Vectorial analysis and modeling of EM wave propagation in second order nonlinear optical waveguide structures

Abstract

The aim of this thesis is to formulate an accurate full-wave model inside non-linear optical waveguide structures. A vectorial nonlinear finite-difference time-domain method is used to simulate an integrated optical structure containing second order nonlinearity. A continuous wave TM signal is used as excitation for the simulated waveguide structure at the fundamental wavelength to generate a second harmonic TE signal with a new wavelength. Two theoretical models: the envelop-carrier and envelop-only models are derived by these models to a AlGaAs waveguide structure. The simulated algorithm is enhanced by using the formulation of the perfectly matched layer technique to provide an effective boundary condition. Finite-difference time-domain equations of the second harmonic generation model are produced in both formulations: the envelop-carrier and envelop-only formulations. To reduce the computational time of the simulation, a special numerical technique called moving computational window is used. Simulation results of the second harmonic generation with no-matching, perfect phase-matching, and quasi phase-matching for non-depleted inputs are discussed. Also, depleted input is presented in the simulation results to study the effects of the second harmonic field on the fundamental field.