Fiber-optic extrinsic Fabry-Perot dc magnetic field sensor

Area of Science:

• Optoelectronics
• Materials Science
• Sensor Technology

Background:

• Fiber-optic sensors offer remote and sensitive measurement capabilities.
• Magnetostrictive materials provide a direct link between magnetic fields and mechanical strain.
• Extrinsic Fabry-Perot interferometers (EFPIs) are versatile optical sensing platforms.

Purpose of the Study:

• To develop a compact fiber-optic sensor for measuring DC magnetic fields.
• To utilize a magnetostrictive amorphous metallic wire as the sensing element.
• To model and validate the sensor's performance.

Main Methods:

• An extrinsic Fabry-Perot interferometer (EFPI) was constructed using a magnetostrictive amorphous metallic wire (Unitika AF-10).
• A theoretical model based on Gaussian electric field distribution was developed to analyze sensor operation.
• Experimental measurements were performed to validate the theoretical model and assess sensor performance.

Main Results:

• The sensor demonstrated effective measurement of DC magnetic fields.
• The theoretical model showed good agreement with experimental results.
• A high resolution of 50 nT over a range of 50-40,000 nT was achieved.
• A simple passive temperature compensation method was successfully implemented.

Conclusions:

• A compact and effective fiber-optic sensor for DC magnetic field measurement was demonstrated.
• The developed theoretical model accurately describes the sensor's behavior.
• The sensor exhibits excellent resolution and a wide dynamic range, suitable for various applications.
• The integration of magnetostrictive materials with EFPIs offers a promising approach for magnetic field sensing.