High-resolution micro-optical accelerometer with an electromagnetic driver: Design and analysis

Optical displacement detection is widely used in various micro-electro-mechanical system (MEMS) sensors because of its high sensitivity. The optical accelerometer has a high theoretical resolution. However, due to the small working range of optical detection, the open-loop measuring range of a high-resolution optical accelerometer is usually only tens to hundreds of milligrams. To increase the measurement range, we propose a high-resolution micro-optical accelerometer with electromagnetic force feedback. The optical principle, mechanical structure, and manufacturing process are analyzed. The accelerometer is predicted to work in the first modal with displacement sensitivity at 2.56 µm/g, corresponding to 0th diffraction beam optical sensitivity 1.93%/nm. The designed electromagnetic driver can increase the acceleration measurement range from 0.012 to ±20 g. These results provide a theoretical basis for the design and fabrication of a high-resolution micro-optical accelerometer with an electromagnetic driver. The electromagnetic drive scheme introduced effectively improves the dynamic range of high-precision optical accelerometers and can be applied to other optical MEMS sensors.