A High-sensitivity Optical MEMS Accelerometer based on SOI Double-side Micromachining

High-sensitivity micro-electromechanical systems (MEMS) accelerometers have been widely used in many applications. Although the optical MEMS accelerometers have the advantage of insensitive to electromagnetic interferences, there are still difficulties of integration and fabrication. Therefore, capacitive MEMS accelerometers are more commonly used. This paper introduces a high-sensitivity optical MEMS accelerometer based on silicon-on-insulator (SOI) double-side micromachining technology which can overcome the difficulties of both optical component integration and low-frequency suspension system micromachining. The proposed sensor is a silicon flexure accelerometer whose spring-mass structure consists of the compliant spring beams, the proof mass and the sensor frame. When acceleration applies, the in-plane motion of the proof mass can be transduced by an optical interferometer with the Fabry-Perot (F-P) cavity formed between the fiber end-face and the proof mass sidewall. The sensitivity of the micro-machined optical accelerometer is measured as 100 ng/vHz@1 Hz which is better than most of the reported optical MEMS accelerometers.