Investigation on Dynamic Nonlinearity of RSOA for OFDM-PON Performance Optimization

A theoretical study has been carried out to explore the dynamic nonlinearity of reflective semiconductor optical amplifiers (RSOA) as an optical modulator. Beginning with integration of the optical gain per unit length in RSOA active cavity, the rate equation has been decomposed into a static equation, which gives expression for static optical gain versus bias current and a dynamic equation that turns to describe the modulation properties of RSOA. A Volterra series analysis gives the frequency response and high-order transfer functions in closed forms, which are useful to determine the intermodulation interference in the uplink of orthogonal frequency division multiplexed (OFDM)-passive optical network (PON) based on RSOA. The optimal driving OFDM power to RSOA is found to minimize the system BER.