Brillouin effects in distributed Raman amplifiers under saturated conditions

This paper analyzes experimentally the limitations observed in lightwave systems using distributed Raman amplifiers operating under large pump power input conditions. The Brillouin effect is observed as the pump power becomes equal to 1 watt centered in a specific pump wavelength. The presence of Brillouin peaks degrades the system performance. The Raman amplifier is set with singlemode and dispersion compensating fibers and evaluated in a high capacity WDM link at transmission rates up to 40 Gb/s per channel. The dispersion compensation was accomplished by adjusting the length of the dispersion compensating fiber. The system and amplifier characterization were developed in terms of the on-off gain, ripple, optical signal-to-noise ratio, eye diagram and extinction ratio.