Study On Transmission Characteristics Of Dispersion-managed Optical Soliton

With the development of the ultra-high speed and ultra-long haul optical fiber communication, nonlinear effects become a major obstacle hindering its development. Optical soliton overcomes the influence of nonlinear effects and the group velocity dispersion (GVD); it can maintain the shape and amplitude unchanged when transmitting in the ideal optical fiber. A range of issues affect its applications in optical fiber communication, such as, the low utilization of frequency band, strong Gordon-Haus timing jitter, interactions between solitons and the channels. In the mid 1990s, dispersion management concept is introduced to the optical soliton fiber communication system, the concept of dispersion-managed optical soliton (DMS) is proposed, it laid the dispersion-managed soliton foundation. Compared with traditional optical soliton, dispersion-managed soliton can obtain higher power under the same conditions and higher signal to noise, and reduce the Gordon-Haus timing jitter and four-wave mixing effect, so it became the hot spot in recent years. The paper has done several respect work on the theoretical analysis and numerical simulation as following:1. The research background of the soliton communication and the significance of this research are summarized.2. Nonlinear Schr?dinger Equation (NLSE) is deduced, several methods of obtaining soliton solution were introduced; the advantages of dispersion-managed soliton are analyzed compared with the traditional optical soliton, the principles of dispersion-managed soliton and some typical dispersion management are introduced.3. The split-step Fourier method is introduced; using the averaging method, after several times of average, exactly periodic dispersion managed solitons is found. Using split-step Fourier method,soliton evolution in dispersion management system is numerical simulated. By changing the distribution of dispersion map parameters, the impact of the types of dispersion distribution, the average dispersion of the positive (normal dispersion) or negative (anomalous dispersion), and the size of dispersion depth upon the optical pulse is discussed.4. The modulation instability (MI) on dispersion management system is analyzed. Then adopting the method of linear stability analysis, the MI gain spectrum in dispersion management system is gained, each order MI gain curve is drawn, and the conditions of the based-order MI leading role are analyzed. Then impact of the path average dispersion value and dispersion depth on the based-order MI is discussed.5. Using the variational method, the influence of the amplifier spontaneous emission (ASE) noise upon the optical pulse in dispersion management system is discussed, thus, the pulse phase variance, the central time variance and center frequency variation with distance is gained; The numerical simulation results show: the densely dispersion managed soliton system and the larger negative average dispersion can reduce the pulse impact of ASE noise.