SPATIOTEMPORAL COUPLING IN DISPERSIVE NONLINEAR PLANAR WAVE-GUIDES

The multidimensional nonlinear Schrodinger equation governs the spatia l and temporal evolution of an optical field inside a nonlinear disper sive medium. Although spatial (diffractive) and temporal (dispersive) effects can be studied independently in a linear medium, they become m utually coupled in a nonlinear medium. We present the results of numer ical simulations showing this spatiotemporal coupling for ultrashort p ulses propagating in dispersive Kerr media. We investigate how spatiot emporal coupling affects the behavior of the optical field in each of the four regimes defined by the type of group-velocity dispersion (nor mal or anomalous) and the type of nonlinearity (focusing or defocusing ). We show that dispersion, through spatiotemporal coupling, can eithe r enhance or suppress self-focusing and self-defocusing. diffraction c an either enhance or suppress pulse compression or broadening. can be controlled with optical phase modulation, such as that provided by a l ens (spatial phase modulation) or frequency chirping (temporal phase m odulation). (C) 1995 Optical Society of America