优化算法在偏振模色散自适应补偿技术中的应用

Optimization Algorithm in Adaptive PMD compensation

介绍了10Gb/s的光纤通信系统中,优化算法在偏振模色散(PMD)自适应补偿技术中的应用。偏振模色散在线监测技术建立在偏振度(DOP)的基础上,偏振度随着微分群时延(DGD)的增加而减小。为了使用DOP做为PMD的监测反馈信号,需要在传输线路中模拟DGD的状态,为此设计了一个PMD仿真器。在光纤输入复用器端使用一个偏振控制器(PC)来调整光信号的偏振态,在光纤输出复用器端使用一个起偏器。随后信号到达控制计算机,优化程序运行,寻找全局最优点并通过PC来控制PMD。对现代非线性优化算法进行了讨论,比较了它们在PMD自适应补偿技术中的优缺点。在实验过程中选择遗传算法,取得良好效果。在很短时间内一阶二阶PMD能达到最大补偿效果,其动态补偿时间不超过10ms。

In this paper, the optimization algorithms are introduced in adaptive PMD compensation in 10Gb/s optical communication system. The PMD monitoring technique based on degree of polarization (DOP) is adopted. DOP can be a good indicator of PMD with monotonically deceasing of DOP as differential group delay (DGD) increasing. In order to use DOP as PMD monitoring feedback signal,it is required to emulate the state of DGD in the transition circuitry. A PMD emulator is designed. A polarization controller (PC) is used in fiber multiplexer to adjust the polarization state of optical signal, and at the output of fiber multiplexer a polarizer is used. After the feedback signal reach the control computer, the optimization program run to search the global optimization spot and through the PC to control the PMD. Several popular modern nonlinear optimization algorithms are discussed and the comparisons among them are made to choose the best optimization algorithm. We chose the GA algorithm into the experiment and get the well result. The PMD can be compensated in very few steps by using this algorithm. And the dynamic compensation time is no more then 10ms. The application foreground is very wide.