Rigorous field analysis of step discontinuity based on mode theory for thin-film multilayered 3-D optical waveguide

Rigorous field analysis for 3-D optical waveguide step discontinuity is needed for the exact design of optical integrated circuits. In this paper, mode theory based equivalent networks in lateral direction and that along wave propagation direction are practically applied to the analysis of step discontinuity for thin-film multilayered 3-D optical waveguide. Network parameters are calculated by mode theory and excited amplitude of higher modes including dominant are calculated by circuit theory. The calculated results are demonstrated to be valid by power conservation and the field continuity at step. Finally, radiated power is estimated and dynamic field distribution around step discontinuity is calculated, which will be demonstrated on site.