JP2757912B2 - Optical fiber communication system - Google Patents
Optical fiber communication systemInfo
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- JP2757912B2 JP2757912B2 JP8004500A JP450096A JP2757912B2 JP 2757912 B2 JP2757912 B2 JP 2757912B2 JP 8004500 A JP8004500 A JP 8004500A JP 450096 A JP450096 A JP 450096A JP 2757912 B2 JP2757912 B2 JP 2757912B2
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- Prior art keywords
- optical fiber
- wavelength
- communication system
- transmission line
- optical
- Prior art date
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Description
【０００１】[0001]
【発明の属する技術分野】本発明は、光ファイバ増幅器
を用いた光ファイバ通信方式に関する。The present invention relates to an optical fiber communication system using an optical fiber amplifier.
【０００２】[0002]
【従来の技術】近年、コア内にＥｒイオンを添加した光
ファイバを増幅媒体として用いる光ファイバ増幅器が開
発され、光ファイバ通信システムにおいて光ブースタ増
幅器、光前置増幅器、光中継器など多種多様に応用され
ている。このような光ファイバ増幅器およびその光ファ
イバ通信システムへの適用については、例えば、Ｋ．Ｎ
ａｋａｇａｗａ，ｅｔ ａｌ．，“Ｔｒｕｎｋ ａｎｄ
Ｄｓｉｔｒｉｂｕｔｉｏｎ Ｎｅｔｗｏｒｋ Ａｐｐ
ｌｉｃａｔｉｏｎ ｏｆ Ｅｒｂｉｕｍ−Ｄｏｐｅｄ
Ｆｉｂｅｒ Ａｍｐｌｉｆｉｅｒ”，アイ・イー・イー
・ジャーナル・オブ・ライトウエイブ・テクノロジー誌
（ＩＥＥＥ Ｊ．Ｌｉｇｈｔｗａｖｅ Ｔｅｃｈｎｏｌ
ｏｇｙ）、第ＬＴ−９巻、１９８−２０８ページに述べ
られている。2. Description of the Related Art In recent years, an optical fiber amplifier using an optical fiber doped with Er ions in a core as an amplification medium has been developed. In an optical fiber communication system, a variety of optical boosters, optical preamplifiers, optical repeaters and the like have been developed. Applied. Such an optical fiber amplifier and its application to an optical fiber communication system are described in, for example, K. N
Akagawa, et al. , “Trunk and
Distribution Network App
ligation of Erbium-Doped
Fiber Amplifier, ”IEJ Journal of Lightwave Technology (IEEE J. Lightwave Technology)
ogy), LT-9, pp. 198-208.
【０００３】また、最近、送信および受信端局から励起
光を送出し、光ファイバ伝送路上に配置した光ファイバ
増幅器を励起することにより長スパン化を計る光ファイ
バ通信方式に関する研究開発が活発に検討されている。
この方式は、励起光源と光ファイバ増幅器が所定長の光
ファイバ伝送路を介して離れて設置されることから、遠
隔励起方式と呼ばれている。[0003] Recently, research and development on an optical fiber communication system in which pumping light is transmitted from a transmitting and receiving terminal station to lengthen a span by pumping an optical fiber amplifier arranged on an optical fiber transmission line has been actively studied. Have been.
This method is called a remote pumping method because the pumping light source and the optical fiber amplifier are installed separately via an optical fiber transmission line of a predetermined length.
【０００４】[0004]
【発明が解決しようとする課題】この遠隔励起方式で
は、励起光パワーを大きくできれば、光ファイバ増幅器
を端局装置からより離れた場所に設置でき、スパン長を
より長くすることができる。励起光パワーとしては、例
えば、２個の波長１４８０ｎｍ帯半導体レーザを偏波合
成することにより、数１００ｍＷ以上の値が報告されて
いる。［例えば、Ｓ．Ｓｉｅｎ，ｅｔ ａｌ．，“５１
１ ｋｍ ａｔ ２．５ Ｇｂｉｔ／ｓ ａｎｄ ５３
１ ｋｍ ａｔ ６２２ Ｍｂ／ｓ−Ｕｎｒｅｐｅａｔ
ｅｒｅｄ Ｔｒａｎｓｍｉｓｓｉｏｎ ｗｉｔｈ Ｒｅ
ｍｏｔｅ ｐｕｍｐｅｄ ａｍｐｌｉｆｉｅｒｓ，Ｆｏ
ｒｗａｒｄ Ｅｒｒｏｒ Ｃｏｒｒｅｃｔｉｏｎ ａｎ
ｄ Ｄｉｓｐｅｒｓｉｏｎ Ｃｏｍｐｅｎｓａｔｉｏ
ｎ”，１９９５ Ｃｏｎｆｅｒｅｎｃｅ ｏｎ Ｏｐｔ
ｉｃａｌ Ｆｉｂｅｒ Ｃｏｍｍｕｎｉｃａｔｉｏｎ
（ＯＦＣ ９５），Ｓａｎ Ｄｉｅｇｏ Ｃａｌｉｆｏ
ｒｎｉａ，ＵＳＡ１９９５，Ｐｏｓｔｄｅａｄｌｉｎｅ
Ｐａｐｅｒｓ，ＰＤ−２６．］。In this remote pumping system, if the pumping light power can be increased, the optical fiber amplifier can be installed at a place farther from the terminal equipment, and the span length can be further lengthened. As the excitation light power, for example, a value of several hundred mW or more has been reported by performing polarization synthesis of two semiconductor lasers having a wavelength of 1480 nm. [For example, S.A. Sien, et al. , "51
1 km at 2.5 Gbit / s and 53
1 km at 622 Mb / s-Unrepeat
ered Transmission with Re
move pumped amplifiers, Fo
backward Error Correction an
d Dispersion Compensation
n ", 1995 Conference on Opt
Ial Fiber Communication
(OFC 95), San Diego Califo
rnia, USA 1995, Postdeadline
Papers, PD-26. ].
【０００５】現在の半導体レーザモジュールで出力可能
なレベルは、最大でも１００ｍＷ〜２００ｍＷであり、
上記の様な偏波合成手段あるいは波長合成手段を用いて
も、光ファイバ伝送路に結合できる励起光パワーは数１
００ｍＷ程度が限界であった。このため、遠隔励起用光
ファイバ増幅器の配置場所は励起光源の出力によって実
質的な限界が存在し、これによりスパン長が制限を受け
ていた。The output level of the current semiconductor laser module is at most 100 mW to 200 mW.
Even if the above-described polarization combining means or wavelength combining means is used, the power of the pump light that can be coupled to the optical fiber transmission line is as follows.
The limit was about 00 mW. For this reason, the location of the remote pumping optical fiber amplifier is substantially limited by the output of the pumping light source, which limits the span length.
【０００６】本発明は、この様な状況を鑑みて、スパン
長を従来に比べてより長くできる光ファイバ通信方式を
提供することを目的とする。The present invention has been made in view of the above circumstances, and has as its object to provide an optical fiber communication system capable of making the span length longer than before.
【０００７】[0007]
【課題を解決するための手段】本発明は、光ファイバ伝
送路上の所定の位置に配置された光ファイバ増幅器を用
いる光ファイバ通信方式であって、この光ファイバ伝送
路端から前記光ファイバ増幅器を励起するための第１の
波長の励起光と、この第１の波長の励起光より、前記光
ファイバ伝送路のラマンシフト量だけ短い、第２の波長
の励起光を同時に前記光ファイバ伝送路に結合させるこ
とを特徴とする。SUMMARY OF THE INVENTION The present invention relates to an optical fiber communication system using an optical fiber amplifier disposed at a predetermined position on an optical fiber transmission line. Pumping light of a first wavelength for pumping and pumping light of a second wavelength shorter than the pumping light of the first wavelength by the amount of Raman shift of the optical fiber transmission line are simultaneously transmitted to the optical fiber transmission line. It is characterized by being combined.
【０００８】[0008]
【作用】本発明では、光ファイバ増幅器を励起するため
の第１の波長の励起光と、この励起光より、光ファイバ
伝送路のラマンシフト量だけ短い波長の第２の励起光を
同時に光ファイバ伝送路に入射させている。この様な構
成によれば、光ファイバの誘導ラマン散乱効果により、
光ファイバ伝搬中に第２の波長の励起光から第１の波長
の励起光への光パワー変換が生じる。すなわち、第１の
波長の励起光は、光ファイバ伝搬中に光増幅される。こ
の結果、従来に比較して、遠隔励起用光ファイバ増幅器
を端局装置からより遠方に配置することができ、よりス
パン長を長くできるという利点が生じる。According to the present invention, pump light of a first wavelength for pumping an optical fiber amplifier and second pump light of a wavelength shorter than the pump light by the amount of Raman shift of the optical fiber transmission line are simultaneously transmitted to the optical fiber. It is incident on the transmission line. According to such a configuration, due to the stimulated Raman scattering effect of the optical fiber,
During the propagation of the optical fiber, the optical power conversion from the pump light of the second wavelength to the pump light of the first wavelength occurs. That is, the pump light of the first wavelength is optically amplified during propagation through the optical fiber. As a result, there is an advantage that the remote pumping optical fiber amplifier can be arranged farther from the terminal device and the span length can be longer than in the conventional case.
【０００９】[0009]
【発明の実施の形態】次に、図１を参照して、本発明の
実施の形態に係る光ファイバ通信方式について詳細に説
明する。Next, an optical fiber communication system according to an embodiment of the present invention will be described in detail with reference to FIG.
【００１０】図１は、本発明の光ファイバ通信方式の一
実施形態である。この実施形態において、光送信器１か
らの情報信号光は、光合波器３によって励起光源２１か
らの第１の波長の励起光および励起光源２２からの第２
の波長の励起光と合波された後に、光ファイバ伝送路４
１に送出される。この情報信号光は、光ファイバ増幅器
５１，５２によって増幅されるとともに光ファイバ伝送
路４２，４３を伝送した後に光分波器６を通過し、光受
信器８によって受光される。そして、この光受信器８よ
り、情報信号が取り出される。受信側においては、励起
光源７１からの第１の波長の励起光および励起光源７２
からの第２の波長の励起光は、光分波器６によって情報
信号光とは逆方向に光ファイバ伝送路４３を伝搬する様
に結合されている。FIG. 1 shows an embodiment of the optical fiber communication system according to the present invention. In this embodiment, the information signal light from the optical transmitter 1 is converted by the optical multiplexer 3 into the first wavelength pump light from the pump light source 21 and the second signal from the pump light source 22.
After being multiplexed with the pumping light having the wavelength of
Sent to 1. The information signal light is amplified by the optical fiber amplifiers 51 and 52 and transmitted through the optical fiber transmission lines 42 and 43, passes through the optical demultiplexer 6, and is received by the optical receiver 8. Then, an information signal is extracted from the optical receiver 8. On the receiving side, the excitation light of the first wavelength from the excitation light source 71 and the excitation light source 72
Are coupled by the optical demultiplexer 6 so as to propagate through the optical fiber transmission line 43 in the opposite direction to the information signal light.
【００１１】本実施形態において、光送信器１は、単一
軸モード半導体レーザを光源として、ＬｉＮｂＯ3 光強
度変調器を用いて外部変調しており、波長１５５５ｎ
ｍ、ビットレート２．４８８Ｇｂ／ｓ、出力パワー＝＋
１７ｄＢｍの信号光を発出している。また、光受信器８
は、Ｅｒ添加光ファイバ前置増幅器とＩｎＧａＡｓ−Ｐ
ＩＮフォトダイオードで構成している。In the present embodiment, the optical transmitter 1 externally modulates using a single-axis mode semiconductor laser as a light source and a LiNbO 3 light intensity modulator, and has a wavelength of 1555n.
m, bit rate 2.488 Gb / s, output power = +
The signal light of 17 dBm is emitted. Also, the optical receiver 8
Is an Er-doped optical fiber preamplifier and InGaAs-P
It consists of an IN photodiode.
【００１２】励起光源２１および７１には、波長１４８
０ｎｍ帯のＩｎＧａＡｓＰ／ＩｎＰファブリぺロ型半導
体レーザモジュール、励起光源２２および７２には、波
長１４００ｎｍ帯のＩｎＧａＡｓＰ／ＩｎＰファブリぺ
ロ型半導体レーザモジュールを用いており、出力は全て
約１９０ｍＷである。また、光ファイバ増幅器５１，５
２は、いずれもＥｒ添加光ファイバ、光ファイバ伝送路
４１，４２，４３は、単一モード光ファイバであり、長
さはそれぞれ６０ｋｍ、３４０ｋｍ、１１０ｋｍであ
る。ここで、それぞれ波長１４００ｎｍ、１４８０ｎ
ｍ、１５５５ｎｍ帯での伝送損失は、０．３ｄＢ／ｋ
ｍ、０．２２ｄＢ／ｋｍ、０．１７ｄＢ／ｋｍである。
さらに、光合波器３および光分波器６は、波長１４００
ｎｍ帯と波長１４８０ｎｍ帯は全反射し、波長１５５５
ｎｍ帯は透過率＝９０％以上の特性を有する誘電体多層
膜フィルタを用いた波長多重カップラを適用しており、
挿入損失は約１ｄＢである。The excitation light sources 21 and 71 have a wavelength of 148.
The InGaAsP / InP Fabry-Perot type semiconductor laser module of the 0 nm band, and the InGaAsP / InP Fabry-Perot type semiconductor laser module of the wavelength of 1400 nm are used as the pumping light sources 22 and 72, and the output is all about 190 mW. In addition, the optical fiber amplifiers 51 and 5
Numeral 2 is an Er-doped optical fiber, and optical fiber transmission lines 41, 42, and 43 are single-mode optical fibers, and their lengths are 60 km, 340 km, and 110 km, respectively. Here, the wavelengths are 1400 nm and 1480 n, respectively.
m, the transmission loss in the 1555 nm band is 0.3 dB / k
m, 0.22 dB / km and 0.17 dB / km.
Further, the optical multiplexer 3 and the optical demultiplexer 6 have a wavelength of 1400.
The nm band and the 1480 nm band are totally reflected, and the wavelength is 1555.
In the nm band, a wavelength multiplexing coupler using a dielectric multilayer filter having a transmittance of 90% or more is applied.
The insertion loss is about 1 dB.
【００１３】この実施形態では、送信側においては、信
号光パワー＝＋１６ｄＢｍ、波長１４００ｎｍの励起光
パワー＝１７０ｍＷ、波長１４８０ｎｍの励起光パワー
＝１６０ｍＷを光ファイバ伝送路４１に送出している。
この時、光ファイバ伝送路４１では、誘導ラマン効果に
より、信号光に対しては３．２ｄＢ、波長１４８０ｎｍ
の励起光については３．０ｄＢの光増幅が生じ、光ファ
イバ増幅器５１に信号光＝＋９．２ｄＢｍ、波長１４８
０ｎｍの励起光＝１６ｍＷが到達している。この１６ｍ
Ｗの１４８０ｎｍ励起光により、光ファイバ増幅器５１
にて５ｄＢの光利得を生じている。さらに、信号光は、
光ファイバ伝送路４２を伝搬し、光ファイバ増幅器５２
には−４３ｄＢｍの信号光パワーが入力される。一方、
受信側からは、波長１４８０ｎｍと波長１４００ｎｍの
励起光を各々１６０ｍＷ、１８０ｍＷ送出しており、光
ファイバ増幅器５２には３ｍＷの１４８０ｎｍ励起光が
到達し、約１８ｄＢの光利得を生じている。ここで、光
ファイバ伝送路４３における１４８０ｎｍ励起光のラマ
ン増幅利得は４ｄＢ、信号光のラマン利得は５ｄＢであ
った。この構成により、この実施形態では光受信器８に
は、約−４５ｄＢｍの信号光が受信でき、受信感度−４
７ｄＢｍに対して２ｄＢのマージンでエラーフリー動作
が可能で、スパン長５１０ｋｍのシステムが実現され
た。In this embodiment, on the transmission side, the signal light power = + 16 dBm, the pump light power of 1400 nm wavelength = 170 mW, and the pump light power of 1480 nm wavelength = 160 mW are transmitted to the optical fiber transmission line 41.
At this time, in the optical fiber transmission line 41, due to the stimulated Raman effect, 3.2 dB and 1480 nm in wavelength for signal light
Of the pump light, 3.0 dB optical amplification occurs, and the signal light = + 9.2 dBm and the wavelength 148 are supplied to the optical fiber amplifier 51.
0 nm excitation light = 16 mW has arrived. This 16m
The optical fiber amplifier 51 is
, An optical gain of 5 dB is generated. Furthermore, the signal light is
Propagating through the optical fiber transmission line 42, the optical fiber amplifier 52
Is input with a signal light power of -43 dBm. on the other hand,
160 mW and 180 mW of pumping light having a wavelength of 1480 nm and a wavelength of 1400 nm are transmitted from the receiving side, respectively. Here, the Raman amplification gain of the 1480 nm pump light in the optical fiber transmission line 43 was 4 dB, and the Raman gain of the signal light was 5 dB. With this configuration, in this embodiment, the optical receiver 8 can receive the signal light of about −45 dBm, and has a reception sensitivity of −4 dBm.
An error-free operation was possible with a margin of 2 dB relative to 7 dBm, and a system with a span length of 510 km was realized.
【００１４】一方、比較のために、従来の様に、波長１
４００ｎｍの励起光を用いず誘導ラマン効果を利用しな
い場合は、５１０ｋｍ伝送後の受信レベルは−５２ｄＢ
ｍとなり、受信不能であった。On the other hand, for comparison, the wavelength 1
When the stimulated Raman effect is not used without using 400 nm pump light, the reception level after transmitting 510 km is -52 dB.
m, and reception was not possible.
【００１５】以上、本発明による光ファイバ通信方式に
ついて一実施形態を用いて説明したが、本発明はこの実
施形態に限られることなくいくつかの変形が考えられ
る。As described above, the optical fiber communication system according to the present invention has been described using one embodiment. However, the present invention is not limited to this embodiment, and some modifications can be considered.
【００１６】例えば、上記実施形態では、光ファイバ増
幅器としてはＥｒ添加光ファイバ増幅器を用いたが、Ｐ
ｒ（プラセオジウム）などの他種の光ファイバ増幅器を
用いてもよい。また、励起光源は、ＩｎＧａＡｓＰ／Ｉ
ｎＰファブリぺロ型半導体レーザを適用したが、他の構
造・材料の半導体レーザあるいは他種のレーザでもよ
く、励起光源の波長および数量は制限されない。さら
に、光合分波器は、その性能を有する限りいかなる構造
・種類であってもよく、上記実施形態に限定されない。For example, in the above embodiment, an Er-doped optical fiber amplifier was used as the optical fiber amplifier.
Other types of optical fiber amplifiers such as r (praseodymium) may be used. The excitation light source is InGaAsP / I
Although the nP Fabry-Perot type semiconductor laser is applied, a semiconductor laser of another structure or material or another type of laser may be used, and the wavelength and the number of the excitation light sources are not limited. Further, the optical multiplexer / demultiplexer may have any structure and type as long as it has the performance, and is not limited to the above embodiment.
【００１７】[0017]
【発明の効果】以上説明したように、本発明では、光フ
ァイバ増幅器を用いた光ファイバ通信方式において、光
ファイバ増幅器を励起するための第１の波長の励起光
と、この励起光より、光ファイバ伝送路のラマンシフト
量だけ短い波長の第２の励起光を同時に光ファイバ伝送
路に入射させ、誘導ラマン散乱効果を利用して光ファイ
バ伝搬中に第２の波長の励起光から第１の波長の励起光
への光パワー変換を生ぜしめている。この結果、従来に
比較して、遠隔励起用光ファイバ増幅器を端局装置から
より遠方に配置することができ、よりスパン長を長くで
きるという利点が生じる。As described above, according to the present invention, in an optical fiber communication system using an optical fiber amplifier, the first wavelength pumping light for exciting the optical fiber amplifier and the pumping light having the first wavelength are used. The second pump light having a wavelength shorter by the amount of Raman shift of the fiber transmission line is simultaneously incident on the optical fiber transmission line, and the first pump light is transmitted from the second wavelength to the first pump light during propagation through the optical fiber using the stimulated Raman scattering effect. This causes optical power conversion of wavelength to excitation light. As a result, there is an advantage that the remote pumping optical fiber amplifier can be arranged farther from the terminal device and the span length can be longer than in the conventional case.
【図１】本発明の一実施形態の構成を示す図である。FIG. 1 is a diagram showing a configuration of an embodiment of the present invention.
１ 光送信器 ３ 光合波器 ６ 光分波器 ８ 光受信器 ２１，７１ （第１の波長の）励起光源 ２２，７２ （第２の波長の）励起光源 ４１，４２，４３ 光ファイバ伝送路 ５１，５２ 光ファイバ増幅器 REFERENCE SIGNS LIST 1 optical transmitter 3 optical multiplexer 6 optical demultiplexer 8 optical receiver 21, 71 (first wavelength) excitation light source 22, 72 (second wavelength) excitation light source 41, 42, 43 optical fiber transmission line 51,52 Optical fiber amplifier
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 ＦＩ Ｈ０４Ｂ 10/17 ──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. 6 Identification code FI H04B 10/17
Claims (4)
置された光ファイバ増幅器を用いる光ファイバ通信方式
であって、前記光ファイバ伝送路の端部から前記光ファ
イバ増幅器を励起するための第１の波長の励起光と、該
第１の波長の励起光より、前記光ファイバ伝送路のラマ
ンシフト量だけ短い、第２の波長の励起光を同時に前記
光ファイバ伝送路に結合させることを特徴とする光ファ
イバ通信方式。1. An optical fiber communication system using an optical fiber amplifier disposed at a predetermined position on an optical fiber transmission line, wherein the optical fiber communication system excites the optical fiber amplifier from an end of the optical fiber transmission line. The pump light of the first wavelength and the pump light of the second wavelength shorter than the pump light of the first wavelength by the amount of Raman shift of the optical fiber transmission line are simultaneously coupled to the optical fiber transmission line. Characteristic optical fiber communication system.
いて、前記光ファイバ増幅器は、コア内にＥｒイオンを
添加した光ファイバを増幅媒体として用いていることを
特徴とする光ファイバ通信方式。2. An optical fiber communication system according to claim 1, wherein said optical fiber amplifier uses an optical fiber doped with Er ions in a core as an amplification medium.
いて、前記光ファイバ増幅器は、コア内にＰｒイオンを
添加した光ファイバを増幅媒体として用いていることを
特徴とする光ファイバ通信方式。3. An optical fiber communication system according to claim 1, wherein said optical fiber amplifier uses an optical fiber doped with Pr ions in a core as an amplification medium.
いて、前記第１の波長の励起光及び前記第２の波長の励
起光を励起する励起光源として、ＩｎＧａＡｓＰ／Ｉｎ
Ｐファブリぺロ型半導体レーザを用いていることを特徴
とする光ファイバ通信方式。4. An optical fiber communication system according to claim 1, wherein InGaAsP / In is used as an excitation light source for exciting the first wavelength excitation light and the second wavelength excitation light.
An optical fiber communication system using a P Fabry-Perot type semiconductor laser.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8004500A JP2757912B2 (en) | 1996-01-16 | 1996-01-16 | Optical fiber communication system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8004500A JP2757912B2 (en) | 1996-01-16 | 1996-01-16 | Optical fiber communication system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH09197452A JPH09197452A (en) | 1997-07-31 |
| JP2757912B2 true JP2757912B2 (en) | 1998-05-25 |
Family
ID=11585789
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8004500A Expired - Fee Related JP2757912B2 (en) | 1996-01-16 | 1996-01-16 | Optical fiber communication system |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2757912B2 (en) |
Families Citing this family (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6760148B2 (en) | 1998-03-24 | 2004-07-06 | Xtera Communications, Inc. | Nonlinear polarization amplifiers in nonzero dispersion shifted fiber |
| US6631025B2 (en) | 2000-01-12 | 2003-10-07 | Xtera Communications, Inc. | Low-noise distributed Raman amplifier using bi-directional pumping using multiple Raman orders |
| US6693737B2 (en) | 1998-03-24 | 2004-02-17 | Xtera Communications, Inc. | Dispersion compensating nonlinear polarization amplifiers |
| US6101024A (en) | 1998-03-24 | 2000-08-08 | Xtera Communications, Inc. | Nonlinear fiber amplifiers used for a 1430-1530nm low-loss window in optical fibers |
| US6618192B2 (en) | 1998-06-16 | 2003-09-09 | Xtera Communications, Inc. | High efficiency raman amplifier |
| JP3527671B2 (en) | 1999-04-23 | 2004-05-17 | 富士通株式会社 | Method of controlling wavelength characteristics of optical transmission power by Raman amplification, wavelength division multiplexing optical communication system and optical amplifier using the same |
| KR100329603B1 (en) * | 1999-05-08 | 2002-03-21 | 윤덕용 | Raman-effect based fiber optic modulator and method of modulating light beam |
| CA2339115A1 (en) * | 1999-05-31 | 2000-12-07 | The Furukawa Electric Co., Ltd. | Raman amplification system and optical signal transmission method using the same |
| US7274880B2 (en) | 2000-11-16 | 2007-09-25 | Tyco Telecommunications (Us) Inc. | Raman assisted EDFA system and method |
| JP4551007B2 (en) * | 2001-02-06 | 2010-09-22 | 富士通株式会社 | Raman amplifier and optical transmission system using the same |
| JP4541574B2 (en) | 2001-02-07 | 2010-09-08 | 富士通株式会社 | Optical repeater transmission system and optical repeater transmission method |
| US6532101B2 (en) | 2001-03-16 | 2003-03-11 | Xtera Communications, Inc. | System and method for wide band Raman amplification |
| US6825973B1 (en) | 2002-03-15 | 2004-11-30 | Xtera Communications, Inc. | Reducing leading edge transients using co-propagating pumps |
| JP2007158980A (en) * | 2005-12-08 | 2007-06-21 | Nippon Telegr & Teleph Corp <Ntt> | Remote excitation light transmission system |
-
1996
- 1996-01-16 JP JP8004500A patent/JP2757912B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH09197452A (en) | 1997-07-31 |
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