提出了一种基于飞秒光学频率梳相关探测的绝对距离测量方法,通过检测测量信号与参考信号的相关条纹,实现了绝对距离测量。研究了一阶相关函数的测量模型,建立了基于非平衡迈克耳孙干涉光路的测量系统,通过拟合一阶相关函数包络并提取其峰值精确判断脉冲重合位置,获得了被测距离。设计并配合长导轨进行了3 m的绝对距离测量实验,并与商用干涉仪测量结果进行实时比对。基于大量实验数据,针对环境因素及系统误差进行了分析,并进行了误差消除与补偿。研究结果表明,所提方法在500 min长期测量中,在3 m的测量范围内的最大测量误差为5.85 μm,测量标准差为2.20 μm。

An absolute distance measurement method is proposed based on coherent detection by a femtosecond optical frequency comb. The absolute distance measurement is realized by the detection of coherence patterns between measurement signals and reference signals. The measurement model of the first-order coherence function is studied. The measurement system based on an unbalanced Michelson interferometer is constructed. The target distance is obtained by the envelope fitting of the first-order coherence function and by the high-precision extraction of peaks on the overlapped pulse positions. The 3 m absolute distance measurement experiment on a long range guide is designed and a real-time comparison with those by the commercial interferometers is conducted. In addition, the ambient factors and system errors are analyzed based on a large number of experimental results. The errors are eliminated and compensated. The results show that in the 500 min long term measurement process, the maximum measurement error is 5.85 μm and the standard deviation is 2.20 μm as for the proposed method with a measurement range of 3 m.