JPH0492483A - Optical amplifier exciting system - Google Patents
Optical amplifier exciting systemInfo
- Publication number
- JPH0492483A JPH0492483A JP2208050A JP20805090A JPH0492483A JP H0492483 A JPH0492483 A JP H0492483A JP 2208050 A JP2208050 A JP 2208050A JP 20805090 A JP20805090 A JP 20805090A JP H0492483 A JPH0492483 A JP H0492483A
- Authority
- JP
- Japan
- Prior art keywords
- optical
- power
- signal
- doped
- earth element
- 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.)
- Granted
Links
- 230000003287 optical effect Effects 0.000 title claims abstract description 66
- 239000013307 optical fiber Substances 0.000 claims abstract description 21
- 229910052761 rare earth metal Inorganic materials 0.000 claims abstract description 20
- 150000002910 rare earth metals Chemical class 0.000 claims abstract description 10
- 238000005086 pumping Methods 0.000 claims description 30
- 230000005284 excitation Effects 0.000 claims description 14
- 238000000034 method Methods 0.000 claims description 11
- 239000000835 fiber Substances 0.000 abstract 2
- 230000001105 regulatory effect Effects 0.000 abstract 2
- 239000002131 composite material Substances 0.000 abstract 1
- 230000001276 controlling effect Effects 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 7
- 239000004065 semiconductor Substances 0.000 description 6
- 230000010287 polarization Effects 0.000 description 4
- 230000000694 effects Effects 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
- H01S3/13—Stabilisation of laser output parameters, e.g. frequency or amplitude
- H01S3/1301—Stabilisation of laser output parameters, e.g. frequency or amplitude in optical amplifiers
- H01S3/13013—Stabilisation of laser output parameters, e.g. frequency or amplitude in optical amplifiers by controlling the optical pumping
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
- H01S3/06—Construction or shape of active medium
- H01S3/063—Waveguide lasers, i.e. whereby the dimensions of the waveguide are of the order of the light wavelength
- H01S3/067—Fibre lasers
- H01S3/06754—Fibre amplifiers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/09—Processes or apparatus for excitation, e.g. pumping
- H01S3/091—Processes or apparatus for excitation, e.g. pumping using optical pumping
- H01S3/094—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light
- H01S3/094061—Shared pump, i.e. pump light of a single pump source is used to pump plural gain media in parallel
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
- H01S3/13—Stabilisation of laser output parameters, e.g. frequency or amplitude
- H01S3/1305—Feedback control systems
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/23—Arrangements of two or more lasers not provided for in groups H01S3/02 - H01S3/22, e.g. tandem arrangements of separate active media
- H01S3/2383—Parallel arrangements
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- Optics & Photonics (AREA)
- Lasers (AREA)
- Semiconductor Lasers (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、希土類元素をドープした希土類元素ドープ光
ファイバとこれを励起する励起光源から構成される光増
幅器励起方式に関するものである。DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an optical amplifier pumping system that includes a rare earth element-doped optical fiber and a pumping light source that pumps it.
（従来の技術）
希土類元素をドープした希土類元素ドープ光ファイバと
これを励起する励起光源から構成される光増幅器は、利
得が偏光に依存しないこと、結合損失が小さい等の利点
がある。(Prior Art) An optical amplifier composed of a rare-earth element-doped optical fiber and a pumping light source that pumps it has advantages such as gain not depending on polarization and small coupling loss.
光増幅器の従来の励起方式として、第６図の方式がある
［ＥＬＥＣＴＲＯＮＩＣ３ＬＥＴＴＥＲ３，Ｖｏｌ、２
６． Ｎｏ、８゜１２ｔｈ Ａｐｒｉｌ １９９０．
Ｈ，Ｔａｇａ ｅｔ、ａｌ、、 ”４５９ｋｍ、 ２．
４Ｇｂｉｔ／ｓ ＦＯＵＲＷＡＶＥＬＥＮＧＴＨＭＵＬ
ＴＩＰＬＥＸＩＮＧ ０ＰＴＩＣＡＬ ＦＩＢＥＲＴＲ
ＡＮＳＭＩＳＳＩＯＮ ＥＸＰＥＲＩＭＥＮＴ ＵＳＩ
ＮＧ Ｓ（Ｘ ［Ｅｒ−ＤＯＰＥＤ ＦＩＢＥＲＡＭＰ
Ｌ（ＦＩＥＲＳ“］。図において、ｌは信号光と励起光
を合波する光合波器、２はＥｒ等の希土類元素をドープ
した希土類元素ドープ光ファイバ、３ａ〜３ｂは希土類
元素を励起する半導体レーザ、４は偏光面の異なる２台
の半導体レーザ３ａと３ｂの各出力光を合波する偏光合
波器を示す。第６図では、１組の励起光源を２台の半導
体レーザて構成している。図のように従来の励起方式で
は１台の光増幅器に２台１組の励起光源を用い、各励起
光源の光出力電力レベルを変えることによって光増幅器
の利得を制御している。As a conventional pumping method for an optical amplifier, there is a method shown in Fig. 6 [ELECTRONIC3LETTER3, Vol. 2
6. No, 8°12th April 1990.
H, Taga et, al., “459km, 2.
4Gbit/s FOURWAVE LENGTHMUL
TIPLEXING 0PTICAL FIBERTR
ANSMISSION EXPERIMENT USI
NG S(X [Er-DOPED FIBERAMP
L (FIERS"). In the figure, l is an optical multiplexer that combines signal light and excitation light, 2 is a rare earth element-doped optical fiber doped with a rare earth element such as Er, and 3a to 3b are semiconductors that excite rare earth elements. Laser 4 indicates a polarization multiplexer that combines the respective output lights of two semiconductor lasers 3a and 3b with different polarization planes.In Fig. 6, one set of excitation light sources is composed of two semiconductor lasers. As shown in the figure, the conventional pumping method uses a set of two pumping light sources for one optical amplifier, and controls the gain of the optical amplifier by changing the optical output power level of each pumping light source.
（発明か解決しようとする問題点）
しかし、従来の駆動方式の光増幅器を、例えば長距離光
通信システムの中継器に用いる場合、上り回線と下り回
線かあるのて２組の励起光源か必要となる。このために
励起光源用半導体レーザの数が多くなり、システムのコ
ストか高くなるという問題点がある。(Problem to be solved by the invention) However, when an optical amplifier with a conventional drive method is used, for example, as a repeater in a long-distance optical communication system, two sets of excitation light sources are required for uplink and downlink. becomes. Therefore, there is a problem that the number of semiconductor lasers for excitation light sources increases, which increases the cost of the system.
本発明は、上述した従来技術の問題点を解決するために
なされたもので、低コストな光増幅器励起方式を提供す
ることを目的とする。The present invention was made to solve the problems of the prior art described above, and an object of the present invention is to provide a low-cost optical amplifier pumping system.
（問題点を解決するための手段）
この目的を達成するために、本発明による光増幅器励起
方式は、希土類元素をドープした複数の希土類元素ドー
プ光ファイバと該希土類元素ドープ光ファイバを励起す
る１組の励起光源から構成される光増幅器の励起方式に
おいて、
一つの光源から前記１組の励起光源の光出力をとり出す
ように分岐させる分岐手段と、複数の前記希土類元素ド
ープ光ファイバへの励起光電力を個別に変える電力調整
手段と、複数の前記希土類元素ドープ光ファイバの各出
力における光信号電力を個別に検出し予め定めた基準電
力と比較して前記電力調整手段を調整して各希土類元素
ドープ光ファイバへの前記励起光電力を制御する比較・
制御手段と
を備え、
複数の光増幅器の利得を個別に制証するように構成され
ている。(Means for Solving the Problems) In order to achieve this object, an optical amplifier pumping system according to the present invention includes a plurality of rare earth element-doped optical fibers doped with a rare earth element and a single pump pumping system for pumping the rare earth element doped optical fibers. In a pumping system for an optical amplifier comprising a set of pumping light sources, a branching means for branching so as to extract the optical output of the set of pumping light sources from one light source, and pumping to a plurality of the rare earth element-doped optical fibers. A power adjusting means for individually changing the optical power; and a power adjusting means for individually detecting the optical signal power at each output of the plurality of rare earth element doped optical fibers and comparing it with a predetermined reference power to adjust the power adjusting means to adjust the power for each rare earth element doped optical fiber. Comparison of controlling the excitation light power to the element-doped optical fiber
and a control means, and is configured to individually verify the gains of the plurality of optical amplifiers.
（作用）
以上のように構成することにより、従来の励起方式に比
へて、大幅に励起光源用半導体レーザの数を減少させる
ことか可能となり、光増幅器システムの低コスト化を図
ることかできる。(Function) By configuring as described above, it is possible to significantly reduce the number of semiconductor lasers for the pumping light source compared to the conventional pumping method, and it is possible to reduce the cost of the optical amplifier system. .
（実施例１）
第１図は本発明の第一の実施例である光増幅器励起方式
のブロック図である。本発明による励起方式か従来例と
異なるのは、励起光源５の出力光を光分波器６で分岐し
、２台の光増幅器を励起するのに用いる点である。可変
光減衰器７ａ、７ｂを用いて２台の光増幅器の利得を個
別に制御することを特徴としている。(Embodiment 1) FIG. 1 is a block diagram of an optical amplifier pumping system according to a first embodiment of the present invention. The pumping method according to the present invention differs from the conventional example in that the output light from the pumping light source 5 is split by an optical demultiplexer 6 and used to pump two optical amplifiers. It is characterized in that the gains of the two optical amplifiers are individually controlled using variable optical attenuators 7a and 7b.
第１図において、励起光源５からの出力光は、光分波器
６で分岐され、それぞれ可変減衰器７ａ、７ｂを通り、
光合波器１ａ、ｌｂによって信号光と合成された後、希
土類をドープした光ファイバ２ａ、２ｂを励起する。光
ファイバ２ａで増幅された信号光の一部を光分波器８ａ
で取り出し、光検出器９ａ、増幅器１０ａ１低域ろ波器
１１ａを通して信号電力レベルを検出し、比較器１２ａ
において基準電圧発生器１３ａから出力される予め定め
られた信号電力レベルとの比較を行なう。光ファイバ２
ｂからの信号も同様の処理か行なわれる。制御回路１４
において、両方の信号電力レベルか予め定められた信号
電力レベルより低い場合は励起光源出力を大きくする。In FIG. 1, output light from a pumping light source 5 is branched by an optical demultiplexer 6, passes through variable attenuators 7a and 7b, and
After being combined with signal light by optical multiplexers 1a and lb, rare earth-doped optical fibers 2a and 2b are excited. A part of the signal light amplified by the optical fiber 2a is transferred to an optical demultiplexer 8a.
The signal power level is detected through a photodetector 9a, an amplifier 10a, a low-pass filter 11a, and a comparator 12a.
A comparison is made with a predetermined signal power level output from the reference voltage generator 13a. optical fiber 2
The signal from b is also subjected to similar processing. Control circuit 14
In this step, if both signal power levels are lower than a predetermined signal power level, the excitation light source output is increased.
一方の信号電力レベルのみか基準電圧より大きくなった
場合には可変減衰器７ａ、７ｂで励起光電力を小さくす
る。If only one signal power level becomes higher than the reference voltage, the pump light power is reduced by variable attenuators 7a and 7b.
これにより、光増幅器出力における出力信号光の電力レ
ベルを一定にしている。Thereby, the power level of the output signal light at the output of the optical amplifier is kept constant.
（第二の実施例）
第２図は本発明の第二の実施例である光増幅器のブロッ
ク図である。この光増幅器か第１図の実施例と異なるの
は、励起光源の分岐方法と光ファイバへの入力励起光電
力の制卸方法である。励起光源５からの光を反射率可変
の光分波器１５て分岐している点である。光分岐器１５
は、クロム膜の厚さを矢印の方向に沿って連続的に変え
てコーティングされており、透過光と反射光の電力比を
連続的に変化させる。この電力比と励起光源出力電力レ
ベルを変えることによって２台の光増幅器の利得を個別
に制御する事を可能としている。(Second Embodiment) FIG. 2 is a block diagram of an optical amplifier that is a second embodiment of the present invention. This optical amplifier differs from the embodiment shown in FIG. 1 in the method of branching the pumping light source and the method of controlling the power of the pumping light input to the optical fiber. The point is that the light from the excitation light source 5 is branched by an optical demultiplexer 15 with variable reflectance. Optical splitter 15
is coated with a chromium film whose thickness is continuously changed in the direction of the arrow, and the power ratio of transmitted light and reflected light is continuously changed. By changing this power ratio and the pumping light source output power level, it is possible to individually control the gains of the two optical amplifiers.
（第三の実施例）
第３図は本発明の第三の実施例である光増幅器のブロッ
ク図である。この光増幅器か第２図の実施例と異なるの
は、励起光源５からの光を音響光学素子を用いた光分波
器１６て分岐している点である。光分岐器１６は、音響
光学効果を利用し、入射光を０次回折光と１次回折光に
分岐し、その分岐比は音響光学素子への印加電圧で制御
される。(Third Embodiment) FIG. 3 is a block diagram of an optical amplifier that is a third embodiment of the present invention. This optical amplifier differs from the embodiment shown in FIG. 2 in that the light from the excitation light source 5 is branched by an optical demultiplexer 16 using an acousto-optic device. The optical splitter 16 uses the acousto-optic effect to split the incident light into a 0th-order diffracted light and a 1st-order diffracted light, and the splitting ratio is controlled by the voltage applied to the acousto-optic element.
この分岐比と励起光源出力電力レベルを変えることによ
って２台の光増幅器の利得を個別に制御する事を可能と
している。By changing this branching ratio and the pumping light source output power level, it is possible to individually control the gains of the two optical amplifiers.
（第四の実施例）
第４図は本発明の第四の実施例である光増幅器のブロッ
ク図である。この光増幅器が第２図の実施例と異なるの
は、直列に接続された２台の光増幅器を励起している点
である。本実施例では光分波器１５を用いて励起光源を
制御しているが、第２図と同じく、光分波器と可変減衰
器の組み合わせあるいは第３図と同じく音響光学素子を
用いた分波器１６を使用することも可能である。(Fourth Embodiment) FIG. 4 is a block diagram of an optical amplifier that is a fourth embodiment of the present invention. This optical amplifier differs from the embodiment shown in FIG. 2 in that it excites two optical amplifiers connected in series. In this embodiment, the excitation light source is controlled using an optical demultiplexer 15, but as in FIG. 2, a combination of an optical demultiplexer and a variable attenuator, or as in FIG. It is also possible to use a waver 16.
（第五の実施例）
第５図は本発明の第五の実施例である光増幅器のブロッ
ク図である。この光増幅器が第４図の実施例と異なるの
は、光分波器１７と光合波器１８を用いて並列に接続さ
れた２台の光増幅器を励起している点である。本実施例
では光分波器１５を用いて励起光源５の出力光電力を制
御しているか、第２図と同じく、光分波器と可変減衰器
の組み合わせあるいは第３図と同じく音響光学素子を用
いた分波器を使用することも可能である。(Fifth Embodiment) FIG. 5 is a block diagram of an optical amplifier that is a fifth embodiment of the present invention. This optical amplifier differs from the embodiment shown in FIG. 4 in that an optical demultiplexer 17 and an optical multiplexer 18 are used to excite two optical amplifiers connected in parallel. In this embodiment, the output optical power of the excitation light source 5 is controlled using an optical demultiplexer 15, or a combination of an optical demultiplexer and a variable attenuator as in FIG. 2, or an acousto-optic element as in FIG. It is also possible to use a duplexer using
［発明の効果］
以上詳述したように本発明によれば、光増幅器励起方式
において、２台の光増幅器を１台で励起し、且つ、利得
を個別に制御することにより、光増幅器を用いた光中継
システムの小型化、低コスト化が図れるという利点を有
する。[Effects of the Invention] As detailed above, according to the present invention, in the optical amplifier pumping method, two optical amplifiers are pumped by one and the gains are individually controlled, thereby making it possible to use optical amplifiers. This has the advantage that the optical relay system used in the conventional optical relay system can be made smaller and lower in cost.
第１図から第５図は本発明の実施例のブロック図、第６
図は従来例のブロック図である。
１．１ａ、Ｉｂ、１Ｂ−・・光合波器、２．２ａ、２ｂ
・・・希土類元素ドープ光ファイバ３ａ、３ｂ・・・半
導体レーザ、
４・・・偏光合波器、
５・・・励起光源、
６．８ａ、８ｂ、１０，１５．１６−光分波器、７ａ、
７ｂ・・・可変光減衰器、
９ａ、９ｂ・・・光検出器、
１０ａ、 １０ｂ−・・増幅器、
１１ａ、ｌｌｂ・・・低減ろ波器、
１２ａ、ｌ２ｂ−・・比較器、
１３ａ、１３ｂ・・・基準電圧発生器、１４・・・制純
回路。1 to 5 are block diagrams of embodiments of the present invention, and FIG.
The figure is a block diagram of a conventional example. 1.1a, Ib, 1B--optical multiplexer, 2.2a, 2b
...Rare earth element doped optical fibers 3a, 3b...Semiconductor laser, 4...Polarization multiplexer, 5...Excitation light source, 6.8a, 8b, 10, 15.16-Optical demultiplexer, 7a,
7b... variable optical attenuator, 9a, 9b... photodetector, 10a, 10b... amplifier, 11a, llb... reduction filter, 12a, l2b... comparator, 13a, 13b ...Reference voltage generator, 14...Purity control circuit.
Claims (1)
イバと該希土類元素ドープ光ファイバを励起する１組の
励起光源から構成される光増幅器の励起方式において、 一つの光源から前記１組の励起光源の光出力をとり出す
ように分岐させる分岐手段と、 複数の前記希土類元素ドープ光ファイバへの励起光電力
を個別に変える電力調整手段と、 複数の前記希土類元素ドープ光ファイバの各出力におけ
る光信号電力を個別に検出し予め定めた基準電力と比較
して前記電力調整手段を調整して各希土類元素ドープ光
ファイバへの前記励起光電力を制御する比較・制御手段
と を備え、 複数の光増幅器の利得を個別に制御するように構成され
たことを特徴とする光増幅器励起方式。[Scope of Claims] In a pumping system for an optical amplifier comprising a plurality of rare-earth element-doped optical fibers doped with a rare-earth element and a set of pump light sources for pumping the rare-earth element-doped optical fibers, the pumping method includes: branching means for branching so as to extract the optical outputs of the plurality of excitation light sources; power adjustment means for individually changing the excitation light power to the plurality of rare earth element-doped optical fibers; and each of the plurality of rare earth element doped optical fibers. Comparing and controlling means for individually detecting the optical signal power at the output and comparing it with a predetermined reference power to adjust the power adjusting means to control the excitation light power to each rare earth element-doped optical fiber, An optical amplifier pumping method characterized in that the gain of a plurality of optical amplifiers is individually controlled.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2208050A JP2652265B2 (en) | 1990-08-08 | 1990-08-08 | Optical amplifier excitation method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2208050A JP2652265B2 (en) | 1990-08-08 | 1990-08-08 | Optical amplifier excitation method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0492483A true JPH0492483A (en) | 1992-03-25 |
| JP2652265B2 JP2652265B2 (en) | 1997-09-10 |
Family
ID=16549817
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2208050A Expired - Fee Related JP2652265B2 (en) | 1990-08-08 | 1990-08-08 | Optical amplifier excitation method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2652265B2 (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06318907A (en) * | 1993-05-07 | 1994-11-15 | Nec Corp | Optical amplifier alarm circuit |
| JP2003283019A (en) * | 2002-03-20 | 2003-10-03 | Nec Corp | Optical repeater and optical transmission system |
| JP2004104473A (en) * | 2002-09-10 | 2004-04-02 | Mitsubishi Electric Corp | Optical amplification repeater |
| JP2010177346A (en) * | 2009-01-28 | 2010-08-12 | Nippon Telegr & Teleph Corp <Ntt> | Optical amplifier and method of amplifying light |
| JP2013123205A (en) * | 2011-11-07 | 2013-06-20 | Nippon Telegr & Teleph Corp <Ntt> | Optical amplifier system and optical amplification method |
| JP2020074537A (en) * | 2015-09-29 | 2020-05-14 | 日本電気株式会社 | Optical repeater and control method therefor |
-
1990
- 1990-08-08 JP JP2208050A patent/JP2652265B2/en not_active Expired - Fee Related
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06318907A (en) * | 1993-05-07 | 1994-11-15 | Nec Corp | Optical amplifier alarm circuit |
| JP2003283019A (en) * | 2002-03-20 | 2003-10-03 | Nec Corp | Optical repeater and optical transmission system |
| JP2004104473A (en) * | 2002-09-10 | 2004-04-02 | Mitsubishi Electric Corp | Optical amplification repeater |
| JP2010177346A (en) * | 2009-01-28 | 2010-08-12 | Nippon Telegr & Teleph Corp <Ntt> | Optical amplifier and method of amplifying light |
| JP2013123205A (en) * | 2011-11-07 | 2013-06-20 | Nippon Telegr & Teleph Corp <Ntt> | Optical amplifier system and optical amplification method |
| JP2020074537A (en) * | 2015-09-29 | 2020-05-14 | 日本電気株式会社 | Optical repeater and control method therefor |
| US11463190B2 (en) | 2015-09-29 | 2022-10-04 | Nec Corporation | Optical repeater and control method for optical repeater |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2652265B2 (en) | 1997-09-10 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |