Dispersion compensating Raman amplifiers with pump reflectors for increased efficiency

The effect of retroreflecting the pump in discrete Raman amplifiers is investigated. Simulations are used to estimate the increase in gain and efficiency and decrease in multipath interference due to double Rayleigh backscatter for typical module configurations. The effect of reflecting only a portion of the pump spectrum is considered. Experimental measurements confirm the expected increase in gain. Finally, the effect of pump-signal relative intensity noise transfer is investigated experimentally.