基于光纤色散相位补偿的高分辨率激光频率扫描干涉测量研究  

High-resolution laser frequency scanning interferometer based on fiber dispersion phase compensation

作　　者：许新科[1] 刘国栋[1] 刘炳国[1] 陈凤东[1] 庄志涛[1] 甘雨[1] 

机构地区：[1]哈尔滨工业大学电气工程及其自动化学院,哈尔滨150001

出　　处：《物理学报》2015年第21期466-478,共13页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:51275120;61275096)资助的课题~~

摘　　要：为了实现更高分辨率的激光频率扫描干涉测量,增大光源的扫频范围以及减小扫描频率的非线性成为关键.采用外腔式大带宽扫频光源结合光纤辅助干涉仪构建的外部时钟频率采样非线性校正是目前较为常用的方法.本研究发现随着扫频带宽和测量范围的增加,光纤辅助干涉仪与测量光路中存在的色散失配导致频谱出现严重展宽,极大的降低了测量的分辨率.本文建立了辅助干涉仪和测量干涉仪色散失配影响的理论模型,利用该模型分析了扫频带宽和测量范围与测量分辨率的变化关系,与实验结果相一致,并进而提出了基于峰值演化消畸变的色散相位补偿方法,有效地提高了测量的分辨率,在2.53 m处实现了接近理论值的64.5μm的测量分辨率.该色散失配模型及补偿方法为提高大尺寸激光频率扫描干涉仪的测量分辨率及测距范围提供了参考.The laser frequency scanning interferometer has several advantages, such as non-contact, high accuracy and low signal to noise ratio in detection. In order to achieve higher resolution of the laser frequency scanning interferometer,increasing the tuning range of the light source and reducing the tuning non-linearity have become the key factors. The commonly used method is to correct the non-linearity of the wide bandwidth external cavity tuning laser by a fiber optical auxiliary interferometer constructed external frequency sampling clock. When using the broadband external cavity tuning laser and the auxiliary interferometer with an optical path difference of 220 m, it is found experimentally that the single-mode fiber dispersion makes the frequency of sampled signals change over time, causing the spectrum to broaden and resolution to decline. This paper has established the dispersion mismatch model which shows that the fiber dispersion of the auxiliary interferometer causes linear chirp frequency changes during the measurement of signals. The linear chirp frequency is proportional to the tuning bandwidth and measured distance. The phenomenon and theoretical model of dispersion mismatch is verified by experiments. The results for targets in the air are shown to linearly decrease as the tuning range increases with the maximum offset of 156.3 μm for the 20 nm tuning bandwidth.The experiment also proves the peak broadening intensifies with increasing distance measured, and thus verifies as the time delay of free space increase, and the peak broadening and distortion also increases. This result means that it will limit the ranging distance and make large errors in measurement result for long distance targets. The dispersion of the auxiliary interferometer should be compensated in the laser frequency scanning interferometer for large-sized high resolution measurements. In this paper, phase dispersion compensation method based on the evolution of peak variation distortion elimination is proposed, by taking the peak am

关 键 词：干涉仪 激光频率扫描干涉仪 激光测距 光纤色散 

分 类 号：TN249[电子电信—物理电子学]