THEORETICAL ANALYSIS OF GAIN SATURATION CHARACTERISTICS OF WIDE-BAND FIBER RAMAN AMPLIFIERS

Abstract

The gain saturation characteristics of wide-band fiber Raman amplifiers (FRAs) are analyzed by numerical solution of the FRA equations. The results show that the stimulated Raman scattering induced gain-tilt in saturated FRAs is not only related to the signal power, but also depends on the pumping geometry of the amplifier. The saturated gain spectrum tilts towards the longer wavelength for counter-pumped FRAs while it tilts towards the shorter wavelength for co-pumped ones. These results indicate that gain-flatness-preserving FRAs with the changing of the signal power can be designed.