Analysis of post detection ad-hoc filter based loopback WDM-PONs to enhance the tolerance against rayleigh backscattering noise

Rayleigh backscattering noise has significant effect on Reflective SOAs based loopback WDM-PONs. The system tolerance against this crosstalk noise can be enhanced by simply using an appropriate high pass electrical filter in optical receiver. However, the cut-off frequency of this filter need to be optimized to minimize the penalty from filter induced ISI along with crosstalk noise. Here, a semi-analytical approach is considered for the detail analysis of this novel proposal. The optimum filter cut-off is determined by considering the impact of data rate, type of bit sequence (PRBS/8b10b coded), and also the length of bit sequence.