A Magnetic Field Sensor Based on a Magnetic Fluid-Filled FP-FBG Structure

Area of Science:

• Optoelectronics
• Materials Science
• Sensor Technology

Background:

• Magnetic fluids exhibit a magnetic-controlled refractive index, making them suitable for magnetic field sensing.
• Fiber optic Fabry-Perot (FP) sensors are susceptible to temperature cross-sensitivity, affecting magnetic field measurement accuracy.

Purpose of the Study:

• To develop a temperature-compensated fiber optic magnetic sensor.
• To overcome the cross-sensitivity effect in magnetic field measurements.

Main Methods:

• Utilized a magnetic fluid as the sensing medium within a fiber optic Fabry-Perot cavity.
• Integrated a fiber Bragg grating (FBG) for real-time temperature compensation.
• Proposed a modified sensor structure incorporating the FBG into the FP cavity.

Main Results:

• Enhanced magnetic field detection sensitivity from 0.23 nm/mT to 0.53 nm/mT.
• Achieved a magnetic field measurement resolution of 37.7 T.
• Demonstrated effective temperature compensation, mitigating cross-sensitivity.

Conclusions:

• The developed fiber optic FP-FBG magnetic sensor offers a small volume and high sensitivity.
• This sensor presents a promising solution for magnetic field monitoring in power industry and defense applications.