Wideband Time-Domain Transfer Matrix Model Equivalent Circuit for Short Pulse Propagation in Semiconductor Optical Amplifiers

A general time-domain transfer matrix model is presented which is able to handle waves perturbed by a locally uniform medium and which is particularly well adapted to equivalent circuit implementations. We use this model for the simulation of a picosecond pulse propagating through a semiconductor optical amplifier (SOA). The signal propagation through the SOA is described by an envelope propagation equation, taking into account the optical carrier´s wavelength evolution (modulated wavelenght division multiplexing spectrum consideration). We present the SOA equivalent circuit and its implementation under a commercially available software. The SOA is described through the wideband definition of all parameters which makes it comparable to a real component. Simulations have been validated with experimental results over at least 60 nm. We simulate both amplitude and phase evolutions of a picosecond pulse and a continuous-wave probe at various pulse´s optical carrier wavelengths. We show a strong influence of the imaginary part of the complex time delay on the phase variations, and as a consequence on the additional spectral red or blue shift.