High-Sensitivity Three-Axis FBG Accelerometer Based on Elliptical Spring

We propose an elliptical spring-based three-axis fiber Bragg grating (FBG) accelerometer fabricated by appropriately arranging and encapsulating three identical one-axis sensing structures in a cylindrical shell. The derived theoretical equations and the established simulation model of the sensing structure are in good agreement with the experimental results. Sensors on three axes operate in a frequency band of 10–70 Hz; the sensitivities of the proposed accelerometer in $X$ – $Z$ directions are 1197.82, 1157.78, and 1223.04 pm/g, respectively, showing high sensitivity, good consistency, directional response, and resistance to transverse interference.