Micro-electro-mechanical systems ultra-sensitive accelerometer with independent sensitivity adjustment

摘要

An accelerometer is based upon the monolithic integration of a Fabry-Perot interferometer and a p<+>n silicon photosensor. Transmission of light through a Fabry-Perot interferometer cavity is exponentially sensitive to small displacements in a movable mirror due to an applied accelerating force. The photosensor converts this displacement into an electrical signal as well as provides for additional amplification. Because the interferometer and photosensor are monolithically integrated on a silicon substrate, the combination is compact and has minimal parasitic elements, thereby reducing the accelerometer's noise level and increasing its signal-to-noise ratio (SNR).The accelerometer's sensitivity can be user-controlled by any one or a combination of factors: adjusting the length between the mirrors of the Fabry-Perot cavity; adjusting the power of the light projected to the photosensor; and pulsing the light at a selected frequency to minimize 1/f inherent system noise in the response of the accelerometer.