All-optical accelerometer based on micromachined silicon wafer

The conventional electronic accelerometer meets electromagnetic compatibility problem in environments with strong electromagnetic filed. We herein design an all-optical accelerometer to solve this problem. A series of miniature plane spring-mass components were micromachined on silicon wafer by means of lithography and reactive ion etching. These components were served as sensitive structures. The fiber-optic extrinsic Fabry-Perot interferometer is adopted as the sensing structure. Two reflectors, one of which is cleaved fiber end while the other is sensitive structure with Au film, are used to constitute the F-P cavity. The proposed structure did not require high-precision alignment. Therefore, it is easily fabricated. The assembled sensor possesses small volume, which is 5 mm in radical and 12 mm in longitudinal. High-precision interferometric optical phase detection technique is used for signal recovery. The sensitivity of the fabricated sensor is about -11.2 dB re. rad/g with the resonance frequency at 2530 Hz. The equivalent noise acceleration is about 31.2 μg/√Hz. All these experimental results indicated a high-performance accelerometer. The fabricated accelerometer has potentials in large engine testing.