JPH11168255A - Optical fiber amplifier - Google Patents
Optical fiber amplifierInfo
- Publication number
- JPH11168255A JPH11168255A JP9333387A JP33338797A JPH11168255A JP H11168255 A JPH11168255 A JP H11168255A JP 9333387 A JP9333387 A JP 9333387A JP 33338797 A JP33338797 A JP 33338797A JP H11168255 A JPH11168255 A JP H11168255A
- Authority
- JP
- Japan
- Prior art keywords
- optical fiber
- optical
- light source
- excitation light
- fiber amplifier
- 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
Landscapes
- Light Guides In General And Applications Therefor (AREA)
- Lasers (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、光通信システム等
に使用されて光信号を直接増幅する光ファイバアンプに
関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber amplifier used in an optical communication system or the like to directly amplify an optical signal.
【０００２】[0002]
【従来の技術】希土類元素がドープされた光ファイバを
用いた光ファイバアンプは、光−電気変換を伴わずに光
信号を増幅できるので利便性がよく、将来の光通信に必
要不可欠なデバイスとして開発が進められている。光フ
ァイバアンプに用いられる希土類元素がドープされた光
ファイバとしては、１．０６μｍまたは１．３２μｍ帯
の光信号を増幅するネオジム（Ｎｄ）ドープ光ファイ
バ、１．３μｍ帯の光信号を増幅するプラセオジム（Ｐ
ｒ）ドープ光ファイバなどが挙げられるが、中でも光通
信に用いられる１．５５μｍ帯に利得を有するエルビウ
ム（Ｅｒ）ドープ光ファイバを用いた光ファイバアンプ
の研究が盛んである。2. Description of the Related Art An optical fiber amplifier using an optical fiber doped with a rare earth element can amplify an optical signal without optical-electrical conversion, so that it is convenient and is an indispensable device for future optical communication. Development is underway. As an optical fiber doped with a rare earth element used for an optical fiber amplifier, a neodymium (Nd) -doped optical fiber for amplifying an optical signal in a 1.06 μm or 1.32 μm band, a praseodymium for amplifying an optical signal in a 1.3 μm band. (P
r) Doped optical fibers and the like can be mentioned. Among them, researches on optical fiber amplifiers using erbium (Er) doped optical fibers having a gain in the 1.55 μm band used for optical communication have been actively conducted.
【０００３】従来の光ファイバアンプについて図２を参
照して説明する。従来の光ファイバアンプ１０におい
て、２は受信した光信号が入力される光信号入力光ファ
イバ、３、９は矢印の方向にのみ光信号を伝搬させ、反
対方向は阻止するアイソレータ、４は、エルビウム等の
希土類元素をドープした希土類元素ドープ光ファイバ、
５は励起光を供給するレーザダイオードなどの励起光
源、６は光合分波器である。A conventional optical fiber amplifier will be described with reference to FIG. In the conventional optical fiber amplifier 10, reference numeral 2 denotes an optical signal input optical fiber into which a received optical signal is input, and reference numerals 3 and 9 denote an isolator for transmitting an optical signal only in the direction of the arrow and blocking in the opposite direction, and reference numeral 4 denotes erbium. Rare earth element doped optical fiber doped with rare earth elements such as
Reference numeral 5 denotes an excitation light source such as a laser diode for supplying excitation light, and reference numeral 6 denotes an optical multiplexer / demultiplexer.
【０００４】光信号入力光ファイバ２からの入力光信号
は、第１のアイソレータ３を経てエルビウムなどの希土
類元素がドープされた光ファイバ４を通り、光合分波器
６に供給される。一方、励起光源５は、入力光信号の波
長に対応する所定の波長の励起光を生じ、この励起光を
光合分波器６に供給する。光合分波器６は互いに波長の
異なる入力光信号と励起光とを合波し、増幅された増幅
光信号は第２のアイソレータ９を経て光信号出力光ファ
イバ８に出力される。An optical signal input from the optical signal input optical fiber 2 passes through a first isolator 3, passes through an optical fiber 4 doped with a rare earth element such as erbium, and is supplied to an optical multiplexer / demultiplexer 6. On the other hand, the excitation light source 5 generates excitation light having a predetermined wavelength corresponding to the wavelength of the input optical signal, and supplies the excitation light to the optical multiplexer / demultiplexer 6. The optical multiplexer / demultiplexer 6 multiplexes the input optical signal and the pump light having different wavelengths from each other, and outputs the amplified amplified optical signal to the optical signal output optical fiber 8 via the second isolator 9.
【０００５】従来より光ファイバアンプ１０の利得制御
は、上記励起光を発生する励起光の強度を増減すること
によって行われるのが一般的である。例えば励起光源と
してレーザダイオードを用いた場合には、レーザダイオ
ードの起動電流を制御すればよい。レーザダイオードの
駆動電流を増加させると、上記励起光の強度が増加し、
光信号の増幅利得が増すことになる。逆に、この光ファ
イバアンプの光出射端に大きなレベルの光信号を必要と
しないときには、レーザダイオードの駆動電流を減少さ
せて上記励起光の強度を弱くする。Conventionally, gain control of the optical fiber amplifier 10 is generally performed by increasing or decreasing the intensity of the pumping light for generating the pumping light. For example, when a laser diode is used as an excitation light source, the starting current of the laser diode may be controlled. When the drive current of the laser diode is increased, the intensity of the excitation light increases,
The amplification gain of the optical signal will increase. Conversely, when a large-level optical signal is not required at the light emitting end of the optical fiber amplifier, the drive current of the laser diode is reduced to weaken the intensity of the excitation light.
【０００６】しかし、従来の光ファイバアンプでは、上
記レーザダイオードの起動電流をしきい値近傍にまで低
くすると励起光波長が不安定となり、その結果、光合分
波器から出射される励起光出力が安定しなくなる。ま
た、通常励起光源の温度調整は冷却のみによって行われ
ているが、低電流駆動時には励起光源の発熱量が小さい
ために、温度調整が有効に機能しないということもあ
り、光ファイバアンプの出力が安定しないという問題が
あった。However, in the conventional optical fiber amplifier, when the starting current of the laser diode is reduced to a value close to the threshold value, the wavelength of the pump light becomes unstable. As a result, the output of the pump light emitted from the optical multiplexer / demultiplexer is reduced. Will not be stable. In addition, although the temperature adjustment of the pump light source is usually performed only by cooling, the output of the optical fiber amplifier may not function effectively at low current drive due to the small amount of heat generated by the pump light source. There was a problem that it was not stable.
【０００７】[0007]
【発明が解決しようとする課題】本発明は上記の問題を
解決するためになされたもので、低いレベルの光信号で
も安定して出力することができる光ファイバアンプを提
供する。SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides an optical fiber amplifier capable of stably outputting a low-level optical signal.
【０００８】[0008]
【課題を解決するための手段】すなわち本発明において
は、希土類元素がドープされた光ファイバと、この光フ
ァイバに励起光を供給する励起光源を備え、前記励起光
源の出力端に光減衰器が接続された、光ファイバアンプ
を提供する。また、前記光減衰器が軸ずれ融着により励
起光を減衰させる構成である光ファイバアンプを提供す
る。According to the present invention, there is provided an optical fiber doped with a rare earth element and an excitation light source for supplying excitation light to the optical fiber, and an optical attenuator is provided at an output end of the excitation light source. Provide a connected fiber optic amplifier. Further, the present invention provides an optical fiber amplifier wherein the optical attenuator is configured to attenuate the excitation light by off-axis fusion welding.
【０００９】[0009]
【発明の実施の形態】本発明について図１を参照して説
明する。図１の光ファイバアンプ１は、図２に示す従来
の光ファイバアンプの構成と同様に、光信号入力光ファ
イバ２と光信号出力光ファイバ８、第１のアイソレータ
３と第２のアイソレータ９、および希土類元素ドープ光
ファイバ４と光合分波器６と励起光源５とを備え、これ
に加えて励起光源５の出力端に接続した光減衰器７を備
えている。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to FIG. The optical fiber amplifier 1 shown in FIG. 1 has an optical signal input optical fiber 2 and an optical signal output optical fiber 8, a first isolator 3 and a second isolator 9, similarly to the configuration of the conventional optical fiber amplifier shown in FIG. And a rare earth element doped optical fiber 4, an optical multiplexer / demultiplexer 6, and an excitation light source 5. In addition, an optical attenuator 7 connected to an output terminal of the excitation light source 5 is provided.
【００１０】本発明の光ファイバアンプ１においては、
励起光源５から出力される励起光の強度を必要に応じて
光減衰器７により減衰させてから光合分波器６に供給す
ることによって、光信号出力光ファイバに出射する光信
号のレベルを変化させることができる。したがって、従
来ならば励起光源をしきい値近傍で起動しなければ得ら
れなかった小さなレベルの光信号も安定して出力するこ
とができる。In the optical fiber amplifier 1 of the present invention,
By attenuating the intensity of the pumping light output from the pumping light source 5 by the optical attenuator 7 as necessary and supplying the light to the optical multiplexer / demultiplexer 6, the level of the optical signal emitted to the optical signal output optical fiber is changed. Can be done. Therefore, even a small-level optical signal that could not be obtained unless the pumping light source was started near the threshold value can be stably output.
【００１１】光減衰器７としては、例えば軸ずれ融着に
より励起光を減衰させる構成のものや耐熱性に優れた減
衰膜を埋め込んだ構成のものなど、一般に用いられる各
種の光学素子によって構成することができる。また、複
数の光減衰器を組み合わせてもよい。The optical attenuator 7 is composed of various commonly used optical elements such as a configuration in which excitation light is attenuated by off-axis fusion and a configuration in which an attenuation film having excellent heat resistance is embedded. be able to. Further, a plurality of optical attenuators may be combined.
【００１２】図１の光ファイバアンプ１は、希土類元素
ドープ光ファイバ４に後方から励起光を入射する後方励
起方式の場合であるが、前方励起または双方励起のいず
れを採用してもよい。The optical fiber amplifier 1 shown in FIG. 1 is of a backward pumping type in which pumping light is incident on the rare earth element-doped optical fiber 4 from the rear, but either forward pumping or dual pumping may be employed.
【００１３】[0013]
【実施例】（従来例）図２に示す構成の従来の光ファイ
バアンプ１０において、４はエルビウムドープの光ファ
イバ、５は励起光波長１．４８μｍ、駆動電流５００ｍ
Ａにて励起光出力が９０ｍＷのレーザダイオード、６は
１．４８μｍの波長の励起光を反射して１．５５μｍの
波長の信号光を透過する誘電体多層膜フィルタを備えた
光合分波器である。この光ファイバアンプ１０では、出
力光＋３ｄＢｍの出力を得るための励起光源５の駆動電
流は８５ｍＡ、励起光源のしきい値は５２ｍＡである。
この光ファイバアンプの出力安定度は±０．３ｄＢ／ｈ
であった。また、レーザダイオードの発熱量が小さいた
め、温度調整のための冷却機能がうまく作動しなかっ
た。(Conventional example) In the conventional optical fiber amplifier 10 having the configuration shown in FIG. 2, reference numeral 4 denotes an erbium-doped optical fiber, 5 denotes a pumping light wavelength of 1.48 μm, and a driving current of 500 m.
A is a laser diode having an excitation light output of 90 mW, and 6 is an optical multiplexer / demultiplexer equipped with a dielectric multilayer filter that reflects excitation light having a wavelength of 1.48 μm and transmits signal light having a wavelength of 1.55 μm. is there. In the optical fiber amplifier 10, the drive current of the pump light source 5 for obtaining an output of +3 dBm of output light is 85 mA, and the threshold value of the pump light source is 52 mA.
The output stability of this optical fiber amplifier is ± 0.3 dB / h
Met. In addition, since the heat generated by the laser diode is small, the cooling function for adjusting the temperature did not work well.
【００１４】（実施例）図１は、励起光源５の出力端に
減衰量３ｄＢとなるように調整した軸ずれ融着構成の光
減衰器７を接続した以外は上記した従来例と同様の構成
の本発明の光ファイバアンプ１である。この光ファイバ
アンプ１では、従来例の光ファイバアンプ１０と同じ出
力光＋３ｄＢｍの出力を得るための励起光源５の駆動電
力は１６０ｍＡであり、出力安定度は±０．１ｄＢ／ｈ
であった。また、温度調整の冷却機能は適正に作動し
た。(Embodiment) FIG. 1 shows a configuration similar to that of the above-described conventional example except that an optical attenuator 7 having an off-axis fusion-adjusted configuration adjusted so as to have an attenuation of 3 dB is connected to the output end of an excitation light source 5. 1 is an optical fiber amplifier 1 according to the present invention. In the optical fiber amplifier 1, the driving power of the pumping light source 5 for obtaining the same output light +3 dBm as that of the conventional optical fiber amplifier 10 is 160 mA, and the output stability is ± 0.1 dB / h.
Met. In addition, the cooling function for temperature adjustment worked properly.
【００１５】実施例の光ファイバアンプでは、従来の光
ファイバアンプでは安定しない出力光＋３ｄＢｍを得る
のに、励起光源５のしきい値５２ｍＡにくらべて大きな
１６０ｍＡという駆動電力で動作させることができるた
め励起光が安定し、安定した出力光を得ることができ
た。The optical fiber amplifier of the embodiment can be operated with a driving power of 160 mA, which is larger than the threshold value 52 mA of the pumping light source 5, in order to obtain +3 dBm of output light that is not stable with the conventional optical fiber amplifier. The pump light was stabilized, and stable output light could be obtained.
【００１６】[0016]
【発明の効果】本発明の光ファイバアンプにおいては、
励起光源の出力端に光減衰器が接続されているために低
いレベルの光信号も安定して出力することができる。According to the optical fiber amplifier of the present invention,
Since the optical attenuator is connected to the output terminal of the pump light source, a low-level optical signal can be stably output.
【図１】本発明の光ファイバアンプの構成を説明する説
明図である。FIG. 1 is an explanatory diagram illustrating a configuration of an optical fiber amplifier according to the present invention.
【図２】従来の光ファイバアンプの構成を説明する説明
図である。FIG. 2 is an explanatory diagram illustrating a configuration of a conventional optical fiber amplifier.
１ 本発明の光ファイバアンプ ２ 光信号入力光ファイバ ３ 第１のアイソレータ ４ 希土類元素ドープ光ファイバ ５ 励起光源 ６ 光合分波器 ７ 光減衰器 ８ 光信号出力光ファイバ ９ 第１のアイソレータ １０ 従来の光ファイバアンプ REFERENCE SIGNS LIST 1 optical fiber amplifier of the present invention 2 optical signal input optical fiber 3 first isolator 4 rare earth element doped optical fiber 5 excitation light source 6 optical multiplexer / demultiplexer 7 optical attenuator 8 optical signal output optical fiber 9 first isolator 10 conventional Optical fiber amplifier
Claims (2)
と、この光ファイバに励起光を供給する励起光源を備
え、前記励起光源の出力端に光減衰器が接続された、光
ファイバアンプ。1. An optical fiber amplifier comprising: an optical fiber doped with a rare earth element; an excitation light source for supplying excitation light to the optical fiber; and an optical attenuator connected to an output terminal of the excitation light source.
光を減衰させる構成を有する、請求項１に記載の光ファ
イバアンプ。2. The optical fiber amplifier according to claim 1, wherein the optical attenuator has a configuration for attenuating the excitation light by off-axis fusion welding.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33338797A JP3599543B2 (en) | 1997-12-04 | 1997-12-04 | Optical fiber amplifier |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33338797A JP3599543B2 (en) | 1997-12-04 | 1997-12-04 | Optical fiber amplifier |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH11168255A true JPH11168255A (en) | 1999-06-22 |
| JP3599543B2 JP3599543B2 (en) | 2004-12-08 |
Family
ID=18265556
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP33338797A Expired - Lifetime JP3599543B2 (en) | 1997-12-04 | 1997-12-04 | Optical fiber amplifier |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3599543B2 (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2007036986A1 (en) * | 2005-09-27 | 2007-04-05 | Fujitsu Limited | Exciting light supplying device and its exciting light supplying method and optical amplifier |
| JP2010177346A (en) * | 2009-01-28 | 2010-08-12 | Nippon Telegr & Teleph Corp <Ntt> | Optical amplifier and method of amplifying light |
| US8027082B2 (en) | 2006-12-27 | 2011-09-27 | Fujitsu Limited | Raman amplifier and excitation light source used thereof |
| JP2013516057A (en) * | 2009-12-23 | 2013-05-09 | テールズ | Laser emitting pulses with variable period and stabilized energy |
| US9215009B2 (en) | 2008-06-25 | 2015-12-15 | Fujitsu Limited | Light output control apparatus |
| CN105301697A (en) * | 2015-11-26 | 2016-02-03 | 中英海底***有限公司 | Method for connecting optical filters into optical cable splice box |
-
1997
- 1997-12-04 JP JP33338797A patent/JP3599543B2/en not_active Expired - Lifetime
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2007036986A1 (en) * | 2005-09-27 | 2007-04-05 | Fujitsu Limited | Exciting light supplying device and its exciting light supplying method and optical amplifier |
| JPWO2007036986A1 (en) * | 2005-09-27 | 2009-04-02 | 富士通株式会社 | Excitation light supply apparatus, excitation light supply method, and optical amplifier |
| US8027082B2 (en) | 2006-12-27 | 2011-09-27 | Fujitsu Limited | Raman amplifier and excitation light source used thereof |
| US9215009B2 (en) | 2008-06-25 | 2015-12-15 | Fujitsu Limited | Light output control apparatus |
| JP2010177346A (en) * | 2009-01-28 | 2010-08-12 | Nippon Telegr & Teleph Corp <Ntt> | Optical amplifier and method of amplifying light |
| JP2013516057A (en) * | 2009-12-23 | 2013-05-09 | テールズ | Laser emitting pulses with variable period and stabilized energy |
| CN105301697A (en) * | 2015-11-26 | 2016-02-03 | 中英海底***有限公司 | Method for connecting optical filters into optical cable splice box |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3599543B2 (en) | 2004-12-08 |
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