JP3534696B2 - Bidirectional optical amplifying transmission line and fault finding method thereof - Google Patents
Bidirectional optical amplifying transmission line and fault finding method thereofInfo
- Publication number
- JP3534696B2 JP3534696B2 JP2000357251A JP2000357251A JP3534696B2 JP 3534696 B2 JP3534696 B2 JP 3534696B2 JP 2000357251 A JP2000357251 A JP 2000357251A JP 2000357251 A JP2000357251 A JP 2000357251A JP 3534696 B2 JP3534696 B2 JP 3534696B2
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- JP
- Japan
- Prior art keywords
- transmission line
- bidirectional
- optical
- amplification
- amplification transmission
- 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.)
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- Testing Of Optical Devices Or Fibers (AREA)
- Monitoring And Testing Of Transmission In General (AREA)
- Optical Communication System (AREA)
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、光反射試験器を用
いて行う双方向光増幅伝送路の障害点探査方法に関する
ものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of searching for a fault point in a bidirectional optical amplification transmission line using a light reflection tester.
【０００２】[0002]
【従来の技術】双方向光増幅伝送方式は上り・下りの光
信号が光ファイバ及び光増幅器を共用できるので、通常
の単一方向光増幅伝送方式に比べ経済的である。ところ
で、例えば上り光信号が発生した散乱光は反対方向（下
り方向）にも伝搬し、下り光信号と一緒に下り受信器で
受信され、下り光信号の伝送特性の大きな劣化要因にな
る。この間遭を解決するため、上り・下りの光信号は異
なる波長域を使用し、上り波長域に属する光信号は下り
方向に、また、下り波長域に属する光信号は上り方向に
伝搬できない手段を増幅中継器に設ける種種の方法が提
案されている。2. Description of the Related Art A bidirectional optical amplification transmission system is more economical than an ordinary unidirectional optical amplification transmission system because upstream and downstream optical signals can share an optical fiber and an optical amplifier. By the way, for example, the scattered light generated by the upstream optical signal propagates in the opposite direction (downward direction) and is received by the downstream receiver together with the downstream optical signal, which causes a great deterioration in the transmission characteristics of the downstream optical signal. In order to solve this conflict, upstream and downstream optical signals use different wavelength ranges, optical signals belonging to the upstream wavelength range cannot be propagated in the downstream direction, and optical signals belonging to the downstream wavelength range cannot be propagated in the upstream direction. Various methods have been proposed for providing amplification repeaters.
【０００３】光ファイバを伝播する光信号はわずかであ
るが散乱を受ける。この性質を利用して探査光パルスを
被測定光ファイバに入力し、探査光パルスが発生し逆方
向に伝播して入射端に戻ってきた散乱光の強度の時間変
化を測定することにより、光ファイバの損失を距離の関
数として求める光反射試験器が光伝送路の障害点探査に
広く使用されている。The optical signal propagating through an optical fiber is slightly scattered. This property is used to input an exploration light pulse into the optical fiber under measurement, and the time change in the intensity of scattered light that is generated by the exploration light pulse and propagates in the opposite direction and returns to the incident end is measured. Light reflection testers, which determine the loss of a fiber as a function of distance, are widely used to search for faults in optical transmission lines.
【０００４】[0004]
【発明が解決しようとする課邁】光反射試験器を上り信
号の入力端に置いて双方向光増幅伝送路の障害点を探査
する場合を考える。この場合、探査パルスが伝送路を上
り方向に伝搬していくためには、その波長は第一波長域
の属することが必要である。しかしながら、本探査パル
スが発生した散乱光は双方向光増幅器で下り方向への伝
搬を遮断されるので、上り信号の入力端にある光反射試
験器で散乱光を受信することができない。このように、
双方向光増幅伝送路では光反射試験器を用いて障害点探
査ができないという欠点があった。本発明は、双方向光
増幅伝送路に適用可能な光反射試験器による障害点探査
方法を提供することを目的とする。Consider a case in which a light reflection tester is placed at the input end of an upstream signal to search for a failure point in a bidirectional optical amplification transmission line. In this case, in order for the exploration pulse to propagate through the transmission path in the upstream direction, the wavelength must belong to the first wavelength range. However, since the scattered light generated by the main search pulse is blocked from propagating in the downward direction by the bidirectional optical amplifier, the light reflection tester at the input end of the upstream signal cannot receive the scattered light. in this way,
The bidirectional optical amplification transmission line has a drawback in that it is not possible to search for a fault point using a light reflection tester. An object of the present invention is to provide a fault point search method using a light reflection tester applicable to a bidirectional optical amplification transmission line.
【０００５】[0005]
【課題を解決するための手段】本発明は上記目的を達成
するため、双方向光増幅伝送路を２本組み合わせて対と
し、対方の伝送路で発生した散乱光を相互に導き合う手
段を対をなす双方向増幅器に設け、且つ、双方向増幅器
の有する伝搬方向の一方性の波長関係を二本の伝送路で
逆方向になるようにし、一方の伝送路を他方の伝送路で
探査信号が発生した散乱光の帰還路として使用する構成
とした。In order to achieve the above-mentioned object, the present invention provides a means for mutually combining two bidirectional optical amplification transmission lines to form a pair and mutually guiding scattered light generated in the opposite transmission line. It is provided in a pair of bidirectional amplifiers, and the bidirectional amplifier has a unidirectional wavelength relationship in the propagation direction so that the two transmission paths have opposite wavelength directions, and one transmission path is searched for in the other transmission path. It is configured to be used as a return path for scattered light generated by.
【０００６】[0006]
【発明の実施の形態】図１は本発明による双方向光増幅
伝送路及びその障害探査方法の実施例を示す図である。
本発明では、第１及び第２の双方向増幅伝送路１及び２
を用い、これら２本の双方向増幅伝送路を互いに対をな
すように配置する。以下の説明において、図面の左から
右へ向く方向を下り方向と称し、右から左に向く方向を
上り方向と称することにする。第１の双方向増幅伝送路
１にはｎ個の増幅中継器（図面上３個の増幅中継器３ａ
〜３ｃだけを図示する）を接続し、第１の波長域の光信
号が第１双方向増幅伝送路に沿って下り方向に伝搬す
る。第２の双方向増幅伝送路２にも同様にｎ個の増幅中
継器（図面上３個の増幅中継器４ａ〜ａｃだけを図示す
る）が接続され、この第２の双方向増幅伝送路に沿って
第１の波長域とは異なる第２の波長域の光信号が上り方
向に伝搬する。第１の双方向増幅伝送路１に接続した増
幅中継器は、下り方向に伝搬する第１の波長域の光信号
を増幅すると共に、上り方向に伝搬する第１の波長域の
光信号及び下り方向に伝搬する第２の波長域の光信号の
伝搬を遮断する機能を有する。従って、第１の双方向増
幅伝送路１に沿って、第１の波長域の光信号は第１の端
部１ａから反対側の第２の端部１ｂに向けて下り方向に
伝搬し、第２の波長域の光信号は第２端部１ｂから反対
側の第１の端部１ａに向けて上り方向に伝搬する。ま
た、第２の双方向増幅伝送路２に沿って、第１の波長域
の光信号は第２の端部２ｂから反対側の第１の端部２ａ
に向けて上り方向に伝搬し、第２の波長域の光信号は第
１の端部２ａから反対側の第２の端部２ｂに向けて下り
方向に伝搬する。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing an embodiment of a bidirectional optical amplification transmission line and a fault detecting method therefor according to the present invention.
In the present invention, the first and second bidirectional amplification transmission lines 1 and 2 are provided.
Are used to arrange these two bidirectional amplification transmission lines in pairs. In the following description, the direction from left to right in the drawings will be referred to as the downward direction, and the direction from right to left will be referred to as the upward direction. The first bidirectional amplification transmission line 1 has n amplification repeaters (three amplification repeaters 3a in the drawing).
˜3c are shown), and the optical signal in the first wavelength band propagates in the downstream direction along the first bidirectional amplification transmission line. Similarly, n number of amplification repeaters (only three amplification repeaters 4a to ac are shown in the drawing) are connected to the second bidirectional amplification transmission line 2, and the second bidirectional amplification transmission line is connected to the second bidirectional amplification transmission line 2. An optical signal in a second wavelength band different from the first wavelength band propagates in the up direction. The amplification repeater connected to the first bidirectional amplification transmission line 1 amplifies the optical signal in the first wavelength band propagating in the down direction and at the same time transmits the optical signal in the first wavelength band propagating in the up direction and the downlink signal. It has a function of blocking the propagation of the optical signal of the second wavelength band propagating in the direction. Therefore, along the first bidirectional amplification transmission line 1, the optical signal in the first wavelength band propagates from the first end 1a toward the second end 1b on the opposite side in the down direction, The optical signal in the wavelength range of 2 propagates in the up direction from the second end 1b toward the opposite first end 1a. Further, along the second bidirectional amplification transmission line 2, the optical signal in the first wavelength range is transmitted from the second end 2b to the opposite first end 2a.
The optical signal in the second wavelength band propagates in the downward direction from the first end 2a to the second end 2b on the opposite side.
【０００７】互いに対をなす第１及び第２の双方向増幅
伝送路１と２との間に、第１の波長域の光及び第２の波
長域の光の両方を伝搬させることができる光伝送経路５
（図面上、３本の光伝送経路５ａ〜５ｃだけを図示す
る）を接続する。従って、第１の双方向増幅伝送路１を
第１の波長域の光信号が下り方向に伝搬する際に発生し
た散乱光の一部は、光伝送路５を介して反対側の第２の
双方向増幅伝送路に移行する。また、第２の双方向増幅
伝送路２を第１の波長域の光信号が上り方向に伝搬する
際に発生した散乱光の一部は光伝送経路５を介して反対
側の第１の双方向増幅伝送路に移行する。Light capable of propagating both the light of the first wavelength band and the light of the second wavelength band between the first and second bidirectional amplification transmission lines 1 and 2 forming a pair. Transmission path 5
(Only three optical transmission paths 5a to 5c are shown in the drawing) are connected. Therefore, a part of the scattered light generated when the optical signal in the first wavelength band propagates in the downward direction through the first bidirectional amplification transmission line 1 is transmitted through the optical transmission line 5 to the second side on the opposite side. Move to bidirectional amplification transmission line. In addition, a part of the scattered light generated when the optical signal in the first wavelength band propagates in the upstream direction through the second bidirectional amplification transmission path 2 is transmitted through the optical transmission path 5 to the opposite first side. Move to the direct amplification transmission line.
【０００８】図２は本発明に用いる増幅中継器の一例の
構成を示す線図である。本例では、４ポート合分波器を
使用した双方向光増幅器を用いる。合分波器１０の第１
のポートに入力した第１の波長域の光信号及び第２の波
長域の光信号は、第３のポート及び第４のポートにそれ
ぞれ出力される。また、第２のポートに入力した第１の
波長域の光信号及び第２の波長域の光信号は、それぞ
れ、第４と第３ポートに出力される。上り光信号として
第１の波長域の光信号を用い、下り信号として第２波長
域の光信号を用いる。上り光信号（第１の波長域）は合
分波器１０の第１ポートに入力し、第３のポートから出
力された後、単一方向光増幅器１１で増幅され、合分波
器１０の第４のポートに入力し、第２のポートから出力
し、伝送路を上り方向に伝搬する。一方、下り光信号
（第２の波長域）は合分波器１０の第２のポートに入力
し、第３のポートから出力された後、単一方向光増幅器
１１で増幅され、合分波器１０の第４ポートに入力し、
第１のポートから出力され、伝送路を下り方向に伝搬す
る。FIG. 2 is a diagram showing the structure of an example of an amplifier repeater used in the present invention. In this example, a bidirectional optical amplifier using a 4-port multiplexer / demultiplexer is used. First of the multiplexer / demultiplexer 10
The optical signal in the first wavelength band and the optical signal in the second wavelength band input to the port of are output to the third port and the fourth port, respectively. Further, the optical signal in the first wavelength band and the optical signal in the second wavelength band input to the second port are output to the fourth and third ports, respectively. An optical signal in the first wavelength band is used as the upstream optical signal, and an optical signal in the second wavelength band is used as the downstream signal. The upstream optical signal (first wavelength band) is input to the first port of the multiplexer / demultiplexer 10, is output from the third port, is amplified by the unidirectional optical amplifier 11, and is then output from the multiplexer / demultiplexer 10. It is input to the fourth port, output from the second port, and propagates in the up direction on the transmission path. On the other hand, the downstream optical signal (second wavelength band) is input to the second port of the multiplexer / demultiplexer 10, is output from the third port, is amplified by the unidirectional optical amplifier 11, and is then multiplexed / demultiplexed. Input to the 4th port of the vessel 10,
It is output from the first port and propagates down the transmission path.
【０００９】一方、第１の波長域の光信号が下り方向に
伝搬する場合には、この光信号は合分波器１０の第２ポ
ートに入力するので、第４ポートから出射し、単一方向
光増幅器１１に反対方向から入力するので、その伝搬が
遮断される。また、第２の波長域の光信号が上り方向に
伝搬する場合、この光信号は合分波器１０の第１のポー
トに入力するので、第４のポートから出力され、単一方
向光増幅器１１に反対方向から入力するので、その伝搬
が遮断される。この結果、増幅中継器３又は４が接続さ
れている光伝送路は、例えば第１の波長域の光が第１の
方向（例えば、上り方向）に伝搬する場合並びに第２の
波長域の光が第１の方向とは反対の第２の方向に伝搬す
る場合、これらの光信号は光増幅されながら伝搬し、第
１の波長域の光が第２の方向（例えば、下り方向）に伝
搬する場合並びに第２の波長域の光が第１の方向（例え
ば、上り方向）に伝搬する場合には増幅中継器３又は４
により遮断されることになる。On the other hand, when the optical signal in the first wavelength band propagates in the downward direction, this optical signal is input to the second port of the multiplexer / demultiplexer 10 and thus is emitted from the fourth port to be a single signal. Since the light is input to the directional optical amplifier 11 from the opposite direction, its propagation is blocked. Further, when the optical signal in the second wavelength band propagates in the upstream direction, this optical signal is input to the first port of the multiplexer / demultiplexer 10 and is therefore output from the fourth port to be a unidirectional optical amplifier. Since 11 is input from the opposite direction, its propagation is blocked. As a result, the optical transmission line to which the amplification repeater 3 or 4 is connected, for example, when the light in the first wavelength band propagates in the first direction (for example, the upstream direction) and the light in the second wavelength band Are propagated in the second direction opposite to the first direction, these optical signals propagate while being optically amplified, and the light in the first wavelength band propagates in the second direction (for example, the down direction). In the case of doing so and when the light in the second wavelength band propagates in the first direction (for example, the upstream direction), the amplification repeater 3 or 4
Will be blocked by.
【００１０】次に、図１に示す本発明による双方向増幅
伝送路について障害点探査を行う方法について説明す
る。初めに、第１の双方向増幅伝送路１の障害点探査を
行う場合について説明する。図１に示すように、伝送路
１の第１の端部１ａ側に光反射試験器６を置き、光反射
試験器６の探査光信号を送信する送信部を第１の双方向
増幅伝送路１の第１の端部１ａに光学的に結合し、散乱
光を受信する受信部を第２の双方向増幅伝送路２の第１
の端部２ａに光学的に結合する。光反射試験器６の探査
光の波長を第１の波長域のものにすると、探査光は第１
の双方向増幅伝送路１を下り方向に伝搬することが可能
である。この探査光が双方向増幅伝送路１中に存在する
障害点に遭遇すると探査光は損失を受け、探査光が発生
する散乱光の強度も減少する。従って、散乱光強度を距
離の関数として図示すると、障害点を境に不連続な減少
がおこり、障害点の特定が可能となる。この散乱光の一
部は、経路５を介して反対側の第２の双方向増幅伝送路
２に導かれ、第２の双方向増幅伝送路２を下り方向とは
反対の上り方向に伝搬し、光反射試験器６の受信部に戻
っる。従って、光反射試験器６により散乱光の有無が検
出され、この検出結果により障害点の探査が可能とな
る。Next, a method for searching for a fault point in the bidirectional amplification transmission line according to the present invention shown in FIG. 1 will be described. First, description will be made regarding a case where a fault point search for the first bidirectional amplification transmission line 1 is performed. As shown in FIG. 1, a light reflection tester 6 is placed on the side of the first end 1a of the transmission line 1, and a transmission unit for transmitting a probe optical signal of the light reflection tester 6 is provided as a first bidirectional amplification transmission line. 1 is optically coupled to the first end 1a of the first bidirectional amplifying transmission line 2 and is used as a receiving unit for receiving scattered light.
Is optically coupled to the end portion 2a. When the wavelength of the probe light of the light reflection tester 6 is set to the first wavelength range, the probe light is
It is possible to propagate in the downward direction through the bidirectional amplification transmission line 1. When this probe light encounters a fault point existing in the bidirectional amplification transmission line 1, the probe light is lost, and the intensity of scattered light generated by the probe light also decreases. Therefore, if the scattered light intensity is illustrated as a function of distance, a discontinuous decrease occurs at the boundary of the obstacle, and the obstacle can be identified. A part of this scattered light is guided to the second bidirectional amplification transmission line 2 on the opposite side via the path 5 and propagates through the second bidirectional amplification transmission line 2 in the up direction opposite to the down direction. , And returns to the receiving section of the light reflection tester 6. Therefore, the presence or absence of scattered light is detected by the light reflection tester 6, and it is possible to search for a failure point based on the detection result.
【００１１】双方向増幅伝送路２の障害点探査を行う時
には、第２の伝送路の右端の第２の端部で光反射試験器
７の送信部を双方向増幅伝送路２に結合し、受信部を第
１の双方向増幅伝送路１と接続し、探査光の波長を第１
の波長域に設定する。この探査光が第２の双方向増幅伝
送路２を伝搬する間に障害点に遭遇すると探査光は損失
を受け、探査光により生ずる散乱光の強度も減少する。
従って、散乱光強度を距離の関数として図示すると、障
害点を境に不連続な減少がおこり、障害点の特定が可能
となる。散乱光は、経路５を介して第１の双方向増幅伝
送路１に導かれ、第１の双方向増幅伝送路１を下り方向
に伝搬し、光反射試験器７の受信部に戻ってくるので、
光反射試験器７により障害点探査を行うころが可能とな
る。When searching for a fault point in the bidirectional amplification transmission line 2, the transmitter of the light reflection tester 7 is coupled to the bidirectional amplification transmission line 2 at the second end, which is the right end of the second transmission line. The receiver is connected to the first bidirectional amplification transmission line 1 and the wavelength of the probe light is set to the first
Set to the wavelength range of. If the probe light encounters a fault point while propagating through the second bidirectional amplification transmission line 2, the probe light is lost, and the intensity of scattered light generated by the probe light also decreases.
Therefore, if the scattered light intensity is illustrated as a function of distance, a discontinuous decrease occurs at the boundary of the obstacle, and the obstacle can be identified. The scattered light is guided to the first bidirectional amplification transmission line 1 via the path 5, propagates in the first bidirectional amplification transmission line 1 in the downward direction, and returns to the receiving unit of the light reflection tester 7. So
The light reflection tester 7 makes it possible to perform a fault point search.
【００１２】図３は本発明の障害探査方法の別の実施例
を示す図である。第１の波長域および第２の波長域に属
する光の伝搬方向は図１と同一とする。第１の双方向増
幅伝送路１の増幅中継器３−Ｎ−１、３−Ｎの間の伝送
路で第２波長域の光信号が発生した散乱光は、経路５−
Ｎを介して双方向増幅伝送路２に導かれ下り方向に伝搬
していくようになっている。また、双方向増幅伝送路２
の増幅中継器４−Ｎと４−Ｎ＋１の間の伝送路で第２波
長域の光信号が発生した散乱光は、経路５−Ｎを介して
双方向増幅伝送路１に導かれ上り方向に伝搬していくよ
うになっている。FIG. 3 is a diagram showing another embodiment of the fault detection method of the present invention. The propagation directions of light belonging to the first wavelength band and the second wavelength band are the same as in FIG. The scattered light generated by the optical signal in the second wavelength band in the transmission path between the amplification repeaters 3-N-1 and 3-N of the first bidirectional amplification transmission path 1 is the path 5-
The signal is guided to the bidirectional amplification transmission line 2 via N and propagates in the downward direction. In addition, the bidirectional amplification transmission line 2
The scattered light generated by the optical signal in the second wavelength band in the transmission line between the amplification repeaters 4-N and 4-N + 1 is guided to the bidirectional amplification transmission line 1 via the route 5-N and is transmitted in the upward direction. It is supposed to propagate.
【００１３】双方向増幅伝送路１の障害点探査を行う時
には、図２に示すように伝送路の右端に光反射試験器７
を置き．、光反射試験器７の送信部を双方向増幅伝送路
１に、受信部を双方向増幅伝送路２と接続する。また、
双方向増幅伝送路２の障害点探査を行う時には、図２に
示すように伝送路の左端に光反射試験器６を置き、光反
射試験器６の送信部を双方向増幅伝送路２に、受信部を
双方向増幅伝送路１に接続する。光反射試験器６，７の
探査信号光の波長として第一波長域にある光を使用する
と、探査信号が双方向増幅伝送路１で発生した散乱光を
経路５を介して双方向増幅伝送路２から受信でき、ま
た、探査信号が双方向増幅伝送路２発生した散乱光を経
路５を介して双方向増幅伝送路１から受信できるので、
光反射試験器を使用して双方向光増幅伝送路の障害点探
査が可能となる。When searching for a fault point in the bidirectional amplification transmission line 1, a light reflection tester 7 is provided at the right end of the transmission line as shown in FIG.
Put. The transmitter of the light reflection tester 7 is connected to the bidirectional amplification transmission line 1, and the reception unit is connected to the bidirectional amplification transmission line 2. Also,
When searching for a failure point in the bidirectional amplification transmission line 2, a light reflection tester 6 is placed at the left end of the transmission line as shown in FIG. 2, and the transmitter of the light reflection tester 6 is placed in the bidirectional amplification transmission line 2. The receiver is connected to the bidirectional amplification transmission line 1. When the light in the first wavelength range is used as the wavelength of the exploration signal light of the light reflection testers 6 and 7, the scattered light generated in the bidirectional amplification transmission line 1 by the exploration signal is transmitted through the route 5 to the bidirectional amplification transmission line. 2, and the scattered light generated by the exploration signal from the bidirectional amplification transmission path 2 can be received from the bidirectional amplification transmission path 1 via the path 5.
Using a light reflection tester, it is possible to search for faults in a bidirectional optical amplification transmission line.
【００１４】さて、本発明の汲方向伝送路は通常状態で
は、通信信号の送受信を行っている。この時、図１に示
す双方向増幅伝送路１には第一波長域に属する通信信号
光が上り方向に、第二波長域に属する通信信号光が下り
方向に伝搬している。また、双方向増幅伝送路２には第
一波長域に属する通信信号光が下り方向に、第二波長域
に属する通信信号光が上り方向に伝擬している。これら
の通信信号光も散乱光を発生している。双方向増幅伝送
路１を下り方向に伝擬する第二波長域に属する通信信号
光が発生した散乱光は、経路５を介して双方向増幅伝送
路２に導かれ、双方向増幅伝送路２を上り方向に伝搬す
る。この散乱光は双方向増幅伝送路２を上り方向に伝擬
している通信信号と一緒に双方向増幅伝送路２の左端に
ある通信信号受信器で受信されるので、通信信号の雑音
として作用し通信信号の伝送特性を劣化させる。また、
双方向増幅伝送路２を上り方向に伝搬する第二波長域に
属する通信信号光が発生した散乱光も、双方向増幅伝送
路１の右端にある通信信号受信器の雑音となる。In the normal state, the pumping direction transmission line of the present invention transmits and receives communication signals. At this time, the communication signal light belonging to the first wavelength band propagates in the up direction and the communication signal light belonging to the second wavelength band propagates in the down direction in the bidirectional amplification transmission line 1 shown in FIG. Further, the communication signal light belonging to the first wavelength band is transmitted in the downward direction and the communication signal light belonging to the second wavelength band is transmitted in the upward direction in the bidirectional amplification transmission line 2. These communication signal lights also generate scattered light. The scattered light generated by the communication signal light belonging to the second wavelength band that simulates the bidirectional amplification transmission line 1 in the downward direction is guided to the bidirectional amplification transmission line 2 via the route 5, and the bidirectional amplification transmission line 2 Propagate in the up direction. Since this scattered light is received by the communication signal receiver at the left end of the bidirectional amplification transmission line 2 together with the communication signal which is transmitted through the bidirectional amplification transmission line 2 in the upward direction, it acts as noise of the communication signal. However, the transmission characteristics of the communication signal are deteriorated. Also,
The scattered light generated by the communication signal light belonging to the second wavelength band that propagates in the upward direction on the bidirectional amplification transmission line 2 also becomes noise of the communication signal receiver at the right end of the bidirectional amplification transmission line 1.
【００１５】この間題を解決するため、本発明の請求項
２では、通信信号と探査信号が異なる波長の光を使用
し、かつ、図３に示すように経路５に探査信号の波長の
みを通過させる帯域通過手段８を設けている。本手段と
しては例えば誘電体多層膜を用いた光帯域通過フィルタ
がある。双方向増幅伝送路１を下り方向に伝搬する第二
波長域に属する通信信号光あるいは探査信号光が発生し
た散乱光は、帯域通過手段８により探査信号が発生した
散乱光のみが選択され経路５を介して、双方向増幅伝送
路２に導かれるようになっている。また、双方向増幅伝
送路２を上り方向に伝搬する第二波長域に属する通信信
号光あるいは探査信号光が発生した散乱光は、帯域通過
手段８により探査信号が発生した散乱光のみが選択され
経路５を介して、双方向増幅伝送路１に導かれるように
なっている。このように探査信号が発生した散乱光は帰
還するが、通信信号が発生した散乱光は帰還しないの
で、通信信号の伝送特性を劣化させることなく、光反射
試験による障害点の探査が可能である。In order to solve this problem, according to claim 2 of the present invention, light having a different wavelength between the communication signal and the search signal is used, and only the wavelength of the search signal is passed through the path 5 as shown in FIG. A band passing means 8 is provided. This means is, for example, an optical bandpass filter using a dielectric multilayer film. As for the scattered light generated by the communication signal light or the search signal light belonging to the second wavelength band that propagates in the downward direction through the bidirectional amplification transmission line 1, only the scattered light generated by the search signal is selected by the bandpass means 8 and the path 5 is selected. It is designed to be guided to the bidirectional amplification transmission line 2 via. As for the scattered light generated by the communication signal light or the search signal light belonging to the second wavelength band that propagates in the upward direction through the bidirectional amplification transmission line 2, only the scattered light generated by the search signal is selected by the bandpass means 8. It is adapted to be guided to the bidirectional amplification transmission line 1 via the route 5. In this way, the scattered light generated by the search signal is returned, but the scattered light generated by the communication signal is not returned, so it is possible to search for a fault point by a light reflection test without degrading the transmission characteristics of the communication signal. .
【００１６】[0016]
【発明の効果】以上説明したように、本発明では、伝搬
方向の波長関係が逆方向にある２本の双方向光増幅伝送
路を対とし、反射試験器が発生した散乱光を相互に導き
合う手段を設け、対方の伝送路を散乱光の帰還路として
使用できるようにしているので、双方向伝送路でも光反
射試験器を用いて障害点探査が可能となっている。As described above, in the present invention, two bidirectional optical amplification transmission lines whose wavelengths in the propagation directions are opposite to each other are used as a pair, and the scattered light generated by the reflection tester is guided to each other. Since matching means is provided so that the opposite transmission line can be used as a return line for scattered light, it is possible to search for a fault point using a light reflection tester even in a bidirectional transmission line.
【図１】 本発明の障害探査方法の実施例示す囲。FIG. 1 is a diagram showing an embodiment of a fault detection method of the present invention.
【図２】 本発明の障害探査方法の別の実施例示す図。FIG. 2 is a diagram showing another embodiment of the fault detection method of the present invention.
【図３】 本発明請求項２の障害探査方法の実施例示す
図。FIG. 3 is a diagram showing an embodiment of the fault search method according to claim 2 of the present invention.
【図４】 双方向増幅器の構成例を示すブロック図。FIG. 4 is a block diagram showing a configuration example of a bidirectional amplifier.
１、２ 双方向増幅伝送路 ３、４ 双方向増幅器 ５ 散乱光を導く経路 ６、７ 光反射試験器 ８ 帯域通過手段 ９ 合分波器 １０ 単一方向光増幅器 1, 2 bidirectional amplification transmission line 3, 4 bidirectional amplifier 5 Path that guides scattered light 6,7 Light reflection tester 8 bandpass means 9 Multiplexer 10 Unidirectional optical amplifier
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ Ｈ０４Ｂ 17/02 (58)調査した分野(Int.Cl.7，ＤＢ名) G01M 11/00 - 11/08 H04B 10/00 - 10/28 ─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. 7 identification code FI H04B 17/02 (58) Fields investigated (Int.Cl. 7 , DB name) G01M 11/00-11/08 H04B 10/00 -10/28
Claims (5)
れている第１の双方向増幅伝送路と、同様に１個又はそ
れ以上の増幅中継器が接続され、第１の双方向増幅伝送
路と対をなす第２の双方向増幅伝送路と、これら第１の
双方向増幅伝送路と第２の双方向増幅伝送路とを光学的
に接続する１個又はそれ以上の光伝送路とを有し、 前記第１の双方向増幅伝送路に接続されている増幅中継
器は、第１の方向に伝搬する第１の波長域の信号光を増
幅して出力すると共に第１の方向と反対の第２の方向に
伝搬する第１の波長域の信号光を遮断し、第１の方向に
伝搬する第１の波長域とは異なる第２の波長域の信号光
を遮断すると共に第２の方向に伝搬する第２の波長域の
信号光を増幅して出力する双方向光増幅特性を有し、 前記第２の双方向増幅伝送路に接続されている増幅中継
器は、前記第１の方向に伝搬する前記第１の波長域の信
号光を遮断すると共に前記第１の方向と反対の第２の方
向に伝搬する第１の波長域の信号光を増幅して出力し、
前記第１の方向に伝搬する前記第２の波長域の信号光を
増幅して出力すると共に前記第２の方向に伝搬する第２
の波長域の信号光を遮断する双方向光増幅特性を有する
ことを特徴とする双方向光増幅伝送路。1. A first bidirectional amplifying transmission line to which one or more amplifying repeaters are connected, and a first bidirectional amplifying transmission line to which one or more amplifying repeaters are similarly connected. A second bidirectional amplification transmission line that forms a pair with the transmission line, and one or more optical transmission lines that optically connect the first bidirectional amplification transmission line and the second bidirectional amplification transmission line. And an amplification repeater connected to the first bidirectional amplification transmission line, amplifies and outputs the signal light in the first wavelength band propagating in the first direction, and And blocking the signal light of the first wavelength band propagating in the second direction opposite to the first wavelength band and blocking the signal light of the second wavelength band different from the first wavelength band propagating in the first direction. 2 has a bidirectional optical amplification characteristic of amplifying and outputting the signal light of the second wavelength band propagating in the direction of 2. The amplification repeater connected to the path blocks the signal light of the first wavelength band propagating in the first direction and propagates in the second direction opposite to the first direction. Amplify and output the signal light in the wavelength range,
A second signal that propagates in the second direction while amplifying and outputting the signal light in the second wavelength band that propagates in the first direction
A bidirectional optical amplification transmission line, which has a bidirectional optical amplification characteristic of blocking signal light in the wavelength range.
る合分波器と、一方向に伝搬する光信号だけを増幅して
出力し、反対方向に伝搬する光信号を遮断する単一方向
光増幅器とを有することを特徴とする請求項１に記載の
双方向増幅伝送路。2. The amplifying repeater has a four-port multiplexer / demultiplexer and a single direction that amplifies and outputs only an optical signal propagating in one direction and blocks an optical signal propagating in the opposite direction. The bidirectional amplification transmission line according to claim 1, further comprising an optical amplifier.
存在する障害点を探査する方法であって、 前記第１の双方向増幅伝送路の第１の端部から探査用の
第１の波長域の光パルスを投射し、前記第２の双方向増
幅伝送路の第１の端部から出射する散乱光を受光する工
程と、 前記第２の双方向増幅伝送路の第１の端部から探査用の
第２の波長域の光パルスを投射し、前記第１の双方向増
幅伝送路の第１の端部から出射する散乱光を受光する工
程とを具えることを特徴とする双方向増幅伝送路の障害
点探査方法。3. A method for searching for a fault existing in the bidirectional amplification transmission line according to claim 1, wherein the first bidirectional amplification transmission line is searched for from a first end of the first bidirectional amplification transmission line. Projecting an optical pulse in a wavelength range of 1 and receiving scattered light emitted from a first end of the second bidirectional amplification transmission line; and a first step of the second bidirectional amplification transmission line. Projecting an optical pulse in the second wavelength band for exploration from the end, and receiving scattered light emitted from the first end of the first bidirectional amplification transmission line. Method for searching for faults in bidirectional amplification transmission line.
発生した散乱光を他方の双方向光増幅伝送路に導く手段
は、探査信号光の波長光のみを通過することを特徴とし
た双方向光増幅伝送路。4. The means for guiding scattered light generated in one of the parent optical amplification transmission lines to the other bidirectional optical amplification transmission line according to claim 1, passes only the wavelength light of the search signal light. Bidirectional optical amplification transmission line.
増幅伝送路に第一あるいは第二波長域に属し、かつ、通
信信号光の波長とは異なる探査信号光を入射し、他方の
親方向光増幅路から散乱光を受信して障害点を探査する
ことを特徴とする双方向光増幅伝送路の障害点探査方
法。5. A probe signal light belonging to the first or second wavelength range and being different from the wavelength of the communication signal light is incident on one of the two bidirectional optical amplification transmission paths to the transmission path pair of claim 3, A method of searching for a failure point in a bidirectional optical amplification transmission path, which comprises detecting scattered light from the other parent optical amplification path and searching for a failure point.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000357251A JP3534696B2 (en) | 2000-11-24 | 2000-11-24 | Bidirectional optical amplifying transmission line and fault finding method thereof |
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