Miniature tri-axis accelerometer based on fiber optic Fabry-Pérot interferometer.

Area of Science:

• Optoelectronics
• Sensor Technology
• Mechanical Engineering

Background:

• Low-frequency acceleration sensing is crucial for applications like seismic monitoring.
• Existing accelerometers often face limitations in sensitivity, noise, or size.
• Fiber optic sensors offer potential advantages due to their immunity to electromagnetic interference.

Purpose of the Study:

• To propose and demonstrate a novel fiber optic accelerometer.
• To achieve high sensitivity, low noise, and a compact form factor for low-frequency acceleration measurements.
• To evaluate the performance and potential applications of the developed sensor.

Main Methods:

• Designed a sensor with a spherical outer frame and a 3D spring-mass structure.
• Integrated three Fabry-Pérot interferometers (FPI) using fiber facets and cubic mass surfaces.
• Measured dynamic signal response, sensitivity, minimum detectable acceleration, and transverse sensitivity.

Main Results:

• Achieved high acceleration sensitivity of 42.6 dB re rad/g within a 1-80 Hz band.
• Obtained an average minimum detectable acceleration of 4.5 µg/Hz^1/2.
• Demonstrated simple assembly, compact size, light weight, good consistency, and low transverse sensitivity (<3%).

Conclusions:

• The developed fiber optic accelerometer meets the requirements for high sensitivity and low noise.
• The sensor's performance indicates significant potential for seismic wave detection and structural health monitoring.
• The compact and robust design facilitates practical implementation in various sensing applications.