Optical SOI micro-gravimeters with bulk PZT excitation

This paper deals with the development and characterization of a novel mass microsensor with optical output. PZT screen-printed elements, behaving as thickness-mode resonators provide energy to SOI-based micro-resonators. A significant degree of innovation lies in the miniaturization of the system, in the relevant decreasing of operating frequency, in the novel optical sensing strategy based on metal-dielectric (MD) photonic band gap (PBG) structures, and in selective thermal-deposition of polymer which has been predisposed. A signal conditioning architecture based on a closed loop configuration is considered to measure the variation of frequency as a function of the micro-mechanical proof-mass variation. A high benefit is obtained in tracking the resonance condition variations, due to the very high quality factor, which has been experimentally measured. A theoretical sensitivity of 580 (Hz/μg) have been evaluated for test devices having resonance frequencies less than 10 kHz.