Simple but accurate method to compute LP11 mode cutoff frequency of nonlinear optical fibers by Chebyshev technique

Abstract. We propose a simple method to compute the first higher order mode cutoff frequency of a single-mode fiber in the presence of optical nonlinearity. We consider optical Kerr-type nonlinearity for these fibers having dispersion-shifted and dispersion-flattened profiles. Our analysis involves the Chebyshev method but introduces a linearization of cubic terms of fields due to Kerr-type nonlinearity. Our results are shown to match excellently with the available exact numerical values. Thus, this formulation and stepwise algorithm should be considered as a simple but accurate alternative to deeply involved numerical technique and used as a guideline in calculating and minimizing the modal noise in single-mode nonlinear fibers.