Design of high sensitivity isotropic fiber optic F–P three-dimensional geophone with high consistency

Abstract A highly sensitive isotropic Fabry–Pérot (F–P) three-dimensional geophone is proposed and demonstrated experimentally. The concept of three-dimensional high symmetry structure based on the F–P is ingeniously proposed, a highly sensitive three-dimensional F–P geophone model with high consistency in three directions is established, and the corresponding elastomer is designed. Based on the design concept, the geophone based on the F–P structure design is optimized to improve its consistency and comprehensively enhance its sensitivity. The experiment result obtained shows that the geophone has a bandwidth of 20–560 Hz in the X, Y and Z directions. The sensitivities in the flat regions of the X, Y , and Z directions are 6.05 nm G −1 −12.25 nm G −1 , 5.88 nm G −1 −11.84 nm G −1 and 6.16 nm G −1 −12.47 nm G −1 , respectively, and the consistency of triaxial performance is evaluated accordingly. The Allan variance noise characteristics along the three orthogonal axes are analyzed. The geophone featuring this characteristic has the advantages of small size, high sensitivity, and good three-dimensional response consistency, providing a high-performance solution for high-precision inertial measurement.