Modal analysis and dispersion curves of a curvilinear triangular cored light guide using Goell's point matching method

This paper gives, in brief the theoretical and computational investigation of a new light guide having a curvilinear triangular core cross-section. This structure is here introduced for the first time and may be conceived as a distortion of a rectangular core cross-section. Using Goell's point matching method under weak guidance approximation, the modal characteristics equations for the lowest order mode have been derived in two cases. In one case, all the sides of the proposed light guide are bounded by dielectric material. In other case we will consider all the sides bounded by conducting materials. From these equations the modal dispersion curves are obtained and compared. It is seen that the dielectric light guide supports more modes than the metallic light guide. Thus, metallic light guide may be used as a mode filter.