提出了一种可用于振动检测的新型光纤光栅传感技术.用偏振控制器和高双折射保偏光纤构建成Sagnac环,结合掺铒光纤、单模光纤和隔离器,形成了单波长光纤激光器,由粘有光纤Bragg光栅的悬臂梁作为传感探头,并利用sagnac环本身的线性边缘,解调振动信号.阐述了sagnac环原理及其产生的边缘效应,并进行了数值模拟计算,对振动信号进行了检测实验,检测系统从L_1到L_l+L_2之间对应的周期可调,灵敏度高达38.2uW/nm,线性度为0.9996,动态范围在40-70 dB,可满足振动传感检测的技术参数要求.
A novel fiber grating sensing technique utilized for vibration detection is proposed and experimentally demonstrated.A single wavelength laser is formed by polarization controllers and polarization maintaining fiber(PMF) to construct the high birefringence (Hi-Bi) Sagnac loop,PMF combined with erbium-doped fiber,single mode fiber and polarizer.The cantilever glued to an FBG is used as a sensor probe,and the linear edge of Sagnac ring laser are used to demodulate fiber optic seismic vibration signal.Sagnac ring theory and its edge effects are described in detail,and numerical simulation and experiment show that the vibration signal detection system is adjusted periodically in a range from L_1 to L_1 + L_2,sensitivity goes up to 38.2μW/nm of discrimination,the linearity is 0.9996,and the dynamic range is 40—70 dB,these meeting the requirements for vibration detection technical parameters.