双膜片结构光纤光栅地震检波器低频特性的研究

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

提出了一种双膜片式的光纤光栅(FBG)地震检波器,此结构有效限制了检波器横向响应。对该检波器的纵向加速度灵敏度和幅频特性进行了理论分析,并指出了影响这种检波器纵向加速度灵敏度的因素。实验结果表明,该种检波器在5～200Hz频率范围内频响平坦,纵向加速度灵敏度为24.3pm/g,谐振峰在900Hz附近,与理论计算较好的吻合。

A novel fiber Bragg grating（FBG） geophone based on double-diaphragm is presented in this paper. The double-diaphragm structure effectively limits transverse vibration of the FBG geophone. The important parameters such as longitudinal acceleration sensitivity and amplitude-frequency response function of the FBG geophone are analyzed theoretically. In addition,we pointed out the factors that affect the longitudinal acceleration sensitivity of the FBG geophone. The experimental results show that the frequency response is flat,and the longitudinal acceleration sensitivity of the FBG geophone keeps 24.3 pm/g at 5 Hz to 200 Hz,and the natural frequency is 900 Hz,which agree well with the theoretical analysis.