Research Of PMD Measurement

With people's increasing demand on communication band width in recent years,fiber communication backbone network is developing towards high-speed, greatcapacity and long distance in a single channel. Especially after the utilization of Erdium-doped fiber amplifier (EDFA) and various techniques of dispersioncompensation, fiber loss and chromatic dispersion are no longer the main limitingfactor of transmission distance systems. However, it brings about another problem that constantly added up in the course of transmission,formerly negligible PMD(Polarization Mode Dispersion) has badly influenced the optical fiber communication systems. Research shown that when the transmission speed of systems is up to lOGbit/s or above, Polarization Mode Dispersion (PMD) can noticeable damage thetransmission performances of systems and became the final decisive factor limiting the transmission speed and distance of the high-speed optical fiber communication system. So it is an urgent problem to study how to deal with the impact of PMD on the transmission systems. However, it is very difficult to overcome the PMD effect because of its stochastic feature.The impact of PMD on high-speed data transmission and the key technologies of PMD compensation are the focus of optical fiber communication system in the world.The basic research task about PMD includes the fundamental theory ,the techniques of measurement and compensation.First, a summary of the relating concepts of PMD and its statistics nature was given in this paper, which are the fundamentals for farther discussion. system performance is discussed from the statistical characteristic of first-order PMD, the relation of average DGD and transmission distance, PMD restrict the system etc, which are based on pulse broadening theory. The focus topic of this thesis is the PMD measurement in high speed optical communication systems.