一种基于相干光时域反射的分布式光纤振动传感系统研制

Development of a distributed optical fiber vibration sensing system based on coherent optical time domain reflectometry

针对基于相干光时域反射的分布式光纤振动传感系统中数据量庞大,且需要信号发生器外部驱动,集成度低的缺点,利用现场可编程逻辑门阵列实现传感数据的高速采集与声光调制器的同步驱动,采用USB 3.0实现采集模块与上位机的实时数据传输。搭建一种基于相干光时域反射的分布式光纤振动传感系统,利用本地光与后向瑞利散射光的拍频效应,实现对微弱后向瑞利散射光信号的探测,并提高系统的传感距离。采用正交相位解调方法获取振动信号的位置信息。实验结果表明:该系统可在22km传感光纤上对振动信号进行有效定位,定位误差在20m以内,且系统对正弦波和方波等不同形态的振动信号定位效果一致。

To solve the problem of large data, the need for external driving of the signal generator and low integration of the distributed optical fiber vibration sensing system based on coherent optical time domain reflection, the high-speed acquisition of the sensing data and the synchronous driving of the acousto-optic modulator are realized by the field programmable logic gate array, and USB 3.0 is used to complete the realtime transmission of data between the acquisition module and the host computer. A distributed optical fiber vibration sensing system based on coherent optical time domain reflection is built. The beat effect of local light and backward Rayleigh scattered light is used to detect the weak backward Rayleigh scattered light signal and improve the sensing distance of the system. The quadrature phase demodulation method is used to obtain the position information of the vibration signal. The experimental results show that the system can effectively locate different vibration signals such as sine wave and square wave and the vibration signals can be located effectively on the 22 km sensing fiber, and the positioning error is within 20 m.