JPH06216452A - Dummy-light input controlled constant-gain optical fiber amplification method and apparatus thereof - Google Patents
Dummy-light input controlled constant-gain optical fiber amplification method and apparatus thereofInfo
- Publication number
- JPH06216452A JPH06216452A JP5007812A JP781293A JPH06216452A JP H06216452 A JPH06216452 A JP H06216452A JP 5007812 A JP5007812 A JP 5007812A JP 781293 A JP781293 A JP 781293A JP H06216452 A JPH06216452 A JP H06216452A
- Authority
- JP
- Japan
- Prior art keywords
- light
- optical
- dummy
- input signal
- signal light
- 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
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
-
- 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
- H01S3/10007—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating in optical amplifiers
- H01S3/10015—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating in optical amplifiers by monitoring or controlling, e.g. attenuating, the input signal
-
- 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
- H01S3/005—Optical devices external to the laser cavity, specially adapted for lasers, e.g. for homogenisation of the beam or for manipulating laser pulses, e.g. pulse shaping
- H01S3/0078—Frequency filtering
-
- 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
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- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- Optics & Photonics (AREA)
- Lasers (AREA)
- Optical Communication System (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は光信号の直接増幅方法に
関し、特に入力信号光レベルによって利得が変化せず、
かつ入力信号光の変調周波数によって波形歪の生じない
光ファイバ増幅方法および装置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 for directly amplifying an optical signal, and in particular, the gain does not change depending on the input signal light level,
In addition, the present invention relates to an optical fiber amplification method and apparatus in which waveform distortion does not occur due to the modulation frequency of input signal light.
【０００２】[0002]
【従来の技術】従来の光ファイバ増幅器は、その利得が
入力信号光レベルによって変化する特性をもっていた。
すなわち入力信号光レベルが小さいときは利得が大き
く、入力信号光レベルが増大するに従って”利得の飽和
効果”により利得が減少する。また従来の光ファイバ増
幅方法における入力信号光波形に対する応答特性は、入
力信号光の変調周波数によって異なっていた。2. Description of the Related Art A conventional optical fiber amplifier has a characteristic that its gain changes depending on the input signal light level.
That is, when the input signal light level is low, the gain is large, and as the input signal light level increases, the gain decreases due to the "gain saturation effect". In addition, the response characteristic to the input signal light waveform in the conventional optical fiber amplification method differs depending on the modulation frequency of the input signal light.
【０００３】例えばＥｒドープ光ファイバ増幅器を用い
る場合、パルス変調信号を入力すると、入力パルスの繰
り返し周波数ｆｒが約１０kHz 以上であれば出力パルス
の歪は小さい。しかしｆｒが約１０kHz 以下になると、
入力パルスの前部が後部に比べてより強く増幅される現
象が発生する。これはＥｒドープ光ファイバ増幅器を用
いる増幅方法に特有の現象であり、入力信号光がパルス
変調以外の変調方式で変調されていても、変調周波数成
分に約１０kHz 以下の成分がある場合には出力信号光波
形に歪が生じることは避けられなかった。For example, when an Er-doped optical fiber amplifier is used, when a pulse modulation signal is input, the distortion of the output pulse is small if the repetition frequency fr of the input pulse is about 10 kHz or more. However, when fr becomes less than about 10kHz,
A phenomenon occurs in which the front part of the input pulse is amplified more strongly than the rear part. This is a phenomenon peculiar to the amplification method using the Er-doped optical fiber amplifier, and even if the input signal light is modulated by a modulation method other than pulse modulation, if the modulation frequency component has a component of about 10 kHz or less, it is output. It is unavoidable that the signal light waveform is distorted.
【０００４】またＥｒ以外の希土類元素をドープした光
ファイバを用いた光ファイバ増幅器を用いる場合、その
希土類元素の緩和時間により、波形歪を発生させるｆｒ
（周波数）の値が変動するが、そのｆｒ以下の周波数成
分を有する変調光に対して波形歪が生じることには変わ
りない。When an optical fiber amplifier using an optical fiber doped with a rare earth element other than Er is used, the relaxation time of the rare earth element causes a waveform distortion fr.
Although the value of (frequency) fluctuates, waveform distortion is still generated for the modulated light having a frequency component equal to or lower than fr.
【０００５】[0005]
【発明が解決しようとする課題】従来の光ファイバ増幅
器を多チャンネル光通信システムに用いる場合、トータ
ルの入力信号光レベルは、各チャンネルのｏｎ／ｏｆｆ
の状態によって変化する。このため、あるチャンネルの
利得は他のチャンネルのｏｎ／ｏｆｆの状態によって変
化してしまうという問題がある。また各チャンネルのｏ
ｎ／ｏｆｆは不規則に行われ、またｏｎ／ｏｆｆの繰り
返しは一般にかなりゆっくり行われるため、チャンネル
のｏｎ／ｏｆｆが行れわる瞬間に出力信号光波形に歪が
生じるという問題点がある。また従来の光ファイバ増幅
器を光計測に用いる場合、その増幅特性が入力信号光レ
ベルや変調周波数によって変化してしまうという問題も
ある。そこで、一般的には、利得が入力信号光レベルに
よらず一定で、かつ直流から高周波までの広い帯域で変
調された光信号を、歪なく増幅できる光ファイバ増幅方
法および装置の出現が望まれている。When a conventional optical fiber amplifier is used in a multi-channel optical communication system, the total input signal light level is on / off of each channel.
It changes according to the state of. Therefore, there is a problem that the gain of one channel changes depending on the on / off state of another channel. Also o of each channel
Since the n / off is irregularly performed and the on / off repetition is generally fairly slow, there is a problem that the output signal light waveform is distorted at the moment when the channel on / off occurs. Further, when the conventional optical fiber amplifier is used for optical measurement, there is a problem that its amplification characteristic changes depending on the input signal light level and the modulation frequency. Therefore, in general, it is desired to provide an optical fiber amplification method and apparatus that can amplify an optical signal whose gain is constant regardless of the input signal light level and which is modulated in a wide band from direct current to high frequency without distortion. ing.
【０００６】本発明の目的は、従来の光ファイバ増幅器
による増幅方法の上記の欠点を解消し、入力信号光レベ
ルが変化しても光ファイバ増幅の利得が変わらず、かつ
低周波数で変調された場合でも入力信号光を波形歪なく
増幅する光ファイバ増幅方法を提供することにある。The object of the present invention is to solve the above-mentioned drawbacks of the conventional amplification method using an optical fiber amplifier, to keep the gain of the optical fiber amplification unchanged even if the input signal light level changes, and to modulate at a low frequency. Even in the case, it is to provide an optical fiber amplification method for amplifying input signal light without waveform distortion.
【０００７】[0007]
【課題を解決するための手段】本発明に係るダミー光入
力制御型定利得光ファイバ増幅方法は、入力信号光を、
光ファイバ増幅器を用いて増幅するに際し、この光ファ
イバ増幅器の増幅部の上流において、当該増幅域の増幅
波長帯域内において、前記入力信号光の波長とは異なる
波長を有するダミー光を前記入力信号光に合流し、この
とき、前記ダミー光のパワーを、それと前記入力信号光
とのパワーとの合計値が一定になるように制御し、この
合流光を前記増幅部に入力し、それによって当該光ファ
イバ増幅器の利得を、前記入力信号光レベルに依存する
ことなく一定に保持し、かつ前記入力信号光を、波形歪
なく増幅し、その後、前記合流光から前記ダミー光を除
去して、増幅された信号光のみを出力する、ことを特徴
とするものである。A dummy optical input control type constant gain optical fiber amplifying method according to the present invention,
When amplifying using the optical fiber amplifier, the dummy light having a wavelength different from the wavelength of the input signal light is provided in the amplification wavelength band of the amplification region upstream of the amplification unit of the optical fiber amplifier. The power of the dummy light is controlled so that the total value of the power of the dummy light and the power of the input signal light is constant, and the merged light is input to the amplification unit, whereby the light The gain of the fiber amplifier is kept constant without depending on the input signal light level, the input signal light is amplified without waveform distortion, and then the dummy light is removed from the combined light to be amplified. It is characterized by outputting only the signal light.
【０００８】本発明に係るダミー光入力制御型定利得光
ファイバ増幅装置は、入力信号光を入力する光合波器６
と、この光合波器６に励起光半導体レーザ光を入力する
手段（７，８）と、前記光合波器６に連結された希土類
元素ドープ光ファイバからなる増幅部１０とを有する光
ファイバ増幅器において、前記光合波器６がその上流に
配置された光分岐器５、および更にその上流に配置され
た光合流器１に連結され、前記光合流器１が、前記入力
信号光とは異なる波長のダミー光を発光するダミー光発
光器２に連結され、前記光分岐器５が、こゝで分岐され
た光を受光する受光器４に連結され、前記受光器４と、
前記ダミー光発光器２とが、前記ダミー光発光器２を、
前記受光器４に入力した光のパワーに対応して、前記ダ
ミー光と前記入力信号光との合計パワーが一定になるよ
うに制御するダミー光発光制御手段３を介して連結され
ており、更に、前記増幅部１０がその下流に配置された
前記信号光のみを透過する光フイルターに連結されてい
ることを特徴とするものである。A dummy optical input control type constant gain optical fiber amplifier according to the present invention is an optical multiplexer 6 for inputting input signal light.
In the optical fiber amplifier, the means (7, 8) for inputting the pumping light semiconductor laser light into the optical multiplexer 6 and the amplification section 10 composed of the rare earth element-doped optical fiber connected to the optical multiplexer 6 are provided. , The optical multiplexer 6 is connected to the optical branching device 5 arranged upstream thereof, and the optical combiner 1 arranged further upstream thereof, and the optical multiplexer 1 has a wavelength different from that of the input signal light. The light branching device 5 is connected to a dummy light emitting device 2 that emits dummy light, and the optical branching device 5 is connected to a light receiving device 4 that receives the branched light.
The dummy light-emitter 2 and the dummy light-emitter 2 are
Corresponding to the power of the light input to the light receiver 4, they are connected via a dummy light emission control means 3 for controlling so that the total power of the dummy light and the input signal light becomes constant. The amplification unit 10 is connected to an optical filter disposed downstream of the amplification unit 10 that transmits only the signal light.
【０００９】[0009]
【作用および実施例】本発明方法および装置の実施態様
について、図面により詳細に説明する。図１は、本発明
の方法に用いられる光ファイバ増幅器の一実施例を示す
構成説明図である。図１において光ファイバ増幅器は、
図１に示されているように希土類元素ドープ光ファイバ
により互に連結された光合流器１、ダミー光半導体レー
ザ発光器２、ダミー光半導体レーザ発光制御回路３、受
光器４、光分岐器５、信号光、ダミー光と励起光の合波
用光合波器６、励起用半導体レーザ発光器７、励起用半
導体レーザ発光器駆動回路８、光アイソレータ９，１
１、希土類元素ドープ光ファイバからなる増幅部１０、
光フイルタ１２から構成されている。The embodiments of the method and apparatus of the present invention will be described in detail with reference to the drawings. FIG. 1 is a structural explanatory view showing an embodiment of an optical fiber amplifier used in the method of the present invention. In FIG. 1, the optical fiber amplifier is
As shown in FIG. 1, an optical coupler 1, a dummy optical semiconductor laser light emitting device 2, a dummy optical semiconductor laser light emitting control circuit 3, a light receiving device 4, and an optical branching device 5 which are connected to each other by a rare earth element-doped optical fiber. , Signal light, optical multiplexer 6 for combining dummy light and excitation light, excitation semiconductor laser light emitter 7, excitation semiconductor laser light emitter drive circuit 8, optical isolators 9, 1
1. An amplification unit 10 made of a rare earth element-doped optical fiber,
It is composed of an optical filter 12.
【００１０】図１において波長λ1 の入力信号光が希土
類元素ドープ光ファイバからなる増幅部１０に向って入
力される。このとき、入力信号光は先づ光合流器１を経
て、光分岐器５に入力される。そして入力信号光パワー
の一部が光分岐器５によって取り出され、受光器４に入
力される。In FIG. 1, an input signal light having a wavelength λ 1 is input toward an amplifying section 10 made of a rare earth element-doped optical fiber. At this time, the input signal light is first input to the optical branching device 5 via the optical combiner 1. Then, a part of the input signal light power is taken out by the optical branching device 5 and input to the light receiving device 4.
【００１１】ダミー光半導体レーザ発光制御回路３はダ
ミー光半導体レーザ発光器２を駆動して、入力信号光と
は異なる波長を存するダミー光を発光し、これを光合流
器１に入力する。このとき、入力信号光とダミー光との
合計パワーが常に一定になるようにダミー光パワーを制
御する。すなわち、入力信号光パワーが小さいときはレ
ーザ発光器２から出力するダミー光パワーを大きくし、
この入力信号光パワーが大きいときは前記ダミー光パワ
ーを小さくして両者の合計パワーを一定値に制御する。
レーザ発光器２から出力したダミー光は、光合流器１に
おいて波長λ1を有する入力信号光と合流し、この合流
光は光分岐器５を経て、光合波器６に入力される。The dummy optical semiconductor laser light emission control circuit 3 drives the dummy optical semiconductor laser light emitter 2 to emit dummy light having a wavelength different from that of the input signal light, and inputs this to the optical combiner 1. At this time, the dummy light power is controlled so that the total power of the input signal light and the dummy light is always constant. That is, when the input signal light power is low, the dummy light power output from the laser light emitter 2 is increased,
When the input signal light power is high, the dummy light power is decreased to control the total power of both to a constant value.
Dummy light output from the laser emitter 2, joins the input signal light having a wavelength lambda 1 in the optical combiners 1, the merged light through the optical splitter 5 is input to the optical multiplexer 6.
【００１２】別に励起用半導体レーザ駆動回路８によっ
て駆動された励起用半導体レーザ発光器７は励起光を発
光し、この励起光は、光合波器６に入力され、こゝで入
力信号光およびダミー光と合波する。この合波光は、光
アイソレータ９を通って希土類元素ドープ光ファイバ１
０に入力される。希土類元素ドープ光ファイバ１０は励
起光によって励起され、このため、信号光とダミー光は
希土類元素ドープ光ファイバ１０を通る間に増幅され
る。増幅された信号光とダミー光は、アイソレータ１１
を通った後、波長λ1 の信号光のみを通す光フィルタ１
２に入力され、こゝでダミー光が除去され波長λ1 の増
幅された信号光のみが出力される。The pumping semiconductor laser light-emitting device 7, which is separately driven by the pumping semiconductor laser driving circuit 8, emits pumping light, and this pumping light is input to the optical multiplexer 6, where the input signal light and the dummy are emitted. Combine with light. This combined light passes through the optical isolator 9 and the rare earth element-doped optical fiber 1
Input to 0. The rare earth element-doped optical fiber 10 is excited by the excitation light, so that the signal light and the dummy light are amplified while passing through the rare earth element-doped optical fiber 10. The amplified signal light and dummy light are transmitted to the isolator 11
Optical filter 1 that passes only the signal light of wavelength λ 1 after passing through
2, the dummy light is removed, and only the amplified signal light of wavelength λ 1 is output.
【００１３】図２は本発明方法および装置による光ファ
イバ増幅特性の一例を示す。この例では、従来の光ファ
イバ増幅方法においては、その利得は、入力信号光レベ
ルが−３０ｄＢｍのとき、２０ｄＢであるが、入力信号
光レベルが０ｄＢｍとなると、利得は１０ｄＢに低下す
る。すなわち利得は入力信号光レベルの増大に伴って減
少し、入力信号光レベルに対して一定ではない。しかし
本発明の光ファイバ増幅方法においては、入力信号光レ
ベルが−３０ｄＢｍから０ｄＢｍの範囲で、その利得は
一定値１０ｄＢに保持される。FIG. 2 shows an example of optical fiber amplification characteristics according to the method and apparatus of the present invention. In this example, in the conventional optical fiber amplification method, the gain is 20 dB when the input signal light level is −30 dBm, but when the input signal light level becomes 0 dBm, the gain drops to 10 dB. That is, the gain decreases as the input signal light level increases, and is not constant with respect to the input signal light level. However, in the optical fiber amplification method of the present invention, the gain is maintained at a constant value of 10 dB when the input signal light level is in the range of -30 dBm to 0 dBm.
【００１４】図３は、本発明の光ファイバ増幅方法およ
び装置の作用効果の説明図である。入力信号光が低速の
パルス変調光Ｓである場合、信号パルスＳのｏｎ／ｏｆ
ｆの波形と逆の特性を有する、ダミー光Ｄを、信号光Ｓ
と合流して、この入力信号光Ｓと入力ダミー光Ｄのパワ
ーの和の波形Ｔが一定となるように、光ファイバ増幅器
に入力する。このようにすると希土類元素ドープ光ファ
イバからなる増幅部内の反転分布密度を一定に保つこと
ができるため、増幅された合流光からダミー光を除去す
ると、得られる出力信号光は歪なく増幅されたパルス波
形Ｓ′を有するものとなる。この作用効果は、入力信号
光レベルの大小に無関係である。FIG. 3 is an explanatory view of the function and effect of the optical fiber amplifying method and apparatus of the present invention. When the input signal light is the low-speed pulse-modulated light S, on / of the signal pulse S
The dummy light D, which has characteristics opposite to the waveform of f,
And is input to the optical fiber amplifier so that the waveform T of the sum of the powers of the input signal light S and the input dummy light D becomes constant. In this way, since the population inversion density in the amplification section composed of the rare earth element-doped optical fiber can be kept constant, if the dummy light is removed from the amplified combined light, the output signal light obtained is a pulse without distortion. It has a waveform S '. This effect is independent of the level of the input signal light level.
【００１５】上記の説明は、信号光波長とダミー光波長
に対する光ファイバ増幅器の利得が同じである場合を例
にとり説明したが、光ファイバ増幅器の利得が信号光波
長とダミー光波長により異なる場合には、この光ファイ
バ増幅器の利得差を考慮してダミー光のレベルを制御す
るようにできることは、本発明により自明のことであ
る。In the above description, the case where the gain of the optical fiber amplifier with respect to the signal light wavelength and the dummy light wavelength is the same is explained as an example, but when the gain of the optical fiber amplifier differs depending on the signal light wavelength and the dummy light wavelength. It is obvious from the present invention that the dummy light level can be controlled in consideration of the gain difference of the optical fiber amplifier.
【００１６】図４は、従来の光ファイバ増幅器の作用の
説明図である。入力信号光が低速のパルス変調光Ｓであ
る場合、希土類元素ドープ光ファイバからなる増幅部内
の反転分布密度は信号パルスＳがｏｎのとき減少し、ｏ
ｆｆのとき増加する。このため、出力信号光は波形歪を
伴ったパルス波形Ｓ′となる。このようなパルス波形の
変化は入力信号光レベルが大である程大きくなる。FIG. 4 is an explanatory view of the operation of the conventional optical fiber amplifier. When the input signal light is the low-speed pulse-modulated light S, the population inversion density in the amplification section composed of the rare earth element-doped optical fiber decreases when the signal pulse S is on, and o
It increases when ff. Therefore, the output signal light has a pulse waveform S'with waveform distortion. Such a change in the pulse waveform increases as the input signal light level increases.
【００１７】[0017]
【発明の効果】上記の説明から明らかなように本発明に
よる光ファイバ増幅方法およひ装置においては、利得が
入力信号光レベルに依存せずに一定に保持され、かつ低
い周波数で変調された入力信号光が波形歪なく増幅でき
るため、光ファイバ増幅方法、および増幅器の応用分野
を著しく拡大することができる。また本発明による光フ
ァイバ増幅方法および増幅器の高周波応答特性は従来の
光ファイバ増幅方法および増幅器と何等変わらないた
め、低周波から高周波までの広い変調周波数成分をもつ
入力信号光を歪なく増幅することができる。As is apparent from the above description, in the optical fiber amplifying method and device according to the present invention, the gain is kept constant without depending on the input signal light level and is modulated at a low frequency. Since the input signal light can be amplified without waveform distortion, the optical fiber amplification method and the application field of the amplifier can be remarkably expanded. Further, since the high-frequency response characteristics of the optical fiber amplification method and amplifier according to the present invention are no different from those of the conventional optical fiber amplification method and amplifier, it is possible to amplify the input signal light having a wide modulation frequency component from low frequency to high frequency without distortion. You can
【図１】図１は、本発明方法を実施するための光ファイ
バ増幅装置の構成を示す説明図。FIG. 1 is an explanatory diagram showing the configuration of an optical fiber amplifier for carrying out the method of the present invention.
【図２】図２は、従来方法および本発明方法による光フ
ァイバ増幅において、入力信号光レベルと利得との関係
を比較して示すグラフ。FIG. 2 is a graph showing a comparison between a relationship between an input signal light level and a gain in optical fiber amplification according to the conventional method and the method of the present invention.
【図３】図３は、本発明方法および装置による光ファイ
バ増幅の一例において、入力信号光レベルが小のとき、
および大のときの、入力信号光の波形およびパワー、入
力ダミー光の波形、およびパワー、入力合流光の波形お
よびパワー、並びに出力信号光の波形およびパワーを示
す説明図。FIG. 3 shows an example of optical fiber amplification according to the method and apparatus of the present invention, when the input signal light level is low,
6A and 6B are explanatory diagrams showing the waveform and power of the input signal light, the waveform and power of the input dummy light, the waveform and power of the input converging light, and the waveform and power of the output signal light when and.
【図４】図４は、従来方法による光ファイバ増幅の一例
において、入力信号光レベルが小および大のときの入力
信号光、および出力信号光の波形およびパワーを示す説
明図。FIG. 4 is an explanatory diagram showing waveforms and powers of the input signal light and the output signal light when the input signal light level is low and high in an example of optical fiber amplification according to a conventional method.
１…光合流器 ２…ダミー光半導体レーザ発光器 ３…ダミー半導体レーザ発光器制御手段 ４…受光器 ５…光分岐器 ６…光合波器 ７…励起用半導体レーザ発光器 ８…励起用半導体レーザ発光器駆動手段 ９…光アイソレータ １０…希土類元素ドープ光ファイバからなる増幅部 １１…光アイソレータ １２…光フイルタ DESCRIPTION OF SYMBOLS 1 ... Optical combiner 2 ... Dummy optical semiconductor laser light emitter 3 ... Dummy semiconductor laser light emitter control means 4 ... Photoreceiver 5 ... Optical branching device 6 ... Optical multiplexer 7 ... Excitation semiconductor laser light emitter 8 ... Excitation semiconductor laser Light emitting device driving means 9 ... Optical isolator 10 ... Amplification section composed of rare earth element-doped optical fiber 11 ... Optical isolator 12 ... Optical filter
Claims (2)
て増幅するに際し、この光ファイバ増幅器の増幅部の上
流において、当該増幅域の増幅波長帯域内において、前
記入力信号光の波長とは異なる波長を有するダミー光を
前記入力信号光に合流し、このとき、前記ダミー光のパ
ワーを、それと前記入力信号光とのパワーとの合計値が
一定になるように制御し、この合流光を前記増幅部に入
力し、それによって当該光ファイバ増幅器の利得を、前
記入力信号光レベルに依存することなく一定に保持し、
かつ前記入力信号光を、波形歪なく増幅し、その後、前
記合流光から前記ダミー光を除去して、増幅された信号
光のみを出力する、ことを特徴とするダミー光入力制御
型定利得光ファイバ増幅方法。1. When amplifying an input signal light using an optical fiber amplifier, the wavelength of the input signal light is different in the amplification wavelength band of the amplification region upstream of the amplification section of the optical fiber amplifier. Dummy light having a wavelength is merged with the input signal light, at this time, the power of the dummy light is controlled so that the total value of the power of the dummy light and the power of the input signal light is constant, and the merged light is The gain of the optical fiber amplifier is kept constant without depending on the input signal light level,
Further, the input signal light is amplified without waveform distortion, then the dummy light is removed from the combined light, and only the amplified signal light is output, and the dummy light input control type constant gain light is provided. Fiber amplification method.
の光合波器６に、励起光半導体レーザ光を入力する手段
（７，８）と、前記光合波器６に連結された希土類元素
ドープ光ファイバからなる増幅部１０とを有する光ファ
イバ増幅器において、前記光合波器６がその上流に配置
された光分岐器５、および更にその上流に配置された光
合流器１に連結され、前記光合流器１が、前記入力信号
光とは異なる波長のダミー光を発光するダミー光発光器
２に連結され、前記光分岐器５が、こゝで分岐された光
を受光する受光器４に連結され、前記受光器４と、前記
ダミー光発光器２とが、前記ダミー光発光器２を、前記
受光器４に入力した光のパワーに対応して、前記ダミー
光と前記入力信号光との合計パワーが一定になるように
制御するダミー光発光制御手段３を介して連結されてお
り、更に、前記増幅部１０が、その下流に配置された前
記信号光のみを透過する光フイルターに連結されている
ことを特徴とするダミー光入力制御型定利得光ファイバ
増幅装置。2. An optical multiplexer 6 for inputting input signal light, a means (7, 8) for inputting pumping light semiconductor laser light to the optical multiplexer 6, and a rare earth element connected to the optical multiplexer 6. In an optical fiber amplifier having an amplifying section 10 composed of an element-doped optical fiber, the optical multiplexer 6 is connected to an optical branching device 5 arranged upstream thereof and an optical combiner 1 arranged further upstream thereof, The optical combiner 1 is connected to a dummy optical light emitter 2 which emits dummy light having a wavelength different from that of the input signal light, and the optical branching device 5 receives the light branched by this optical receiver 4. And the dummy light emitter 4 and the dummy light emitter 2 are connected to the dummy light emitter 2 and the dummy light emitter 2 in accordance with the power of light input to the light receiver 4. And a dummy light source that controls so that the total power of The dummy optical input control type is characterized in that it is connected via an optical control means 3, and further that the amplification section 10 is connected to an optical filter arranged downstream of the optical section for transmitting only the signal light. Constant gain optical fiber amplifier.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5007812A JP2907666B2 (en) | 1993-01-20 | 1993-01-20 | Dummy optical input control type constant gain optical fiber amplification method and apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5007812A JP2907666B2 (en) | 1993-01-20 | 1993-01-20 | Dummy optical input control type constant gain optical fiber amplification method and apparatus |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06216452A true JPH06216452A (en) | 1994-08-05 |
| JP2907666B2 JP2907666B2 (en) | 1999-06-21 |
Family
ID=11676016
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5007812A Expired - Fee Related JP2907666B2 (en) | 1993-01-20 | 1993-01-20 | Dummy optical input control type constant gain optical fiber amplification method and apparatus |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2907666B2 (en) |
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| EP0772264A3 (en) * | 1995-10-30 | 1997-10-29 | Nec Corp | Optical surge preventing method and system for use with or in a rare earth doped fiber circuit |
| US5923463A (en) * | 1996-10-02 | 1999-07-13 | Nec Corporation | Optical amplifier and method for controlling the same |
| JPH10262032A (en) * | 1997-03-19 | 1998-09-29 | Fujitsu Ltd | Light amplification device |
| US6134372A (en) * | 1997-10-01 | 2000-10-17 | Sumitomo Osaka Cement Co., Ltd. | Light intensity attenuator and attenuating method |
| EP0915459A1 (en) * | 1997-11-10 | 1999-05-12 | Fujifilm Electronic Imaging Limited | Method and apparatus for exposing an image recording medium |
| EP0933665A2 (en) * | 1998-01-30 | 1999-08-04 | Nec Corporation | Light limiter |
| EP0933665A3 (en) * | 1998-01-30 | 2001-09-19 | Nec Corporation | Light limiter |
| US6606189B2 (en) | 2000-12-22 | 2003-08-12 | Nec Corporation | Light amplifier and light amplifying method |
| JP2005277569A (en) * | 2004-03-23 | 2005-10-06 | Fujitsu Ltd | Optical transmitter and optical transmission system |
| JP4594636B2 (en) * | 2004-03-23 | 2010-12-08 | 富士通株式会社 | Optical transmission equipment |
| EP1942565A2 (en) * | 2006-12-08 | 2008-07-09 | General Instrument Corporation | Method and apparatus for controlling an optical amplifier for use in an passive optical network |
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