The Study Of Frequency Domain Nonlinear Effect Estimation Model In High-Speed Optical Transmission Systems

As the development of cloud computing, big data and other new technology, people’s demand for data traffic showing spurt growth and this without doubt putting forward higher requirement to the basic transmission network. And because of its large scale, high speed and ultra-long haul transmission, optical transmission systems become the mainstream of the development of next generation broadband information network. In high speed long-haul optical transmission systems, in order to overcome the fiber loss during transmission, and also obtain a sufficient OSNR at the receiving end, a large launch power at the transmit end is needed. However, large launch power may result in serious fiber nonlinear effects, which may hugely impact the optical transmission systems. So it is necessary to study the non-linear effects in ultra-high speed long-haul optical transmission systems, thereby compensating or suppressing the nonlinear noise. The existing nonlinear effects compensation method is no longer applicable to the current narrow channel spacing ultra-high-speed optical transmission systems. For this ultra-dense optical transmission system, it is need to research on its nonlinear effects mechanism.In this paper, we mainly research on the mechanism of nonlinear effects in long-haul optical transmission systems, on the basic of the relevant technical background and theoretical supporting. We carry out a broad range of simulations by analyzing in both linear and nonlinear regimes in order to gain a thorough insight in ultra-dense wavelength division multiplexing system. The research content and related achievements are as follows:1. Firstly we study the relevant principles of ultra-high-speed long-haul optical transmission systems, especially the mechanism of nonlinear effects. Then further describe the composition and implementation methods of ultra-high-speed long-haul optical transmission systems, and finally building a different modulation formats and encoding of T bits stage optical transmission system.2. Ultra-dense wavelength division multiplexing technology as the key technology of T bit/s transmission systems, covering the ultra-dense OFDM technology and ultra-dense wavelength division multiplexing Nyquist technology. We also conduct in-depth analysis and study of its principles and methods of production.3. Based on1.2Tbit/s WDM CO-OFDM system, we research on its nonlinear noise distribution characteristics. During the process, we build wave wavelength division multiplexing OFDM systems with three modulation formats. Then we research on the mechanism of nonlinear noise and analyze its causes, to give reliable and innovative achievements.4. Then we further research on the nonlinear noise mechanism and distribution characteristics in Nyquist-WDM systems. In order to study the nonlinear noise Gaussian distribution model proposed by researchers, we build a9channel Nyquist-WDM QPSK system. Then we verify the validity and scope of this non-linear noise model and further draw reliable nonlinear noise model by combining the theoretical model and our simulation results.