Study Of Endless Control Theory And Implementation Techniques For Polarization Controllers

With the rapid development of communication technology, communication systems are more and more sensitive to the series damages caused by polarization when the transmission speed improves, such as polarization mode dispersion (PMD), polarization dependent loss (PDL), atc. Accordingly, the application of polarization controller appears a wider new world, such as PMD measurement and compensation, polarization scrambling, PDL inspecting and compensation.Rapid polarization controllers mostly have reset problems: With the endless excursion of the input signal's state of polarization, the control quantity may reach the boundary of its range, and then it needs reset to keep on turning. It's a big difficulty in studying polarization controller's control methods, which is how to realize the reset of the controller without affecting previous control results. The contents of this thesis are important works base on the national"Tenth Five"tackle key project and Wuhan city's tackle key project. It systematically analyzed the principle and the reset scheme of typical four channel polarization controller which is based on squeezing fiber. And the systematical test results are given in detail. The main research contents and results are given as follows:(1) Principles and characteristics of different types of polarization controllers are analyzed, the compare of the difference of these polarization controllers are discussed based on them, drawn a conclusion that the polarization controller which based on squeezing fiber and has variable delay quantity are suitable for high speed optical communication system.(2) The reset principle of the typical four channel polarization controller which is based on squeezing fiber is analyzed, and the design of its concrete reset scheme is given based on them. The reset process and the corresponding operation list are given in detail.(3) The systematical experiment is made when the typical four channel polarization controller is put into the PMD compensator. The experiment result showed that the channel which needs reset can efficiently return to the mean place, and the effect of reset was good, it didn't cause any badness infection on PMD compensation.(4) A new type optical signal time-domain depolarizer is given, and a new PMD compensate method is given based on it. This method can not only realize multi-channel PMD compensation, but also can wipe off the polarization effect such as PDL etc. It exploits the new idea of multi-channel PMD compensation, and it does have some practicality.