MEMS Interferometric Accelerometer

Overview

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.

Technical Details

Design Implementation

• Surface-micromachined interdigital fingers

• Alternating attachment between:

  • Proof mass

  • Support substrate

• Coherent light illumination system

• Diffracted optical beam measurement

Performance Metrics

• 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

Construction

• Two-mask silicon process

• Standard laser diode implementation

• Conventional photodetector

• Subangstrom displacement detection

Media

Technical Innovation

• Novel optical sensing approach

• High-precision measurement capability

• Integrated optical system

• Advanced MEMS fabrication techniques

• Superior sensitivity compared to traditional methods

Applications

• Precision navigation

• Seismic sensing

• Vibration measurement

• Inertial guidance

• High-sensitivity motion detection

Contributors

Emily Cooper, Rehmi Post, Saul Griffith, Jeremy Levitan, and Scott Manalis

Related Work

• Particle Trap IMU

• Haltere IMU