Optical OFDM phase shift and compensation in frequency domain based on the training sequence

A new method to compensate phase offset for single side band direct detection orthogonal frequency division multiplexing(O-OFDM) system in the frequency domain is proposed.The rule of phase offset related with signal frequency in O-OFDM system is obtained by sending training sequence,analyzed the phase shift of O-OFDM system,and compensated phase shift for long distance transmission signal which effected by dispersion according to the rule.The simulation results show that the O-OFDM system can transmit over 4000km SSMF at 40 GB/s with the phase compensation scheme and verified that the O-OFDM has very good application prospects for ultra-long haul and the high-speed optical communications.