光纤压力传感器测量的最小偏差腔长解调算法

Minimum-deviation Demodulation Algorithm for Measurement of Fiber Optic Pressure Sensors

在光纤传感技术领域应用基于法珀腔(外腔式法布里-珀罗干涉腔)结构的光纤压力传感器进行气体压力测量时,由于传感器结构决定了腔长动态范围相对较小,需要高分辨率的腔长测量方法。因此针对基于法珀腔结构的光纤压力传感器进行绝对腔长解调算法研究,提出一种高精度最小偏差腔长解调算法,通过将法珀腔光纤压力传感器密封在压力标准源中,对等间隔压力变化产生的不同腔长进行实时解调,实现了气体压力的实时测量。实验结果表明,法珀腔光纤压力传感器腔长值随压差变化呈现出良好的线性关系和重复性,腔长测量的重复性为±1 nm,精度为0.1496%,压力测量的重复性为0.12%,压力测量的精度优于0.5%。

When the gas pressure measurement is performed with fiber optic pressure sensors based on EFPI structures,a high-resolution cavity length measurement method is required,because the sensor structure determines that the dynamic range of the cavity length is relatively small.A high precision minimum-deviation cavity-length demodulation algorithm is proposed and experimentally demonstrated.The absolute cavity length of an optical fiber pressure sensor based on EFPI structure is recovered by using the demodulation algorithm.Through sealing an EFPI fiber optic pressure sensor in a pressure standard source,the real-time measurement of gas pressure is realized.The experimental results show that the cavity length of the EFPI fiber pressure sensor has a good linear relationship and repeatability with the change of pressure.The repeatability of cavity length measurement is±1 nm,the nonlinear error is 0.1496%,the repeatability of pressure measurement is 0.12%,and the accuracy of pressure measurement is better than 0.5%.