We have numerically analysed the effects of SOA’s medium length on four-wave mixing (FWM) characteristics in semiconductor optical amplifier (SOA). We have studied the shape, spectrum, full width at half maximum (FWHM), timebandwidth product, peak shift and frequency shift of the FWM signal for weak and strong input pump and probe pulses. We have used the nonlinear propagation equation taking into account gain spectrum dynamic gain saturation which depends on carrier depletion, carrier heating, spectral hole-burning, group velocity dispersion, self phase modulation and two photon absorption. We have used finite-difference beam propagation method (FD-BPM) to simulate the wave evolution both in time and spectral domain in the SOA. From this simulation, it has become clear that the FWM signal characteristics are dependent to the length of SOA. In high power regime, nonlinear phenomena in SOA have more influences on the FWM signal characteristics.
