Weak guidance modal dispersion characteristics of an optical waveguide having a core with a sinusoidally varying gear-shaped cross section

Abstract

We present a rigorous study of a circular waveguide which, due to a manufacturing defect or due to deliberate choice, takes a new shape resembling that of a gear. Goell's point-matching method under weak guidance is used to study the modal dispersion curves of the proposed waveguide for an aspect ratio (the ratio of two orthogonal dimensions) of (b/a) = 0.1 and 0.2. It is found that the dispersion curves are similar in nature in both cases. When these findings are compared with the cutoff behavior of the circular fiber under weak guidance, it is seen that the cutoff values are shifted toward higher values of the V-parameter as the aspect ratio is increased from 0.1 to 0.2.