Differential frequency shift of picosecond pulse four-wave mixing in semiconductor optical amplifiers

A numerical investigation of picosecond optical pulse four-wave mixing in semiconductor optical amplifiers has been undertaken to evaluate differential frequency shifting. This phenomenon appears as a shift of the central frequencies of the pump, probe and conjugate pulses during the mixing processes. The differential frequency shift is highly dependent upon the probe-pump frequency detuning and becomes more significant for shorter pulsewidths and higher pulse energies. It is also established that the differential frequency shifts between the pump, probe and conjugate pulses are different.