Modulation instability induced by cross-phase modulation in dispersion-decreasing fiber with high-order dispersion and high-order nonlinearity

Abstract

The modulation instability (MI) induced by cross-phase modulation (XPM) in dispersion-decreasing fiber (DDF) is investigated based on extended nonlinear Schrödinger equations with high-order dispersion and high-order nonlinearity considered. The effects of fourth-order dispersion, quintic nonlinearity, dispersion decaying factor and different group velocity dispersion (GVD) on the gain spectra are analyzed. The results show that due to fourth-order dispersion, XPM occurs at two spectral regions in both the normal and the anomalous dispersion regimes of DDF. The positive (negative) quintic nonlinearity will make the width and the peak value of the gain spectra larger (smaller). The spectral width of XPM in DDF increases with increasing dispersion decaying factor. There are still two XPM regions in both the normal and anomalous dispersion regimes in DDF with different GVD.