一种聚合物封装的光纤布拉格光栅超声波传感器  

A polymer⁃encapsulated fiber Bragg grating ultrasonic sensor

作　　者：涂兴华[1] 赵海洋[1] TU Xinghua;ZHAO Haiyang(Research Center of Optoelectronic Sensing Engineering,College of Electronic and Optical Engineering&College of Flexible Electronics(Future Technology),Nanjing University of Posts and Telecommunications,Nanjing 210023,China)

机构地区：[1]南京邮电大学电子与光学工程学院柔性电子(未来技术)学院光电传感工程研究中心,江苏南京210023

出　　处：《量子电子学报》2025年第2期286-294,共9页Chinese Journal of Quantum Electronics

基　　金：国家自然科学基金(62374092)。

摘　　要：针对裸光纤光栅对超声波响应灵敏度较低的问题,本文提出一种聚合物封装的光纤光栅传感器,通过在光纤光栅周围封装一层厚度远超光纤直径的聚合物涂覆层,提高了光纤光栅在受到超声波作用时的应变灵敏度。首先,建立光纤光栅传感模型,根据传输矩阵法仿真分析了聚合物杨氏模量和泊松比对光纤光栅应变的影响。随后,利用聚氨酯(PU)、聚丙烯酸酯(ABR)与聚氯乙烯(PVC)塑料三种不同参数的聚合物材料封装光纤光栅,通过线性边缘滤波法将光纤光栅的波长漂移转化为电压信号,测量封装后的传感器对超声波的传感特性。研究结果表明,聚合物杨氏模量的降低与泊松比的提高有助于改善光纤光栅对超声波的响应灵敏度。三种材料中,PU封装后的效果最好,峰值电压达到139.6 mV,约是裸光纤光栅的15倍,且封装后的传感器的峰值电压随着距声源距离的增大呈指数型衰减,符合超声波在水中的理论衰减趋势,可以用来还原空间中的声场状态。In response to the problem of low sensitivity of bare fiber Bragg gratings to ultrasound,the article proposes a series of polymer encapsulated fiber Bragg grating sensors.By encapsulating a polymer coating layer aroud the gratings that is much thicker than the diameter of the fiber,the strain sensitivity of the fiber Bragg gratings under ultrasound action is improved.Firstly,a fiber grating sensing model is established,and the influence of polymer Young's modulus and Poisson's ratio on fiber grating strain is analyzed based on the transfer matrix method.And then,fiber Bragg gratings are encapsulated using three polymer materials with different parameters,namely polyurethane(PU),polyacrylate(ABR),and polyvinyl chloride(PVC).The wavelength drift of the fiber Bragg grating is converted into a voltage signal using linear edge filtering method,and the sensing characteristics of the encapsulated sensors for ultrasound are measured.The results show that the decrease of Young's modulus and the increase of Poisson's ratio of polymers are helpful to improve the sensitivity of fiber gratings to ultrasonic response.And among the three materials,PU packaging has the best effect,with a peak voltage of 139.6 mV,which is about 15 times that of the bare fiber gratings.In addition,the peak voltage of the packaged sensor decays exponentially with the increasing distances from the sound source,which conforms to the attenuation trend of ultrasound in water and can restore the sound field state in space.

关 键 词：纤维与波导光学 光纤布拉格光栅 线性边缘滤波法 聚合物 超声波传感 

分 类 号：TN253[电子电信—物理电子学]