An equivalent step-index model for single-mode fibers based onmatching of bend loss and spot size at one wavelength: a simulationstudy

A method for the determination of equivalent step index (ESI) parameters for a given single-mode fiber is presented. The method is based on the matching of bend loss characteristics and (Petermann II) spot size at one wavelength. Numerical simulation studies have been carried out for fibers with parabolic and triangular index profiles having zero total dispersion at 1300 or 1550 nm. The results show that the method gives a model that is both stable with respect to the matched wavelength in the 1500-1600-nm range and accurate for predicting fiber characteristics such as spot size, waveguide dispersion, bend loss, and the cutoff wavelength (of the next higher mode) over this range of wavelength