Lightguides with core cross-section bounded by two spirals: Effect of curvature on dispersion curves

Abstract

Recently Sing et al. investigated the dispersion characteristics and cutoff conditions of a wave guide whose guiding cross-section was assumed to be bounded by two spirals, r = ce-θ(2)/2 and r = be-θ(2)/2. In that paper the width (b-c) is allowed to change by changing the parameter b and keeping c fixed at 2.0 μm. Here in this paper, we want to study how the dispersion characteristic change with curvature considering a few more fixed values of c. We choose c = 4.0 μm and c = 6.0 μm, so that the average curvature may be less than curvature corresponding to c = 2.0 μm. It is found that as the curvature of the guide decreases the number of sustained modes for a given value V shows a tendency to decrease.