Closed-loop MOEMS accelerometer

Area of Science:

• Micro-opto-electro-mechanical systems (MOEMS)
• Optical sensing technologies
• Inertial measurement units

Background:

• Traditional accelerometers face limitations in range and resolution.
• Fabry-Pérot interferometry offers high sensitivity for displacement sensing.
• Integrating optical and mechanical elements enables novel sensor designs.

Purpose of the Study:

• To develop and characterize a closed-loop MOEMS accelerometer.
• To leverage Fabry-Pérot interferometry for enhanced acceleration measurement.
• To demonstrate a silicon-based fabrication process for MOEMS accelerometers.

Main Methods:

• Fabrication of a MOEMS accelerometer using silicon-on-insulator (SOI) wafer and bulk micromachining.
• Formation of a Fabry-Pérot cavity between an optical fiber and a proof mass.
• Implementation of a closed-loop electrostatic feedback system for proof mass stabilization.
• Characterization of sensor performance including linearity, sensitivity, and bias instability.

Main Results:

• The accelerometer exhibits a linear response within the ±5g range.
• Closed-loop operation significantly improves the measurement range without compromising resolution.
• Achieved sensitivity of 1.16 V/g and bias instability of 40 µg in closed-loop mode.

Conclusions:

• The developed closed-loop MOEMS accelerometer demonstrates promising performance for acceleration sensing.
• The Fabry-Pérot interferometer integrated with electrostatic feedback offers a robust platform for high-performance inertial sensing.
• The bulk micromachining fabrication method is suitable for producing these advanced MOEMS devices.