Effect Of Raman Gain On The State Ofpolarization Evolution In A Low-Birefringence Fiber

With the continuous development of optical communication technology, more and more people start to study nonlinear system in optical fiber with the purpose of high speed and large capacity transmission, By electromagnetic theory, because of the influence of internal factors and external environment in the fiber during the transmission, the optical state of polarization will be changed with periodic or aperiodic, and then the phenomenon will be occurred such as distortion and deformity. Therefore, polarization of light waves in optical fiber changes should not be ignored. In this work, the following research activities are investigated. (1)Explain the Raman scattering by the quantum theory and study the state of polarization in a low birefringence fiber. Containing the Raman gain coupling model equation which is derived Maxwell’s equations. (2) The theory of the polarization is introduced in optical fiber. And then the coupling model equation satisfied by the Stokes parameters is derived by introducing the Stokes parameters. (3)The equations which expressed by Stokes parameters can be solved by the elliptic integral. Then mainly studied the polarization ellipticity can be changed due to Raman scattering effect with the Poincare sphere model and the solutions of the equations. The study shows that the state of polarization and its stability can be changed by Raman scattering effect,when the input pulses of optical intensity is different in a low birefringence fiber.