Influence of Higher-Order Dispersions and Raman Delayed Response on Modulation Instability in Microstructured Fibres

Modulation instability (MI) in microstructured photonic crystal fibres is studied by using an extended nonlinear Schrödinger equation. The roles of arbitrary higher-order dispersions and Raman delayed response in MI are identified. It is shown that all the odd-order dispersions contribute nothing to MI, whereas all the even-order dispersions not only affect the conventional instability regions but also may lead to the appearance of new MI regions. Raman delayed response makes MI occur in both the normal and anomalous dispersive regimes and exerts different influences on the Stokes and anti-Stokes components to some extent.