基于拍频解调边孔光纤光栅传感系统研究  

Research on side hole fiber Bragg grating sensing system based on beat frequency demodulation

作　　者：曾子可 陈天威 梁磊[2] ZENG Zi-ke;CHEN Tian-wei;LIANG Lei(Department of Physics,College of Science,Wuhan University of Technology,Wuhan 430070,China;National Engineering Laboratory of Fiber Optic Sensing Technology,Wuhan University of Technology,Wuhan 430070,China)

机构地区：[1]武汉理工大学理学院物理系,湖北武汉430070 [2]武汉理工大学光纤传感技术国家工程实验室,湖北武汉430070

出　　处：《激光与红外》2024年第9期1491-1496,共6页Laser & Infrared

基　　金：三亚崖州湾科技城管理局科研项目(No.SKJC-2020-01-016);分布式光纤流量监测与解释技术研究项目(No.P21052)资助。

摘　　要：针对边孔光纤光栅传感器在井下高温高压环镜波长扫描分辨率低的问题,对传统拍频解调的传感光路进行改进,设计了一种适用于井下环镜的基于激光拍频的边孔光纤光栅压力传感系统,可以在井下进行长距离传感,有效的提高了其分辨率。并且结合自注入锁定技术,与传统拍频解调光路把激光器作为传感器不同,将传感器和光纤激光器分离,便于应用于井下环境。系统使用线性啁啾光纤布拉格光栅作为色散补偿单元和激光器一侧的反射镜,将光纤光栅由于压力引起的波长变化转变为谐振腔的腔长变化,提升了系统的检测灵敏度。解释了所用方法的结构和测量原理,分析和计算了测量的结果和精度。实验结果表明,该系统具有较高的灵敏度和测量精度,压力灵敏度为0.12553 MHz/MPa。所提方法具有解调系统简单,稳定性好,传感距离可调等优点。In response to the problem of low wavelength scanning resolution of side hole fiber Bragg grating sensors in high-temperature and high-pressure annular mirrors underground,the traditional sensing optical path for frequency demodulation is improved,and a laser frequency based side hole fiber Bragg grating pressure sensing system suitable for underground annular mirrors is designed,which can perform long-distance sensing underground and effectively improve its resolution.In addition,combined with self-injection locking technology,it separates the sensor from the fiber laser unlike the traditional beat frequency demodulation optical path that uses lasers as sensors,making it easy to be applied in underground environments.The system uses a linearly chirped fiber Bragg grating as a dispersion compensation unit and a reflector on one side of the laser,transforming the wavelength change caused by pressure on the fiber Bragg grating into the cavity length change of the resonant cavity,thereby improving the detection sensitivity of the system.Moreover,the structure and measurement principle of the method used are explained,and the measurement results and accuracy are analyzed and calculated.The experimental results show that the system has high sensitivity and measurement accuracy with a pressure sensitivity of 0.12553 MHz/MPa.The proposed method has the advantages of a simple demodulation system,good stability,and adjustable sensing distance.

关 键 词：光纤传感 光纤布拉格光栅 光纤激光器 拍频检测 

分 类 号：TN256[电子电信—物理电子学] TH74[机械工程—光学工程]