GAUSSIAN-BEAM EXCITATION AND STABILITY OF 3-DIMENSIONAL NONLINEAR GUIDED-WAVES

The propagation of stationary three-dimensional nonlinear guided waves and of Gaussian beams in a slab waveguide in which the cladding displ ays both Kerr-law and saturable instantaneous self-focusing nonlineari ties is simulated numerically. The numerical analysis supports the hyp othesis that the stationary three-dimensional nonlinear guided waves a re stable on propagation for propagation constants corresponding to th e ascending branches of the nonlinear dispersion curves. The numerical simulations of the Gaussian-beam propagation in the nonlinear slab wa veguide illustrate both diffraction and nonlinear effects such as soli tary-wave emission. The transparent-boundary condition, which employs no adjustable parameters and is easily incorporated into a Crank-Nicol son finite-difference scheme, was used in the three-dimensional calcul ations.