Abstract

In this paper we discuss the nonlinear propagation of three coherently coupled pulses interacting through the parametric four-photon mixing process in a dispersive fiber. An intense pump pulse whose wavelength lies near the zero group velocity dispersion (GVD) wavelength gives rise to a pair of Stokes and anti-Stokes pulses whose amplitudes grow from noise. The Stokes and anti-Stokes wavelengths are symmetrically disposed about the zero GVD wavelength and hence these pulses propagate with the same group velocity. Since the Stokes pulse lies in the region of negative GVD it experiences substantial compression through the combined effects of cross-phase modulation, self-phase modulation, and dispersion. The anti-Stokes pulse lies in the region of positive GVD, is much broader than the Stokes, and can propagate as a dark pulse. While phase-matched parametric interactions in the zero-GVD region have been studied before (Refs. 1-3), this paper is the first to fully incorporate nonlinear pulse propagation effects by solving a set of coupled nonlinear Schroedinger equations. The results are particularly relevant in view of the recent demonstration of a parametric soliton laser (Ref. ⁴).

© 1989 Optical Society of America