Soliton transmission has been proposed for achieving a high-bit-rate long-distance optical fiber communication system.1 In the absence of fiber loss, distortionless pulses can be propagated along the fiber due to the balance between the frequency dispersion and self-phase modulation. However, in practical situations the pulse intensity decays because of fiber loss, resulting in a weaker self-phase modulation and hence the destruction of soliton. To solve this problem, loss compensation techniques using stimulated Raman scattering have been Introduced recently.2,3 In such a technique, cw pump waves are injected periodically into the fiber so that the signal pulses are amplified through the stimulated Raman scattering. It has been found that stable transmission of solitons over a long distance can be obtained using this amplification scheme. Nevertheless, the technique proposed so far is mainly focused on the soliton reconstruction for single-channel communication systems. An amplification scheme for multichannel systems is practically needed.
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