Studies of the dispersion characteristics and cutoff frequencies of a new lightguide having an Archimedian spiral core cross-section under the weak guidance condition

Abstract

In this analysis we have taken the scalar wave approximation in the field under the weak guidance condition to study the modal behaviour, dispersion characteristics and cutoff frequencies of a new optical waveguide having an Archimedian spiral core cross-section. By choosing appropriate orthogonal coordinates (ξ, η, z) and using the boundary conditions of the proposed waveguide, the eigenvalue equation (characteristic equation) has been derived analytically. Using this equation model dispersion curves and cutoff frequencies have been obtained for some low order modes.