and system |
| US7167652B2 (en) | 1992-04-08 | 2007-01-23 | Hitachi, Ltd | Optical transmission system constructing method and system |
| US7292785B2 (en) | 1992-04-08 | 2007-11-06 | Hitachi, Ltd. | Optical transmission system constructing method and system |
| US5668658A (en) * | 1995-02-28 | 1997-09-16 | Nec Corporation | Transfer of repeater information signals in in-line optical amplifier repeater system |
| CN117154535A (en) * | 2023-08-25 | 2023-12-01 | 密尔医疗科技(深圳)有限公司 | Waveform shaping circuit of laser driving circuit, laser driving circuit and laser |
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