Study On Fiber Polarization Mode Compensation With Phase Sensitive Amplifier In Soliton Transmission System

For optical fiber communication, the transmission with high speed, large capacity and long haul is always the goal to pursue. But the effects of fiber loss and dispersion are the main obstacles. The appearance of the erbium-doped fiber amplifier (EDFA),has overcome the effect of fiber loss,but EDFA can not compensate the dispersion of fiber. During the pulse transmission, group-velocity dispersion (GVD) makes the pulse broader, but the nonlinearity makes it narrower. The reciprocity between GVD and the nonlinearity becomes the soliton which can prevents pulse from getting broader. As the increase of transmission bit rate and distance, polarization mode dispersion (PMD) also became a primary obstacle of the system. Because of strong phase sensitivity of its optical gain, phase-sensitive amplifier (PSA) not only provides gain to the main part of signal pulse, but also acts as filter to its orthogonal part. Therefore using PSA as in-line amplifiers can not only compensate fiber loss but also compensate PMD in some degree.In this dissertation, we get the soliton's solution through solving the generalized nonlinear Schrodinger equation (NLSE). Then we introduce average-soliton transmission system and dynamic-soliton transmission system. With the split-step FFT, it focuses on the effect of using PSA as in-line amplifiers to compensate fiber PMD in soliton transmission system.With computer simulation, we focus on researching the performances of average-soltion system and dynamic-soliton system when using PSA or EDFA as in-line amplifiers to compensate PMD. The simulation results shows that with different PMD parameters, the performance of soliton system using PSA as in-line amplifiers can receive better results than that of using EDFA. Then, on the condition of thinking about the PMD, we mainly do some researches on the influences of system and amplifier parameters.The result of research shows that: under the same conditions, increasing transmission speed can make the system's performance worse. Under the same transmission speed, different soliton initial pulse widths will affect the system's performance. Therefore, we should choose suitable pulse widths. The higher the value of PMD is in fiber, the shorter the distance of soliton pulse can transmit. Larger fiber dispersion parameter will also result in more severely deteriorating system performance and stronger enhancing soliton interaction. In average soliton regime, increasing the amplifier's gain can receive good results for compensating soliton energy loss caused by PSA amplification. But the effect in dynamic soliton regime is not as good as that in average soliton regime. Increasing amplifier spacing will make one soliton split into two, which will interact with other solitons'transmission. If the phase-shift is controlled in some degree, the soliton energy descending will be acceptable.In a word, in the condition of PMD, we get some valuable conclusions through our research, which can give some reference to the actual application of PSA's solution transmission systems in future.