Backward pumped distributed Raman amplifier: enhanced gain.

The backward Raman amplifier (RA) can considered as one of the best solutions for optical communication, especially in Wavelength Division Multiplexing technology. They reduce the nonlinear effects, have low noise figure and a wide frequency range. The work in this paper aims to reduce the attenuation of optical signal due to its propagation optical fiber and increase both amplifier gain and output signal power. Two backward Raman models are proposed. Proposal one model consists of two cascaded RAs and the other (proposal two) consists of three cascaded RAs. Three backward pump power levels 200, 400, and 600 mW are used to simulate the models with the three types of fibers: single-mode fiber, Truewave, and Freelight, at an amplifier length of 100 km. Proposal two achieves a maximum gain of 31 dB at 600 mW pump power 600 mW using Truewave optical fiber, with 27.7 dBm maximum output signal power. This proposal is evaluated showing 11.15% gain enhancement and 200 mW saved power when compared to previously published work. [ABSTRACT FROM AUTHOR]