Abstract

Cross-phase modulation (XPM) is important whenever two optical fields copropagate and at least one of them is intense. In this work we investigate the role of walk-off between two optical fields copropagating in an optical fiber. We consider a cw signal in the anomalous dispersion regime and an intense picosecond pulse in the normal dispersion regime. The continuous wave is modulated through XPM and can evolve into a short pulse whose duration and amplitude depend on the degree of walk-off. The signal pulses are longer and less intense than in the no walk-off case, and a longer fiber is necessary to form it. When the walk-off length is shorter than the necessary length for short pulse formation the signal wave becomes amplitude modulated, with a modulation depth of a few percent. In this case a frequency chirp exists in the signal wave and can be used to generate short pulses on propagation through an appropriate dispersive element.

© 1989 Optical Society of America