Raman Gain Effect On Soliton Trapping In The High Bireingence Fiber

In the high birefringence fiber, two orthogonal polarization components of soliton will be frequency shift in the opposite direction that the slow axis component will be blue shift as the fast axis component will be red shift, due to the action of cross phase modulation.Ultimately they transmit in the same group velocity,as the soliton self-trapping. Soliton trapping has get great attention because of great value in all-optical switching field. Stimulated Raman scattering as an important nonlinear effects on soliton trapping should not be underestimated.The coupled nonlinear Schrodinger equation including Raman gain has been utilized for high birefringence fiber. We study Raman gain effect on bright soliton and dark soliton respectively.Results show that Raman gain increases the soliton trapping threshold when the value of group velocity mismatch is small and it destroys the transmission of soliton pulse when the value of group velocity mismatch is large. While there is an opposite effect on dark soliton trapping,the amplitude threshold of dark soliton can be reduced due to Raman gain and the threshold is reduced faster with the increasing of Raman gain.In this paper, the main structure is divided into three parts:(1 introduction mainly contains the research status at home and abroad,selected topic basis and significance in the field of soliton capture;(2)Background theory, introduced the birefringence of the fiber, stimulated Raman scattering, and soliton capture; (3)Raman gain effect on bright soliton trapping in high birefringence fiber.Based on the coupled nonlinear Schrodinger equation including Raman gain and self-steepening effect in high birefringence fiber,the evolution of two orthogonal polarization components of soliton has been simulated with utilizing the fractional Fourier method,and then the impact of Raman gain and self-steepening effect on soliton trapping has been analyzed.(4)Raman gain effect on dark soliton trapping in high birefringence fiber.The coupled nonlinear Schrodinger equation including Raman gain has been utilized for high birefringence fiber.The trapping threshold of dark soliton considering Raman gain is deduced by the Lagrangian approach when input pulse is the dark soliton pulse that the amplitude of two polarized components of the dark soliton are the same.Propagation of the two orthogonal polarization components of dark soliton is simulated by the fractional Fourier transform method.We compare the analytical solution to the numerical solution and discuss the effect of Raman gain on dark soliton trapping;(5)Conclusion.