基于Michelson 干涉仪的光纤分布式扰动传感器

提出并研究了基于Michelson 干涉仪的应用于检测时变扰动的光纤分布式传感器。所提出的光纤传感器由两个Michelson 干涉仪和一个光纤延迟环组成。扰动作用在传感光纤上,引起传输光波相位的调制作用,可以通过该传感器进行检测并得到扰动的位置信息。通过光电探测器对干涉信号进行接收。对接收到的信号进行隔直,并通过求取峰峰值的方法对隔直后的信号进行预处理。通过希尔伯特变换、相位去包裹和三角函数运算可以提取出预处理信号中包含的相位信息。最后,通过频谱分析和相应的数学运算可以实现扰动的定位。在20 km 的监测距离内通过实验验证了传感器的可行性。所提出的光纤传感器具有实时性好、抗偏振性、低成本的独特优势。

Fiber- optic sensor based on Michelson interferometers for distributed disturbance detection

A fiber-optic distributed sensor based on Michelson interferometers for detecting the time-varying disturbance was presented in the paper. The proposed sensor is constituted of two Michelson interferometers with an optical fiber delay loop. The disturbance causes a phase modulation which is detected by the proposed sensor and converted to the location information. The interference signals received by the photo detectors through capacitive coupling separated directly to eliminate the DC component are preprocessed by the peak-to-peak value calculation method. The phase information of the preprocessed signals is acquired by the Hilbert transform, phase unwrapping and the corresponding trigonometric equations calculation. The frequency spectrum analysis and the mathematical operations are then conducted to locate the disturbance. Experimental results obtained with a 20 km long sensing fiber are discussed in the paper. The proposed distributed disturbance sensor has the significant advantages of capability of real time sensing, insensitive to the polarization state and low cost.