Study Of Fiber Nonlinearities, Higher-Order Dispersions And Polarization Mode Dispersions In High-Speed Long-Haul Optical Fiber Communication Systems

In the future, the key point of the development of the optical fiber communication systems is to achieve the goal of transmitting optical signals in ultrahigh-speed over long-haul distance without repeaters.The primary limiting factors which make it difficult to transmit signals in high-speed and long-haul optical fiber communication systems are fiber losses, fiber nonlinearities and chromatic dispersions. Using low-lose fibers and Erbium-doped fiber amplifiers (EDFA) had contributed to reduce the limitation caused by fiber losses. Non-zero dispersion shifted fibers (NZDSF), dispersion management and Wavelength-division multiplexed (WDM) technologies had weakened influences that group-velocity dispersion (GVD) and fiber nonlinearities make on performances of optical fiber communication systems. In short, there are many new technologies that had made it come true to enhance propagation speed and to increase transmission distance.However, when optical pulses travel at higher speeds over longer distances, fiber nonlinearities caused by the high pulse power, higher-order dispersions and polarization mode dispersions (PMD), which were ignored usually, begin to make great effects on the performances of optical fiber communication systems. In this case, the communication capacities of these systems are limited extremely.In this thesis, an analysis of the affection of fiber nonlinearities, higher-order dispersion and polarization mode dispersion on the performances of optical fiber communication systems was achieved. Based on the Nonlinear Schrodinger equation and Split-step Fourier method, the propagation of the optical pulse in the nonlinear dispersive optical fiber systems was simulated. According to the simulation results, the tolerances to variations of the peak pulse power and the dispersion slope in high-speed long-haul single-channel optical fiber communication links using NRZ and RZ codes were introduced. It is demonstrated that the system performance was improved observably when the peak pulse power and the dispersion slope were controlled in an acceptable range and the dispersion slope was compensated reasonably.