JP3487572B2 - Optical repeater transmission system - Google Patents
Optical repeater transmission systemInfo
- Publication number
- JP3487572B2 JP3487572B2 JP17018396A JP17018396A JP3487572B2 JP 3487572 B2 JP3487572 B2 JP 3487572B2 JP 17018396 A JP17018396 A JP 17018396A JP 17018396 A JP17018396 A JP 17018396A JP 3487572 B2 JP3487572 B2 JP 3487572B2
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- optical
- optical fiber
- repeater
- transmission system
- optical repeater
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Description
【０００１】[0001]
【発明の属する技術分野】本発明は、光中継器を用いて
光ファイバ伝送路における信号光損失を補償する光中継
伝送システムに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical repeater transmission system that uses an optical repeater to compensate for signal light loss in an optical fiber transmission line.
【０００２】[0002]
【従来の技術】図７は、従来の光中継伝送システムの光
中継器（光ファイバ増幅器）の基本構成を示す。図にお
いて、光中継器１０は、希土類添加ファイバ１１と、励
起光源１２と、合波カプラ１３とにより構成される。励
起光源１２から出力された励起光は、合波カプラ１３を
介して希土類添加ファイバ１１に入力され、光ファイバ
伝送路１−１から希土類添加ファイバ１１に入力される
信号光を増幅して光ファイバ伝送路１−２に送出する。
希土類添加ファイバ１１としては、一般的にエルビウム
ドープファイバが用いられる。2. Description of the Related Art FIG. 7 shows a basic structure of an optical repeater (optical fiber amplifier) of a conventional optical repeater transmission system. In the figure, the optical repeater 10 is composed of a rare earth-doped fiber 11, a pumping light source 12, and a multiplexing coupler 13. The pumping light output from the pumping light source 12 is input to the rare earth-doped fiber 11 via the multiplexing coupler 13, and the signal light input to the rare earth-doped fiber 11 from the optical fiber transmission line 1-1 is amplified to obtain an optical fiber. It is sent to the transmission line 1-2.
An erbium-doped fiber is generally used as the rare earth-doped fiber 11.
【０００３】図８は、従来の光中継伝送システムの光信
号レベルダイアグラムを示す。図において、送信器２か
ら送信された光信号は、光ファイバ伝送路１を通過する
ことにより減衰し、光中継器１０で元の光信号レベルま
で増幅される。光信号は、このような減衰と増幅を繰り
返して受信器３に伝達される。このとき、光ファイバ増
幅器を用いた光中継器１０では、光信号の増幅と同時に
自然放出光雑音が発生し、これが各光中継器１０で累積
し、受信器３における信号対雑音比の主たる劣化要因と
なることが知られている（ Journal of Lightwave Tech
nology,vol.LT-9, No.2, pp.170-173) 。自然放出光雑
音電力ＰASE は、増幅器の利得Ｇ、反転分布パラメータ
ｎsp、プランク定数ｈ、光信号周波数ν、光中継器数
ｍ、受信器帯域Ｂとすると、
ＰASE ＝２ｎsp(Ｇ−１)ｈνｍＢ …(1)
と表され、光中継器数ｍに応じて大きくなることがわか
る。FIG. 8 shows an optical signal level diagram of a conventional optical repeater transmission system. In the figure, the optical signal transmitted from the transmitter 2 is attenuated by passing through the optical fiber transmission line 1 and is amplified to the original optical signal level by the optical repeater 10. The optical signal is transmitted to the receiver 3 after repeating such attenuation and amplification. At this time, in the optical repeater 10 using the optical fiber amplifier, spontaneous emission optical noise is generated at the same time as the amplification of the optical signal, which is accumulated in each optical repeater 10 and the main deterioration of the signal-to-noise ratio in the receiver 3. Known to be a factor (Journal of Lightwave Tech
nology, vol.LT-9, No.2, pp.170-173). The spontaneous emission noise power P ASE, the gain of the amplifier G, population inversion parameter n sp, Planck's constant h, the optical signal frequency [nu, optical repeater number m, if the receiver bandwidth B, P ASE = 2n sp ( G- 1) hνmB is expressed as (1), and it can be seen that it increases with the number m of optical repeaters.
【０００４】[0004]
【発明が解決しようとする課題】ところで、光中継伝送
システムの全長をＬtot とし、各中継区間長をＬrep と
すると、光中継器数ｍは、
ｍ＝Ｌtot／Ｌrep …(2)
と表される。中継利得は、中継区間内の光ファイバ損失
を補償するので、光ファイバの損失係数をαとすると、
Ｇ＝exp(αＬrep) …(3)
の関係が成り立つ。式(1) から式(3) により、光中継伝
送システムの全長Ｌtotが与えられたときの自然放出光
雑音と中継利得の関係は、If the total length of the optical repeater transmission system is L tot and each repeater section length is L rep , the number m of optical repeaters is m = L tot / L rep (2) Is expressed as Since the relay gain compensates for the optical fiber loss in the relay section, if the loss coefficient of the optical fiber is α, the following relationship holds: G = exp (αL rep ) (3) From the equations (1) to (3), when the total length L tot of the optical repeater transmission system is given, the relation between the spontaneous emission optical noise and the repeater gain is
【０００５】[0005]
【数１】 [Equation 1]
【０００６】となる。この式(3),(4) における[0006] In this equation (3), (4)
【０００７】[0007]
【数２】 [Equation 2]
【０００８】の関係をみると、中継間隔Ｌrep を長くす
るほど自然放出光雑音電力ＰASE が大きくなることがわ
かる。一方、光中継器の光信号出力レベルは、希土類添
加ファイバの効率およびこれを励起する励起光源出力に
より制限されている。また、光信号出力レベルの増大と
ともに光ファイバ伝送路の非線形効果が顕著になるの
で、これによっても光信号出力レベルは制限されてい
る。From the relationship, it can be seen that the spontaneous emission light noise power P ASE increases as the relay interval L rep increases. On the other hand, the optical signal output level of the optical repeater is limited by the efficiency of the rare earth-doped fiber and the output of the pumping light source that excites the fiber. Further, as the optical signal output level increases, the non-linear effect of the optical fiber transmission line becomes conspicuous, which also limits the optical signal output level.
【０００９】したがって、光ファイバ増幅器を光中継器
として用いた光中継伝送システムでは、所要の信号対雑
音比を確保するために、中継間隔をある程度以上長くす
ることはできない。また、式(5) によれば、光中継器数
を減らすより、中継間隔を短くする方が自然放出光雑音
電力を小さくでき、信号対雑音比が改善されることがわ
かる。しかし、これでは光中継器数が増えることにな
り、システム全体のコストを上昇させ、信頼性を低下さ
せることになる。Therefore, in the optical repeater transmission system using the optical fiber amplifier as the optical repeater, the repeater interval cannot be lengthened to some extent in order to secure the required signal-to-noise ratio. Also, according to equation (5), it is understood that the spontaneous emission optical noise power can be reduced and the signal-to-noise ratio can be improved by shortening the repeater interval rather than reducing the number of optical repeaters. However, this increases the number of optical repeaters, which increases the cost of the entire system and lowers the reliability.
【００１０】本発明は、光中継器数を削減して中継間隔
を増大させても、信号対雑音比の劣化を低減することが
できる光中継伝送システムを提供することを目的とす
る。An object of the present invention is to provide an optical repeater transmission system capable of reducing the deterioration of the signal-to-noise ratio even if the number of optical repeaters is reduced and the repeater interval is increased.
【００１１】[0011]
【課題を解決するための手段】本発明の光中継伝送シス
テムは、光ファイバ増幅器を含む光中継器内に、光ファ
イバ伝送路のラマン増幅帯域が信号光波長を含むような
条件を有する波長の励起光を光ファイバ伝送路に入力
し、光ファイバ伝送路の分布損失を補償する手段を備え
る。なお、光中継器では、従来通りの光ファイバ伝送路
で生じた信号光損失を補償する光増幅が行われる。According to the present invention, there is provided an optical repeater transmission system in which an optical repeater including an optical fiber amplifier has a wavelength range having a condition that a Raman amplification band of an optical fiber transmission line includes a signal light wavelength. A means for inputting the excitation light into the optical fiber transmission line and compensating for the distribution loss of the optical fiber transmission line is provided. In the optical repeater, optical amplification is performed to compensate for signal light loss that has occurred in the conventional optical fiber transmission line.
【００１２】本発明では、さらに光ファイバ伝送路に上
記の条件の励起光を入力し、所定の利得が得られるよう
にする。これにより、光信号はラマン増幅効果により分
布的に増幅され、光中継器への光信号入力レベルが増大
する。その結果、光中継器では、従来と同じ光信号出力
レベルを得るための中継利得を減少させることができ、
それに伴って自然放出光雑音を減少させることができ、
信号対雑音光の向上を図ることができる。また、中継利
得の減少は、光増幅器を励起する励起光源の出力を軽減
させることできるので、消費電力の低減と信頼性を向上
させることができる。In the present invention, the pumping light under the above conditions is further input to the optical fiber transmission line so that a predetermined gain can be obtained. As a result, the optical signal is distributedly amplified by the Raman amplification effect, and the optical signal input level to the optical repeater is increased. As a result, in the optical repeater, the repeater gain for obtaining the same optical signal output level as the conventional one can be reduced,
As a result, spontaneous emission noise can be reduced,
The signal-to-noise light can be improved. Further, since the reduction of the relay gain can reduce the output of the pumping light source that pumps the optical amplifier, it is possible to reduce the power consumption and improve the reliability.
【００１３】なお、ラマン増幅は非線形効果によるもの
であるとともに分布的に行われるので、これによる雑音
発生量は同利得の集中型増幅器に比べて十分に小さいこ
とが知られている（参考文献：Nonlinear Fiber Optic
s, Academic Press発行）。Since Raman amplification is caused by a non-linear effect and is performed in a distributed manner, it is known that the amount of noise generated by this is sufficiently smaller than that of a lumped amplifier of the same gain (reference: Nonlinear Fiber Optic
s, Academic Press).
【００１４】[0014]
（第１の実施形態…請求項１）図１は、本発明の光中継
伝送システムの第１の実施形態を示す。図において、光
中継器２０は、希土類添加ファイバ１１、励起光源１
２、合波カプラ１３により構成される光ファイバ増幅器
と、励起光源２１およびその光出力を光ファイバ伝送路
１−１に入力する合波カプラ２２とにより構成される。
光ファイバ増幅器については、従来と同様であるので説
明は省略する。(First Embodiment: Claim 1) FIG. 1 shows a first embodiment of an optical repeater transmission system of the present invention. In the figure, an optical repeater 20 includes a rare earth-doped fiber 11 and an excitation light source 1.
2. An optical fiber amplifier composed of the multiplexing coupler 13, a pumping light source 21 and a multiplexing coupler 22 for inputting its optical output to the optical fiber transmission line 1-1.
Since the optical fiber amplifier is the same as the conventional one, its explanation is omitted.
【００１５】励起光源２１は、光ファイバ伝送路１−１
に光信号波長でラマン増幅を起こさせるのに適した波長
と、所定の利得を実現するだけの光出力レベルを有す
る。これにより、光ファイバ伝送路１−１から光中継器
２０に入力される光信号を所定のレベルまで増幅するこ
とができる。図２は、本発明の光中継伝送システムの光
信号レベルダイアグラムを示す。The pumping light source 21 is an optical fiber transmission line 1-1.
In addition, it has a wavelength suitable for causing Raman amplification at an optical signal wavelength and an optical output level sufficient to realize a predetermined gain. Thereby, the optical signal input from the optical fiber transmission line 1-1 to the optical repeater 20 can be amplified to a predetermined level. FIG. 2 shows an optical signal level diagram of the optical repeater transmission system of the present invention.
【００１６】図において、送信器２から送信された光信
号は、光ファイバ伝送路１を通過することにより減衰す
るが、図中実線で示すようにラマン増幅によって分布
的に増幅される。なお、破線は従来の光信号レベルを
示す。これにより、光中継器２０への光信号入力レベル
が増大する。光中継器１０では、元の光信号レベルまで
増幅するが、従来と同じ光信号出力レベルを得るための
中継利得は減少する。それに伴って、図中実線で示す
ように自然放出光雑音も減少する。なお、破線は従来
の自然放出光雑音レベルを示す。光信号は、このような
減衰と増幅を繰り返して受信器３に伝達される。In the figure, the optical signal transmitted from the transmitter 2 is attenuated by passing through the optical fiber transmission line 1, but is distributedly amplified by Raman amplification as shown by the solid line in the figure. The broken line shows the conventional optical signal level. As a result, the optical signal input level to the optical repeater 20 increases. The optical repeater 10 amplifies to the original optical signal level, but the repeater gain for obtaining the same optical signal output level as the conventional one decreases. Along with this, the spontaneous emission noise also decreases as shown by the solid line in the figure. The broken line indicates the conventional spontaneous emission noise level. The optical signal is transmitted to the receiver 3 after repeating such attenuation and amplification.
【００１７】一般に、ラマン増幅は、励起光源周波数に
対して媒質によって決まる一定周波数離れた帯域に利得
をもち、光ファイバの場合は13ＴHz程度であることが知
られている。例えば、1.55μｍ帯の光信号波長を増幅す
るためには、励起光源波長は1.45μｍ付近であることが
必要である。増幅利得ＧA は、ラマン増幅利得係数をｇ
R 、励起光源出力をＰO 、励起光源波長におけるファイ
バ損失係数をαp 、ファイバ長をＬ、ファイバの有効断
面積をＡeff とすると、It is generally known that Raman amplification has a gain in a band apart from a pumping light source frequency by a constant frequency determined by a medium, and is about 13 THz in the case of an optical fiber. For example, in order to amplify the optical signal wavelength in the 1.55 μm band, the pump light source wavelength needs to be around 1.45 μm. The amplification gain G A is the Raman amplification gain coefficient g
Let R be the pump light source output P O , the fiber loss coefficient at the pump light source wavelength be α p , the fiber length be L, and the effective area of the fiber be A eff ,
【００１８】[0018]
【数３】 [Equation 3]
【００１９】と表される。なお、各パラメータは、通常
ｇR ＝４×10-14 〔ｍ／Ｗ〕、αp ＝0.25〔dB／ｋ
ｍ〕、Ａeff ＝50〔μｍ2 〕程度である。ここで、ファ
イバ長Ｌ＝100〔ｋｍ〕、励起光源出力ＰO ＝ 100〔ｍ
Ｗ〕とすると、式(6) よりファイバ出力端での光信号利
得は６〔dB〕となる。光信号波長におけるファイバ損失
係数を 0.2〔dB／ｋｍ〕とすれば、 100〔ｋｍ〕の中継
間隔で70〔ｋｍ〕の中継間隔と同等の信号対雑音比が得
られることになる。Is expressed as The parameters are usually g R = 4 × 10 -14 [m / W], α p = 0.25 [dB / k]
m] and A eff = 50 [μm 2 ] or so. Here, fiber length L = 100 [km], pump light source output P O = 100 [m
W], the optical signal gain at the fiber output end is 6 [dB] from the equation (6). If the fiber loss coefficient at the optical signal wavelength is 0.2 [dB / km], a signal-to-noise ratio equivalent to a relay interval of 70 [km] can be obtained with a relay interval of 100 [km].
【００２０】図３は、本発明の光中継伝送システムの一
中継区間における測定結果を示す。ここでは、80〔ｋ
ｍ〕長の光ファイバ伝送路の光信号レベル分布をオプテ
ィカル・タイムドメイン・リフレクトメトリ装置を用い
て測定した。図において、横軸は距離、縦軸は光信号レ
ベルである。ラマン増幅用励起光を光ファイバ伝送路に
入力することにより、出力端における光信号レベルが増
大していることがわかる。FIG. 3 shows a measurement result in one repeater section of the optical repeater transmission system of the present invention. Here, 80 [k
The optical signal level distribution of the [m] long optical fiber transmission line was measured using an optical time domain reflectometry apparatus. In the figure, the horizontal axis is the distance and the vertical axis is the optical signal level. It can be seen that the optical signal level at the output end is increased by inputting the Raman amplification pumping light into the optical fiber transmission line.
【００２１】図４は、本発明の光中継伝送システムにお
ける2400〔ｋｍ〕伝送後の光スペクトル測定結果を示
す。図において、横軸は波長、縦軸は光パワースペクト
ル密度である。ラマン増幅用励起光を入力したときの光
スペクトル（図中実線）と、入力しないときの光スペク
トル（図中破線）を比較すると、本発明による著しい信
号対雑音比の向上が認められる。FIG. 4 shows an optical spectrum measurement result after 2400 [km] transmission in the optical repeater transmission system of the present invention. In the figure, the horizontal axis represents wavelength and the vertical axis represents optical power spectral density. Comparing the optical spectrum when the pumping light for Raman amplification is input (solid line in the figure) and the optical spectrum when not input (broken line in the figure), a remarkable improvement in the signal-to-noise ratio according to the present invention is recognized.
【００２２】（第２の実施形態…請求項２）図５は、本
発明の光中継伝送システムの第２の実施形態を示す。本
実施形態の特徴は、第１の実施形態における希土類添加
ファイバ１１を励起するための励起光源１２と、光ファ
イバ伝送路１−１でラマン増幅するための励起光源２１
を同一波長帯とし、各励起光を希土類添加ファイバ１１
および光ファイバ伝送路１−１に入力するための合波カ
プラ１３，２２を兼用させたところにある。これによ
り、構成の簡略化と合波カプラの挿入損失の低減を図る
ことができる。(Second Embodiment: Claim 2) FIG. 5 shows a second embodiment of the optical repeater transmission system of the present invention. The feature of this embodiment is that the pumping light source 12 for pumping the rare earth-doped fiber 11 in the first embodiment and the pumping light source 21 for Raman amplification in the optical fiber transmission line 1-1.
In the same wavelength band and each pumping light is supplied to the rare-earth-doped fiber 11
And the multiplexing couplers 13 and 22 for inputting to the optical fiber transmission line 1-1 are also used. This can simplify the configuration and reduce the insertion loss of the multiplexing coupler.
【００２３】（第３の実施形態…請求項１）図６は、本
発明の光中継伝送システムの第３の実施形態を示す。第
１の実施形態および第２の実施形態では、光中継器２０
の入力側に接続された光ファイバ伝送路１−１に、ラマ
ン増幅のための励起光を入力する構成を示した。図６に
示す第３の実施形態では、光中継器２０の出力側に接続
された光ファイバ伝送路１−２に、ラマン増幅のための
励起光を入力する構成を示す。(Third Embodiment ... Claim 1) FIG. 6 shows a third embodiment of the optical repeater transmission system of the present invention. In the first embodiment and the second embodiment, the optical repeater 20
The configuration is shown in which the pumping light for Raman amplification is input to the optical fiber transmission line 1-1 connected to the input side of. The third embodiment shown in FIG. 6 shows a configuration in which pumping light for Raman amplification is input to the optical fiber transmission line 1-2 connected to the output side of the optical repeater 20.
【００２４】なお、光中継器２０の光ファイバ増幅器が
後方励起型であり、励起光源１２と励起光源２１が同一
波長帯にあれば、第２の実施形態と同様に２つの合波カ
プラ１３，２２を兼用させることができる。また、光中
継器２０の入力側および出力側の双方から、光ファイバ
伝送路１−１，１−２にそれぞれラマン増幅のための励
起光を入力する構成であってもよい。If the optical fiber amplifier of the optical repeater 20 is of the backward pumping type and the pumping light source 12 and the pumping light source 21 are in the same wavelength band, the two multiplexing couplers 13, 13 are provided as in the second embodiment. 22 can also be used in common. Further, the pumping light for Raman amplification may be input to each of the optical fiber transmission lines 1-1 and 1-2 from both the input side and the output side of the optical repeater 20.
【００２５】[0025]
【発明の効果】以上説明したように、本発明の光中継伝
送システムは、光ファイバ伝送路中で光信号のラマン増
幅を起こさせることにより、自然放出光雑音を減少させ
ることができ、信号対雑音光の向上を図ることができ
る。これによって、光中継伝送システムにおける中継間
隔に対する要求条件を大幅に緩和することができ、光中
継器の削減によってシステム全体のコストを低減させ、
信頼性を向上させることができる。As described above, the optical repeater transmission system of the present invention can reduce spontaneous emission optical noise by causing Raman amplification of an optical signal in an optical fiber transmission line, and the signal pair can be reduced. It is possible to improve noise light. As a result, the requirements for the repeater interval in the optical repeater transmission system can be significantly eased, and the cost of the entire system can be reduced by reducing the number of optical repeaters.
The reliability can be improved.
【図１】本発明の光中継伝送システムの第１の実施形態
を示す図。FIG. 1 is a diagram showing a first embodiment of an optical repeater transmission system of the present invention.
【図２】本発明の光中継伝送システムの光信号レベルダ
イアグラム。FIG. 2 is an optical signal level diagram of the optical repeater transmission system of the present invention.
【図３】本発明の光中継伝送システムの一中継区間にお
ける測定結果を示す図。FIG. 3 is a diagram showing a measurement result in one repeater section of the optical repeater transmission system of the present invention.
【図４】本発明の光中継伝送システムにおける2400〔ｋ
ｍ〕伝送後の光スペクトル測定結果を示す図。[Fig. 4] 2400 [k in the optical repeater transmission system of the present invention
m] The figure which shows the optical spectrum measurement result after transmission.
【図５】本発明の光中継伝送システムの第２の実施形態
を示す図。FIG. 5 is a diagram showing a second embodiment of an optical repeater transmission system of the present invention.
【図６】本発明の光中継伝送システムの第３の実施形態
を示す図。FIG. 6 is a diagram showing a third embodiment of an optical repeater transmission system of the present invention.
【図７】従来の光中継伝送システムの光中継器（光ファ
イバ増幅器）の基本構成を示す図。FIG. 7 is a diagram showing a basic configuration of an optical repeater (optical fiber amplifier) of a conventional optical repeater transmission system.
【図８】従来の光中継伝送システムの光信号レベルダイ
アグラム。FIG. 8 is an optical signal level diagram of a conventional optical repeater transmission system.
１ 光ファイバ伝送路 ２ 送信器 ３ 受信器 １０，２０ 光中継器 １１ 希土類添加ファイバ １２，２１ 励起光源 １３，２２ 合波カプラ 1 Optical fiber transmission line 2 transmitter 3 receiver 10,20 Optical repeater 11 Rare earth doped fiber 12,21 Excitation light source 13,22 Multiplexing coupler
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) H04B 10/00 - 10/28 ─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. 7 , DB name) H04B 10/00-10/28
Claims (2)
し、光ファイバ伝送路で生じた信号光損失を光中継器に
備えた光ファイバ増幅器で補償する光中継伝送システム
において、 前記光中継器内に、前記光ファイバ伝送路
のラマン増幅帯域が信号光波長を含むような条件を有す
る波長の励起光を出力する励起光源と、この励起光を前
記光ファイバ伝送路に入力する結合手段とを備え、前記
光ファイバ伝送路でラマン増幅された信号光を前記光中
継器の光ファイバ増幅器に入力する構成であることを特
徴とする光中継伝送システム。1. An optical repeater is arranged in an optical fiber transmission line, and a signal light loss generated in the optical fiber transmission line is transmitted to the optical repeater.
In an optical repeater transmission system for compensating with an optical fiber amplifier provided, a pumping light source for outputting pumping light of a wavelength having a condition that a Raman amplification band of the optical fiber transmission line includes a signal light wavelength in the optical repeater. When, and a coupling means for inputting the pumping light to the optical fiber transmission line, said
Signal light Raman-amplified in the optical fiber transmission line
An optical repeater transmission system characterized in that it is configured to be input to an optical fiber amplifier of a relay.
と光ファイバ伝送路に入力するラマン増幅用の励起光を
同一波長帯とし、各励起光を光ファイバ増幅器および光
ファイバ伝送路に入力する結合手段を兼用した構成であ
ることを特徴とする請求項１に記載の光中継伝送システ
ム。Wherein the same wavelength band excitation light for Raman amplification to be input to the excitation light and the optical fiber transmission path to be input to the optical fiber amplifier, inputs each pump light to the optical fiber amplifier and an optical fiber transmission path coupling The optical repeater transmission system according to claim 1, wherein the optical repeater transmission system has a configuration that also serves as means.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17018396A JP3487572B2 (en) | 1996-06-28 | 1996-06-28 | Optical repeater transmission system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17018396A JP3487572B2 (en) | 1996-06-28 | 1996-06-28 | Optical repeater transmission system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH1022931A JPH1022931A (en) | 1998-01-23 |
| JP3487572B2 true JP3487572B2 (en) | 2004-01-19 |
Family
ID=15900234
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP17018396A Expired - Lifetime JP3487572B2 (en) | 1996-06-28 | 1996-06-28 | Optical repeater transmission system |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3487572B2 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001249369A (en) | 2000-03-02 | 2001-09-14 | Nec Corp | Optical amplifier and optical amplification repeater using the same, and wavelength multiplex transmission device |
| JP4057214B2 (en) | 2000-03-06 | 2008-03-05 | 富士通株式会社 | Distributed optical amplification apparatus and method, and optical communication system |
| JP4628523B2 (en) | 2000-06-13 | 2011-02-09 | 富士通株式会社 | Method, apparatus and system for evaluating characteristics of optical fiber transmission line |
| US6480326B2 (en) | 2000-07-10 | 2002-11-12 | Mpb Technologies Inc. | Cascaded pumping system and method for producing distributed Raman amplification in optical fiber telecommunication systems |
| WO2002021203A1 (en) * | 2000-09-07 | 2002-03-14 | Fujitsu Limited | Optical amplifier and optical communication system |
| KR100421140B1 (en) * | 2002-05-17 | 2004-03-04 | 삼성전자주식회사 | Raman optical fiber amplifier using erbium doped fiber |
| KR100474721B1 (en) * | 2002-12-11 | 2005-03-10 | 삼성전자주식회사 | Wideband amplifiers using erbium-doped fiber |
-
1996
- 1996-06-28 JP JP17018396A patent/JP3487572B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH1022931A (en) | 1998-01-23 |
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