Dynamic beam propagation method for flared semiconductor power amplifiers

In this paper, we present the results of a dynamic two-dimensional time-domain beam propagation method (two spatial dimensions plus time) for simulating travelling wave semiconductor optical amplifiers with nonuniform transverse section in pulsed regime. Using the effective refractive index method, the paraxial approximation and a moving timeframe, we reduce the scalar wave equation to a nonlinear parabolic partial differential equation for the slow complex envelope of the electric field. Diffraction, refractive index dispersion up to the second order, gain saturation and gain dispersion are included in the model. We numerically solve the equation through a locally one-dimensional (LOD) method employing both finite-difference techniques and FFT-based pseudospectral methods.