Polarization Mode Dispersion, High-speed Fiber-optic Wavelength-division Multiplexing System

Polarization mode dispersion (PMD) is regarded as a severe, ultimate limitation in optical communication systems. The inner comprehension to it and how to reduce its impacts is a vital subject in the development of high speed and long haul optical communication systems, which has become one hot reach topics of optical fiber communication systems.In China the research on PMD mainly concentrates upon the measurements and the effects on the communication systems, whereas the model to analyze PMD limits in single channel systems and the study of PMD in wavelength-divided-multiplexing (WDM) systems seldom appears in papers. Based on this the thesis emphasizes on PMD in WDM systems. The model to analyze PMD in WDM systems is established, which is the premise of the numerical simulation.In this thesis the coupled nonlinear Schrodinger equation is solved by means of split-step Fourier transform. The coupled nonlinear Schrodinger equation in four-channel WDM system is numerically solved and the effects of PMD on WDM system are analyzed, then the effects of channel separation and input power on WDM systems are analyzed synthetically. Conclusion is that PMD limits the channel separation, the shorter the channel separation, the more the effects, simultaneously input power may affect on the system. In addition, in this dissertation sliding-frequency filter is used in WDM system for the first time, and the numerical simulation shows that this method can restrain PMD effectively.One method is put forward to restrain PMD, i.e. the characters of optical pulse transmission. During optical pulse transmission several factors result in chirp, and the theory of this scheme is explained in physics, the feasibility of this method is also proved. Finally the effect of XPM on first-order PMD compensation in WDM systems is analyzed.