Modulation instability and short-pulse generation in media with relaxing Kerr nonlinearity and high self-steepening

The modulation instability in waveguides with high Kerr nonlinearity, characterised by a delayed nonlinear response, has been investigated with allowance for the self-steepening parameter and third-order dispersion. General expressions for the modulation gain are obtained. The influence of the waveguide parameters on the gain is analysed. It is shown that the joint effect of the delayed nonlinear response and negative nonlinearity dispersion leads to an increase in the modulation gain. The relations obtained are confirmed by numerical simulation. The results of this study can be used to design compact generators of high-frequency pulse trains.