Multiwave mixing of terahertz detuned optical pulses in semiconductor optical amplifiers

A new model describing multiwave mixing of terahertz detuned picosecond optical pulses in semiconductor optical amplifiers (SOAs) is presented, by taking into account carrier depletion, carrier heating, spectral hole-burning, two-photon absorption, ultrafast nonlinear refraction and small signal gain differences for different mixing pulses. Special attention is paid to the influence of probe depletion (PD) and cross-gain modulation (XGM) on four-wave mixing (FWM) of optical pulses in SOAs. The effects of PD and XGM become more significant for shorter input pulsewidth, higher pulse energy and smaller pump-probe frequency detuning. Results indicate that if the effects of PD and XGM are neglected the FWM efficiency can be seriously overestimated