Profile dispersion in multimode fibres: measurement and analysis

Abstract

An electronically scanned interference microscope has been used to measure the refractive-index profile and its dispersion in optical fibres. From these measurements, we find that the power-law profile that best equalises modal delays in GeO2-S1O2 fibres should have an exponent that varies between 1.9 and 2.5 in the wavelength range from 0.5 to 1.1 μm and is close to 2 at 0.9 μm.