Propagation characteristics of radially inhomogeneous optical fibre

A numerical method for computing the propagation characteristics of a radially inhomogeneous fibre is presented. The method is quite general and can be applied to a fibre with any refractive-index profile. The fibre considered here consists of a core with a parabolic refractive-index profile and a thin homogeneous cladding. Dispersion curves for the seven lowest-order modes are computed with and without the infinite-cladding approximation. The results have been found to agree with those of other investigators. The effect of the finite cladding, however, has not been studied previously.