Reduction of the fiber nonlinearity impairment using optical phase conjugation in 40Gb/s CO-OFDM systems

Abstract: In this paper, optical phase conjugation (OPC) located in the transmitter based on four wave mixing (FWM) in a semiconductor optical amplifier (SOA) is first simulated in 40Gb/s CO-OFDM systems, and the fiber nonlinearity impairment of the transmission link is precompensated before OPC by transmission through a fiber with large nonlinearity coefficient. Simulation results show that the nonlinear threshold (NLT) can be increased by about >3dB and maximum Q factor can be increased by about 2dB for the single-channel system. For 50-GHz-Spacing WDM systems, the maximum Q and NLT are increased by about 1dB, even in the presence of cross phase modulation (XPM) from neighbouring WDM channels. It is found that this OPC subsystem located in the transmitter, not necessary to be inserted into the middle of link, can mitigate the fiber nonlinearity impairment for both single-channel and WDM systems. [Copyright &y& Elsevier]