Optimization of output signal power spectrum in Raman-assisted WDM system

We analyze the output signal power spectrum with different initial input signal power spectrum in a long-haul wavelength-division-multiplexed system with backward multiple-pump Raman amplifiers. The genetic algorithm is used to optimize the output signal power. The results using fixed pump wavelengths are compared with the case in which the pump wavelengths are allowed to vary. We experimentally show that the optimal design algorithm is proper.