A High-Sensitivity Dual-Axis Accelerometer with Two FP Cavities Assembled on Single Optical Fiber

Area of Science:

• Optoelectronics
• Fiber Optics Sensing
• Inertial Measurement

Background:

• Traditional accelerometers face limitations like electromagnetic interference and bulky designs.
• Fiber optic sensors offer advantages such as immunity to EMI, small size, and remote sensing capabilities.

Purpose of the Study:

• To propose and demonstrate a novel dual-axis fiber optic accelerometer based on the Fabry-Pérot (FP) interference principle.
• To evaluate the performance characteristics, including sensitivity, cross-axis sensitivity, and angular error, of the developed sensor.

Main Methods:

• A dual-axis FP accelerometer was constructed using a single optical fiber, a beam-splitting prism, and a vibration-sensitive Beryllium-Copper (Be-Cu) spring with a proof mass.
• Two perpendicular FP cavities were formed by a semi-permeable film on the prism and a reflective sheet on the spring.
• Vibration signals caused changes in cavity lengths, which were detected via optical interference, bandpass filtering, and demodulation to obtain dual-axis acceleration measurements.

Main Results:

• The dual-axis fiber optic accelerometer exhibited a resonant frequency of approximately 280 Hz.
• Sensitivities of 3.93 μm/g (X-axis) and 4.19 μm/g (Y-axis) were achieved.
• Cross-axis sensitivity was measured to be below 5.1%, and the maximum error within a 180° angle range was less than 3.77%.

Conclusions:

• The proposed fiber optic dual-axis FP accelerometer demonstrates high sensitivity, excellent immunity to electromagnetic interference, and potential for miniaturization and mass production.
• The flexible FP construction method offers significant development potential for advanced inertial sensing applications.