Parametric amplification in optical fibre with longitudinally varying dispersion

We analyse modulation instability in fibre with longitudinally varying dispersion and the associated parametric amplification and confirm that modulation instability in such fibre is observed even in the case of positive dispersion. Highly nonlinear fibre with periodic dispersion modulation is shown to be potentially attractive as a component of a parametric amplifier with an extended gain band due to parametric resonances. Issues related to the influence of SRS and SBS on the operation of parametric amplifiers are discussed.