Abstract

Distributed fiber Raman amplifiers (FRAs) are considered to be key technologies to increase the transmission capacity and the span length in WDM systems. Another challenge of FRAs is to extend the usable optical bandwidth outside C-band and L-band covered by Erbium-doped fiber amplifiers. One of possible limitations of FRAs is double Rayleigh scattering (DRS) noise.^1,2 Portion of the signal is backscattered by Rayleigh scattering process and it suffers the gain, supplied by Raman pumping, more than twice before it is combined with the signal. The DRS noise can be detrimental in high gain region, however, the calculation of the DRS noise is not easy because it has the same wavelength as the signal.

© 2002 Optical Society of America