Optimum Carrier to Signal Power Ratio for Remote Heterodyne DD-OFDM in PONs

The carrier to signal power ratio (CSPR) in a direct-detection optical orthogonal frequency division multiplexing (OFDM) system based on remote heterodyne scheme is optimized in a passive optical network (PON) downlink. A numerical investigation shows that nonlinearities in fiber have the effects of increasing the optimum CSPR and making the system more vulnerable to CSPR changes.