We demonstrate a promising type of microfabricated accelerometer based on optical interferometry. The interferometer consists of surface-micromachined interdigital fingers that are alternately attached to a proof mass and support substrate. This novel approach achieved superior sensitivity and accuracy compared to conventional capacitive sensing methods.
Surface-micromachined interdigital fingers
Alternating attachment between:
Proof mass
Support substrate
Coherent light illumination system
Diffracted optical beam measurement
Minimum detectable acceleration: 2 µg/√Hz
Measurement bandwidth: 1 Hz centered at 650 Hz
Performance level: Six orders of magnitude below the acceleration of gravity
Two-mask silicon process
Standard laser diode implementation
Conventional photodetector
Subangstrom displacement detection
Novel optical sensing approach
High-precision measurement capability
Integrated optical system
Advanced MEMS fabrication techniques
Superior sensitivity compared to traditional methods
Precision navigation
Seismic sensing
Vibration measurement
Inertial guidance
High-sensitivity motion detection
Emily Cooper, Rehmi Post, Saul Griffith, Jeremy Levitan, and Scott Manalis