Pulse dispersion in optical fibers of arbitrary refractive-index profile

A complete computational procedure operating within the framework of geometric optics is presented for obtaining the pulse response of multimode graded-index fibers, which have circular cross sections but arbitrary refractive-index profiles. The profile is approximated by parabolic sections, thus reducing the ray transit time calculation to an exact procedure, which involves only the solution of quadratic equations, and the analytical evaluation of standard integrals. The effect of material dispersion, absorption, and tunneling rays can be incorporated exactly within the adopted profile approximation and computational procedure.