Research On Polarization Mode Dispersion And Fiber Raman Amplifier

Polarization mode dispersion (PMD) has been one of the main obstacles for long-haul optical fiber communication systems with the speed beyond l0Gbit/s, and it has also been a hot topic in optical fiber communication fields at these years. Based on the theory foundation of polarization mode dispersion, descriptions of PMD in Stokes, Jones, Poynting space and the relationship of these three are discussed, then statistic character of PMD, compensation and experiments etc are discussed respectively, spun fiber's parameter and spectrum character on PMD, on Fiber Raman Amplifer's gain and polarization dependent gain are also studied.First, a summary of the relating concepts of PMD and its statistics nature was given in chapter 2, which are the fundamentals for farther discussion.A indepth analysis on expression of PMD in Stokes, Jones, Poynting space and the relationship of these three is made .Further more, as the consequence, a discussion is made on the information of eye diagram prediction, and evaluating the divergence of current on detector induced by PMD.Secondary, we presented the depict and calculation on correlation function which describing PMD, and development a method to calculate frequency correlation function. By derivation of expression on spectrum of un-spun fiber, a conclusion is made on unidirectional spun-fiber on its affection on single frequency signal transmitting. Changing characters of spectrum that caused by relationship of periodic pitch and beat length of fiber is also made.Based on discussing on the mechanism of feedback and internal structure of optical compensate technique of PMD, principle of PMD compensation is outlined. Noting that PSP methods perform better because they don't add PMD to the system, a principal state polarization (PSP) compensation method is investigated both theoretically and experimentally, and the experimental results in the same outcome as the theory predicts.Analytical and numerical results on the design of low-PMD fibers by means of spinning techniques are presented, and its affecting on PMD mitigation to fiber with constant birefringence and random birefringence is discussed respectively.Finally, this thesis is intended to provide a comprehensive study on polarization mode dispersion (PMD) induces large fluctuations in the amplified signal in fiber Raman amplifier which uses spun fiber. We also discuss the statistic nature of the Raman gain ,polarization dependent gain (PDG) in spun fiber Raman amplifiers and its tendency with the variations of PMD coefficient and spin parameters like periodic pitch and amplitude of spun fiber. ASE is also discussed, especially on generating.