基于光电振荡器的长度测量方法温度误差

基于光电振荡器的距离测量方法将包含待测长度的空间光路耦合入光学谐振腔，通过测量振荡频率得到被测距离，借助振荡频率对谐振腔长的高敏感特性，具有实现大尺度高精度距离测量的潜力。但是长光纤作为谐振腔中的高Q值器件，容易受环境温度影响，导致测量精度及稳定性严重恶化。文中理论分析了温度变化对距离测量的影响，建立并分析了温度误差与温度变化、光纤长度的关系。针对温度误差提出了系统参数优化方法，进行了不同长度光纤与温度误差的实验，实验结果与误差模型相符，为测量误差补偿奠定了基础。

Thermally-induced error of the length measurement method based on optoelectronic oscillators

The length measurement method based on Optoelectronic Oscillator (OEO) introduces a free optical space, containing the measured length, into the optical cavity of OEO. The measured length is derived from the oscillation frequency corresponding to the cavity length. By virtue of the high sensitivity between oscillation frequency and group delay of the loop, this method promises high accuracy absolute length measurement at long range. However, long optical fiber, which is the high Q component of the cavity, is too sensitive to ambient temperature, leading to serious deterioration in accuracy and stability. In this paper, the influence of temperature variation was theoretically analyzed. The relation among thermally -induced error, temperature variation and length of optical fiber was established and analyzed, and optimization method of parameter was proposed. Experiments on optical fiber with different length and thermally-induced error were carried out. Experimental results consist with the error model, providing important basis for error compensation.