Volterra series analysis of semiconductor optical amplifiers

Recently, semiconductor optical amplifiers (SOAs) have attracted much attention as potential candidates for active photonic circuits. In this paper, a Volterra series for the input-output map of such a device is derived using an existing nonlinear state space model. A second-order Volterra approximation is then compared in a specific instance against the full nonlinear model and a linearized model. It is shown that the Volterra model gives a more accurate estimate of gain and interchannel crosstalk than can a linearized model, especially when RMS power is used as the metric. The Volterra model is then employed to estimate the accuracy of the linearized model as a function of device length.