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Phase conjugation of picosecond optical pulses in semiconductor optical amplifiers

A numerical investigation of the four-wave mixing efficiency of picosecond optical pulses in semiconductor optical amplifiers is performed. Special attention is paid to the influence of probe depletion (PD) and cross-gain modulation (XGM) on four-wave mixing (FWM) efficiency. It is shown that variations in FWM efficiency induced by both PD and XGM can be significantly enhanced by shorter pulsewidth, higher pulse energy and smaller pump-probe frequency detuning, and that the variation of FWM efficiency caused by PD is symmetrical with respect to negative and positive frequency detunings, while the FWM efficiency change due to XGM exhibits an asymmetric lineshape.