Optical Fiber Grating Geophone Assisted With a Hollow Triangle Beam

Abstract

In order to improve the beam structure of the fiber Bragg grating (FBG) geophone’s sensitivity and horizontal anti-interference ability, a hollow triangle beam FBG geophone is proposed and demonstrated, analysing the acceleration geophone detection theory, deducing its natural frequency and transverse anti-interference ability, through COMSOL software to build the geophone model, then through MATLAB optimize the structural parameters of the geophone, Finally, the parameters which can not only satisfy the practical application of geophone but also improve the performance of geophone are obtained. The geophone object is made through integrated processing, and experiments are carried out. The experimental results show that the flat area of the geophone is 0.6 Hz~50.0 Hz, and the natural frequency is 61.0 Hz. The measured acceleration sensitivity is 120.1 pm/g, which has a good linear relationship with the vibration signal frequency. The hollow triangular beam geophone has a good transverse anti-interference ability due to its mechanical structure. The lateral interference degree in X and Y direction is 2.8 % and 4.6 % respectively, This will have important research significance in the field of seismic wave detection in oil and gas exploration.