Vector magnetic field sensor based on U-bent single-mode fiber and magnetic fluid

Area of Science:

• Photonics and optical sensing
• Magnetometry
• Materials science

Background:

• Accurate measurement of vector magnetic fields is crucial for various scientific and technological applications.
• Existing vector magnetic field sensors often involve complex fabrication processes or lack compactness.
• Developing novel, cost-effective, and high-performance magnetic field sensors remains an active research area.

Purpose of the Study:

• To propose and investigate a novel, compact, and easily fabricated vector magnetic field sensor.
• To demonstrate the sensor's capability in measuring both the direction and intensity of a magnetic field.
• To explore the potential of whispering gallery modes in a U-bent fiber structure for magnetic field sensing.

Main Methods:

• Fabrication of a sensor comprising a U-bent single-mode fiber immersed in a magnetic fluid.
• Utilizing whispering gallery modes supported by the U-bent fiber structure.
• Analyzing the spectral response of the sensor to applied magnetic fields to determine direction and intensity.

Main Results:

• The sensor successfully measured the direction of the magnetic field with a sensitivity of 0.251 nm/°.
• The sensor achieved a maximum sensitivity of 0.517 nm/mT for magnetic field intensity.
• The fabrication process requires no mechanical modification or additional fiber gratings.

Conclusions:

• A novel, compact, and easy-to-fabricate vector magnetic field sensor based on a U-bent fiber and magnetic fluid has been successfully demonstrated.
• The proposed sensor effectively measures magnetic field direction and intensity using whispering gallery modes.
• This work validates the feasibility of employing similar bending structures for future vector magnetic sensor development.