We present an analysis and design method for multiwavelength pumped fiber Raman amplifiers for massive wavelength division multiplexing (WDM) systems with signal bandwidths of 10 to 12 THz and a very large number of channels. We solve self-consistently the optimal design problem for backward-pumped distributed Raman amplifiers with special gain profiles that compensate for the Raman tilt and wavelength-dependent fiber loss. We study the noise performance of these optimally designed amplifiers and address the issues of multispan amplification for long-haul transmission of such broadband signals.
Victor E. Perlin and Herbert G. Winful, "On Distributed Raman Amplification for Ultrabroad-Band Long-Haul WDM Systems," J. Lightwave Technol. 20, 409- (2002)