JPH11150511A - Wavelength multiplex light reception device/system and transmission line switching method - Google Patents
Wavelength multiplex light reception device/system and transmission line switching methodInfo
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- JPH11150511A JPH11150511A JP9313501A JP31350197A JPH11150511A JP H11150511 A JPH11150511 A JP H11150511A JP 9313501 A JP9313501 A JP 9313501A JP 31350197 A JP31350197 A JP 31350197A JP H11150511 A JPH11150511 A JP H11150511A
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- wavelength
- signal light
- optical
- wavelength division
- attenuator
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Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は、波長多重光通信シ
ステムに関し、特に現用系光伝送路と予備系光伝送路を
備え、これらと無瞬断パス切り替え装置を組み合わせた
波長多重光通信システム、該システムの波長多重信号光
受信装置、および上記両光伝送路間の切り替え方法に関
する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wavelength division multiplexing optical communication system, and more particularly, to a wavelength division multiplexing optical communication system having an active optical transmission line and a protection optical transmission line, and combining these with an instantaneous path switching device. The present invention relates to a wavelength division multiplexed signal light receiving device of the system and a method for switching between the two optical transmission lines.
【0002】[0002]
【従来の技術】現用系光伝送路と、予備系光伝送路と、
無瞬断パス切り替え装置を有する波長多重光通信システ
ムの従来例を図2に示す。ここでは4波長の信号光が波
長多重される例を示す。2. Description of the Related Art An active optical transmission line, a standby optical transmission line,
FIG. 2 shows a conventional example of a wavelength division multiplexing optical communication system having an uninterrupted path switching device. Here, an example is shown in which signal light of four wavelengths is wavelength-multiplexed.
【0003】図2では、2つの波長多重光通信装置が光
伝送路11を介して配置された光伝送系が2系統設けら
れている。光伝送系の両側に配置された波長多重光通信
装置は、光受信部と光送信部を備えている。光受信部
は、光伝送路11を伝送された波長多重信号光を増幅す
る増幅器4と、増幅された波長多重信号光を分波する光
分波器5と、分波された波長多重信号光から所定の波長
の信号光を分離するバンドパスフィルタ6を備えてい
る。一方、光送信部は、各波長の信号光を合波する光合
波器8と、合波された波長多重信号光を増幅する増幅器
3を備えている。In FIG. 2, two optical transmission systems in which two wavelength division multiplexing optical communication devices are arranged via an optical transmission line 11 are provided. The wavelength division multiplexing optical communication devices disposed on both sides of the optical transmission system include an optical receiving unit and an optical transmitting unit. The optical receiving unit includes an amplifier 4 for amplifying the wavelength-division multiplexed signal light transmitted through the optical transmission line 11, an optical demultiplexer 5 for demultiplexing the amplified wavelength-division multiplexed signal light, and a wavelength-division multiplexed signal light. And a band-pass filter 6 for separating a signal light having a predetermined wavelength from the light. On the other hand, the optical transmission unit includes an optical multiplexer 8 for multiplexing the signal light of each wavelength and an amplifier 3 for amplifying the multiplexed wavelength multiplexed signal light.
【0004】また、波長多重光通信システムの一方の端
局を構成する2つの波長多重光通信装置には各波長の信
号光毎に無瞬断パス切り替え装置9が設置されている。
無瞬断パス切り替え装置9の出力部はそれぞれ現用系及
び予備系にそれぞれ属する2つの光送信部の光合波器8
に接続している。また無瞬断パス切り替え装置9の入力
部には、同じく2つの受信部の所定波長に対応するバン
ドパスフィルタ6から出力される信号光が入力される。[0004] Two wavelength division multiplexing optical communication devices constituting one terminal station of a wavelength division multiplexing optical communication system are provided with a pathless switching device 9 for each signal light of each wavelength.
The output unit of the uninterrupted path switching device 9 is an optical multiplexer 8 of two optical transmission units respectively belonging to the working system and the protection system.
Connected to The signal light output from the bandpass filter 6 corresponding to the predetermined wavelength of the two receiving units is also input to the input unit of the instantaneous interruption path switching device 9.
【0005】次に、上記光伝送システムの動作について
説明する。該システムの一方の端局において各波長の信
号光は該波長に対応する無瞬断パス切り替え装置9を介
して両光伝送系の合波器8にそれぞれ入力し、波長多重
される。この波長多重信号光は増幅され、光伝送路11
を伝送される。他方の端局の受信側において、波長多重
信号光は分波器5及びバンドパスフィルタ6によって波
長毎に分離される。この後、各信号光はそれぞれ対応す
る無瞬断パス切り替え装置9に入力される。受信側の無
瞬断パス切り替え装置9は現用として設定された光伝送
系を介して受信する信号光を選択する。Next, the operation of the optical transmission system will be described. At one terminal of the system, the signal light of each wavelength is input to the multiplexers 8 of both optical transmission systems via the uninterrupted path switching device 9 corresponding to the wavelength, and wavelength-multiplexed. This wavelength-division multiplexed signal light is amplified, and
Is transmitted. On the receiving side of the other terminal station, the wavelength division multiplexed signal light is separated for each wavelength by the demultiplexer 5 and the band pass filter 6. Thereafter, each signal light is input to the corresponding instantaneous interruption path switching device 9. The instantaneous uninterrupted path switching device 9 on the receiving side selects the signal light to be received via the optical transmission system set as working.
【0006】[0006]
【発明が解決しようとする課題】無瞬断パス切り替え装
置9は対応する信号光またはこれを変換した電気信号を
常に検出しており、信号光に断またはレベル低下などの
異常が検出されると、無瞬断となるように(すなわち位
相を合わせるように)当該波長の信号光を予備の伝送系
から送信される信号光に切り替える。しかし、受信側の
各無瞬断パス切り替え装置9は光伝送系の切り替えを独
自に行っているため、障害が発生した波長の信号光は予
備系に切り替えられが、他の波長の信号光は元の現用系
が使用されるという状況が発生する。すなわち、両系と
も現用系となってしまう事態が発生する。The non-interruptible path switching device 9 always detects a corresponding signal light or an electric signal converted from the signal light, and when an abnormality such as disconnection or a decrease in level is detected in the signal light. Then, the signal light of the wavelength is switched to the signal light transmitted from the spare transmission system so that there is no instantaneous interruption (that is, the phases are matched). However, since each uninterruptible path switching device 9 on the receiving side independently switches the optical transmission system, the signal light of the wavelength in which the failure has occurred is switched to the standby system, but the signal light of another wavelength is not. A situation arises in which the original working system is used. That is, a situation occurs in which both systems become active systems.
【0007】このような場合、現用回線に影響が出ない
ように、保守者が全ての無瞬断パス切り替え装置9を予
備系へ強制切り替えし、その後保守作業を行っていた。
このため、速やかな障害の復旧が困難であった。In such a case, the maintenance person has forcibly switched all the non-instantaneous path switching devices 9 to the standby system so as not to affect the working line, and then performs maintenance work.
For this reason, it was difficult to quickly recover from the failure.
【0008】しかるに本発明の目的は、このような現用
系及び予備系の波長多重光伝送系において、障害発生に
より一部波長の伝送系が切り替わった場合、回復を速や
かに行うことのできるシステムおよび方法を提供するも
のである。SUMMARY OF THE INVENTION It is an object of the present invention to provide a system capable of promptly recovering when a transmission system of a part of a wavelength is switched due to a failure in such a working system and a protection system. It provides a method.
【0009】[0009]
【課題を解決するための手段】すなわち上記課題を解決
するための、波長多重光受信装置は、光伝送路を伝送さ
れた波長多重信号光を分波する光分波器と、分波された
波長多重信号光から特定波長の信号光を取り出す複数の
波長選択フィルタと、上記波長選択フィルタが選択する
信号光を受信し信号光が正常に受信されない場合に警報
信号を出力する警報回路と、該警報回路の出力する警報
信号を受信したとき波長多重光信号を減衰させるアッテ
ネータを備える。該アッテネータは上記光分波器の前段
に設けることが望ましい。SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a wavelength division multiplexing optical receiving apparatus comprises: an optical demultiplexer for demultiplexing a wavelength division multiplexed signal light transmitted through an optical transmission line; A plurality of wavelength selection filters for extracting a signal light of a specific wavelength from the wavelength multiplexed signal light; an alarm circuit for receiving a signal light selected by the wavelength selection filter and outputting an alarm signal when the signal light is not normally received; An attenuator is provided for attenuating the wavelength multiplexed optical signal when receiving an alarm signal output from the alarm circuit. The attenuator is desirably provided in a stage preceding the optical demultiplexer.
【0010】次に、波長多重光通信システムは、現用光
伝送系及び予備光伝送系として波長多重信号光の送信部
と受信部を備えた波長多重光通信装置が光伝送路を介し
て配置された光伝送系をそれぞれ有し、現用系及び予備
系の波長多重光通信装置にそれぞれ接続する無瞬断パス
切り替え装置を備え、波長多重光通信装置の受信部は波
長多重信号光を分波する分波器と、分波された波長多重
信号光から特定波長の信号光を取り出す複数の波長選択
フィルタと、該波長選択フィルタが選択する信号光を受
信し信号光が正常に受信されないときに警報信号を出力
する警報回路と、該警報回路の出力する警報信号を受信
したとき波長多重信号光を減衰させるアッテネータを備
えている。Next, in a wavelength division multiplexing optical communication system, a wavelength division multiplexing optical communication device having a transmission part and a reception part of a wavelength division multiplexed signal light as an active optical transmission system and a standby optical transmission system is arranged via an optical transmission line. Each having an optical transmission system, and a non-interruptible path switching device connected to the working and protection wavelength multiplexing optical communication devices, respectively, and the receiving unit of the wavelength multiplexing optical communication device separates the wavelength multiplexing signal light. A demultiplexer, a plurality of wavelength selection filters for extracting signal light of a specific wavelength from the demultiplexed wavelength multiplexed signal light, and an alarm when the signal light selected by the wavelength selection filter is received and the signal light is not normally received An alarm circuit that outputs a signal, and an attenuator that attenuates the wavelength-division multiplexed signal light when an alarm signal output by the alarm circuit is received.
【0011】また、現用系光伝送路と予備系光伝送路と
の間の切り替え方法は、上記いずれかの光伝送路の波長
多重光通信装置の受信部において1以上の信号光の異常
を検出した場合、波長多重信号光を減衰させ、前記波長
多重光通信装置に接続する無瞬断パス切り替え装置によ
り波長多重信号光をすべて他方の光伝送路へ切り替える
方法である。Further, the method for switching between the working optical transmission line and the protection optical transmission line includes detecting an abnormality of one or more signal lights in the receiving section of the wavelength division multiplexing optical communication device of any one of the above optical transmission lines. In this case, the wavelength-division multiplexed signal light is attenuated, and all the wavelength-division multiplexed signal light is switched to the other optical transmission line by the hitless path switching device connected to the wavelength-division multiplexed optical communication device.
【0012】上記本発明により、波長多重される信号光
に異常が検出されたとき、波長多重信号光のすべてが自
動的に予備系に切り替えられるので速やかな保守が可能
となる。According to the present invention, when an abnormality is detected in the wavelength multiplexed signal light, all of the wavelength multiplexed signal light is automatically switched to the standby system, so that quick maintenance becomes possible.
【0013】[0013]
【発明の実施の形態】図1に基づき本発明の実施の形態
について説明する。基本的な構成は図2に示した従来の
システムと同様である。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG. The basic configuration is the same as the conventional system shown in FIG.
【0014】波長多重光通信装置の受信部は、まず光伝
送路を伝送された波長多重信号光を増幅する光増幅器4
と、該光増幅器4の出力側には警報信号を受信したとき
波長多重信号光を減衰させるアッテネータ7が接続して
いる。アッテネータ7には波長多重信号光を分波する光
分波器5が接続し、光分波器5には分波された波長多重
信号光から特定の波長を選択するバンドパスフィルタ6
が配置されている。波長選択フィルタ6から取り出され
た各波長の信号光は、それぞれ波長毎に設けられた無瞬
断パス切り替え装置9に送られると共に、各波長ごとの
警報回路1に送られる。警報回路1はオア回路2を介し
て上記アッテネータ7に接続している。上記無瞬断パス
切り替え装置9は、各波長毎に設けられ、現用系および
予備系それぞれの波長多重光通信装置の受信部、および
送信部と接続している。The receiving section of the wavelength division multiplexing optical communication apparatus first comprises an optical amplifier 4 for amplifying the wavelength division multiplexed signal light transmitted through the optical transmission line.
The output side of the optical amplifier 4 is connected to an attenuator 7 for attenuating the wavelength multiplexed signal light when an alarm signal is received. The attenuator 7 is connected to an optical demultiplexer 5 for demultiplexing the wavelength multiplexed signal light, and the optical demultiplexer 5 is connected to a band pass filter 6 for selecting a specific wavelength from the demultiplexed wavelength multiplexed signal light.
Is arranged. The signal light of each wavelength extracted from the wavelength selection filter 6 is sent to the instantaneous uninterrupted path switching device 9 provided for each wavelength, and also sent to the alarm circuit 1 for each wavelength. The alarm circuit 1 is connected to the attenuator 7 via an OR circuit 2. The instantaneous uninterrupted path switching device 9 is provided for each wavelength, and is connected to the receiving unit and the transmitting unit of the wavelength division multiplexing optical communication device of each of the working system and the protection system.
【0015】各信号光は、無瞬断パス切り替え装置9を
通って現用系及び予備系の各送信部で波長多重され、そ
れぞれの光伝送路に送られる。Each signal light is wavelength-multiplexed in each of the active and standby transmission units through the non-interruptible path switching device 9 and sent to each optical transmission line.
【0016】光伝送路から入力した波長多重信号光は、
現用系及び予備系の各送信部の増幅器4で増幅され、ア
ッテネータ7を通り、分波器5で分波され、バンドパス
フィルタ6により各波長の信号光が取り出される。各波
長の信号光は対応する無瞬断パス切り替え装置9に入力
される。該無瞬断パス切り替え装置9では現用系として
設定された光伝送路からの信号光を選択する。The wavelength multiplexed signal light input from the optical transmission line is
The signal light is amplified by the amplifiers 4 of the transmission units in the working system and the protection system, passes through the attenuator 7, is demultiplexed by the demultiplexer 5, and the signal light of each wavelength is extracted by the bandpass filter 6. The signal light of each wavelength is input to the corresponding uninterrupted path switching device 9. The hitless path switching device 9 selects the signal light from the optical transmission line set as the working system.
【0017】一方、各波長の信号光は波長毎の警報回路
1にも送られるが、該警報回路1は通常の受信レベルの
信号光を受信している限り警報信号を出さない。しかし
受信している信号光に信号断やレベル低下などの何らか
の異常が発生したとき、警報回路1から警報信号が送出
され、オア回路2をとおってアッテネータ7に送られ
る。On the other hand, the signal light of each wavelength is also sent to the alarm circuit 1 for each wavelength, but the alarm circuit 1 does not output an alarm signal as long as the signal light of the normal reception level is received. However, when any abnormality such as a signal interruption or a level drop occurs in the received signal light, an alarm signal is sent from the alarm circuit 1 and sent to the attenuator 7 through the OR circuit 2.
【0018】アッテネータ7は警報信号を受信すると、
光増幅器4から入力される波長多重信号光を所定のレベ
ルまで減少させる。レベルが減少した波長多重信号光は
分波器5で分波され、各バンドパスフィルタ6で特定の
波長が取り出され、対応する無瞬断パス切り替え装置9
に入力される。ここで各波長の信号光のレベルは、アッ
テネータ7により所定のレベルにまでレベルが減少させ
られているため、各無瞬断パス切り替え装置9は信号光
が異常と判断し、それぞれ受信している波長の信号光を
予備系の光伝送路に切り替える動作を行う。When the attenuator 7 receives the alarm signal,
The wavelength multiplexed signal light input from the optical amplifier 4 is reduced to a predetermined level. The wavelength-division multiplexed signal light whose level has been reduced is demultiplexed by the demultiplexer 5, a specific wavelength is extracted by each band pass filter 6, and the corresponding non-interruptible path switching device 9
Is input to Here, since the level of the signal light of each wavelength has been reduced to a predetermined level by the attenuator 7, each instantaneous uninterrupted path switching device 9 determines that the signal light is abnormal and receives each signal. An operation of switching the signal light of the wavelength to the optical transmission line of the standby system is performed.
【0019】以上のように本発明では、波長多重信号光
のうち1波長でも異常が発生したとき、上記動作により
波長多重光が現用系から予備系に自動的に切り替えられ
るので、現用光伝送系に対し速やかに保守、復旧作業が
開始できる。As described above, according to the present invention, when an abnormality occurs in even one wavelength of the wavelength multiplexed signal light, the wavelength multiplexed light is automatically switched from the working system to the standby system by the above operation. Maintenance and recovery work can be started immediately.
【0020】図1の例で、信号光がどのレベルまで減少
したときに異常とするかは、システムの設計によって異
なってくる。またオア回路2は必ずしも必要でなく、警
報回路1の出力する警報信号を直接アッテネータ7に入
力させてもよい。警報回路1は各波長毎に異常を検出す
る構成であるが、波長多重信号光全体のレベルを検出し
所定のレベル変動を異常と判断する構成も可能である。
この場合、光増幅器4のすぐ後段に警報回路を接続する
ことができる。減衰量可変アッテネータは既に公知であ
り、2枚の所定のフィルタを組み合わせこれらを回転さ
せることにより構成できる。In the example of FIG. 1, the level to which the signal light is reduced when the signal light becomes abnormal depends on the system design. The OR circuit 2 is not always necessary, and the alarm signal output from the alarm circuit 1 may be directly input to the attenuator 7. The alarm circuit 1 is configured to detect an abnormality for each wavelength, but may be configured to detect the level of the entire WDM signal light and determine a predetermined level fluctuation as abnormal.
In this case, an alarm circuit can be connected immediately after the optical amplifier 4. Variable attenuation attenuators are already known, and can be configured by combining two predetermined filters and rotating them.
【0021】[0021]
【発明の効果】本発明では、現用系光伝送路と予備系光
伝送路と無瞬断パス切り替え装置を有する波長多重光通
信システムにおいて、受信側に置いて、波長多重された
信号光のうち1波長でも異常と判断された場合、波長多
重される全ての信号光を他方の光伝送路に自動的に切り
替えることができ、従来に比べて格段に速やかな保守、
復旧作業が可能となる。According to the present invention, in a wavelength division multiplexing optical communication system having an active optical transmission line, a protection optical transmission line, and an instantaneous uninterrupted path switching device, the wavelength division multiplexed signal light is placed on the receiving side. If it is determined that even one wavelength is abnormal, all of the wavelength division multiplexed signal light can be automatically switched to the other optical transmission line, which makes maintenance and maintenance much faster than before.
Recovery work becomes possible.
【図1】本発明の波長多重光通信システム構成例を示す
ブロック図。FIG. 1 is a block diagram illustrating a configuration example of a wavelength division multiplexing optical communication system according to the present invention.
【図2】従来の波長多重光通信システム構成例を示すブ
ロック図。FIG. 2 is a block diagram showing a configuration example of a conventional wavelength division multiplexing optical communication system.
1 警報回路 2 オア回路 3、4 光増幅回路 5 分波器 6 バンドパスフィルタ 7 アッテネータ 8 合波器 9 無瞬断パス切り替え装置 11 光伝送路 REFERENCE SIGNS LIST 1 alarm circuit 2 OR circuit 3, 4 optical amplifier circuit 5 demultiplexer 6 bandpass filter 7 attenuator 8 multiplexer 9 uninterrupted path switching device 11 optical transmission line
Claims (9)
分波する光分波器と、分波された波長多重信号光から特
定波長の信号光を取り出す複数の波長選択フィルタを備
える波長多重光受信装置であって、前記波長選択フィル
タが選択する信号光を受信し該信号光が正常に受信され
ないときに警報信号を出力する警報回路と、該警報回路
の出力する警報信号を受信したとき波長多重信号光を減
衰させるアッテネータを備えることを特徴とする波長多
重光受信装置。An optical demultiplexer for demultiplexing a wavelength division multiplexed signal light transmitted through an optical transmission line, and a plurality of wavelength selection filters for extracting a signal light of a specific wavelength from the demultiplexed wavelength division multiplexed signal light. A multiplex optical receiving device, comprising: an alarm circuit that receives a signal light selected by the wavelength selection filter and outputs an alarm signal when the signal light is not normally received; and receives an alarm signal output by the alarm circuit. A wavelength multiplexing optical receiver, comprising: an attenuator for attenuating the wavelength multiplexing signal light.
に設けられる請求項1記載の波長多重光受信装置。2. The wavelength division multiplexing optical receiving device according to claim 1, wherein said attenuator is provided at a stage preceding said optical demultiplexer.
毎に設けられる請求項1または2記載の波長多重光受信
装置。3. The wavelength division multiplexing optical receiving device according to claim 1, wherein said alarm circuit is provided for each of said wavelength selective filters.
路が配置されている請求項3記載の波長多重光受信装
置。4. The wavelength division multiplexed optical receiving device according to claim 3, wherein an OR circuit is arranged between the alarm circuit and the attenuator.
波長多重信号光を増幅する光増幅器が設けられている請
求項1、2、3または4記載の波長多重光受信装置。5. The wavelength-division multiplexed optical receiving apparatus according to claim 1, further comprising an optical amplifier for amplifying the transmitted wavelength-division multiplexed signal light before the attenuator.
長多重信号光の送信部と受信部を備えた波長多重光通信
装置が光伝送路を介して配置された光伝送系をそれぞれ
有し、現用系及び予備系の波長多重光通信装置にそれぞ
れ接続する無瞬断パス切り替え装置を備える波長多重光
通信システムにおいて、波長多重光通信装置の受信部は
波長多重信号光を分波する分波器と、分波された波長多
重信号光から特定波長の信号光を取り出す複数の波長選
択フィルタと、該波長選択フィルタが選択する信号光を
受信し信号光が正常に受信されないときに警報信号を出
力する警報回路と、該警報回路の出力する警報信号を受
信したとき波長多重信号光を減衰させるアッテネータを
備えることを特徴とする波長多重光通信システム。6. A wavelength division multiplexing optical communication device having a wavelength division multiplexed signal light transmission unit and a reception unit as an active optical transmission system and a standby optical transmission system respectively has an optical transmission system arranged via an optical transmission line. In a wavelength division multiplexing optical communication system including a non-interruptible path switching device connected to each of a working wavelength division multiplexing optical communication device and a protection wavelength division multiplexing optical communication device, a receiving unit of the wavelength division multiplexing optical communication device separates the wavelength division multiplexed signal light. Device, a plurality of wavelength selection filters for extracting signal light of a specific wavelength from the demultiplexed wavelength multiplexed signal light, and an alarm signal when the signal light selected by the wavelength selection filter is received and the signal light is not normally received. A wavelength division multiplexing optical communication system comprising: an alarm circuit that outputs the signal; and an attenuator that attenuates the wavelength division multiplex signal light when an alarm signal output by the alarm circuit is received.
に設けられる請求項6記載の波長多重光通信システム。7. The wavelength division multiplexing optical communication system according to claim 6, wherein said attenuator is provided at a stage prior to said optical demultiplexer.
毎に設けられる請求項6または7記載の波長多重光通信
システム。8. The WDM optical communication system according to claim 6, wherein said alarm circuit is provided for each of said wavelength selective filters.
の切り替え方法であって、前記いずれかの光伝送路の波
長多重光通信装置の受信部において1以上の信号光の異
常を検出した場合、波長多重信号光を減衰させ、前記波
長多重光通信装置に接続する無瞬断パス切り替え装置に
より波長多重信号光をすべて他方の光伝送路へ切り替え
ることを特徴とする光伝送路切り替え方法。9. A method for switching between an active optical transmission line and a standby optical transmission line, wherein one or more signal light abnormalities are detected in a receiving unit of the wavelength division multiplexing optical communication device of any one of the optical transmission lines. Wherein the wavelength-division multiplexed signal light is attenuated, and all of the wavelength-division multiplexed signal light is switched to the other optical transmission line by the hitless path switching device connected to the wavelength-division multiplexed optical communication device. Switching method.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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JP9313501A JP3033547B2 (en) | 1997-11-14 | 1997-11-14 | WDM optical receiver, WDM optical communication system, and optical transmission line switching method |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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JP9313501A JP3033547B2 (en) | 1997-11-14 | 1997-11-14 | WDM optical receiver, WDM optical communication system, and optical transmission line switching method |
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Publication Number | Publication Date |
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JPH11150511A true JPH11150511A (en) | 1999-06-02 |
JP3033547B2 JP3033547B2 (en) | 2000-04-17 |
Family
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JP9313501A Expired - Fee Related JP3033547B2 (en) | 1997-11-14 | 1997-11-14 | WDM optical receiver, WDM optical communication system, and optical transmission line switching method |
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7372804B2 (en) | 2002-01-11 | 2008-05-13 | Nec Corporation | Multiplex communication system and method |
US8515288B2 (en) | 2005-09-30 | 2013-08-20 | Fujitsu Limited | Optical signal transmission control apparatus and optical signal transmission control method |
-
1997
- 1997-11-14 JP JP9313501A patent/JP3033547B2/en not_active Expired - Fee Related
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7372804B2 (en) | 2002-01-11 | 2008-05-13 | Nec Corporation | Multiplex communication system and method |
US8515288B2 (en) | 2005-09-30 | 2013-08-20 | Fujitsu Limited | Optical signal transmission control apparatus and optical signal transmission control method |
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JP3033547B2 (en) | 2000-04-17 |
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