Optical and microwave dispersion curves of a waveguide with a guiding region having a cross-section with a lunar shape

Abstract

A numerical analysis based on Goell's point matching method is made to study the dispersion characteristics of the optical waveguide whose guiding region has a cross-section resembling a lune. If the parallel boundaries of a planar waveguide are given different curvatures, the distortion may be represented by a lune. The weak guidance condition is used to obtain the normalized dispersion curves corresponding to some low order modes. The dispersion curves show that a large number of modes can be sustained for a low value of the V-parameter where V = 2 πdλ0-1 (n12 - n22) 1/2 , d, λ0, n1 and n2 being respectively the size parameter, operating wavelength and the refractive indices of the guiding and the non guiding regions. The structure shows a broad-band performance in respect of the number of modes sustained both in the optical frequency range and also in the microwave range.