JP3500878B2 - Optical amplifier - Google Patents
Optical amplifierInfo
- Publication number
- JP3500878B2 JP3500878B2 JP29178196A JP29178196A JP3500878B2 JP 3500878 B2 JP3500878 B2 JP 3500878B2 JP 29178196 A JP29178196 A JP 29178196A JP 29178196 A JP29178196 A JP 29178196A JP 3500878 B2 JP3500878 B2 JP 3500878B2
- Authority
- JP
- Japan
- Prior art keywords
- optical fiber
- optical
- terminal
- rare
- earth
- 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.)
- Expired - Fee Related
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
- H01S3/10007—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating in optical amplifiers
- H01S3/10023—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating in optical amplifiers by functional association of additional optical elements, e.g. filters, gratings, reflectors
-
- 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
- H01S2301/00—Functional characteristics
- H01S2301/04—Gain spectral shaping, flattening
-
- 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
- H01S3/2308—Amplifier arrangements, e.g. MOPA
- H01S3/2316—Cascaded 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
- H01S3/23—Arrangements of two or more lasers not provided for in groups H01S3/02 - H01S3/22, e.g. tandem arrangements of separate active media
- H01S3/2308—Amplifier arrangements, e.g. MOPA
- H01S3/2325—Multi-pass amplifiers, e.g. regenerative amplifiers
- H01S3/2333—Double-pass amplifiers
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- Optics & Photonics (AREA)
- Lasers (AREA)
Description
【発明の詳細な説明】
【０００１】
【発明の属する技術分野】本発明は、光ファイバを用い
た光増幅器に関する。
【０００２】
【従来の技術】従来の光増幅器について図２を用いて説
明する。図２は従来の光増幅器のブロック図である。
【０００３】同図に示すように、信号光Ｌｉが入力され
る光ファイバ１が光アイソレータ２を介して希土類添加
光ファイバ３の入力側に接続されると共にその間に、光
合分波器４が接続されている。光合分波器４には励起光
源５が接続され、希土類添加光ファイバ３の出力側には
光アイソレータ６を介して信号光Ｌｏが出力する光ファ
イバ７が接続されて光増幅器８が構成されている。
【０００４】このような光増幅器８において、信号光Ｌ
ｉ（パワーＰｉ）は、光アイソレータ２及び光合分波器
４を経て希土類添加光ファイバ３に入力される。励起光
源５より出力される励起光は、光合分波器４を介して希
土類添加光ファイバ３に入力される。励起光は添加され
た希土類イオンの励起準位に相当する波長を有してい
る。励起光により形成された希土類イオンのエネルギー
準位の反転分布により生ずる誘導放出現象により信号光
Ｌｉが増幅される。増幅された信号光Ｌｏは光アイソレ
ータ６を経て光ファイバ７から出力される。
【０００５】ここで、光増幅器８の入出力側に設けられ
た光アイソレータ２，６は、外部からの反射により信号
光Ｌｉ，Ｌｏや自然放出光が再び光増幅器８内に戻り、
発振等の不安定状態に陥るのを防止するためのものであ
る。尚、図２に示した従来例では希土類添加光ファイバ
の前方（信号光入射側）から励起する光増幅器について
述べたが、後方（信号光出力側）から励起するものもあ
る。
【０００６】
【発明が解決しようとする課題】ところで、希土類添加
光ファイバを用いた光増幅器の実用例としてエルビウム
（Ｅｒ）を添加した光ファイバ増幅器（以下ＥＤＦＡと
略す）がある。これは、増幅波長帯が石英系光ファイバ
の最低損失波長帯（１．５５μｍ帯）に一致し、しかも
効率が良く、高利得、低雑音の増幅特性が容易に得られ
ることから、光伝送システムに急速に普及しつつある。
【０００７】しかしながら、ＥＤＦＡにおいてはＥｒ添
加光ファイバの光の吸収、放出スペクトラム形状に依存
して利得の波長依存性が生じるので、異なる波長の複数
の信号光を多重化して伝送する波長多重光伝送方式にＥ
ＤＦＡを用いる場合に障害となる。すなわち、ＥＤＦＡ
は波長多重化された複数の信号光を一括して増幅できる
ことが大きな利点である。
【０００８】しかし各波長の信号光の増幅率が異なる
と、受信端における各波長の信号レベル、信号対雑音比
に偏差を生じ、全体の伝送性能が低下してしまう。ＥＤ
ＦＡを多段接続して長距離を伝送させるシステムでは、
上述した影響がさらに顕著に現れる。
【０００９】そこで、ＥＤＦＡの利得の波長依存性を低
減するために様々な改善が試みられている。これらの改
善例としては、高濃度のアルミニウム（Ａｌ）を共添加
することによる利得の波長依存性の低減や、光フィルタ
による等化などが検討されており、成果を上げている。
例えば、高濃度のＡｌを共添加することにより図３の実
線Ｌ１のような利得の波長依存性が得られており、波長
λ１（１．５３μｍ付近）では利得のピークが残るもの
の、波長λ２（１．５５μｍ付近）においては利得の平
坦性が得られている。尚、図３は図２に示した光増幅器
の波長と利得との関係を示す図であり、横軸が波長、縦
軸が利得を示している。
【００１０】図４は光増幅器の他の従来例を示すブロッ
ク図である。
【００１１】図２に示した光増幅器との相違点は選択的
に波長λ１近傍の光を減衰させる光フィルタ９を光増幅
器８の出力側に挿入した点である。光フィルタ９を挿入
した光増幅器８を用いることにより、図３の波線Ｌ２に
示すような平坦な利得特性を得ることができる。
【００１２】しかしながら、利得の波長依存性を厳密に
補償する光フィルタ９を作成するのは困難である。また
利得の波長依存性は信号光Ｌｉのパワーなどの条件によ
っても変化するので、広い動作範囲において利得の波長
依存性を補償するのは不可能である。このため、広い波
長範囲にわたって利得の波長依存性が小さく、しかも製
作の容易な光増幅器が望まれる。
【００１３】そこで、本発明の目的は、上記課題を解決
し、利得、雑音特性などを損なうことなく、利得の波長
依存性を低減した光増幅器を提供することにある。
【００１４】
【課題を解決するための手段】上記目的を達成するため
に本発明は、信号光が入力される光ファイバが、端子Ａ
から端子Ｂ、端子Ｂ端子Ｃへの順方向伝達特性を有する
光サーキュレータの端子Ａに接続され、この光サーキュ
レータの端子Ｂは、第１の希土類添加光ファイバの一端
に接続されると共にその間に励起光源が接続された光合
分波器が接続され、前記第１の希土類添加光ファイバの
他端は第２の希土類添加光ファイバの一端に接続される
と共にその間に、信号光を通過させ励起光のみを選択的
に反射する波長選択性の光反射器が接続されると共に前
記第２の希土類添加光ファイバの他端には全反射器が接
続されてなるものである。
【００１５】本発明によれば、希土類添加光ファイバの
光路中に励起されない他の希土類添加光ファイバを設け
たことにより、希土類添加光ファイバの吸収特性によっ
て増幅利得の波長依存性が緩和される。また、励起光が
通過する光合分波器の台数が減少することにより過剰な
励起光パワーの損失を防ぐことができる。さらに、利得
特性、雑音特性等従来の光増幅器の特性を損なうことな
く、利得の波長依存性の低減が可能である。さらにま
た、簡単な構成で小型化、低価格化が可能である。
【００１６】
【発明の実施の形態】以下、本発明の実施の形態を添付
図面に基づいて詳述する。
【００１７】図１は本発明の光増幅器の一実施例を示す
ブロック図である。尚、図２に示した従来例と同様の部
材には共通の符号を用いた。
【００１８】図１に示す光増幅器２１において、信号光
Ｌｉが入力される光ファイバ１が光サーキュレータ２２
の端子Ａに接続され、光サーキュレータ２２の端子Ｂは
希土類添加光ファイバ３ａの一端に接続されると共にそ
の間に光合分波器４が接続されている。光合分波器４に
は励起光源５が接続されている。希土類添加光ファイバ
３ａの他端は希土類添加光ファイバ３ｂの一端に接続さ
れると共にその間に、信号光を通過させ励起光のみを選
択的に反射する波長選択性の光反射器１９が接続されて
いる。希土類添加光ファイバ３ｂの他端には全反射器２
３が接続されている。尚、光サーキュレータ２２は端子
Ａから端子Ｂ、端子Ｂから端子Ｃへの順方向伝達特性を
有するものとする。
【００１９】このような光増幅器２１において、光サー
キュレータ２２の端子Ａから入力した信号光Ｌｉは端子
Ｂから出力し、光合分波器４により励起光源５から出射
される励起光と合波されて希土類添加光ファイバ３ａに
入力する。信号光は励起光により励起された希土類添加
光ファイバ３ａを通過することにより増幅される。希土
類添加光ファイバ３ａを通過した励起光は波長選択性の
光反射器１９により反射され、増幅された信号光は光反
射器１９を通過して希土類添加光ファイバ３ｂに至り、
希土類添加光ファイバ３ｂを通過した後、全反射器２３
により反射され、ここまでの経路を再び戻り光サーキュ
レータ２２の端子Ｂより端子Ｃに出力され光ファイバ７
から出力される。
【００２０】このような構成により、増幅された信号光
が、励起されていない希土類添加光ファイバ３ｂを通過
することにより一部吸収され、利得の波長依存性が軽減
される。また、高効率、高利得といった反射型光増幅器
の特徴をそのまま活かすことができる。
【００２１】以上において本実施の形態によれば、増幅
された信号光を励起されていない希土類添加光ファイバ
に通すことにより、希土類添加光ファイバの吸収特性に
応じた損失を付加させ、これにより利得の波長依存性を
低減することができる。また、希土類添加光ファイバの
吸収特性は過飽和特性を有し、入力した信号光のパワー
に依存するので、利得の波長依存性の小さい飽和領域
（入力した信号光のパワーの大きな領域）では吸収が小
さくなる。従って、入力した信号光のパワーに応じて吸
収特性が変化し、広い入力範囲で利得の波長依存性を低
減する効果がある。さらに、利得特性、雑音特性等従来
の光増幅器の特性を損なうことなく、利得の波長依存性
の低減が可能である。さらにまた、簡単な構成で小型
化、低価格化が可能である。
【００２２】
【発明の効果】以上要するに本発明によれば、次のよう
な優れた効果を発揮する。
【００２３】信号光が入力される光ファイバが、端子Ａ
から端子Ｂ、端子Ｂ端子Ｃへの順方向伝達特性を有する
光サーキュレータの端子Ａに接続され、この光サーキュ
レータの端子Ｂは、第１の希土類添加光ファイバの一端
に接続されると共にその間に励起光源が接続された光合
分波器が接続され、前記第１の希土類添加光ファイバの
他端は第２の希土類添加光ファイバの一端に接続される
と共にその間に、信号光を通過させ励起光のみを選択的
に反射する波長選択性の光反射器が接続されると共に前
記第２の希土類添加光ファイバの他端には全反射器が接
続されたので、利得、雑音特性などを損なうことなく、
利得の波長依存性を低減した光増幅器の提供を実現する
ことができると共に、励起光が通過する光合分波器の台
数が減少することにより過剰な励起光パワーの損失を防
ぐことができ、しかも、簡単な構成で小型化、低価格化
が可能である。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical amplifier using an optical fiber. 2. Description of the Related Art A conventional optical amplifier will be described with reference to FIG. FIG. 2 is a block diagram of a conventional optical amplifier. As shown in FIG. 1, an optical fiber 1 to which a signal light Li is input is connected to an input side of a rare earth doped optical fiber 3 via an optical isolator 2, and an optical multiplexer / demultiplexer 4 is connected therebetween. Have been. An excitation light source 5 is connected to the optical multiplexer / demultiplexer 4, and an optical fiber 7 for outputting signal light Lo via an optical isolator 6 is connected to an output side of the rare earth-doped optical fiber 3 to constitute an optical amplifier 8. I have. In such an optical amplifier 8, the signal light L
i (power Pi) is input to the rare earth-doped optical fiber 3 via the optical isolator 2 and the optical multiplexer / demultiplexer 4. The pumping light output from the pumping light source 5 is input to the rare earth-doped optical fiber 3 via the optical multiplexer / demultiplexer 4. The excitation light has a wavelength corresponding to the excitation level of the added rare earth ion. The signal light Li is amplified by a stimulated emission phenomenon caused by a population inversion of the energy level of the rare earth ion formed by the excitation light. The amplified signal light Lo is output from the optical fiber 7 via the optical isolator 6. Here, the optical isolators 2 and 6 provided on the input and output sides of the optical amplifier 8 return the signal lights Li and Lo and the spontaneous emission light to the optical amplifier 8 again by reflection from the outside.
This is for preventing an unstable state such as oscillation from being caused. In the conventional example shown in FIG. 2, an optical amplifier that pumps from the front (signal light incident side) of the rare earth doped optical fiber has been described, but there is also an optical amplifier that pumps from the rear (signal light output side). As a practical example of an optical amplifier using a rare-earth-doped optical fiber, there is an optical fiber amplifier (hereinafter abbreviated as EDFA) doped with erbium (Er). This is because the amplification wavelength band coincides with the lowest loss wavelength band (1.55 μm band) of the silica-based optical fiber, and high efficiency, high gain and low noise amplification characteristics can be easily obtained. Is spreading rapidly. However, in the EDFA, the wavelength dependence of the gain occurs depending on the shape of the light absorption and emission spectrum of the Er-doped optical fiber. Therefore, the wavelength multiplexing optical transmission for multiplexing and transmitting a plurality of signal lights of different wavelengths. Type E
An obstacle when using DFA. That is, EDFA
Is a great advantage that a plurality of wavelength-multiplexed signal lights can be amplified collectively. However, if the amplification factor of the signal light of each wavelength is different, a deviation occurs in the signal level and the signal-to-noise ratio of each wavelength at the receiving end, and the overall transmission performance is reduced. ED
In a system in which FAs are connected in multiple stages and transmitted over long distances,
The above-mentioned effects appear more remarkably. Various attempts have been made to reduce the wavelength dependence of the gain of the EDFA. As examples of these improvements, reduction of the wavelength dependence of gain by co-doping with high concentration of aluminum (Al), equalization by an optical filter, and the like have been studied, and the results have been achieved.
For example, by co-doping Al at a high concentration, the wavelength dependence of the gain as shown by the solid line L1 in FIG. 3 is obtained. Although the gain peak remains at the wavelength λ1 (around 1.53 μm), the wavelength λ2 ( (At around 1.55 μm), gain flatness is obtained. FIG. 3 is a diagram showing the relationship between the wavelength and the gain of the optical amplifier shown in FIG. 2, in which the horizontal axis represents the wavelength and the vertical axis represents the gain. FIG. 4 is a block diagram showing another conventional example of an optical amplifier. The difference from the optical amplifier shown in FIG. 2 is that an optical filter 9 for selectively attenuating light near the wavelength λ1 is inserted on the output side of the optical amplifier 8. By using the optical amplifier 8 in which the optical filter 9 is inserted, a flat gain characteristic as shown by a broken line L2 in FIG. 3 can be obtained. However, it is difficult to produce an optical filter 9 that strictly compensates for the wavelength dependence of the gain. Further, since the wavelength dependence of the gain changes depending on conditions such as the power of the signal light Li, it is impossible to compensate for the wavelength dependence of the gain in a wide operating range. Therefore, there is a demand for an optical amplifier which has a small wavelength dependence of gain over a wide wavelength range and is easy to manufacture. It is an object of the present invention to solve the above-mentioned problems and to provide an optical amplifier in which the wavelength dependence of the gain is reduced without impairing the gain and noise characteristics. In order to achieve the above object, the present invention provides an optical fiber for receiving signal light, comprising:
Is connected to a terminal A of an optical circulator having a forward transmission characteristic from a terminal B to a terminal B to a terminal C. The terminal B of the optical circulator is connected to one end of the first rare earth-doped optical fiber and excited during the connection. An optical multiplexer / demultiplexer to which a light source is connected is connected, and the other end of the first rare-earth-doped optical fiber is connected to one end of a second rare-earth-doped optical fiber. And a total reflector is connected to the other end of the second rare earth-doped optical fiber. According to the present invention, the wavelength dependence of the amplification gain is alleviated by the absorption characteristic of the rare-earth-doped optical fiber by providing another rare-earth-doped optical fiber that is not pumped in the optical path of the rare-earth-doped optical fiber. In addition, since the number of optical multiplexers / demultiplexers through which the pump light passes decreases, excessive loss of the pump light power can be prevented. Further, the wavelength dependence of the gain can be reduced without deteriorating the characteristics of the conventional optical amplifier such as the gain characteristic and the noise characteristic. Furthermore, downsizing and cost reduction are possible with a simple configuration. Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a block diagram showing one embodiment of the optical amplifier of the present invention. The same members as those of the conventional example shown in FIG. In the optical amplifier 21 shown in FIG. 1, the optical fiber 1 to which the signal light Li is input is connected to an optical circulator 22.
The terminal B of the optical circulator 22 is connected to one end of the rare-earth-doped optical fiber 3a, and the optical multiplexer / demultiplexer 4 is connected therebetween. An excitation light source 5 is connected to the optical multiplexer / demultiplexer 4. The other end of the rare-earth-doped optical fiber 3a is connected to one end of the rare-earth-doped optical fiber 3b, and a wavelength-selective optical reflector 19 that allows signal light to pass therethrough and selectively reflects only the excitation light is connected therebetween. I have. A total reflector 2 is provided at the other end of the rare earth-doped optical fiber 3b.
3 are connected. It is assumed that the optical circulator 22 has a forward transmission characteristic from the terminal A to the terminal B and from the terminal B to the terminal C. In such an optical amplifier 21, the signal light Li input from the terminal A of the optical circulator 22 is output from the terminal B, and multiplexed with the pump light emitted from the pump light source 5 by the optical multiplexer / demultiplexer 4. Input to the rare earth doped optical fiber 3a. The signal light is amplified by passing through the rare earth-doped optical fiber 3a excited by the pump light. The excitation light that has passed through the rare earth-doped optical fiber 3a is reflected by the wavelength-selective optical reflector 19, and the amplified signal light passes through the light reflector 19 and reaches the rare earth-doped optical fiber 3b.
After passing through the rare earth-doped optical fiber 3b, the total reflector 23
The optical fiber 7 is returned from the terminal B of the optical circulator 22 to the terminal C,
Output from According to such a configuration, the amplified signal light is partially absorbed by passing through the unexcited rare earth-doped optical fiber 3b, and the wavelength dependence of the gain is reduced. Further, the characteristics of the reflection type optical amplifier such as high efficiency and high gain can be utilized as it is. As described above, according to the present embodiment, by passing the amplified signal light through the unexcited rare earth-doped optical fiber, a loss corresponding to the absorption characteristics of the rare earth-doped optical fiber is added, thereby increasing the gain. Can be reduced in wavelength dependence. Further, the absorption characteristics of the rare-earth-doped optical fiber have supersaturation characteristics and depend on the power of the input signal light. Therefore, the absorption is small in the saturation region where the wavelength dependence of the gain is small (the region where the power of the input signal light is large). Become smaller. Therefore, the absorption characteristics change according to the power of the input signal light, and there is an effect of reducing the wavelength dependence of the gain in a wide input range. Further, the wavelength dependence of the gain can be reduced without deteriorating the characteristics of the conventional optical amplifier such as the gain characteristic and the noise characteristic. Furthermore, downsizing and cost reduction are possible with a simple configuration. In summary, according to the present invention, the following excellent effects are exhibited. The optical fiber into which the signal light is input is connected to the terminal A
Is connected to a terminal A of an optical circulator having a forward transmission characteristic from a terminal B to a terminal B to a terminal C. The terminal B of the optical circulator is connected to one end of the first rare earth-doped optical fiber and excited during the connection. An optical multiplexer / demultiplexer to which a light source is connected is connected, and the other end of the first rare-earth-doped optical fiber is connected to one end of a second rare-earth-doped optical fiber. Is connected to the other end of the second rare-earth-doped optical fiber, and the total reflector is connected to the other end of the second rare-earth-doped optical fiber.
It is possible to provide an optical amplifier in which the wavelength dependence of the gain is reduced, and it is possible to prevent an excessive loss of the power of the pumping light by reducing the number of optical multiplexers / demultiplexers through which the pumping light passes. It is possible to reduce the size and cost with a simple configuration.
【図面の簡単な説明】
【図１】本発明の光増幅器の一実施の形態を示すブロッ
ク図である。
【図２】従来の光増幅器のブロック図である。
【図３】図２に示した光増幅器の波長と利得との関係を
示す図である。
【図４】光増幅器の他の従来例を示すブロック図であ
る。
【符号の説明】
１，７ 光ファイバ
３ａ，３ｂ 希土類添加光ファイバ
４， 光合分波器
５ 励起光源
１９ 波長選択性の光反射器
２２ 光サーキュレータ
２３ 全反射器BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of an optical amplifier according to the present invention. FIG. 2 is a block diagram of a conventional optical amplifier. FIG. 3 is a diagram illustrating a relationship between a wavelength and a gain of the optical amplifier illustrated in FIG. 2; FIG. 4 is a block diagram showing another conventional example of an optical amplifier. [Description of Signs] 1,7 Optical fibers 3a, 3b Rare earth doped optical fiber 4, Optical multiplexer / demultiplexer 5 Excitation light source 19 Wavelength selective light reflector 22 Optical circulator 23 Total reflector
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 平10−22555（ＪＰ，Ａ) 特開 平５−48178（ＪＰ，Ａ) 特開 平５−226734（ＪＰ，Ａ) 特開 平５−107573（ＪＰ，Ａ) 特開 平６−77561（ＪＰ，Ａ) 特開 平７−28105（ＪＰ，Ａ) 特開 平10−107351（ＪＰ，Ａ) 特開 平９−326519（ＪＰ，Ａ) 特開 平９−265116（ＪＰ，Ａ) 国際公開96／029627（ＷＯ，Ａ１) (58)調査した分野(Int.Cl.7，ＤＢ名) H01S 3/00 - 3/30 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-10-22555 (JP, A) JP-A-5-48178 (JP, A) JP-A-5-227674 (JP, A) 107573 (JP, A) JP-A-6-77561 (JP, A) JP-A-7-28105 (JP, A) JP-A-10-107351 (JP, A) JP-A-9-326519 (JP, A) JP-A-9-265116 (JP, A) WO 96/029627 (WO, A1) (58) Fields investigated (Int. Cl. 7 , DB name) H01S 3/00-3/30
Claims (1)
Ａから端子Ｂ、端子Ｂ端子Ｃへの順方向伝達特性を有す
る光サーキュレータの端子Ａに接続され、この光サーキ
ュレータの端子Ｂは、第１の希土類添加光ファイバの一
端に接続されると共にその間に励起光源が接続された光
合分波器が接続され、前記第１の希土類添加光ファイバ
の他端は第２の希土類添加光ファイバの一端に接続され
ると共にその間に、信号光を通過させ励起光のみを選択
的に反射する波長選択性の光反射器が接続されると共に
前記第２の希土類添加光ファイバの他端には全反射器が
接続されてなる光増幅器。(57) Claims 1. An optical fiber to which signal light is input is connected to a terminal A of an optical circulator having forward transmission characteristics from terminal A to terminal B and terminal B to terminal C. A terminal B of the optical circulator is connected to one end of a first rare-earth-doped optical fiber, and an optical multiplexer / demultiplexer having an excitation light source connected therebetween is connected to the other end of the first rare-earth-doped optical fiber. Is connected to one end of a second rare-earth-doped optical fiber, between which is connected a wavelength-selective optical reflector for transmitting signal light and selectively reflecting only excitation light, and connecting the second rare-earth-doped optical fiber. An optical amplifier in which a total reflector is connected to the other end of the optical fiber.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29178196A JP3500878B2 (en) | 1996-11-01 | 1996-11-01 | Optical amplifier |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29178196A JP3500878B2 (en) | 1996-11-01 | 1996-11-01 | Optical amplifier |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH10135544A JPH10135544A (en) | 1998-05-22 |
| JP3500878B2 true JP3500878B2 (en) | 2004-02-23 |
Family
ID=17773349
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP29178196A Expired - Fee Related JP3500878B2 (en) | 1996-11-01 | 1996-11-01 | Optical amplifier |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3500878B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ATE504988T1 (en) * | 2007-04-13 | 2011-04-15 | Ericsson Telefon Ab L M | OPTICAL SIGNAL AMPLIFIER, METHOD FOR OPTICAL AMPLIFICATION AND OPTICAL NETWORK |
-
1996
- 1996-11-01 JP JP29178196A patent/JP3500878B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH10135544A (en) | 1998-05-22 |
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