Sensitivity Prediction of Multiturn Fiber Coil-Based Fiber-Optic Flexural Disk Seismometer via Finite Element Method Analysis

This paper presents a method for predicting strain and sensitivity of a fiber-optic flexural disk seismometer (FODS) based on multiturn fiber coils (MTFC) via finite element method (FEM) analysis. FEM can be used to evaluate sensitivity by taking into account the strain distribution in MTFC. A sample MTFC-based FODS was fabricated according to simulation parameters; the experimental results of strain distribution and sensitivity were determined by Brillouin optical time-domain analysis and vibrator, respectively, which in turn can be used to confirm the correctness of the prediction model. The tested strain distribution of MTFC has the same characteristic with its simulation model; the predicted sensitivity of MTFC-based FODS is 6448.0 rad/g. Three sample sensors are fabricated and tested, which have a fabrication error of 7%. All FODS simulations were carried out in the COMSOL Multiphysics environment, which has significant potential for application as a tool of predicting the FODS sensitivity when designing or fabrication an MTFC-based FODS.