基于飞秒光频梳的压电陶瓷闭环位移控制系统

利用飞秒光频梳、外腔可调谐半导体激光器和法布里-珀罗干涉仪建立了一套压电陶瓷亚纳米级闭环位移控制系统. 将可调谐半导体激光器锁定至光频梳, 通过精确调谐光频梳的重复频率, 实现了半导体激光器在其工作频率范围内的精密调谐. 利用Pound-Drever-Hall锁定技术将带有压电陶瓷的法布里-珀罗腔锁定至半导体激光器, 进而通过频率发生系统控制压电陶瓷产生亚纳米级分辨率的位移. 实验研究发现锁定至光频梳后可调谐半导体激光器1 s的Allan标准偏差为1.68×10^-12, 将其在30.9496 GHz范围内进行连续闭环调谐, 可获得压电陶瓷的位移行程约为4.8 μm; 以3.75 Hz的步长扫描光频梳的重复频率, 实现了压电陶瓷的450 pm闭环位移分辨率并测定了压电陶瓷的磁滞特性曲线. 该系统不存在非线性测量误差, 且激光频率及压电陶瓷位移均溯源至铷钟频率源. 关键词： 光频梳 压电陶瓷 法布里-珀罗腔 可调谐半导体激光器

Closed-loop displacement control system for piezoelectric transducer based on optical frequency comb

A sub-nanometric closed-loop displacement control system for piezoelectric transducers has been set up based on an optical frequency comb, an external cavity diode laser and a Fabry-Perot interferometer. The external cavity diode laser is locked to the optical frequency comb, so that the optical frequency can be set precisely in the working range by tuning the repetition frequency of the optical frequency comb. As a sensor of the piezoelectric transducer, the Fabry-Perot cavity is locked to the external cavity diode laser by means of the Pound-Drever-Hall locking technique. With the aid of precisely controlling the diode laser frequency, displacements of the piezoelectric transducer can be obtained with a sub-nanometric resolution. Experimental results show that the Allan deviation of the diode laser frequency is 1.68×10^-12 after locked to the optical frequency comb. The displacement range of 4.8 μm can be generated by the piezoelectric transducer through continuously and precisely tuning the diode laser frequency in the range of 30.9496 GHz. Meantime, the displacement resolution of 450 pm is achieved by scanning the repetition frequency of the optical frequency comb at a step of 3.75 Hz. Besides, the hysteresis characteristic of the piezoelectric transducer is measured using this system. Compared to those methods based on heterodyne interferometers to calibrate the displacement of piezoelectric transducers, the nonlinear errors are eliminated and the measurement results are traceable to an Rb clock.