基于相位解卷的位移测量系统

Displacement measurement system based on phase unwrapping

为了实现适度光反馈机制下对微位移进行测量的目的,采用了相位解卷的位移测量方法。该方法是在对系统参量 C 和α进行提前分离测量的基础上,通过寻找自混合干涉信号的特殊点,即峰值点、谷值点及转折点,恢复了含光反馈时的外腔相位,对外腔相位进行进一步的处理得到了外部运动物体的位移信息。仿真分析及实验结果验证了该测量方法的可行性。结果表明,对于十几微米的振动,该系统的测量误差仅为±30nm。这一结果对高精度微位移及微振动的测量是有帮助的。

In order to measure the displacement under the condition of moderate optical feedback self-mixing interference, a displacement measurement method based on phase unwrapping was introduced. Firstly, the system parameters C and a were measured respectively. Secondly, the external cavity phase with optical feedback was recovered after finding the special points of self-mixing interference signal, namely the peak, valley and transition points. Finally, the displacement information of the external moving object was obtained after processing the external cavity phase. Simulation and experimental results proved its feasibility. Experiment results show that the error of the system is ＋ 30nm within the oscillating displacement up to 10μm. This method is helpful for high precision measurement of micro displacement and vibration.