Performance comparison for Raman+EDFA and EDFA+Raman hybrid amplifiers using recycled multiple pump lasers for WDM systems

This work extends the optimization of the gain profile for hybrid amplifiers by evaluating the performance of the configurations Raman+EDFA and EDFA+Raman considering multiple input channels simultaneously. An approximated technique to optimize the gain profile of multiple Raman pump lasers in order to obtain broadband hybrid amplifiers under residual pump recycling is applied to hybrid amplifiers with two stages, EDFA and Raman, for WDM systems. Multiple input channels allowed the gain characterization of the hybrid amplifiers of the two proposed configurations in terms of global gain, ripple, and noise figure. Results have presented global gain and noise figure values of approximately 40 dB and 4 dB, respectively, whereas obtained ripple values approximately of 0.8 dB, considering the EDFA+Raman hybrid amplifier configuration.