基于DDS技术的动态偏振控制器驱动电路研究

唐 琦,徐宏杰,郭耀仪

摘 要:偏振控制器广泛应用于光纤通信和传感领域,研制具有高性价比的偏振控制器配套驱动电路是必要的。运用邦加球图示法,分析光纤挤压型动态偏振控制器(DPC)的工作原理。以某种偏振度(DOP)测试系统的硬件为实验平台,介绍基于直接数字频率合成(DDS)技术和FPGA的动态偏振控制器驱动电路的工作原理、系统结构及软、硬件设计。实验测试结果表明,该设计实现了驱动电路的预期目标,产生了4路具有频率可调,相位噪声低等优点的正弦驱动信号。该驱动电路与传统实现方式相比,具有输出信号稳定,控制灵活,实用性和性价比高等优点。

关键词:偏振控制器;DDS技术;FPGA;驱动电路

中图分类号:TN710文献标识码:A

文章编号:1004-373X(2009)12-010-03

Research on Drive Circuit of Dynamic Polarization Controller Based on DDS Technique

TANG Qi,XU Hongjie,GUO Yaoyi

(School of Instrument Science and Optical-Electronics Engineering,Beijing University of Aeronautics and Astronautics,Beijing,100083,China)

Abstract:Polarization controller has been widely used in the fields of fiber transmission and transducer,and it is necessary to study on its assorted drive circuit with high price-to-performance ratio.The operating principle of fiber squeezer Dynamic Polarization Controller (DPC) is analyzed by using the Poincaré sphere.The basic principle is introduced,features and the performance of driving circuit of dynamic polarization controller based on Direct Digital frequency Synthesis (DDS)technology and FPGA by using the hardware of a measurement system Degree of Polarization (DOP) as the experimental platform.The results of testing show that the design of driving circuit can generate 4 Sine waves with some advantages such as convenience for changing frequency and reducing phase noise and the anticipative goal is achieved.Compared with general methods,the output waveform of the signal is stable,firm and flexibly controllable and the design has high practicability and excellent price-to-performance ratio.

Keywords:polarization controller;DDS technique;FPGA;drive circuit

0 引 言

偏振控制器是一种重要的光器件,在光纤通信和传感领域都有着广泛的应用。在光纤通信系统中,准确地控制光纤中的偏振态,关系着系统的稳定性和数据传输的误码率[1]。然而在消偏型光纤陀螺中,准确测量光的偏振度也是保证光纤陀螺精度的有效措施。因此,偏振控制器(PC)作为一种改变输入光偏振态的光器件是不可缺少的一种偏振控制器件,在PMD动态补偿、偏振度(DOP)测试等方面发挥着重要的作用。

但是在实际运用中,偏振控制器的半波电压与厂家给出的标称值并不完全一致,导致了使用的不便。因此在使用时需要有与之配套的驱动电路[2]。但是,许多厂家并不提供配套的驱动电路,即使提供,价格也昂贵,在实际工程开发中不能达到最佳性价比。……