Two-dimensional fiber Bragg grating accelerometer with four identical cantilevers

To address the requirements of two-dimensional (2D) low-frequency vibration monitoring and sensor miniaturization, this paper proposes a compact 2D fiber Bragg grating (FBG) acceleration sensor with four identical cantilever beams. The sensor uses four identical cantilever beams as elastic sensing elements. By applying differential signal processing to the variations in the central wavelength of the FBGs, it suppresses temperature cross-sensitivity and enhances measurement sensitivity. The experimental results demonstrate resonant frequencies of 500 (X-axis) and 525 Hz (Y-axis), with stable operation in the 10–200 Hz range, sensitivities of 38.01 and 38.10 pm/g with excellent linearity (r 2 >0.99), crosstalk ratios of 11.6% and 13.7%, and differential temperature sensitivities of only 1.7–2 pm/°C. Owing to its miniaturized structure and consistent bidirectional sensitivity, the sensor is highly suitable for two-dimensional low-frequency vibration monitoring in space-constrained environments and in scenarios with strong electromagnetic interference (EMI).