Generation and propagation of bright solitonlike pulses in the normal dispersion regime

Abstract

Optical solitons are potentially useful both in future optical communication systems and in optical computing logic gates. As is well known, anomalous dispersion is a necessary condition for the generation and propagation of a bright soliton. We present analytical and numerical results predicting the propagation of bright solitary waves even in the normal dispersion regime. First, we show that when two pulses interact through linear coupling, as in the case of two orthogonal polarization modes in a birefringent fiber, modulational polarization instabilities1 may induce the generation of a train of ultrashort pulses in the visible. We compare the characteristics of these pulses with those obtainable in the anomalous dispersion regime. Another mechanism for the propagation of a bright solitary pulse in the normal dispersion regime is the interaction via cross-phase modulation2 with a fundamental dark soliton, which in turn is allowed to propagate in the anomalous dispersion regime. We discuss the stability of this analytical solution to the coupled nonlinear Schrodinger equations by means of beam propagation simulations. (12 min)