基于CORDIC的交流相位跟踪零差补偿方法及其实现

The Alternating Current Phase Tracking Homodyne Compensation Method and Its Implementation Using CORDIC

为了消除温度、振动等环境因素在光纤干涉测量中的影响,发展了一种基于交流相位跟踪零差补偿(PTAC)的干涉条纹相位稳定技术。利用马赫-泽德光纤干涉仪结构和杨氏双孔干涉原理实现高密度的余弦分布干涉条纹投射。光纤端面菲涅尔反射与光纤耦合器构成迈克尔逊干涉结构,光电探测器检测迈克尔逊干涉仪的输出信号。相位稳定子系统采用相位生成载波(PGC)方法提取环境因素引起的光纤干涉臂相位差,结合坐标旋转数字式计算机(CORDIC)求解相位差,并生成补偿信号反馈给压电陶瓷(PZT)驱动器,实现条纹相位的稳定。该系统相位解调精度达2.75 mrad,环境因素对干涉条纹相位的影响低于53.43 mrad。实验结果验证了该相位稳定方法的可行性。

In order to eliminate the effection of the environmental factors,such as temperature and vibration,a phase stabilization method of interference fringe map based on the Alternating Current Phase Tracking homodyne compensation（ PTAC） is developed. The system makes use of the Mach-Zehnder interferometer structure and Young’s double pinhole interference principle to achieve the high-density interference fringe projection of cosine distribution. The Fresnel reflection on its fiber end face and optical fiber coupler make up a Michelson interferometer structure,the photodetector detects the interference signal. The Phase Generated Carrier （ PGC） method is utilized to achieve the phase difference between interference arms,and the Coordinated Rotation Digital Computer（ CORDIC） counts out it. The compensation signal acts as a feedback to the Piezoelectric Transducer（PZT）driver,and a well stability of the fringe phase is achieved. The demodulated phase can be measured with a precision of 2. 75 mrad,the environmental disturbance can be reduced to 53. 43 mrad for the fringe map. The experiment result has verified the availability of the phase stabilization method.