Optical soliton and modulation instability in the high birefringence fiber

In this paper, we investigate a coupled nonlinear Schrödinger equation which describes the propagation of optical signal in the high birefringence fiber. Analytic one- and two-soliton solutions are obtained through the Hirota bilinear method. Through analyzing the interaction of the two-solitons, the conditions of realizing the optical switch are discussed. In addition, the modulation instability gain spectrum in this system is also analyzed. The results are helpful to the design of the optical switch devices and the study of the nonlinear effects in optical fiber mode division multiplexing systems.