COUPLING EFFICIENCY OF 2 ANISOTROPIC SINGLE-MODE SLAB WAVE-GUIDES BUTT-JOINED VIA A GAP

The fundamental characteristics of the coupling efficiency between two anisotropic slab waveguides with different configurations butt-joined via a gap are analyzed in the case of a TM mode incidence by means of a single-mode slab waveguide model made of equatorial dielectric tens er. The electromagnetic field in the gap is represented by a combinati on of the forward elementary plane wave propagating from the incident side to the output waveguide and the backward elementary plane wave pr opagating in the opposite direction. By applying the boundary conditio ns, the power transmission and reflection coefficients in the guided-w ave system are computed. Further, the effects of the lateral misalignm ent and inclination between the waveguides and the index of refraction and spacing of the gap on the coupling efficiency are studied based o n the numerical results. An optimum condition to maximize the coupling efficiency is obtained.