Study of H-field using higher-order compact (HOC) finite difference method (FDM) in semiconductor rib waveguide structure

Following the recent success with polarized E-field solutions, an efficient and highly accurate semi-vectorial H-field mode solver is proposed for various rib waveguides based on higher (fourth)-order compact FDM in combination with a conjugate gradient (CG) type of iteration. Here, optical waveguide modeling is designed by incorporating the modal index and modal birefringence concept into the refractive index profiles (RIPs) of two specific semiconductor (GaAs/GaAlAs and GeSi) rib waveguide structures for simulating the performances of various photonic integated circuits and corresponding field profiles of guided modes are shown through the surface and contour plots. It is to be confirmed that the used algorithm takes full account of vertical and horizontal discontinuities of RIPs in cell interfaces within the specific waveguide structure where the numerical results ensure its behavior for stability and convergence with less computational time. For Hx and Hy modes, computed modal index and normalised index values are found to be in perfect agreement with other published results. Most importantly, the variations of these indices with waveguide structure parameters help to identify their optimized values which play very decisive role so far as their fabrications are concerned. Also study of confinement factor computation and modal birefringence provides some important additional deep understanding with which the optimized index values clearly verify the material dependence for effective wave propagation.