Date Added: Aug 2012
Raman amplifiers are widely used for high capacity long haul communication systems. One of the main reason for which it can be used is its improved noise figure. In this paper noise figure of Raman amplifiers is studied and analyzed for different pumping schemes. The main sources of noise and their effects on the noise figure are discussed and the methods to reduce the noise figure are proposed. Raman amplifier using the transmission fiber as the gain medium is a promising technology for the optical long haul DWDM communication systems.