The use of FDFD method for obtaining dispersion characteristics of asymmetric coupled anisotropic rectangular dielectric waveguides

The effect of varying the transverse dimensions of coupled rectangular anisotropic waveguides on the propagation characteristics of these waveguides was analyzed using the FDFD method. While the experimental data were obtained for uniaxial anisotropic dielectrics with a step index of refraction profile in the waveguide cross section, the formulation is also applicable to biaxial anisotropic dielectrics, with a combination of step and continuously varying index of refraction profile in the waveguide cross section. The results show that the effective dielectric constant is more influenced at the lower frequencies by the (B/sub 2//B/sub 1/) dimensions´ ratio and at the higher frequencies by the (A/sub 2//A/sub 1/) dimensions´ ratio when the optical axis is positioned along the y direction. When the optical axis is positioned along the x direction an opposite behavior is observed.<>