Broadband accelerometer with a high figure of merit based on a short fiber Bragg grating

This paper proposes a broadband fiber Bragg grating accelerometer based on symmetrical double flexible hinges. A 2 mm short grating inscribed by a femtosecond laser is fixed onto a symmetrical L-shaped amplification mechanism, achieving a high-quality factor to obtain enhanced sensitivity across a broad frequency range. Finite element simulations and experimental validations demonstrate that the sensor's resonance frequency exceeds 2000 Hz while maintaining a high sensitivity of approximately 67.7 pm/g and a figure of merit of 2.71×10⁸pm⋅g^-1⋅Hz². Furthermore, by damping the resonance amplitude, a flat response bandwidth of over 2000 Hz (3 dB) is achieved. This sensor holds great potential for a wideband vibration measurement in applications such as inter-well seismic monitoring, microseismic detection, pipeline leakage monitoring, and electromechanical equipment vibration monitoring.