Study on low-frequency characteristic of double-diaphragm fiber Bragg grating geophone

Abstract

A novel fiber Bragg grating(FBG) geophone based on double-diaphragm is presented in this paperThe double-diaphragm structure effectively limits transverse vibration of the FBG geophoneThe important parameters such as longitudinal acceleration sensitivity and amplitude-frequency response function of the FBG geophone are analyzed theoreticallyIn addition,we pointed out the factors that affect the longitudinal acceleration sensitivity of the FBG geophoneThe experimental results show that the frequency response is flat,and the longitudinal acceleration sensitivity of the FBG geophone keeps 243 pm/g at 5 Hz to 200 Hz,and the natural frequency is 900 Hz,which agree well with the theoretical analysis