Effects of walk-off on cross-phase modulation induced modulation instability in an optical fibre with high-order dispersion

This paper investigates the effects of walk-off among optical pulseson cross-phase modulation induced modulation instability in thenormal dispersion region of an optical fibre with high-orderdispersion. The results indicate that, in the case of high-orderdispersion, the walk-off effect takes on new characteristics and willinfluence considerably the shape, position and especially the numberof the spectral regions of the gain spectra of modulationinstability. Not only the group-velocity mismatch, but also the differenceof the third-order dispersion of two optical waves will alter the gainspectra of modulation instability but in different ways. Depending on thevalues of the walk-off parameters, the number of the spectral regions mayincrease from two to at most four, and the spectral shape and position maychange too.