Approximate analytical approaches to nonlinear pulse propagation in optical fibers: A comparison

Abstract

A comparison is made of two recently suggested approximate analytical methods for the investigation of nonlinear pulse propagation in optical fibers, as described by the nonlinear Schr\"odinger (NLS) equation. One approach is based on a variational procedure involving Ritz's optimization while the other makes use of invariants of the NLS equation. Despite their different character the approximation schemes are shown to lead to identical results for the evolution of the pulse amplitude and pulse width.