JPH0493091A - Optical amplifier - Google Patents
Optical amplifierInfo
- Publication number
- JPH0493091A JPH0493091A JP21109390A JP21109390A JPH0493091A JP H0493091 A JPH0493091 A JP H0493091A JP 21109390 A JP21109390 A JP 21109390A JP 21109390 A JP21109390 A JP 21109390A JP H0493091 A JPH0493091 A JP H0493091A
- Authority
- JP
- Japan
- Prior art keywords
- optical
- light
- wavelength
- optical fiber
- excitation
- 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 description 74
- 230000005284 excitation Effects 0.000 claims abstract description 40
- 230000003321 amplification Effects 0.000 claims abstract description 30
- 238000003199 nucleic acid amplification method Methods 0.000 claims abstract description 30
- 238000005086 pumping Methods 0.000 claims description 30
- 229910052761 rare earth metal Inorganic materials 0.000 claims description 17
- 238000010521 absorption reaction Methods 0.000 claims description 14
- 230000000903 blocking effect Effects 0.000 claims description 5
- 239000013307 optical fiber Substances 0.000 abstract description 38
- 239000004065 semiconductor Substances 0.000 abstract description 21
- 230000010355 oscillation Effects 0.000 abstract description 7
- 229920006395 saturated elastomer Polymers 0.000 abstract description 5
- 230000010287 polarization Effects 0.000 description 11
- 230000005540 biological transmission Effects 0.000 description 7
- 238000010586 diagram Methods 0.000 description 7
- 238000000034 method Methods 0.000 description 7
- 230000002457 bidirectional effect Effects 0.000 description 6
- 230000015572 biosynthetic process Effects 0.000 description 4
- -1 rare earth ion Chemical class 0.000 description 4
- 238000011160 research Methods 0.000 description 4
- 238000003786 synthesis reaction Methods 0.000 description 4
- 239000011248 coating agent Substances 0.000 description 3
- 238000000576 coating method Methods 0.000 description 3
- 150000002910 rare earth metals Chemical class 0.000 description 3
- 238000004891 communication Methods 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000000644 propagated effect Effects 0.000 description 2
- 238000001069 Raman spectroscopy Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
Landscapes
- Lasers (AREA)
Abstract
Description
【発明の詳細な説明】
(産業上の利用分野)
本発明は、希土類を添加した光増幅媒質中で信号光を光
増幅する光増幅器に関する。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an optical amplifier that optically amplifies signal light in an optical amplification medium doped with rare earth elements.
(従来の技術)
近年光通信用中継器の小型化、経済化あるいは光分岐に
よる損失の補償などを目的として、信号光を光電変換す
ることなく直接光のまま増幅する光増幅器に関する研究
が盛んに行われている。光増幅方式としてはこれまでに
■半導体レーザ媒質を用いるもの■コツ部にEr等の希
土類元素を添加した光ファイバを用いるもの■光ファイ
バの誘導ラマン散乱、誘導ブリユアン散乱などの非線形
光学効果を利用するもの■希土類元素をドープした導波
路を持つ結晶あるいはガラスを用いるものなどが報告さ
れている(光学、第18巻、第6号、282ページ)。(Prior art) In recent years, research has been actively conducted on optical amplifiers that directly amplify signal light as light without photoelectric conversion, with the aim of making optical communication repeaters more compact and economical, and compensating for losses due to optical branching. It is being done. Up to now, optical amplification methods have been: ■ Those that use a semiconductor laser medium ■ Those that use an optical fiber doped with a rare earth element such as Er in the tip portion ■ The use of nonlinear optical effects such as stimulated Raman scattering and stimulated Brillouin scattering of optical fibers ■Items using crystals or glass having waveguides doped with rare earth elements have been reported (Optics, Vol. 18, No. 6, p. 282).
なかでも希土類のErを添加した光ファイバを用いた光
増幅器は、光ファイバの損失が最低になる1、5/im
帯で高い利得が得られ、さらに利得の偏波依存性がない
ことや、低損失で伝送路と結合できることなど他の光増
幅方式と比較して多くの利点を有している。そのため、
Er添加光ファイバ増幅に関する研究は多くの研究機関
で盛んに行われている(光学、第19巻、第5号、27
6ページ)。Among them, optical amplifiers using optical fibers doped with rare earth element Er have the lowest optical fiber loss of 1.5/im.
It has many advantages over other optical amplification methods, such as high gain in the band, no polarization dependence of gain, and the ability to couple to a transmission line with low loss. Therefore,
Research on Er-doped optical fiber amplification is being actively conducted at many research institutions (Optics, Vol. 19, No. 5, 27
(page 6).
希土類を添加した光ファイバを用いた光増幅は、その希
土類イオンの吸収帯に対応した波長の励起光を希土類添
加光ファイバに入射して光増幅をおこなう。Erイオン
の吸収波長は主に0.5μm帯、0.6.zm帯、0.
8.zm帯、0.98/、Im帯、1.48.zm帯な
どが知られているが、中でも0.98μm帯と1.48
μm帯は吸収効率が大きくかつ高出力の半導体レーザが
使用できるため、これらの波長で励起したEr添加光フ
アイバ増幅器に関する研究が盛んに行われている。Optical amplification using a rare earth doped optical fiber is performed by inputting excitation light having a wavelength corresponding to the absorption band of the rare earth ion into the rare earth doped optical fiber. The absorption wavelength of Er ions is mainly in the 0.5 μm band and 0.6 μm band. Zm band, 0.
8. Zm band, 0.98/, Im band, 1.48. Zm band etc. are known, but among them, 0.98 μm band and 1.48 μm band.
Since semiconductor lasers with high absorption efficiency and high power can be used in the μm band, research on Er-doped optical fiber amplifiers excited at these wavelengths is being actively conducted.
励起光の入射方向は、信号光の入射側から信号光と同一
方向に入射する前方向励起、信号光の出射側から信号光
の伝搬方向とは反対方向に入射する後方向励起、さらに
前方向励起と後方向励起とを合わせた両方向励起がある
。両方向励起は高い励起光パワーを得るのに有効である
。光増幅器の増幅利得や出力される増幅信号光パワー(
飽和出力)は高いほど望ましいが、そのためにはより大
きな励起光パワーを必要とする。これまでに知られてい
る高い励起光パワーを光増幅媒質に入射する方法は■同
一波長で発振する二つの励起光源を用いた両方向励起、
■同一波長で発振する二つの励起光源を偏波合成して入
射する方法がある(エレクトロニクス・レターズ(El
ectronics Letters)、第25巻、第
24号、1656ページ)。The direction of incidence of the excitation light is forward excitation, which is incident in the same direction as the signal light from the signal light input side, backward excitation, which is incident in the opposite direction to the propagation direction of the signal light from the signal light output side, and further forward. There is bidirectional excitation, which is a combination of excitation and backward excitation. Bidirectional pumping is effective in obtaining high pumping light power. The amplification gain of the optical amplifier and the output amplified signal optical power (
The higher the saturation output), the more desirable it is, but this requires greater pumping light power. The methods known so far for injecting high pumping light power into an optical amplification medium are: - bidirectional pumping using two pumping light sources that oscillate at the same wavelength;
■There is a method in which two excitation light sources that oscillate at the same wavelength are polarized and combined (Electronics Letters (El
electronics Letters), Volume 25, No. 24, Page 1656).
光増幅器を光通信システムに利用する場合、主として■
送信光のブースタ増幅器として使用■光直接増幅中継器
として使用■受信器の前置増幅器として使用する方法が
考えられる。この中で特に受信器の前置増幅器として使
用する場合、受光素子に励起光が入射するのを防ぐため
に、後方向励起以外では光増幅器の出力に励起光を遮断
する光フィルタを設ける必要がある。When using optical amplifiers in optical communication systems, the main
Possible methods include using it as a booster amplifier for transmitted light, using it as an optical direct amplification repeater, and using it as a receiver preamplifier. In particular, when used as a preamplifier of a receiver, in order to prevent pumping light from entering the photodetector, it is necessary to provide an optical filter at the output of the optical amplifier to block pumping light except for backward pumping. .
(発明が解決しようとする課題)
同一波長で発振する励起光を合成するためには、二つの
励起光の偏波面を直交させて合成しなければならないと
いう課題がある。しかも偏波合成では二つの励起光しか
合成できない。偏波合成をせずにこれらの励起光を光増
幅媒質に入射するためには、両方向励起を用いることが
考えられるが、両方向励起のみで励起光源は二つまでし
か利用できない。(Problem to be Solved by the Invention) In order to combine excitation lights that oscillate at the same wavelength, there is a problem that the polarization planes of the two excitation lights must be orthogonal to each other when they are combined. Furthermore, polarization synthesis can only combine two excitation lights. In order to make these pump lights incident on the optical amplification medium without polarization synthesis, it is possible to use bidirectional pumping, but only bidirectional pumping can only use up to two pumping light sources.
本発明の第一の目的は、偏波合成することなく簡便に二
つ以上の励起光パワーが合成でき、これによって増幅利
得や飽和出力が大きい光増幅器を提供することにある。A first object of the present invention is to provide an optical amplifier that can easily combine the powers of two or more pumping lights without polarization combining, and thereby has a large amplification gain and saturation output.
本発明の第二の目的は、上記光増幅器を前置増幅器とし
て用いる場合にも励起光を遮断する光フィルタを新たに
設ける必要がなく、部品点数が少ない光増幅器を提供す
ることにある。A second object of the present invention is to provide an optical amplifier with a small number of parts, which eliminates the need to newly provide an optical filter for blocking pumping light even when the optical amplifier is used as a preamplifier.
(課題を解決するための手段)
本発明の光増幅器は、発振波長の異なる複数の励起光源
を用いることによって、偏波合成をすることなく簡便に
多くの励起光を合成できることを特徴とする。(Means for Solving the Problems) The optical amplifier of the present invention is characterized in that by using a plurality of pumping light sources with different oscillation wavelengths, a large number of pumping lights can be easily synthesized without performing polarization synthesis.
さらに、上記励起光源の中の少なくとも一つを後方向励
起として配置し、この励起光を光増幅媒質に入射するた
めの光合分波器に前方向励起光を遮断する機能を付加し
たことを特徴とする。Furthermore, at least one of the pumping light sources is arranged for backward pumping, and an optical multiplexer/demultiplexer for inputting the pumping light into the optical amplification medium is provided with a function of blocking the forward pumping light. shall be.
(作用)
同一の波長で発振する二つのレーザ光を合波するために
は偏波面を直交させて合波しないと、偏波方向が一致す
る成分が打ち消しあって、合波前のパワーの和より減少
する。しかし、発振波長の異なる複数のレーザ光は偏波
合成することなく適切な光合分波器を用いるだけで簡便
にかつパワーをほとんど損失することなく合波すること
ができる。(Function) In order to combine two laser beams that oscillate at the same wavelength, the polarization planes must be orthogonal to each other. Otherwise, the components with the same polarization directions will cancel each other out, and the sum of the powers before combination will increase. decrease more. However, a plurality of laser beams having different oscillation wavelengths can be simply combined without polarization combining and with almost no power loss by simply using an appropriate optical multiplexer/demultiplexer.
本発明の光増幅器は、希土類イオンが複数の吸収波長帯
を持っていることに着目し、この希土類の持つ複数の吸
収波長帯の中の異なる吸収波長帯を励起する複数個の励
起光源を合波して、希土類イオンの複数の吸収波長帯を
同時に励起する。これにより、偏波合成することな〈従
来より大きな励起光パワーが得られ、増幅利得や飽和出
力が大きな光増幅が可能になる。The optical amplifier of the present invention focuses on the fact that rare earth ions have a plurality of absorption wavelength bands, and combines a plurality of excitation light sources that excite different absorption wavelength bands among the plurality of absorption wavelength bands that rare earth ions have. waves to simultaneously excite multiple absorption wavelength bands of rare earth ions. As a result, it is possible to obtain a pumping light power greater than that of the conventional method without polarization combining, and optical amplification with a large amplification gain and saturation output is possible.
さらに、後方向励起のための光合分波器に前方向励起光
を遮断する機能を付加したことより、光増幅器から増幅
信号光と共に励起光が出力されないようにすることがで
きる。したがって、この光増幅器を前置増幅器として用
いた場合でも、光フィルタを設けることなく高品質な受
信特性が得られる。Furthermore, by adding a function of blocking forward pumping light to the optical multiplexer/demultiplexer for backward pumping, it is possible to prevent the pumping light from being output from the optical amplifier together with the amplified signal light. Therefore, even when this optical amplifier is used as a preamplifier, high quality reception characteristics can be obtained without providing an optical filter.
(実施例)
図面を参照して、本発明の光増幅器について詳細に説明
する。(Example) The optical amplifier of the present invention will be described in detail with reference to the drawings.
第1図は、本発明による光増幅器の実施例の構成図であ
る。この実施例では、光増幅媒質はEr添加光フアイバ
11、励起光源は発振波長1.48□m帯の半導体レー
ザ31と発振波長0.98□m帯の半導体レーザ32、
光合分波器は波長1.48μm帯の光と波長1.54μ
m帯の光の合波が可能な波長多重用単一モード光ファイ
バカップラ21、及び波長1.48pmから1.54□
m帯の光と0,98μm帯の光の合波が可能な波長多重
用単一モード光ファイバカップラ22である。FIG. 1 is a block diagram of an embodiment of an optical amplifier according to the present invention. In this embodiment, the optical amplification medium is an Er-doped optical fiber 11, and the excitation light sources are a semiconductor laser 31 with an oscillation wavelength of 1.48□m band and a semiconductor laser 32 with an oscillation wavelength of 0.98□m band.
The optical multiplexer/demultiplexer combines light with a wavelength of 1.48 μm and light with a wavelength of 1.54 μm.
Single mode optical fiber coupler 21 for wavelength multiplexing capable of multiplexing m-band light, and wavelengths from 1.48 pm to 1.54 □
This is a wavelength multiplexing single mode optical fiber coupler 22 capable of multiplexing m-band light and 0.98 μm-band light.
光フアイバカップラは2本の光ファイバを近接させて加
熱溶融し、伸延して作製したものである。An optical fiber coupler is manufactured by bringing two optical fibers close together, heating and melting them, and stretching them.
溶融部分の長さで透過波長依存性を変化させることがで
きる。The transmission wavelength dependence can be changed by changing the length of the melted portion.
本実施例の光増幅器では、入射信号光は、まず半導体レ
ーザ31から出射された1、48μmの励起光と光フア
イバカップラ21によって合波される。この合波光はさ
らに半導体レーザ32から出射された0、98μmの励
起光と光フアイバカップラ22によって合波され、Er
添加光フアイバ11に入射される。In the optical amplifier of this embodiment, the incident signal light is first combined with the 1.48 μm excitation light emitted from the semiconductor laser 31 by the optical fiber coupler 21 . This combined light is further combined with the excitation light of 0.98 μm emitted from the semiconductor laser 32 by the optical fiber coupler 22, and the Er
The light is incident on the doped optical fiber 11.
本実施例では、1.48μmの半導体レーザ20mWと
0.98μmの半導体レーザ10mWの励起パワーで3
5dBの増幅利得と+4dBmの飽和出力が得られた。In this example, the excitation power of 20 mW of a 1.48 μm semiconductor laser and 10 mW of a 0.98 μm semiconductor laser was used to
An amplification gain of 5 dB and a saturated output of +4 dBm were obtained.
励起光源が波長1.48μmの半導体レーザのみの場合
、励起パワー15mWで20dBの利得と一3dBmの
飽和出力が得られ、また励起光源が波長0.98□mの
半導体レーザのみの場合は励起パワー10mWで20d
Bの利得と一3dBmの飽和出力が得られた。したがっ
て、本発明により増幅利得及び飽和出力が増大できた。When the pump light source is only a semiconductor laser with a wavelength of 1.48 μm, a gain of 20 dB and a saturation output of -3 dBm can be obtained with a pump power of 15 mW, and when the pump light source is only a semiconductor laser with a wavelength of 0.98 □m, the pump power 20d at 10mW
A gain of B and a saturation output of -3 dBm were obtained. Therefore, according to the present invention, the amplification gain and saturation output can be increased.
第2図は本発明による光増幅器の他の実施例の構成図で
ある。この実施例では、光増幅媒質はEr添加光フアイ
バ11、励起光源は発振波長1.48μm帯の半導体レ
ーザ33と発振波長0.98A1m帯の半導体レーザ3
4、光合分波器は波長1.48μm%の光と波長1.5
4μm帯の光の合波が可能な波長多重用単一モード光フ
ァイバカップラ23、及び、1.54μm帯の光と0.
98/im帯の光の合波が可能で、かつ1.48/、m
の光を遮断する特性を持ったフィルタ機能付き波長多重
用単一モード光ファイバカップラ41である。FIG. 2 is a block diagram of another embodiment of the optical amplifier according to the present invention. In this embodiment, the optical amplification medium is an Er-doped optical fiber 11, and the excitation light sources are a semiconductor laser 33 with an oscillation wavelength of 1.48 μm band and a semiconductor laser 3 with an oscillation wavelength of 0.98A1m band.
4. The optical multiplexer/demultiplexer separates light with a wavelength of 1.48μm% and wavelength 1.5%.
A wavelength multiplexing single mode optical fiber coupler 23 capable of combining light in the 4 μm band and light in the 1.54 μm band and 0.5 μm in wavelength.
It is possible to combine light in the 98/im band, and the wavelength is 1.48/, m.
This is a single mode optical fiber coupler 41 for wavelength multiplexing with a filter function that has a characteristic of blocking light.
この光フアイバカップラ41の製法は上に述べたものと
同じであり、製造時に特に透過波長特性を制御したもの
である。光フアイバカップラ41の入出力端子を第3図
(a)に示す。端子411がら端子413への透過波長
特性を第3図(b)に示す。この光フアイバカップラは
、端子411から入射した1、54pmの光はその90
%を端子413に通すが、端子411から入射した1、
48μmの光はその90%を端子414に通す。端子4
14から入射した0、98/、mの光は端子411に9
0%通ず。The manufacturing method of this optical fiber coupler 41 is the same as that described above, and the transmission wavelength characteristics are particularly controlled during manufacturing. The input and output terminals of the optical fiber coupler 41 are shown in FIG. 3(a). The transmission wavelength characteristics from the terminal 411 to the terminal 413 are shown in FIG. 3(b). In this optical fiber coupler, the 1.54 pm light incident from the terminal 411 is
% is passed through the terminal 413, but 1, which is incident from the terminal 411,
90% of the 48 μm light passes through the terminal 414. terminal 4
The light of 0, 98/, m incident from 14 is sent to terminal 411 at 9
0% pass.
本実施例の光増幅器では、入射信号光は、まず半導体レ
ーザ33から出射された1、48μmの励起光と光フア
イバカップラ23によって合波され、Er添加光フアイ
バ11に入射される。Er添加光フアイバ11の出射光
は光フアイバカップラ41を通って光増幅器出力となる
。この光フアイバカップラ41は半導体レーザ34から
出射された0、98□mの励起光をEr添加光フアイバ
11にその後方から入射する。この光フアイバカップラ
41の増幅信号大側端を端子411、出射端を端子41
3とすると、半導体レーザ33からの光はEr添加光フ
アイバ11で全てが吸収されるとは限らないので、端子
411がらは信号光だけでなく1.48□mの光も入射
する。しかし、フィルタ機能付き波長多重用単一モード
光ファイバカップラ41は、信号光と共に伝搬してきた
1、48μmの光が出力端に出るのを防ぐ特性を持つた
め、この光増幅器を前置増幅器として用いた場合、受光
素子には信号光のみが到達する。In the optical amplifier of this embodiment, the incident signal light is first combined with the 1.48 μm excitation light emitted from the semiconductor laser 33 by the optical fiber coupler 23, and is input into the Er-doped optical fiber 11. The light emitted from the Er-doped optical fiber 11 passes through the optical fiber coupler 41 and becomes the output of the optical amplifier. This optical fiber coupler 41 makes the excitation light of 0.98 □m emitted from the semiconductor laser 34 enter the Er-doped optical fiber 11 from behind. The amplified signal large side end of this optical fiber coupler 41 is a terminal 411, and the output end is a terminal 411.
3, not all of the light from the semiconductor laser 33 is absorbed by the Er-doped optical fiber 11, so not only the signal light but also the light of 1.48 □m enters the terminal 411. However, since the single mode optical fiber coupler 41 for wavelength multiplexing with filter function has a characteristic that prevents the 1.48 μm light propagated together with the signal light from exiting the output terminal, this optical amplifier is used as a preamplifier. In this case, only the signal light reaches the light receiving element.
本実施例により、増幅信号出射端から出力される164
8μmの励起光パワーが一17dBm以下になり、この
光を遮断しない場合の一7dBmより1.48μmの光
を大きく遮断できた。According to this embodiment, the 164
The power of the excitation light at 8 μm was 117 dBm or less, and the 1.48 μm light could be blocked to a greater extent than at 17 dBm when this light was not blocked.
以上、本発明による光増幅器について実施例を用いて説
明したが、本発明はこれらの実施例のみに限られること
なく、いくつかの変形が考えられる。Although the optical amplifier according to the present invention has been described above using embodiments, the present invention is not limited to these embodiments, and several modifications can be made.
光増幅媒質は光ファイバに限らない。例えば希土類を添
加した導波路を設けたガラスや結晶でもよい。添加する
希土類もErに限らないことは言うまでもない。したが
って、励起光波長や増幅する信号光波長も、添加する希
土類の持つ吸収波長帯や蛍光波長帯に合わせればよく、
実施例の限りではない。例えば、実施例で取り上げたよ
うなErを添加した光増幅媒質を用いる場合でも、励起
光波長は1.48μmと0.98μmに限らず、0.5
μm帯、0.6pm帯、0.8□m帯などを用いてもよ
く、励起光波長は用いる希土類のどの吸収波長に一致さ
せてもよい。The optical amplification medium is not limited to optical fiber. For example, glass or crystal provided with a waveguide doped with rare earth elements may be used. It goes without saying that the rare earth element to be added is not limited to Er. Therefore, the wavelength of the excitation light and the wavelength of the signal light to be amplified need only be matched to the absorption wavelength band and fluorescence wavelength band of the rare earth element to be added.
This is not limited to the examples. For example, even when using an Er-doped optical amplification medium as discussed in the example, the excitation light wavelength is not limited to 1.48 μm and 0.98 μm, but is 0.5 μm.
A μm band, 0.6 pm band, 0.8 □m band, etc. may be used, and the excitation light wavelength may match any absorption wavelength of the rare earth metal used.
また、多くの吸収波長帯を同時に励起してもよ励起光の
合波方法は従来の偏波合成による合成方法と組み合せて
もよい。例えば、2個の1.48μm帯半導体レーザの
出力光を偏波合成してから信号光と波長合成し、さらに
0.98/J、mの励起光と波長合成してもよい。Furthermore, many absorption wavelength bands may be excited simultaneously, and the method of combining the pumping light may be combined with a conventional method of combining polarized waves. For example, the output lights of two 1.48 μm band semiconductor lasers may be polarized and combined, then wavelength-combined with signal light, and further wavelength-combined with pump light of 0.98/J, m.
励起光の光増幅媒質への入射方法も第1図の実施例のよ
うな信号光と同じ向きに入射する前方向励起に限らず、
後方向励起や、第2図の実施例のような両方向励起の形
にしてもよい。The method of inputting the excitation light into the optical amplification medium is not limited to forward excitation in which the excitation light is input in the same direction as the signal light as in the embodiment shown in FIG.
It is also possible to use backward pumping or bidirectional pumping as in the embodiment of FIG.
使用するレーザも半導体レーザに限らずいかなるレーザ
でもよい。The laser used is not limited to a semiconductor laser, and any laser may be used.
光合分波器もダイクロイックミラーなどを用いてもよく
、その性能を有する限りいかなる素子、要素であっても
よい。フィルタ機能付き光合分波器も同様である。第2
図の実施例では光フアイバカップラの特性を利用したが
、例えば、ダイクロイックミラーにコーティングを施す
ことによって光フィルタの機能を付加してもよい。コー
ティングの透過特性例を第4図に示す。このコーティン
グは長波長透過フィルタになっており、1.54μm帯
の信号光はよく透過するが、1.48□mより短波長側
は反射する。したがって、信号光と共に伝搬してきた1
、48/、mの励起光は遮断されるが、0.98/、m
の励起光は反射されて光増幅媒質に入射される。A dichroic mirror or the like may be used as the optical multiplexer/demultiplexer, and any element may be used as long as it has the performance. The same applies to an optical multiplexer/demultiplexer with a filter function. Second
Although the illustrated embodiment utilizes the characteristics of an optical fiber coupler, the function of an optical filter may be added, for example, by applying a coating to a dichroic mirror. An example of the transmission characteristics of the coating is shown in FIG. This coating serves as a long-wavelength transmission filter, which allows signal light in the 1.54 μm band to pass through well, but reflects light at wavelengths shorter than 1.48 □m. Therefore, the 1 that propagated with the signal light
,48/,m excitation light is blocked, but 0.98/,m
The excitation light is reflected and incident on the optical amplification medium.
また、本発明の光増幅器の構成要素の中に光アイソレー
クな、どを含んでもよい。Furthermore, the optical amplifier of the present invention may include an optical isolator or the like among the components.
(発明の効果)
以上説明した通り、本発明を適用すれば、希土類の持つ
複数の吸収波長帯の中の異なる吸収波長帯を励起する複
数個の励起光源を偏波合成することなく合波することに
より、従来より大きな励起光パワーが得られ、増幅利得
や飽和出力が大きな光増幅器が可能になる。(Effects of the Invention) As explained above, by applying the present invention, multiple excitation light sources that excite different absorption wavelength bands among the plurality of absorption wavelength bands possessed by rare earth elements can be combined without polarization synthesis. As a result, it is possible to obtain a pumping light power greater than that of conventional optical amplifiers, and to achieve an optical amplifier with a large amplification gain and saturation output.
また、光増幅器から増幅信号光共に励起光が出力されな
いようにすることによって、光フィルタを設ける必要が
なくなり、部品点数を増やすことがなくこの光増幅器を
前置増幅器として用いることができるという利点がある
。Furthermore, by preventing the optical amplifier from outputting pump light together with the amplified signal light, there is no need to provide an optical filter, and the advantage is that the optical amplifier can be used as a preamplifier without increasing the number of parts. be.
第1図は、本発明の実施例を示す構成図、第2図は本発
明の他の実施例を示す構成図、第3図(aXb)はそれ
ぞれ、本発明の実施例におけるフィルタ機能を持った光
フアイバカップラの特性を説明するための図及び透過特
性図、第4図は、フィルタ機能を持ったダイクロイック
ミラー光合分波器の特性図、である。
図において、
11・・・光増幅媒質、21.22.23・・・光合分
波器、31、32.33.34・・・励起光源、41・
・・フィルタ機能付き光合分波器、411、412.4
13.414・・・フィルタ機能付き光フアイバカップ
ラの入出力端子
である。Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a block diagram showing another embodiment of the present invention, and Fig. 3 (aXb) each has a filter function in the embodiment of the present invention. FIG. 4 is a diagram and a transmission characteristic diagram for explaining the characteristics of the optical fiber coupler, and FIG. 4 is a characteristic diagram of a dichroic mirror optical multiplexer/demultiplexer having a filter function. In the figure, 11... Optical amplification medium, 21.22.23... Optical multiplexer/demultiplexer, 31, 32.33.34... Pumping light source, 41.
...Optical multiplexer/demultiplexer with filter function, 411, 412.4
13.414: Input/output terminal of optical fiber coupler with filter function.
Claims (2)
つ複数の吸収波長帯の中の異なる吸収波長帯を励起する
複数個の励起光源と、前記励起光源から出力される励起
光及び信号光を前記希土類添加光増幅媒質にそれぞれ入
射させる光合波手段とを含むことを特徴とする光増幅器
。(1) An optical amplification medium doped with a rare earth element, a plurality of excitation light sources that excite different absorption wavelength bands among the plurality of absorption wavelength bands possessed by the rare earth element, and excitation light and signal light output from the excitation light source. and an optical multiplexing means for making each of the rare earth-doped optical amplification medium incident on the rare earth-doped optical amplification medium.
光を前記光増幅媒質の増幅信号光の出射端から光合分波
器によって前記光増幅媒質に入射する光増幅器であって
、この光合分波器が信号光の入射端から入射された励起
光の少なくとも一部を遮断する機能を有することを特徴
とする請求項1記載の光増幅器。(2) An optical amplifier in which excitation light from at least one of the excitation light sources is input to the optical amplification medium from an output end of the amplified signal light of the optical amplification medium by an optical multiplexer/demultiplexer, the optical multiplexer/demultiplexer 2. The optical amplifier according to claim 1, wherein the wave filter has a function of blocking at least a portion of the pumping light incident from the input end of the signal light.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP21109390A JPH0493091A (en) | 1990-08-09 | 1990-08-09 | Optical amplifier |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP21109390A JPH0493091A (en) | 1990-08-09 | 1990-08-09 | Optical amplifier |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH0493091A true JPH0493091A (en) | 1992-03-25 |
Family
ID=16600300
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP21109390A Pending JPH0493091A (en) | 1990-08-09 | 1990-08-09 | Optical amplifier |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH0493091A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH05121818A (en) * | 1991-04-08 | 1993-05-18 | Alcatel Nv | Optical amplifier using optical fiber, to which erbium is doped |
JPH07142796A (en) * | 1993-04-26 | 1995-06-02 | Nec Corp | Optical fiber amplifier |
US6442309B1 (en) | 1998-11-11 | 2002-08-27 | Nec Corporation | Optical amplifier |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH02122581A (en) * | 1988-10-31 | 1990-05-10 | Toshiba Corp | Laser oscillator |
-
1990
- 1990-08-09 JP JP21109390A patent/JPH0493091A/en active Pending
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH02122581A (en) * | 1988-10-31 | 1990-05-10 | Toshiba Corp | Laser oscillator |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH05121818A (en) * | 1991-04-08 | 1993-05-18 | Alcatel Nv | Optical amplifier using optical fiber, to which erbium is doped |
JPH07142796A (en) * | 1993-04-26 | 1995-06-02 | Nec Corp | Optical fiber amplifier |
US6442309B1 (en) | 1998-11-11 | 2002-08-27 | Nec Corporation | Optical amplifier |
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