Jiang Shuo, Liu Bo, Wang Shengjie
Key Laboratory of Science and Technology on Space Optoelectronic Precision Measurement, CAS, Chengdu 610200, China.
Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610200, China.
Sensors (Basel). 2021 Jan 2;21(1):249. doi: 10.3390/s21010249.
In order to eliminate the nonlinearity in the laser modulation process, the dual-interferometers system is often adopted in the frequency modulation continuous wave (FMCW) laser ranging. However, the dispersion mismatch between the fiber reference interferometer and the measurement interferometer will lead to the decrease in ranging accuracy and resolution. In this paper, a dispersion compensation method based on resampling with a modulated signal is proposed. Since the beat signal of the end face of the delay fiber is not affected by dispersion mismatch, it can be modulated to generate a signal whose phase is proportional to that of the target spatial signal. Then, the modulated signal is regarded as the reference clock to sample the target spatial signal. Thereby, the influence of the dispersion mismatch between the two optical interferometers can be eliminated. In this article, simulation is performed to verify the effect of this method, and an experiment is carried out on the target at the distance of 2.4 m. Experiments show that the full width at half maximum (FWHM) of the distance spectrum after dispersion compensation is consistent with the reflected signal from the end face of the delay fiber, and the standard deviation of multiple measurements reached 10.12 μm.
为了消除激光调制过程中的非线性，调频连续波（FMCW）激光测距中常采用双干涉仪系统。然而，光纤参考干涉仪与测量干涉仪之间的色散失配会导致测距精度和分辨率下降。本文提出了一种基于对调制信号进行重采样的色散补偿方法。由于延迟光纤端面的拍频信号不受色散失配影响，可对其进行调制以生成相位与目标空间信号相位成比例的信号。然后，将调制信号作为参考时钟对目标空间信号进行采样。从而消除两个光学干涉仪之间色散失配的影响。本文进行了仿真以验证该方法的效果，并在距离为2.4 m的目标上进行了实验。实验表明，色散补偿后距离谱的半高宽（FWHM）与延迟光纤端面的反射信号一致，多次测量的标准差达到10.12μm。
