Abstract

When ultrashort optical pulses propagate in a single-mode fiber, the interplay between self-phase modulation and group-velocity dispersion can create rapid oscillations in the pulse wings as a result of a phenomenon known as optical wave breaking.¹ We have found that a similar phenomenon can lead to rapid oscillations near one edge of a weak probe pulse that copropagates with a strong pump pulse. In this case the origin of optical wave breaking is related to cross-phase modulation (XPM). If the two pulses are launched simultaneously and the pump pulse travels faster than the probe pulse, the effect of XPM-induced frequency chirp is to slow down the peak of the probe pulse with respect to its tails. Optical wave breaking occurs because the peak lags behind and interferes with the trailing edge. As a result, the probe pulse develops rapid oscillations near the trailing edge while the leading edge remains unaffected. The frequency and amplitude of oscillations depend on the peak power of the pump pulse. We present the numerical results for the pulse shapes and spectra. We also discuss the experimental conditions necessary for observing XPM-induced optical wave breaking.

© 1988 Optical Society of America