纳米级分辨率双频激光回馈位移测量系统

Dual-frequency laser optical feedback displacement measurement system with nanometer resolution

提出了一种基于双频激光回馈原理的高精度位移测量方法。在分析双频激光回馈测量原理的基础上,研究了双频激光回馈的基本现象并给出了理论依据,进一步的在回馈光学系统基础上,对两路正交的光回馈条纹利用电路进行细分处理:即四倍频细分产生大数计数及在一个大数脉冲内再进行小数细分,最后再将二者相结合。主要采用可编程逻辑器件FPGA和单片机设计信号处理电路,四倍频细分主要利用FPGA实现,小数部分主要通过单片机软件查表程序实现。全部电路并通过逻辑、时序仿真,验证了本方法的可行性。目前此系统满足高精度位移测量的要求。

A nanometer-resolution displacement measurement system based on weak feedback effect of birefrin- gent dual-frequency laser has been presented and demonstrated. The experimental setup of an optical feedback dual-frequency laser is developed by using the phase delay between the optical feedback fringes of two orthogonally polarized lights to realize displacement division and direction discrimination. A concise theory is given to explain this experimental result. The sub-circuit is mainly composed of the FPGA and the MCU. The FPGA is used to realize the division of big number and the MCU is used to realize the division of fraction by program to look up the table. The total displacement is the sum of the value of big number and the value of fraction division. A novel displacement apparatus with a high resolution, as well as the function of direction discrimination, can meet the demand of high-precision measurement.