Ultrasensitive Pressure Measurement Using an Extrinsic Fabry-Pérot Interferometer (EFPI) Sensor.

Area of Science:

• Optics and Photonics
• Sensor Technology
• Materials Science

Background:

• Extrinsic Fabry-Pérot Interferometry (EFPI) offers potential for high-precision sensing.
• Development of large-diameter EFPI sensors has been hindered by complex fabrication techniques.
• Existing EFPI sensors often lack the sensitivity required for detecting minute pressure variations.

Purpose of the Study:

• To develop and characterize a novel, large-diameter EFPI fiber optic pressure sensor.
• To investigate various fabrication and diaphragm reduction techniques for EFPI sensors.
• To establish a new benchmark for EFPI pressure-based systems in terms of sensitivity and resolution.

Main Methods:

• Fabrication of an 800 μm diameter EFPI with a 7.4 μm diaphragm.
• Investigation of resin bonding, fusion splicing, and additive manufacturing.
• Exploration of manual polishing, automated polishing, and hydrofluoric acid etching for diaphragm reduction.

Main Results:

• Achieved a sub-Pascal resolution of 3.35 mPa.
• Demonstrated a high sensitivity of 149 nm/kPa.
• Positioned the sensor among the most sensitive fiber optic pressure sensors developed.

Conclusions:

• The developed large-diameter EFPI sensor establishes a new benchmark for high-precision pressure sensing.
• The study provides insights into fabrication and diaphragm reduction methods for future EFPI development.
• Sub-Pascal resolution opens possibilities in microfluidics, atmospheric monitoring, and medical diagnostics.