Calculated and measured spot size of equivalent Gaussian field in single-mode optical fibres

Abstract

Measurements of the integrated far field from a single-mode fibre using a simple set-up for attenuation measurements yields the spot size of the equivalent Gaussian field, or the ESI parameters. Using a multilayer method for calculating the field in the fibre, it is shown that the obtained spot size (ESI values) will depend on how this parameter is extracted.