Analysis of dynamic behaviour of semiconductor optical amplifiers

A study of the transient response of semiconductor optical amplifiers (SOAs) is presented. The gain saturation and recovery times, as well as the pulse distortion due to the cross-gain modulation produced by the bias current and input signal power variations have been evaluated for different scenarios. Observations of the temporal variation of the rate carrier density at the input and output of the amplifier show the effects on gain saturation for different input powers. Gain saturation and saturation-induced inter-channel crosstalk are evaluated. The results show the fast gain dynamic in SOAs. Transient effects of gain saturation and recovery times occur on a time scale of between 500 ps and 1 ns. It is concluded that SOAs are sensible to channel crosstalk in WDM systems operating at high bit rates