JPH0335224A - Optical amplifying device - Google Patents
Optical amplifying deviceInfo
- Publication number
- JPH0335224A JPH0335224A JP16975789A JP16975789A JPH0335224A JP H0335224 A JPH0335224 A JP H0335224A JP 16975789 A JP16975789 A JP 16975789A JP 16975789 A JP16975789 A JP 16975789A JP H0335224 A JPH0335224 A JP H0335224A
- Authority
- JP
- Japan
- Prior art keywords
- optical amplifier
- gain
- intensity
- semiconductor optical
- fluctuation
- 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
- 230000003287 optical effect Effects 0.000 title claims abstract description 67
- 239000004065 semiconductor Substances 0.000 claims abstract description 36
- 230000007423 decrease Effects 0.000 abstract description 9
- 230000002542 deteriorative effect Effects 0.000 abstract 1
- 230000003321 amplification Effects 0.000 description 6
- 238000003199 nucleic acid amplification method Methods 0.000 description 6
- 230000006866 deterioration Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 238000002347 injection Methods 0.000 description 3
- 239000007924 injection Substances 0.000 description 3
- 230000003993 interaction Effects 0.000 description 3
- 238000000034 method Methods 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
Abstract
Description
本発明は、例えば光通信システム（用いて好適な光増幅
装置に関し、特に、飽和による利得変動を補償する機能
を備えた光増幅装置に関する。The present invention relates to an optical amplifier suitable for use in, for example, an optical communication system, and particularly relates to an optical amplifier having a function of compensating for gain fluctuations due to saturation.
【従来の技術Ｊ
半導体光増幅器は、外部から入力された光を光半導体の
活性層中の電子との誘導放出相互作用により増幅して、
出力する装置である。この半導体光増幅器においては、
以下のメカニズムによる増幅利得の飽和現象がある。す
なわち、増幅利得は活性層中の電子数に依存するのであ
るが、電子数は光との誘導放出相互作用により減少する
。誘導放出の量は相互作用にかかわる光強度に比例する
ので、入力光強度が大きいと電子数の減少量が大きくな
り、これに伴い増幅利得が減少する。従って、光強度に
より利得が飽和することになる。この利得の飽和は、例
えば強度変調された波長多重信号光を一括増幅する際に
、チャンネル間クロストークを生じさせる。すなわち、
あるチャンネルの信号光に着目すると、他チャンネルの
オン−オフに応じて利得が変動することになり、クロス
トーク劣化をもたらす。
この利得飽和による信号劣化を補償する方法としては、
光検出器によって光増幅器への入力光強度変化をモニタ
ーし、そのモニター出力に応、じて光増幅器への注入電
流を制御する方法が提案されている。
第２図にこのような従来例の構成を示す。ここで、＾ｌ
は半導体光増幅器、Ｃは光分岐器、Ｄは光検出器、Ｆｌ
は制御回路である。第２図において、送られてきた光入
力信号は光分岐器Ｃによりその一部が光検出器りへ入力
される。光検出器りは入力信号光°の光強度の変化を検
出し、その変化量を制御回路Ｆｌへ入力する。制御回路
Ｆｌは、入力信号光の光強度の変化による増幅器Ａ１の
利得の変動を補償するように、半導体光増幅器＾ｌへの
注入電流を制御する。
例えば、入力光強度が大きく半導体活性層内の電子が減
少する場合は、その減少分を補償するように増幅器＾ｌ
への注入電流を増加させる。逆に、入力光強度が小さい
場合は注入電流を減少させる。この制御により、半導体
活性層内の電子数は人力信号光の光強度の如何によらず
常に一定となり、増幅器利得は変動しない。従って、信
号劣化は生じない。
このような従来例は、Ａ、＾、Ｍ、５ａｌｅｈ、 １．
Ｍ。
Ｊｏｐｓｏｎ、 ａｎｄ Ｔ、Ｅ、Ｄａｒｃ［ｅ、 ”
Ｃｏｍｐｅｎｓａｔｉｏｎ ｏｆｎｏｎｌｉｎｅａｒｉ
ｔｙ ｉｎ、 ｓｅｍｉｃｏｎｄｕｃｔｏｒ ｏｐｔｉ
ｃａｌａｍｐｌｉｆｉｅｒ 、 （Ｅｌｅｃｔｒｏｎｉ
ｃｓ Ｌｅｔｔｅｒｓ、 Ｖｏｌ、２４゜ｐｐ、ｑｓｏ
−ｑｓ２）において報告されたものである。
【発明が解決しようとする課題】
以上の従来例では、利得変動の補償は実現されているも
のの、制御のために入力光の一部を分岐しており、その
分だけ信号光の損失となるという欠点がある。
そこで、本発明の目的は、上記従来例の欠点に鑑み、信
号光の損失を伴わずに入力光強度の変動を検出して利得
飽和を補償することができるようにした半導体光増幅装
置を提供することにある。[Prior art J] A semiconductor optical amplifier amplifies externally input light through stimulated emission interaction with electrons in the active layer of an optical semiconductor.
It is an output device. In this semiconductor optical amplifier,
There is a saturation phenomenon of amplification gain due to the following mechanism. That is, the amplification gain depends on the number of electrons in the active layer, and the number of electrons decreases due to stimulated emission interaction with light. Since the amount of stimulated emission is proportional to the light intensity involved in the interaction, when the input light intensity is high, the amount of decrease in the number of electrons becomes large, and the amplification gain decreases accordingly. Therefore, the gain will be saturated depending on the light intensity. This gain saturation causes inter-channel crosstalk when, for example, intensity-modulated wavelength-multiplexed signal light is collectively amplified. That is,
When focusing on the signal light of a certain channel, the gain will vary depending on whether other channels are turned on or off, resulting in crosstalk deterioration. As a method to compensate for signal deterioration due to gain saturation,
A method has been proposed in which a photodetector monitors changes in the intensity of light input to an optical amplifier and controls the current injected into the optical amplifier according to the monitor output. FIG. 2 shows the configuration of such a conventional example. Here, ^l
is a semiconductor optical amplifier, C is an optical splitter, D is a photodetector, Fl
is the control circuit. In FIG. 2, a portion of the transmitted optical input signal is inputted to a photodetector by an optical splitter C. The photodetector detects a change in the light intensity of the input signal light and inputs the amount of change to the control circuit Fl. The control circuit Fl controls the current injected into the semiconductor optical amplifier ^l so as to compensate for fluctuations in the gain of the amplifier A1 due to changes in the optical intensity of the input signal light. For example, if the input light intensity is large and the number of electrons in the semiconductor active layer decreases, the amplifier should be adjusted to compensate for the decrease.
Increase the injection current to. Conversely, when the input light intensity is low, the injection current is reduced. With this control, the number of electrons in the semiconductor active layer is always constant regardless of the optical intensity of the human input signal light, and the amplifier gain does not vary. Therefore, no signal degradation occurs. Such conventional examples include A, ^, M, 5aleh, 1.
M. Jopson, and T, E, Darc [e, ”
Compensation of nonlinear
ty in, semiconductor opti
calampifier, (Electroni
cs Letters, Vol, 24゜pp, qso
-qs2). [Problems to be Solved by the Invention] In the conventional example described above, although compensation for gain fluctuations has been achieved, part of the input light is branched for control purposes, resulting in a corresponding loss of signal light. There is a drawback. SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks of the conventional example, an object of the present invention is to provide a semiconductor optical amplification device capable of detecting fluctuations in input light intensity and compensating for gain saturation without loss of signal light. It's about doing.
このような目的を達成するために、本発明は、定電流駆
動され、かつ端子間電圧を検出する手段を有する第１の
半導体光増幅器と、第１の半導体光増幅器に縦続接続さ
れた第２の半導体光増幅器と、第１の半導体光増幅器の
端子間電圧に応じて第２の半導体光増幅器への注入−電
流を制御する制御回路とを備えたことを特徴とする。In order to achieve such an object, the present invention provides a first semiconductor optical amplifier that is driven with a constant current and has means for detecting a voltage between terminals, and a second semiconductor optical amplifier that is cascade-connected to the first semiconductor optical amplifier. The present invention is characterized in that it includes a semiconductor optical amplifier, and a control circuit that controls the current injected into the second semiconductor optical amplifier according to the voltage between the terminals of the first semiconductor optical amplifier.
本発明では、２つの半導体光増幅器を直列に接続し、前
段の光増幅器自体により入力光強度の変動をモニターし
、そのモニター出力により後段の光増幅器への注入電流
を制御することにより、増幅利得の変動を補償する０本
発明は、分岐によらｆ Ｌ−１ｆｙ ３１１− ａｌ
ｌｉＦ ｉｎ ？ ｌｈ ＊ 手二々−Ｌ ｆ ＩＡ
！占テ稈来技術とは異なり、これにより信号光の損失を
伴わない利得飽和補償が可能である。In the present invention, two semiconductor optical amplifiers are connected in series, and the preceding stage optical amplifier itself monitors fluctuations in the input light intensity, and the monitor output controls the current injected into the subsequent stage optical amplifier, thereby increasing the amplification gain. The present invention compensates for the variation of f L-1 fy 311- al by branching.
LiFi in? lh * Two hands-L f IA
! Unlike the conventional technology, this allows gain saturation compensation without loss of signal light.
以下、図面を参照して本発明の実施例を詳細に説明する
。
第１図は本発明の一実施例を示す構成図である。ここで
、Ａ２およびＡ３は互いに縦続接続された半導体光増幅
器である。入力信号光はまず半導体光増幅器Ａ２を透過
し、ついで半導体光増幅器Ａ３を通過する。半導体光増
幅器Ａ２は定電流駆動されており、さらにその端子間電
圧を検出する装置が付加されているものとする。 Ｆ２
は半導体光増幅器Ａ２の端子間電圧Ｃ応じて半導体光増
幅器Ａ３への注入電流を制御する制御回路である。
この構成において、利得飽和を起こす程度に強い強度の
光が半導体光増幅器Ａ２に入力されると、その入力光強
度の大きさは半導体光増幅器Ａ２の端子間電圧によりモ
ニターすることができる。これはセ１下の理由Ｃよる−
強い強度の光が半導体光増幅器に人力されると、誘導放
出により活性層内の電子数が減少する。ところでこの活
性層は半導体のｐ−ｎジャンクションから形成される。
ｐ−ｎジャンクション間の端子電圧は、擬フエルミレベ
ルによって与えられ、擬フエルミレベルは電子数に上っ
て変化する。従って、入力光強度に応じてｐ−ｎジャン
クション間の端子間電圧が変化することになり、端子間
電圧から入力光強度の変動をモニターすることが可能と
なる。この活性層への光注入による端子間電圧の変化に
ついては、Ｙ、Ｍｉｔｓｕｈａｓｈｉ。
Ｊ、Ｓｈｉｍａｄａ、 ａｎｄ Ｓ、Ｍｉｔｓｕｔｓｕ
ｋａ、”Ｖｏｌｔａｇｅ Ｃｈａｎｇｅ＾ｃｒｏｓｓ
ｔｈｅ ５ｅｌｆ−Ｃｏｕｐｌｅｄ Ｓｅｍ１ｃｏｎｄ
ｕｃｔｏｒＬａｓｅｒ 、（ＩＥＥＥ、Ｊｏｕｒｎａ
ｌ ｏｆ ＱｕａｎｔｕｍＥｌｅｃｔｒｏｎｉｃｓ、
Ｖｏｌ、ＱＥ−１７，ｐｐ、１２１６−１２２５）、
あるいは、 Ｓ、Ｋｏｂａｙａｓｈｉ ａｎｄ Ｔ
、Ｋｉｍｕｉｒａ、”へｕｔｏｍａｔｉｃＦｒｅｑｕｅ
ｎｃｙ Ｃｏｎｔｒｏｌ ｉｎ ａ Ｓｅｍ１ｃｏｎｄ
ｕｃｔｏｒ Ｌａ５ｅｒａｎｄ ａｎ ｏｐｔｉｃ
ａｌ Ａｉ＋ｐｌｉｆｉｅｒ 、（ＴＥＥＥ、
Ｊｏｕｒｎａｌ ｏｆＬｉｇｈｔｗａｖｅ Ｔｅ
ｃｈｎｏｌｏｇｙ、 Ｖｏｌ、ＬＴ−１，ｐｐ、３９
４−４０２）。
に詳しく述べられている。なおこの時、−段目の光増幅
器へ２の光出力面では、利得変動による出力ゆらぎを受
けた光信号が出力される。
以上の原理により、光増幅器Ａ２の端子間電圧によりモ
ニターされた入力信号光の光強度変化の情報は、制御回
路Ｆ２に入力される。制御回路Ｆ２では、光増幅器Ａ２
で生じた利得変動を補償するように光増幅器へ３への注
入電流を制御する。例えば、人力光強度が大きく利得が
減少する場合には、光増幅苓へ３への注入電流を増加さ
せて利得の減少分を補償するようにする。このように光
増幅器へ３への注入電流を制御することにより、光増幅
器Ａ２とＡ３を合わせた全体の信号利得は入力信号光の
光強度の変動によらず一定の値とすることができる。
このようにして、本実施例では、利得変動による信号劣
化を回避することが可能である。さらにこの実施例では
、−段目の光増幅器Ａ２そのものを利用して入力光強度
をモニターしているので、従来例のような信号光の損失
を伴うことなしに、利得変動を補償することが可能であ
る。
［発明の効果］
以上説明したところから明らかなように、本発明によれ
ば、信号光の損失を伴わない利得変動の補償が可能であ
るので、人力された光信号を有効に、かつ利得変動によ
る信号劣化を生じさせることなく、増幅する光ＭＢ幅装
置を提供することができる。Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention. Here, A2 and A3 are semiconductor optical amplifiers connected in series with each other. The input signal light first passes through the semiconductor optical amplifier A2, and then passes through the semiconductor optical amplifier A3. It is assumed that the semiconductor optical amplifier A2 is driven with a constant current and is further provided with a device for detecting the voltage between its terminals. F2
is a control circuit that controls the current injected into the semiconductor optical amplifier A3 according to the voltage C between the terminals of the semiconductor optical amplifier A2. In this configuration, when light with an intensity strong enough to cause gain saturation is input to the semiconductor optical amplifier A2, the magnitude of the input light intensity can be monitored by the voltage between the terminals of the semiconductor optical amplifier A2. This is due to Reason C under Section 1 - When strong light is applied to a semiconductor optical amplifier, the number of electrons in the active layer decreases due to stimulated emission. By the way, this active layer is formed from a pn junction of a semiconductor. The terminal voltage across the p-n junction is given by the pseudo-Fermi level, which varies with the number of electrons. Therefore, the voltage between the terminals of the p-n junction changes according to the input light intensity, and it becomes possible to monitor the fluctuation of the input light intensity from the voltage between the terminals. Regarding the change in voltage between terminals due to light injection into the active layer, see Y. Mitsuhashi. J, Shimada, and S, Mitsutsu
ka,”Voltage Change＾cross
the 5elf-Coupled Sem1cond
uctorLaser, (IEEE, Journal
l of Quantum Electronics,
Vol, QE-17, pp, 1216-1225),
Alternatively, S., Kobayashi and T.
, Kimuira, “to automatic Freque
ncy Control in a Sem1cond
uctor la5erand an optic
al Ai+plifier, (TEEE,
Journal of Lightwave Te
chnology, Vol, LT-1, pp, 39
4-402). is described in detail. At this time, at the second optical output surface to the −th stage optical amplifier, an optical signal that has undergone output fluctuation due to gain fluctuation is output. Based on the above principle, information on the optical intensity change of the input signal light monitored by the voltage between the terminals of the optical amplifier A2 is input to the control circuit F2. In the control circuit F2, the optical amplifier A2
The current injected into the optical amplifier 3 is controlled so as to compensate for the gain fluctuation caused by. For example, if the human power light intensity is large and the gain decreases, the current injected into the optical amplifier 3 is increased to compensate for the decrease in gain. By controlling the current injected into the optical amplifier 3 in this way, the overall signal gain of the optical amplifiers A2 and A3 can be kept constant regardless of fluctuations in the optical intensity of the input signal light. In this way, in this embodiment, it is possible to avoid signal deterioration due to gain fluctuations. Furthermore, in this embodiment, the input light intensity is monitored using the -th stage optical amplifier A2 itself, so it is possible to compensate for gain fluctuations without causing loss of signal light as in the conventional example. It is possible. [Effects of the Invention] As is clear from the above explanation, according to the present invention, it is possible to compensate for gain fluctuations without causing loss of signal light. It is possible to provide an optical MB width device that amplifies the signal without causing signal deterioration.
第１図は、本発明の一実施例を示す構成図、第２図は、
利得変動補償機能を備えた光増幅装置の従来例を示す構
成図である。
＾１．Ａ２．八３・・・半導体光増幅器、Ｃ・・・光分
岐器、
Ｄ・・・光検出器、
Ｆｌ、Ｆ２・・・制御回路。FIG. 1 is a configuration diagram showing one embodiment of the present invention, and FIG.
1 is a configuration diagram showing a conventional example of an optical amplification device equipped with a gain fluctuation compensation function. ^1. A2. 83... Semiconductor optical amplifier, C... Optical splitter, D... Photodetector, Fl, F2... Control circuit.
Claims (1)
有する第１の半導体光増幅器と、 該第１の半導体光増幅器に縦続接続された第２の半導体
光増幅器と、 前記第１の半導体光増幅器の端子間電圧に応じて前記第
２の半導体光増幅器への注入電流を制御する制御回路と を備えたことを特徴とする光増幅装置。[Claims] 1) A first semiconductor optical amplifier that is driven with a constant current and has means for detecting a voltage between terminals; and a second semiconductor optical amplifier that is cascade-connected to the first semiconductor optical amplifier. , a control circuit that controls current injected into the second semiconductor optical amplifier according to a voltage between terminals of the first semiconductor optical amplifier.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16975789A JPH0335224A (en) | 1989-07-03 | 1989-07-03 | Optical amplifying device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16975789A JPH0335224A (en) | 1989-07-03 | 1989-07-03 | Optical amplifying device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0335224A true JPH0335224A (en) | 1991-02-15 |
Family
ID=15892287
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP16975789A Pending JPH0335224A (en) | 1989-07-03 | 1989-07-03 | Optical amplifying device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0335224A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7359113B2 (en) * | 2005-02-02 | 2008-04-15 | Covega Corp. | Semiconductor optical amplifier having a non-uniform injection current density |
| JP2012255934A (en) * | 2011-06-09 | 2012-12-27 | Mitsubishi Electric Corp | Optical wavelength converter |
-
1989
- 1989-07-03 JP JP16975789A patent/JPH0335224A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7359113B2 (en) * | 2005-02-02 | 2008-04-15 | Covega Corp. | Semiconductor optical amplifier having a non-uniform injection current density |
| US7929202B2 (en) | 2005-02-02 | 2011-04-19 | Thorlabs Quantum Electronics, Inc. | Semiconductor optical amplifier having a non-uniform injection current density |
| USRE43416E1 (en) | 2005-02-02 | 2012-05-29 | Thorlabs Quantum Electronics, Inc. | Semiconductor optical amplifier having a non-uniform injection current density |
| JP2012255934A (en) * | 2011-06-09 | 2012-12-27 | Mitsubishi Electric Corp | Optical wavelength converter |
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