Resonant-Frequency-Adjustable Fiber Bragg Grating Accelerometer Based on Extra Transverse Force Loading

Abstract

We propose a resonant-frequency-adjustable fiber Bragg grating (FBG) accelerometer. The accelerometer employs a special hexagonal energy transfer structure and a microhelical cylinder as a carrier. When the geophone vibrates, transverse force and axial force are applied to FBG at the same time, which breaks the traditional accelerometer that the FBG is only subjected to a single direction force. The resonant frequency can be changed by preadjusting the position of the microhelical cylinder. We introduced the structural principle and experimental model of the accelerometer and determined the structural parameters through finite-element simulation. In addition, we carried out a series of experimental tests, and the results show that the resonant frequency of the accelerometer can be increased from 680 to 980 Hz, and the frequency bandwidth is widened by 300 Hz. When the resonant frequency reaches 800 Hz, the maximum sensitivity can achieve 46.1 pm/g.