A Simple but Accurate Method for Estimation of the Effect of Kerr Nonlinearity on Confinement and Excitation of the Fundamental Mode in Single Mode Graded Index Fiber

Abstract

This paper presents prediction of the fractional modal power and excitation of the fundamental mode inside the core of a single-mode graded index fiber, both in presence and absence of Kerr nonlinearity. Our analysis is based on simple power series expression for fundamental mode of graded index fiber, which has been formulated by applying Chebyshev technique. In absence of nonlinearity, analytical expressions for the concerned propagation parameters are prescribed. Employing these analytical expressions, method of iteration is applied for evaluation of the said parameters in presence of Kerr nonlinearity. In this context, some typical step, parabolic and triangular index fibers are used for our study. In absence of nonlinearity, our results show excellent match with the exact results available in literature. In presence of nonlinearity, the results found by our formalism also agree excellently with the exact results which can be obtained by application of rigorous finite element technique. Thus, this simple but accurate method will prove extremely useful for the system users.