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实验研究了一种基于机械微应变引入长周期光纤光栅(LPFG)的灵敏度可调谐的光纤布拉格光栅(FBG)应变传感系统。利用机械线加工技术设计了周期性压力槽,通过螺旋微位移结构定量推进弹簧进而对光纤施加径向压力,写制出谐振峰值可调谐的LPFG。紫外激光写入技术制作的FBG的波长位于LPFG的谐振边带范围内时,利用该LPFG作为透射滤波器实现了一种新的灵敏度可调谐FBG应变传感系统。实验分析了施加在LPFG上的压力由20 N调节至60 N时对FBG施加0~3 000με的灵敏度可调谐传感实验结果,FBG传感系统光功率变化率由0.802 nW/με增加到1.204 nW/με。
A sensitive fiber Bragg grating (FBG) strain sensing system based on mechanical micro-strain introduced into long-period fiber grating (LPFG) was experimentally studied. The periodic pressure tank was designed by using the mechanical wire processing technology, and the spring was quantitatively pushed by the spiral micro-displacement structure to exert radial pressure on the optical fiber to write LPFG with resonance peak tunable. When the wavelength of FBG made by UV laser writing is within the resonance sideband of LPFG, a new sensitivity tunable FBG strain sensing system is realized by using the LPFG as a transmissive filter. The experiment results show that the sensitivity of tunable FBG is 0 ~ 3000με when the pressure applied on LPFG is adjusted from 20 N to 60 N. The rate of change of optical power of FBG sensing system increases from 0.802 nW / με to 1.204 nW / με.