High-Sensitivity Fiber-Optic Fabry–Perot Acceleration Sensor Based on a Cascaded-Curved Beams Structure

A high-sensitivity fiber-optic Fabry–Perot interferometer (FPI) based on a stainless steel diaphragm for acceleration detection is proposed. The sensitive element is mainly composed of an elastic diaphragm whose both sides are bonded with two mass blocks symmetrically. The optical fiber is coaxial aligned with the sensitive element and the incident light is reflected at the end face of the fiber and the polished surface of the mass block to form an FPI. To improve the sensitivity and reduce cross-interference, a novel diaphragm with a cascaded-curved beams structure was designed. The cascaded-curved beams can extend the length of the beam and increase the lateral stiffness to keep the mass block from being tilted under the cross-interference. The performance of the sensor was simulated and the experimental results are demonstrated. The results indicate that the natural frequency of the sensor is 164 Hz, the sensitivity is $9.07 ~\mu \text{m}$ /g, and the cross-sensitivity is 0.65%. The sensor has a good application prospect for acceleration measurement of engineering structures.