Modulation instabilities in two-core fiber coupler

We have investigated the modulation instability (MI) in a nonlinear optical coupler using a generalized model describing the pulse propagation of two-core fiber. In particular, we discuss some influence of the maximum MI gain and MI bandwidth of two-core fiber coupler. The results show that the anomalous dispersion influences the MI bandwidth, but not the maximum value of the MI gain, and the maximum value of the MI gain, as well as its bandwidth, has been also affected by input power, the ratio of power of two cores and positive nonlinear coefficient. In particular, the MI cannot be produced with negative nonlinear coefficient. In addition, when powers of two cores are not equal, coupling coefficient influences the MI, and when they are equal, the MI will not be affected.