Accurate modeling of second-order nonlinear effect in optical waveguides using the finite element method

The rigorous and efficient FEM based beam propagation method is used to model SHG in semiconductor waveguides. The effect of material loss on the overall efficiency of SHG is also analyzed. It is shown that under certain conditions, GaAlAs based devices with a lower non-linear susceptibility tensor could be more efficient than GaAs with a higher non-linear susceptibility tensor due to their low material loss. Numerical results are also presented, of the effect of domain fabrication error, in the case of quasi phase matched devices on the efficiency of SHG. The finite element method is also extended to the study of cascaded second harmonic generation in optical waveguides. The accuracy of the method is demonstrated by comparison with previously published results. The effect of the second harmonic on the fundamental in the presence of an intense input beam is discussed, through application to a practical waveguide structure.