Structure Design of Out-Plane Evanescent Coupling Accelerometer with Sub-wavelength Gratings

It is the key for MOEMS accelerometer to combine large mass, weak spring and sub-wavelength gratings in order to achieve high precision. A novel out-plane MOEMS accelerometer based on near-field evanescent waves coupling by means of variable period sub-wavelength gratings has been proposed. Structure parameters were optimized by finite element analysis to achieve high sensitivity in an ideal vibration mode. Based on the ANSYS simulation, the novel accelerometer is predicted to work in the first modal with displacement sensitivity at 2023 nm/G and measurement range of 0.3G, corresponding to 1st diffraction beam optical sensitivity 0.46%/mG. These results provide a theoretical basis for design and fabrication of out-plane MOEMS accelerometer with sub-wavelength gratings.