Study on the gain-flatness characteristics of backward-pumped distributed fiber Raman amplifier based on the genetic algorithm

摘要

A theoretical model based on the genetic algorithm is proposed and presented to analyze the gain flatness-characteristics of backward-pumped distributed fiber Raman amplifier (B-DFRA). The relationship between the gain flatness performances with the pump wavelength spacing in B-DFRA is demonstrated theoretically. It is shown that the minimum gain ripple of the B-DFRA can be obtained by optimizing the power of pump source using the genetic algorithm, and the gain spectrum of the B-DFRA which pump wavelengths are arranged in a geometric proportion interval sequence is flatter than the one which pump wavelengths are arranged in an equal interval sequence in the same conditions. Moreover, a design example of an 80-nm bandwidth B-DFRA with the gain ripple of 0.48 dB is presented to verify the accuracy of the theoretical model. This research provides a useful guide to the fabrication of practical B-DFRA.