啁啾相移光纤光栅分布式应变与应变点精确定位传感研究

利用啁啾相移光纤光栅狭缝的中心波长对应变点和应变量的波长敏感性,实现应变与应变点精确定位的传感.当啁啾光纤光栅上的某一位置产生微应变时,该应变点会产生相移,其频谱则会出现一个与之对应的狭缝,且狭缝的深度和中心波长与应变的大小和位置相关.当串接不同中心波长的啁啾光纤光栅后,即可实现一定范围内的分布式应变与应变点精确定位检测.本文通过V-I传输矩阵法建立了狭缝深度和中心波长关于应变量和应变位置的理论模型,分析结果表明理论上可以实现微米量级的精确定位.搭建了级联啁啾相移光纤光栅的分布式应变传感装置,实验获得的最大应变灵敏度为0.19 pm/με.该精确定位传感装置在先进制造、精密加工、航空航天、铁路系统等高新技术领域具有重要的应用前景.

Phase shift chirped fiber Bragg grating based distributed strain and position sensing

A corresponding peak appears on the transmission spectrum, when the micro-strain is induced in a chirped fiber Bragg grating (CFBG). The center wavelength of the peak is sensitive to the location and magnitude of the strain, thus, the CFBG can be used in distributed strain and strain-points precise position sensing. The depth and center wavelength of the peak are determined by the magnitude and location of the strain. The cascaded CFBGs under different center wavelengths can realize the distributed strain and strain-point precise positioning. Considering the fact that the depth and center wavelength of the peak are related to the magnitude and location of strain, a theoretical model is established with V-I transmission matrix formalism. Theoretically, cascaded CFGBs can realize accurately the positioning of micron-scale. Experimentally, two CFBGs are cascaded and a sensitivity of 0.19 pm/με is obtained. The proposed precise position sensing can be applied to the fields of advanced manufacturing, precision machining, aerospace, railway-system, etc.