Mode beating and spontaneous emission noise effects in a variable-waveguide model for the dynamics of gain-guided semiconductor laser arrays

The spatio-temporal dynamics of gain-guided semiconductor laser arrays are studied by means of a generalized variable-waveguide model deduced from the semiclassical Maxwell-Bloch equations including spontaneous emission noise. Lateral confinement of the optical field is provided by the permittivity distribution associated with the spatial distribution of carriers. The laser field is then described by a set of noise-driven rate equations for the complex amplitudes of the slowly varying modal functions coupled to the carrier distribution evolution, which is sensitive to mode beating effects. The model is applied to a four-stripe gain-guided array, where the influences of spontaneous emission noise and mode beating on the final state are discussed. We show that, in this model, mode beating plays a determinant role in the dynamic behavior of the system, while spontaneous emission noise does not affect this behavior except during transient evolution