Impulse response of fibers with ring-shaped parabolic index distribution

Abstract

The index distribution in the cross section of a multimode fiber has an important influence on the modal group velocities and, hence, on the fiber impulse response. In this paper we derive a method for the evaluation of arbitrary circular symmetric index profiles. In particular, we compute the impulse response of a fiber with a ring-shaped parabolic index profile which exhibits useful equalizing properties. The pulse spread is found to be nearly one order of magnitude smaller than that of a fiber with an equal, but abrupt, index decline from core to cladding.