Modelling pulse propagation in semiconductor optical amplifiers using wavelets

A model based on the discrete wavelet transform is presented for the description of short pulse propagation in semiconductor optical amplifiers. The approach is used to analyse amplifier performance taking account of gain saturation, carrier heating, group velocity dispersion and self-phase modulation. Using parameters obtained from fitting to experimental data, simulations are performed that compare well with measured results for semiconductor optical amplifiers and show good agreement with other modelling approaches. The wavelet transform leads naturally to a time-scale representation of the pulse evolution, where the signal is split into a coarse approximation together with a series of local refinements that reveal pulse fine structure which is not apparent in the time domain.