Fiber Nonlinearities In High Speed&Ultra-Long-Haul Dence Wavelength Division Multiplexing Optical Fiber Transmission Systems And Their Effects&Application Of The Systems

Since the fiber-optic communications technology came out, it grows toward two goals: extending the optical transmission distance and enhancing the transmission velocity (capacity). The application and use of Erbium-Doped Fiber Amplifier (EDFA) increased the optical transmission distance; the Dense Wavelenth Division Multiplexing (DWDM) technology enhanced the fiber transmission capacity and reduced the cost. The Fiber-optic communications technology is developed towards the high speed and ultra-long-haul, and it is improving towards the optical network evolution of next gnenration. But with the increase of the wavelength divison multiplexing channel and velocity of single channel, fiber nonlinearities effects will be the major factor that restricts the system's performance. High speed and ultra-long-haul communications system must overcome the nonlinearities'influence. So how to enhance the fiber-optic communications system capacity, increase the optical transmission distance and overcome the nonlinearities'influence become research hotspot in the fiber-optic communications area.Combining theory with practice and according to experience in work and theory analysis in reference materials, this paper summarize the relevant nonlinearities effects in the high speed and ultra-long-haul DWDM communications system.The first chapter reviews the high speed and ultra long haul DWDM communications system's developing process, and analyzes a variety of challenges such as singal loss, dispersion and nonlinearities effects in the process. Then introduces the fiber's nonlinearities characteristics and relevant definitions in detail。The second to sixth chapters are the most important part of this paper. Firstly, these chapters describe a variety of nonlinearities effects in theory such as self-phase modulation, cross phase modulation, four waves mixing, stimulated Raman scattering and simulated Brillouin scattering. Then these theories have been put into practice by doing experiments and test at lab environment and engineering field. According to all the experimental data and test results combining with relevant theory analysis, I came up with some suggestions of how to overcome the various nonlinearities effects on DWDM communincations system, these suggestions will be a very useful reference in design high speed and ultra long haul DWDM communications system and its applications.The final chapter is the conclusion of this paper, it briefly summarizes the paper and gives a prospective vision of the application of nonlinearities effects in DWDM system.I am currently working in the DWDM communications system backbone team and responsible for system scheme suggestion of system configuration, system simulation test in lab and problem resolving in engineering field. I hope this paper will be helpful for DWDM system configuration and engineering problem resolving.