JPH02272432A - Polarized wave modulating device - Google Patents
Polarized wave modulating deviceInfo
- Publication number
- JPH02272432A JPH02272432A JP1091945A JP9194589A JPH02272432A JP H02272432 A JPH02272432 A JP H02272432A JP 1091945 A JP1091945 A JP 1091945A JP 9194589 A JP9194589 A JP 9194589A JP H02272432 A JPH02272432 A JP H02272432A
- Authority
- JP
- Japan
- Prior art keywords
- light
- polarization
- signal
- signal light
- optical fiber
- 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
- 230000010287 polarization Effects 0.000 claims abstract description 53
- 230000003321 amplification Effects 0.000 claims abstract description 30
- 238000003199 nucleic acid amplification method Methods 0.000 claims abstract description 30
- 239000013307 optical fiber Substances 0.000 claims abstract description 26
- 238000005086 pumping Methods 0.000 claims description 10
- 229940125730 polarisation modulator Drugs 0.000 claims description 3
- 230000000295 complement effect Effects 0.000 claims description 2
- 238000001069 Raman spectroscopy Methods 0.000 abstract description 10
- 230000005284 excitation Effects 0.000 description 13
- 230000003287 optical effect Effects 0.000 description 11
- 238000010586 diagram Methods 0.000 description 5
- 239000013078 crystal Substances 0.000 description 4
- 229910052761 rare earth metal Inorganic materials 0.000 description 4
- 239000000835 fiber Substances 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 229910003327 LiNbO3 Inorganic materials 0.000 description 1
- 230000002238 attenuated effect Effects 0.000 description 1
- 238000005253 cladding Methods 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 150000002910 rare earth metals Chemical class 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
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
- H01S3/30—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range using scattering effects, e.g. stimulated Brillouin or Raman effects
- H01S3/302—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range using scattering effects, e.g. stimulated Brillouin or Raman effects in an optical fibre
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- Optics & Photonics (AREA)
- Light Guides In General And Applications Therefor (AREA)
- Lasers (AREA)
- Optical Communication System (AREA)
Abstract
Description
【発明の詳細な説明】
（１）発明の属する技術分野
本発明は、信号光の偏波方向を互いに直交する２つの偏
波方向に時系列的に変える偏波変調装置に関するもので
ある。DETAILED DESCRIPTION OF THE INVENTION (1) Technical field to which the invention pertains The present invention relates to a polarization modulation device that time-sequentially changes the polarization direction of signal light into two mutually orthogonal polarization directions.
（２）従来の技術
従来提案されている偏波変調装置で最も良く知られてい
るものは、ＬｔＮｂＯｓの電気光学効果を利用したもの
である。これは、ＬｉＮｂＯ３の結晶に電界をかけ、結
晶に複屈折を誘起させることにより、その結晶を通過す
る信号光の偏波状態を変化させるものである。この偏波
変調装置の損失は、原理上は零である。しかし、実際に
は、変調器を低電圧で動作させるために、ＬｉＮｂＯ５
の結晶を、バルクではなく、導波路として作製するため
、導波路の伝搬損失、導波路との結晶損失などにより、
３〜５ｄＢの過剰損失が生じる。これが、電気光学効果
型変調器の大きな問題点である。(2) Prior Art The most well-known polarization modulator that has been proposed in the past is one that utilizes the electro-optic effect of LtNbOs. This applies an electric field to a LiNbO3 crystal to induce birefringence in the crystal, thereby changing the polarization state of signal light passing through the crystal. The loss of this polarization modulator is zero in principle. However, in reality, in order to operate the modulator at low voltage, LiNbO5
Since the crystal of
3-5 dB excess loss occurs. This is a major problem with electro-optic modulators.
（３）発明の目的
本発明は、信号光のレベルを減衰させることなく、信号
光の偏波方向を変調するための偏波変調装置を提供する
ことにある。(3) Object of the Invention An object of the present invention is to provide a polarization modulation device for modulating the polarization direction of signal light without attenuating the level of the signal light.
（４）発明の構成
（４−１）発明の特徴と従来の技術との差異本発明は、
増幅用光ファイバにおける利得の偏光依存性を積極的に
利用することを最も主要な特徴とする。本発明は、信号
光の偏波の変調原理が、光増幅そのものを用いているた
め、信号光の減衰が避けられない従来技術とは大きく異
なる。(4) Structure of the invention (4-1) Differences between the characteristics of the invention and the conventional technology The present invention has the following features:
The main feature is that the polarization dependence of the gain in the amplification optical fiber is actively utilized. The present invention uses optical amplification itself as the principle of modulating the polarization of signal light, and is therefore significantly different from conventional techniques in which attenuation of signal light is unavoidable.
（４−２）実施例
（実施例）
第１図は、本発明の詳細な説明する図であって、１は第
１の光源、２は第２の光源、３は駆動回路、４は第１の
合波器、５は第２の合波器、６は増幅用光ファイバ、７
は偏波調節器である。(4-2) Example (Example) FIG. 1 is a diagram for explaining the present invention in detail, in which 1 is a first light source, 2 is a second light source, 3 is a drive circuit, and 4 is a first light source. 1 multiplexer, 5 a second multiplexer, 6 optical fiber for amplification, 7
is a polarization adjuster.
第１．第２の光源は、直接強度変調が可能な高出力半導
体レーザが望ましい。1st. The second light source is preferably a high-power semiconductor laser capable of direct intensity modulation.
第１の光源１からの出射光である励起光Ｅ１と、第２の
光源からの出射光である励起光Ｅ２は、互いの偏光方向
が直交した状態で、第１の合波器４により合波される。The excitation light E1, which is the light emitted from the first light source 1, and the excitation light E2, which is the light emitted from the second light source, are combined by the first multiplexer 4 with their polarization directions orthogonal to each other. be waved.
第１の合波器４としては、偏波分離型ビームスプリッタ
や、偏波保持型ファイバカップラ等が使用できる。合波
された励起光Ｅ１及びＥ２は、さらに、連続波である信
号光Ｓと、第２の合波器５により合波される。合波器５
には、通常の光フアイバ型カップラが使用できる。また
、信号光と励起光の波長が異なる点に着目することによ
り、合波器５として、一種の波長フィルタであるグイク
ロイックミラーを用いることも可能である。このときは
、合波器５の信号光Ｓ、励起光Ｅｌ、Ｅ２に対する挿入
損失を原理的に零とすることができる。合波器５により
合波された信号光Ｓ、励起光Ｅｌ、Ｅ２は、増幅用光フ
ァイバ６に入射される。このとき、第２図に示すように
、偏波調節器７により、信号光Ｓの偏光方向は、励起光
Ｅ１．Ｅ２と４５°の角度をなすように調節しておく。As the first multiplexer 4, a polarization separating type beam splitter, a polarization maintaining type fiber coupler, etc. can be used. The combined excitation lights E1 and E2 are further combined with the signal light S, which is a continuous wave, by the second multiplexer 5. Multiplexer 5
An ordinary fiber optic coupler can be used. Further, by paying attention to the fact that the signal light and the excitation light have different wavelengths, it is also possible to use a guichroic mirror, which is a kind of wavelength filter, as the multiplexer 5. At this time, the insertion loss of the multiplexer 5 for the signal light S, pumping lights El, and E2 can be made zero in principle. The signal light S and the pumping lights El and E2 combined by the multiplexer 5 are input into the amplification optical fiber 6. At this time, as shown in FIG. 2, the polarization adjuster 7 changes the polarization direction of the signal light S to the excitation light E1. Adjust so that it forms a 45° angle with E2.
偏波調節器７は、偏光子、あるいは１／２波長板と１／
４波長板の組合せ、あるいはそれらと等価なものを、コ
イル状の光ファイバで実現したもの、等が使用できる。The polarization adjuster 7 includes a polarizer or a 1/2 wavelength plate and a 1/2 wavelength plate.
A combination of four-wavelength plates or something equivalent thereto realized using a coiled optical fiber can be used.
また、信号光Ｓの波長λ、は、励起光Ｅｌ、Ｅ２の波長
λ１．λ２と、１／λ１−１／λｍ ” ！’ ＊ Ｃ
Ｃｍ−’ ）１／λ２−１／λ、夕ν＊ （ｃｍ−’
）（νえはラマン周波数シフト）
の関係を満足するように設定する。このとき、信号光Ｓ
は励起光Ｅｌ、Ｅ２によりラマン増幅される。増幅用光
ファイバ６として、通常の石英系光ファイバを使用した
場合には、ラマン周波数シフトν、は約４５０ｃｍ−’
である（ｃ「１は光周波数の単位であり、ＩＣ１１−’
は３０ＧＨｚに相当する）。ラマン増幅における利得は
、励起光と信号光の偏光方向が一致したとき最大となり
、直交したとき最低となる。また、その利得が大きいと
き、増幅された信号光の偏光方向は、励起光の偏光方向
と一致する。そこで、今、駆動回路３に第３図Ａに示し
た変調信号Ｍを入力したとき、駆動回路３は、変調信号
Ｍと同一の変調信号Ｍｌ（第３図Ｂ）を第１の光源に送
出し、同時に、変調信号Ｍ１と相補的な関係にある信号
、すなわち、変調信号Ｍ１の°゛０”、“１′°信号を
交換させた変調信号Ｍ２（第３図Ｃ）を第２の光源に送
出する。このとき、変調信号Ｍに応じて、励起光Ｅ１と
Ｅ２が交互に、信号光Ｓを増幅用光ファイバＱ中で増幅
する。従って、その増幅された信号光Ｓの偏光方向は、
変調信号Ｍに応じて、励起光Ｅ１あるいはＥ２と同一の
偏光方向を交互にとる（第３図Ｄ）。すなわち偏波変調
される。第３図りにおける記号／／。Further, the wavelength λ of the signal light S is the wavelength λ1 . of the excitation lights El and E2. λ2 and 1/λ1-1/λm ”!' *C
Cm-' ) 1/λ2-1/λ, evening ν* (cm-'
) (ν is the Raman frequency shift). At this time, the signal light S
is Raman amplified by excitation lights El and E2. When a normal silica-based optical fiber is used as the amplification optical fiber 6, the Raman frequency shift ν is approximately 450 cm-'
(c "1 is the unit of optical frequency, IC11-'
corresponds to 30GHz). The gain in Raman amplification is maximum when the polarization directions of the pump light and signal light match, and is minimum when the polarization directions of the pump light and signal light are orthogonal. Further, when the gain is large, the polarization direction of the amplified signal light matches the polarization direction of the pump light. Therefore, when the modulation signal M shown in FIG. 3A is input to the drive circuit 3, the drive circuit 3 sends out the same modulation signal Ml (FIG. 3B) as the modulation signal M to the first light source. At the same time, a signal having a complementary relationship with the modulation signal M1, that is, a modulation signal M2 (FIG. 3C) in which the °'0' and '1' ° signals of the modulation signal M1 are exchanged, is sent to the second light source. Send to. At this time, in accordance with the modulation signal M, the excitation lights E1 and E2 alternately amplify the signal light S in the amplification optical fiber Q. Therefore, the polarization direction of the amplified signal light S is
Depending on the modulation signal M, the polarization direction is alternately the same as that of the excitation light E1 or E2 (FIG. 3D). That is, polarization modulation is performed. Symbol // in the third diagram.
土は、それぞれ、増幅された信号光Ｓの偏波方向が、励
起光Ｅｌのそれと並行及び直交していることを示してい
る。またその偏波変調された信号光パワーは、光増幅に
より、入射信号光パワーに比べ、１０〜３０ｄＢも大き
な値となり、従来のように、信号光が減衰することはな
い。一般に、偏波変調と同時に、信号光Ｓが強度変調さ
れることは好ましくない。光増幅された信号光Ｓのパワ
ーは、増幅用光ファイバ６への、入射信号光パワーと、
信号光Ｓと同一の偏光成分を持つ励起光パワーの積に比
例する。従って、信号光Ｓと励起光Ｅｌ、Ｅ２の偏光方
向の関係が、第２図のごとく偏波調節器７により調節さ
れており、励起光ＥｌとＥ２のパワーが同一の場合には
、偏波変調と同時に強度変調されることはない。なお、
第１図において、偏波調節器７は、信号光Ｓの偏光方向
を調節するように配置されているが、そのかわりに、励
起光Ｅｌ、Ｅ２の偏波方向を調節するように、第１と第
２の合波器の間に配置しても良い。The lines indicate that the polarization direction of the amplified signal light S is parallel and orthogonal to that of the excitation light El, respectively. Further, the polarization-modulated signal light power becomes 10 to 30 dB larger than the incident signal light power due to optical amplification, and the signal light is not attenuated as in the conventional case. Generally, it is not preferable that the signal light S is intensity modulated at the same time as the polarization modulation. The power of the optically amplified signal light S is the input signal light power to the amplification optical fiber 6,
It is proportional to the product of the power of the pump light having the same polarization component as the signal light S. Therefore, the relationship between the polarization directions of the signal light S and the pumping lights El and E2 is adjusted by the polarization adjuster 7 as shown in FIG. 2, and when the powers of the pumping lights El and E2 are the same, the polarization It is not intensity modulated at the same time as modulation. In addition,
In FIG. 1, the polarization adjuster 7 is arranged to adjust the polarization direction of the signal light S, but instead, the first and the second multiplexer.
以上の説明では、光フアイバ中での増幅機構として、ラ
マン増幅を考えたが、そのほかの光増幅現像を用いるこ
とも可能である。例えば、前記増幅用光ファイバのコア
に、希土類元素（Ｅｒ、 Ｎｄ等）を添加することによ
り、信号光Ｓを増幅することが可能となる。但しこの場
合には、希土類元素固有の原子のエネルギ準位間遷移を
利用することによって光増幅を行うため、前記ラマン増
幅と異なり、信号光の増幅可能な波長帯はその元素固有
のものとなる。Ｅｒを光ファイバに添加した場合、増幅
可能な波長帯は、およそ、１．５３〜１．５５μ通にあ
り、また、励起光Ｅｌ、Ｅ２の波長は、およそ、０．５
３．０．６５． Ｑ、８１．０．９８、あるいは１．４
６〜１．４８−でなければならない。また、Ｎｄを光フ
ァイバに添加した場合には、増幅可能な波長帯は、およ
そ、１．０６．１．３２ｍであり、励起光Ｅｌ、Ｅ２の
波長は、およそ０．８１−でなければならない。以上の
波長に関する制約を除くと、前記ラマン光増幅の場合と
同様に、希土類元素を添加した光ファイバを使用した光
増幅により、偏波変調が可能となる。しかも、その利点
は、僅か２〜３ｍの増幅用光ファイバ６を用いることに
より、２０ｄＢにも達する。In the above explanation, Raman amplification was considered as the amplification mechanism in the optical fiber, but it is also possible to use other optical amplification development. For example, the signal light S can be amplified by adding a rare earth element (Er, Nd, etc.) to the core of the amplification optical fiber. However, in this case, optical amplification is performed by utilizing the transition between energy levels of atoms unique to rare earth elements, so unlike the Raman amplification described above, the wavelength band in which the signal light can be amplified is unique to that element. . When Er is added to the optical fiber, the wavelength band that can be amplified is approximately 1.53 to 1.55μ, and the wavelengths of the excitation lights El and E2 are approximately 0.5μ.
3.0.65. Q, 81.0.98, or 1.4
Must be between 6 and 1.48-. Furthermore, when Nd is added to the optical fiber, the wavelength band that can be amplified is approximately 1.06.1.32 m, and the wavelengths of the pumping lights El and E2 must be approximately 0.81- . If the above restrictions regarding wavelength are removed, polarization modulation becomes possible by optical amplification using an optical fiber doped with a rare earth element, as in the case of Raman optical amplification. Moreover, the advantage can reach as much as 20 dB by using only 2 to 3 m of amplifying optical fiber 6.
以上の説明では、入射した光の偏波方向は、増幅用光フ
アイバ６中で一定に保たれるものと仮定したが、増幅用
光ファイバが長い場合には、直交偏波モード間のモード
結合が生じるため、この仮定は非現実的なものになる。In the above explanation, it is assumed that the polarization direction of the incident light is kept constant in the amplification optical fiber 6. However, if the amplification optical fiber is long, mode coupling between orthogonal polarization modes is possible. occurs, making this assumption unrealistic.
応力付与部をコアの両側に組み込んだ偏波保持型光ファ
イバ、あるいは、コアないしクラッドを楕円化した偏波
保持型光ファイバを、前記ラマン光増幅あるいは希土類
ドープ光ファイバによる光増幅の増幅用光ファイバ６と
して使用することにより、−層安定で利得の大きな偏波
変調が可能となる。なお、このとき、第４図に示すよう
に、励起光Ｅｌ、Ｅ２の偏波方向は、偏波保持型増幅用
光ファイバの主軸Ｘ、Ｙと一致させ、信号光Ｓの偏波方
向は、これまでの説明通り、励起光Ｅｌ、Ｅ２の偏波方
向と４５°の角度をなすものとする。A polarization-maintaining optical fiber in which stress applying parts are incorporated on both sides of the core, or a polarization-maintaining optical fiber in which the core or cladding is ovalized, is used as the amplification light for the Raman optical amplification or optical amplification using the rare earth doped optical fiber. By using it as the fiber 6, polarization modulation with -layer stability and large gain becomes possible. At this time, as shown in FIG. 4, the polarization directions of the excitation lights El and E2 are made to coincide with the main axes X and Y of the polarization-maintaining amplification optical fiber, and the polarization direction of the signal light S is as follows. As explained above, it is assumed that it forms an angle of 45° with the polarization direction of the excitation lights El and E2.
（５）発明の詳細
な説明したように、本発明によれば、信号光を減衰させ
ることなく、むしろ・増幅させて、偏波変調を行うこと
が可能である。また、本発明は、高速な偏波変調を行う
ことにより、光源の偏光を擬似的に解消することができ
るので、偏波変調による、光通信に応用されるだけでな
く、インコヒーレントな光源が必要とされる光計測等に
も応用可能である。(5) As described in detail, according to the present invention, it is possible to perform polarization modulation by amplifying signal light without attenuating it. In addition, the present invention can pseudo-eliminate the polarization of a light source by performing high-speed polarization modulation, so it can be applied not only to optical communications by polarization modulation, but also to the production of incoherent light sources. It can also be applied to necessary optical measurements.
第１図は本発明の実施例を示す系統図、第２図は信号光
Ｓ、励起光Ｅｌ、Ｅ２の偏波方向の関係を示す図、第３
図は変調信号Ｍ、駆動信号Ｍｌ。
Ｍ２の波形と光増幅された信号Ｓの波形と偏波の関係を
示す図、第４図は信号Ｓ、励起光Ｅｌ、Ｅ２の偏波方向
及び偏波保持型増幅用ファイバ６の主軸Ｘ、Ｙの関係を
示す図である。
■・・・第１の光源、２・・・第２の光源、３・・・駆
動回路、４・・・第１の合波器、５・・・第２の合波器
、６・・・増幅用光ファイバ、７・・・偏波調節器。FIG. 1 is a system diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing the relationship between the polarization directions of signal light S, pumping lights El, and E2, and FIG.
The figure shows a modulation signal M and a drive signal Ml. A diagram showing the relationship between the waveform of M2 and the waveform of the optically amplified signal S and polarization. FIG. 4 shows the polarization directions of the signal S, pumping light El, and E2, and the main axis It is a figure showing the relationship of Y. ■...First light source, 2...Second light source, 3...Drive circuit, 4...First multiplexer, 5...Second multiplexer, 6... - Optical fiber for amplification, 7... polarization adjuster.
Claims (1)
源と、 変調信号Ｍを入力され、該第１の光源を強度変調するた
めの該変調信号Ｍと同一の変調信号Ｍ１を出力するとと
もに、該第２の光源を強度変調するための変調信号Ｍ１
と相補的関係にある変調信号Ｍ２を出力する駆動用回路
と、 該第１及び第２の光源から出力される第１及び第２の励
起光をそれぞれの偏波が直交した状態で合波させる第１
の合波器と、 該信号光と該合波された第１及び第２の励起光を合波し
て前記増幅器用光ファイバに入力させるための第２の合
波器と、 該信号光と該第１の励起光の偏波の方向及び該信号光と
該第２の励起光の偏波の方向が互いにおよそ４５°の角
度をなすように偏波を調節するための偏波調節器と、 を備えた偏波変調装置。(1) An amplification optical fiber for optically amplifying signal light, first and second light sources for exciting the amplification optical fiber, and a modulation signal M input to the first light source to increase the intensity of the first light source. a modulation signal M1 for outputting the same modulation signal M1 as the modulation signal M for modulation, and for intensity modulating the second light source;
a driving circuit that outputs a modulation signal M2 having a complementary relationship with the first and second pumping lights, and combining the first and second pumping lights output from the first and second light sources in a state where their respective polarizations are orthogonal to each other. 1st
a second multiplexer for combining the signal light and the combined first and second pumping lights and inputting the combined signal into the amplifier optical fiber; a polarization adjuster for adjusting polarization so that the direction of polarization of the first pump light and the direction of polarization of the signal light and the second pump light make an angle of about 45° to each other; A polarization modulator equipped with , .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1091945A JPH02272432A (en) | 1989-04-13 | 1989-04-13 | Polarized wave modulating device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1091945A JPH02272432A (en) | 1989-04-13 | 1989-04-13 | Polarized wave modulating device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH02272432A true JPH02272432A (en) | 1990-11-07 |
Family
ID=14040728
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1091945A Pending JPH02272432A (en) | 1989-04-13 | 1989-04-13 | Polarized wave modulating device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02272432A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH057047A (en) * | 1991-06-27 | 1993-01-14 | Kansai Electric Power Co Inc:The | Optical fiber amplifier |
| JPH06308547A (en) * | 1993-04-13 | 1994-11-04 | American Teleph & Telegr Co <Att> | Method for reduction of polarization- dependent gain at inside of amplified optical transmission system |
| JPH06342174A (en) * | 1991-09-12 | 1994-12-13 | American Teleph & Telegr Co <Att> | Optical fiber amplifier |
| JP2002006349A (en) * | 2000-04-20 | 2002-01-09 | Lucent Technol Inc | Method for pumping optical system having plural raman pumps |
| EP1202407A2 (en) * | 2000-10-23 | 2002-05-02 | The Furukawa Electric Co., Ltd. | Semiconductor laser device for use as a pumping light source |
-
1989
- 1989-04-13 JP JP1091945A patent/JPH02272432A/en active Pending
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH057047A (en) * | 1991-06-27 | 1993-01-14 | Kansai Electric Power Co Inc:The | Optical fiber amplifier |
| JPH06342174A (en) * | 1991-09-12 | 1994-12-13 | American Teleph & Telegr Co <Att> | Optical fiber amplifier |
| JP2922732B2 (en) * | 1991-09-12 | 1999-07-26 | エイ・ティ・アンド・ティ・コーポレーション | Optical fiber amplifier |
| JPH06308547A (en) * | 1993-04-13 | 1994-11-04 | American Teleph & Telegr Co <Att> | Method for reduction of polarization- dependent gain at inside of amplified optical transmission system |
| JP2002006349A (en) * | 2000-04-20 | 2002-01-09 | Lucent Technol Inc | Method for pumping optical system having plural raman pumps |
| EP1202407A2 (en) * | 2000-10-23 | 2002-05-02 | The Furukawa Electric Co., Ltd. | Semiconductor laser device for use as a pumping light source |
| EP1202407A3 (en) * | 2000-10-23 | 2003-12-03 | The Furukawa Electric Co., Ltd. | Semiconductor laser device for use as a pumping light source |
| US6947463B2 (en) | 2000-10-23 | 2005-09-20 | The Furukawa Electric Co., Ltd. | Semiconductor laser device for use in a laser module |
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