光纤布拉格光栅(FBG)是一种新型的传感元件,具有分辨率高、精度高、抗电磁干扰能力强、频带宽等优点.本文以光纤布拉格光栅为敏感元件,设计并制作了一种地震检波器,建立了地震检波器的力学模型,并推导出地震检波器固有频率和灵敏度的理论公式.理论分析了影响地震检波器动态特性的因素,并进行实验对该FBG地震检波器的性能进行研究,实验结果表明:该FBG地震检波器在5~55Hz的振动频率范围内,具有良好的线性响应,而且输出稳定、灵敏度高,适用于地震勘探.
Fiber Bragg grating (FBG) is a new type sensor, it has high resolution, wide bandwidth, high accuracy and fine immunity to electromagnetic interference. A novel geophone based on FBG is designed and produced in this paper. The mechanic model of the FBG geophone is established, the important parameters such as natural frequency and acceleration sensitivity of the FBG geophone are deduced. Through theoretical analysis, some factors which affect dynamic characteristics of the FBG geophone are found, and performance of the FBG geophone is studied by experiment. The experimental results show that the FBG geophone has the advantages of good linear response, stable output and high sensitivity at 5Hz to 55 Hz,and can be used for seismic prospecting.