AN ITERATIVE FINITE-DIFFERENCE BEAM-PROPAGATION METHOD FOR MODELING 2ND-ORDER NONLINEAR EFFECTS IN OPTICAL WAVE-GUIDES

An iterative finite difference beam propagation method based on the Cr ank-Nicholson scheme is presented to simulate continuous wave (CW) sec ond-order nonlinear effects in optical waveguides with the depletion o f the pump wave taken into account, This method is an extension of the linear finite-difference beam propagation method and preserves the sa me order of accuracy. Comparisons with the previously published explic it finite difference beam propagation method and the rectangular appro ximation method are presented. Quasi-phase matched difference frequenc y generation in AlGaAs and quasi-phase-matched second harmonic generat ion in LiNbO3 are considered in the evaluation, showing that one itera tion for the IFD-BPM is sufficient for the simulation with good accura cy and without increasing much computation time.