In this paper, we propose a new numerical method for solving a rib waveguide TE-mode problem.
In the proposed method, the cross-section of the waveguide is divided into several regions and the
refractive index profile and field distribution in each region are expanded into Fourier cosine series, and
then are substituted in the wave equation. A second-order differential matrix equation is derived with a
closed-form solution obtainable. Finally, with the boundary conditions being used, an eigenmode
equation can be derived and solved numerically to give the modal indices. Here, the proposed method
is used to deal with a silicon dioxide based rib waveguide. Numerical results show that the presented
method is quite efficient, in terms of CPU time, in finding the modal indices accurately. The relative
error of the modal index with the proposed method as compared that of the commercial software
BeamPROP is less than 10-6.
Asian Journal of Health and Information Sciences 1(4):411-424