Frequency-domain model of multiwave mixing in bulk semiconductor optical amplifiers

We present a new steady-state frequency-domain model of highly nondegenerate four-wave mixing in bulk semiconductor optical amplifiers (SOA´s). The model can handle a large number of interacting optical fields and situations in which the nonlinear interactions are complex. It accounts for the longitudinal dependence of the population inversion in the SOA and the spectral dependence of the gain. Carrier population pulsations, spectral-hole burning, and carrier heating, which dominate the nonlinear response over bandwidths into the terahertz range, are included. The model also includes output amplified spontaneous emission noise and allows important system parameters such as signal-to-noise ratio and noise figure to be estimated. A number of applications of the model are presented in which good agreement between theoretical and experimental results is demonstrated