中国激光, 2011, 38 (12): 1208003, 网络出版: 2011-11-15
相位调制型激光自混合干涉仪的动态特性分析及测试
Analysis and Test for the Dynamic Performance of Laser Self-Mixing Interferometer Based on Phase Modulation
摘要
为了提高激光自混合干涉仪在位移测量中的精度,将相位调制技术引入激光自混合干涉系统中,通过在激光器的外腔中放置的电光调制器对光束进行正弦相位调制,采用傅里叶变换在频域中重构自混合干涉信号的相位。采用截止阶数的方法对系统的动态测量范围上限进行了理论分析,获得了正确解调相位所需的电光晶体的最低调制频率与被测振动的频率和振幅的关系。将系统应用于高精度商用压电陶瓷的振动过程的测量,测量数据与Agilent 5529A动态校准仪的同步测量结果进行比对,结果表明,相位调制型激光自混合干涉仪适合于动态信号的实时测量,位移测量精度可达20 nm。
Abstract
In order to ameliorate the performance in vibration measurement, sinusoidal phase modulating technique is introduced into a conventional laser self-mixing interferometer. An electro-optic modulator is placed in the external cavity of the light source to yield sinusoidal phase modulation. The self-mixing interference signal is processed in frequency-domain to retrieve a vibration waveform. The dynamic range of the system is analyzed by proposing the stop-order theory and a relationship between the lowest modulating frequency of the electro-optic modulator, and the parameters of a vibration are obtained to guarantee the validity of a measurement result. Experimental vibration measurement results of a commercial piezoelectric transducer are compared with simultaneous measurement results from Agilent 5529A dynamic calibrator, and an accuracy of 20 nm is achieved. It is shown that the phase-modulated laser self-mixing interferometer is suitable for real-time continuous vibration measurement.
夏巍, 郝辉, 王峰, 王鸣, 郭冬梅, 郭文华. 相位调制型激光自混合干涉仪的动态特性分析及测试[J]. 中国激光, 2011, 38(12): 1208003. Xia Wei, Hao Hui, Wang Feng, Wang Ming, Guo Dongmei, Guo Wenhua. Analysis and Test for the Dynamic Performance of Laser Self-Mixing Interferometer Based on Phase Modulation[J]. Chinese Journal of Lasers, 2011, 38(12): 1208003.