Modal characteristics of three-layered optical fiber waveguides: a modified approach

Abstract

By invoking Debye potentials, we formulate exact eigenvalue equations and the corresponding field distributions for general, three-layered, radially stratified, dielectric, and nonferromagnetic metal, optical fibers. By using cross products of Bessel functions, which may be regarded as the basic functional elements of the eigenvalue equations, a comparison is made between the properties of a three-layer structure and a simple step-index profile, and a simple graphical solution is obtained. The technique is applied to several practical structures, including two-layer fibers having a central index depression in the core, ring-core fibers, W fibers, and progressively stepped three-layered structures. The mathematical procedure is simple, and the results are of interest to optical fiber designers.