Abstract

It was first shown by Hasegawa and Brinkman [1] that as a result of the combined effects of anomalous dispersion and the non-linear optical Kerr effect, amplitude and phase modulations on a c.w. wave in a single mode fibre show an exponential growth rate, with the evolution of sidebands to the central pump frequency, at a frequency separation which is proportional to the optical pump signal. The conditions necessary for the observation of this modulational instability are similar to those required for the generation of envelope solitons in optical fibres. In the time domain, modulational instability manifests itself as an intensity modulational of the c.w. pump signal. "Long" picosecond pulses can be used to observe the effect since, for typical operational parameters, the frequency of the induced modulation is ~10¹² Hz and consequently pulses of the order of 100ps effectively appear c.w.

© 1989 Optical Society of America