基于相干检测的偏振光时域反射光纤振动传感系统

摘要

The coherent detection method with higher detection sensitivity is introduced into the polarization optical time domain reflectometry(POTDR)with the polarization state sensitive to external disturbance.The developed sensing system can realize the fiber distributed sensing,acquiring the vibration signal and positioning the disturbance spot along fiber.First,the related theory of coherent detection and POTDR is given and the technical feasibility is examined.Then,according to the proposed scheme,the measurement system has been built.Experimental results show that the POTDR based on coherent detection method do sense the external vibration and the position of vibration along fiber,which is important to the further development of distributed fiber sensor.%提出将相干检测技术和偏振光时域反射技术POTDR(Polarization Optical Time Domain Reflectometry)相结合,利用相干检测技术的高探测灵敏度和偏振光时域反射技术中偏振态对外界环境敏感的特点,实现光纤分布式传感,测量微弱振动信号并实现定位功能.首先分别介绍了相干检测技术及其与POTDR相结合的相关原理,分析可行性,然后提出实验测试方案并搭建了测试系统.实验结果表明,基于相干检测技术的POTDR传感系统能成功地实现振动信号的探测和振动点的定位功能,这对于光纤分布式传感系统的进一步发展具有重要意义.