Nondestructive refractive-index profile measurement of elliptical optical fibre or preform

Abstract

A nondestructive method of determining the refractive-index profile of an elliptic optical fibre or preform is reported. For the fibre, the pathlength data obtained from interference microscopic measurement are used. For the preform, the ray exit angles are used. These data are put into an integral that can be inverted numerically to obtain the reconstructed profile.