双频激光回馈位移测量研究

Study on displacement measurement with optical feedback of dual frequency laser

提出了一种基于双频激光回馈效应的位移测量系统,并在理论和实验两方面进行了研究.实验中对激光器输出功率变化进行了探测,同时对两正交偏振光的光强变化进行了探测.研究发现当被测物体移动时,激光器输出功率受到调制,物体每移动半个光波长时,回馈信号为调制深度相等的两峰,系统分辨率提高了一倍,达到四分之一光波长.当物体运动方向改变时,两正交偏振光的光强变化顺序也随之改变,可以实现物体位移方向的判断.理论分析及模拟结果与实验结果相符合.研究表明该位移传感系统具有结构简单、分辨率高、可判向、测量范围大、可工作于强回馈区等优点.

A novel displacement measurement with optical feedback of dual frequency laser has been put forward, which has been investigated both theoretically and experimentally. Intensities of the laser and the two orthogonally polarized modes are detected. It is found that the laser output power will be modulated when the object moves. When the displacement of the object is half wavelength, the signal of optical feedback has two peaks with the same depth of modulation. So the resolution of displacement sensor can be doubled. It is also found that when the object changes its moving direction, the order of intensity variation of the two modes will be changed. It can be used to judge the direction of the displacement. The simulation results are in good agreement with the experimental results. It is indicated that the sensor has advantages of simplicity, high resolution, direction identification cepability, large measurement range, operation in high optical feedback regime, and so on.