Cutoff conditions of an annular dielectric waveguide with an exponentially decaying refractive-index profile in the guiding region

Abstract

An analytical method for the cutoff analysis of an annular dielectric waveguide with an exponentially decaying refractive-index profile in the guiding region is presented. The scalar field equation of the guiding region having a graded refractive-index profile is solved analytically, and the cutoff conditions are derived using the proper boundary conditions. Some numerical estimation for the cutoff values of the z-component of the propagation constant is also done.