Lorentzian approximation of the fundamental mode in single mode linear and nonlinear fiber

Abstract

In this paper, we approximate the fundamental mode in single mode step and graded index optical fiber by a single parameter Lorentzian function within scalar variational framework. We show that it works in a low V region, a region important for evanescent wave coupling, more accurately in terms of propagation constant in comparison to single parameter Gaussian for linear and nonlinear fibers. Furthermore, we show that the low V variations of normalized propagation constant b ( V ), group delay d ( V ), and waveguide dispersion g ( V ) with V based on Lorentzian approximation match more accurately with the results for linear optical fiber in comparison to Gaussian approximation in the low V region.