Spatiotemporal solitons in inhomogeneous nonlinear media

We investigate the possibility of forming spatiotemporal solitons (optical bullets) in inhomogeneous, dispersive nonlinear media using a graded-index Kerr medium as an example. We use a variational approach to solve the multi dimensional, inhomogeneous, nonlinear Schrodinger equation and show that sp atiotemporal solitons can be stabilized under certain conditions. We verify their existence by means of a full numerical analysis and show that such s olitons should be observable experimentally. (C) 2000 Published by Elsevier Science B.V. All rights reserved.