Modal behavior, cutoff condition, and dispersion characteristics of an optical waveguide with a core cross section bounded by two spirals

Abstract

This paper presents a theoretical treatment of the modal characteristics, cutoff condition, and dispersion characteristics of a new type of optical waveguide whose guiding region is bounded by two spirals. A segment of the core cross section can be considered as a distorted planar waveguide in which a curvature and a flare have been introduced. Using the boundary conditions for the proposed waveguide under the weak guidance condition, the modal characteristic equation and modal cutoff equation have been derived. Dispersion curves have also been obtained for some low-order modes.