Four wave mixing between short pulses in a semiconductor optical amplifier

This talk describes the principle advantages of using short pulses for four wave mixing (FWM) in semiconductor optical amplifiers. The use of short pulses for FWM in passive nonlinear material is of course widely known. In such passive materials, the short pulses are a means to obtain large optical intensities and their time dependence is actually irrelevant. In contrast, in a semiconductor optical amplifier, the efficiency of the FWM process is bound by gain saturation and large CW optical fields are not capable of overcoming this bound. With short pulses on the other hand FWM is a dynamic process in which the gain is in a transient so it is possible to obtain large intensities in the presence of an unsaturated gain and achieve efficiency increases of several orders of magnitude compared to the CW case.