Parallel-beam excitation method for estimating refractive-index profiles in optical fibres
Abstract
A theoretical model is developed that demonstrates the presence of a ring in the far-field pattern when a graded-index fibre is excited by a collimated beam, incident at a given radius from the core centre. The angular position of tnis ring can be used to obtain an estimate of the fibre refractive-index profile, provided a correction for the finite beam spot size is applied.
