Bidirectional optical fiber transmission systems using Raman amplification

Bidirectional optical fiber transmission systems using Raman amplification are discussed. Analytical expressions for signals amplified by both forward and backward Raman scattering are presented. It is found that there exists an optimal pump power for the maximum unrepeated transmission length in a bidirectional system and that the maximum length is about 450 km, which is about the same as that of the unidirectional system.<
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