Improved High Pass Filtering for Passive Optical Networks

High pass filtering (HPF) is a promising technique to eliminate Rayleigh noise in central light source passive optical networks (CLS-PONs) because it can improve system performance without additional hardware. In this study, the impact of HPF is experimentally investigated. Appropriate filter cutoff frequency is found to be dependent on signal extinction ratio (ER) and pattern length. Proper HPF is found to reduce Rayleigh noise sensitivity in low ER signals by more than 10 dB. This will potentially reduce the cost of future CLS-PONs.