An efficient method for calculating cutoff frequencies in optical fibers with arbitrary index profiles

Abstract

An accurate and simple method of calculating the cutoff frequencies of scalar modes in a fiber having an arbitrary refractive-index profile, including discrete numerical data from profile measurements. is proposed. First, the cutoff problem is transformed into ageneral matrix eigenvalue problem and then cutoff frequencies as the eigenvalues of a real symmetric matrix are evaluated. Representative test examples have been computed to illustrate the accuracy, reliability, and efficiency of the algorithm proposed.

Simple Empirical Formulae for Cutoff Frequencies of Few Moded Graded Index Fibers and Index Profile Determination

“…A number of methods, such as the perturbation method [7,11], the power series expansion method [8], the modified WKB method [9], the direct integration iteration method [10], the matrix method [12] and other kinds of numerical methods [3,[13][14] have been proposed to compute the normalised cutoff frequencies of modes of arbitrarily graded index fibers, each method claiming to be simpler than the other. However, all these methods are time consuming although these are valid for any kind of profile.…”