| High-speed and long-distance communication is the future direction of optical communications development. For its own advantage, optical time division multiplexing (OTDM) technology is an effective way to increase the capacity of optical communication system and in recent years. Fiber loss is no longer the main factors of optical communication transmission for the application of optical amplifiers. With the transmission rate and distance of optical fiber transmission system increasing, fiber dispersion, chromatic dispersion slope, nonlinear effect of optical fiber transmission, etc. have gradually become the major factors of optical communication system performance. Dispersion management technique is an effective way to improve the quality of OTDM communication system, by which high-speed and long-distance communication can be achieved effectively. It needs compensating dispersion and dispersion slope and optimizing power of transmission link, which can avoid dispersion effects and suppress nonlinear effects at the same time.with the national 863 project:"160Gbit/s a multi-pump fiber optical transmission technology research" (No.2007AA01Z258), High-speed optical time division multiplexing system is studied in the paper, which including light source, code pattern, multiplexing techniques, modulation, demultiplexing techniques and clock extraction techniques. Especially, dispersion management technology of 160Gbit/s OTDM system is studied theoretically and experimentally.Main work of paper is as follows:Fiber group velocity dispersion, higher order dispersion and nonlinear effects which have an effect on the signal transmission performance is analysed theoretically. So is code pattern and power which have an effect on the dispersion and nonlinearity of the system.When different frequency components of signals transmit at different rates in optical fiber, dispersion and dispersion slope which result in pulse broadening and distortion are analyzed theoretically.Various dispersion compensation schemes are comparised, and of which the advantages and disadvantages are analyzed. The symmetrical compensation scheme has the best performance, which is theoretically studied and experimentally verified.Based on 160Gbit/s OTDM system experimental platform, dispersion and dispersion slope which cause pulse to broaden is studied. The relation between pulse stretching and pulse width is nonlinear. When the pulse width is less than 2ps, pulse stretches sharply. Dispersion increases with fiber length linearly. For 1.5ps short pulse, 100meter single mode fiber can result in about 3ps pulse stretching, which has a great impact on system performance of 160Gbit/s (period is 6.25ps) high-speed transmission system. When pulse width is 6ps in 10Gbit/s (period is 100ps) lowe-speed transmission system, lkm single mode optical fiber produces less than 2ps pulse stretching, which has hardly effect on system performance.Based on 160Gbit/s OTDM system,100km fiber transmission with high-precision dispersion compensation is studied. High-precision dispersion compensation experiment is done in the transmission link, using dispersion and dispersion slope compensation fiber (D&DSCF) accuratly compensates both dispersion and dispersion slope of 90km single mode fiber. The length of fiber adjustment is on the order of 10m, which is equal to 0.3ps dispersion adjustment in the experiment.160Gbit/s optical time division multiplexing signal 100km transmission experiment is done. Using the above dispersion management, optimizing dispersion map of optical transmission link and operating point of amplifiers,100km long time and error-free transmission is completed. |
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