Intensity-interrogated magnetic sensor based on S-tapered and multimode fiber integrated with ferrofluids

Area of Science:

• Photonics and Sensor Technology
• Materials Science
• Applied Physics

Background:

• Accurate measurement of weak magnetic fields (MFs) is crucial in various scientific and industrial applications.
• Existing MF sensors often face challenges with sensitivity and temperature cross-sensitivity.
• Ferrofluids offer unique magneto-optical properties suitable for sensor development.

Purpose of the Study:

• To propose and demonstrate a high-sensitivity fiber sensor for weak magnetic field (MF) measurement.
• To investigate and resolve the temperature cross-sensitivity of the proposed MF sensor.
• To highlight the sensor's advantages, including high sensitivity and low cost.

Main Methods:

• Fabrication of an intensity-interrogated fiber sensor using offset-tapered single-mode fiber and multimode fiber (MMF).
• Encapsulation of the fiber sensor in a capillary tube filled with ferrofluids.
• Investigation of spectral response to varying MF intensity and ambient temperature.
• Application of a sensing matrix to correct for temperature cross-sensitivity.

Main Results:

• The proposed sensor achieved a high MF sensitivity of -0.1130 dB/Oe within the 40-120 Oe range.
• Demonstrated superior sensitivity compared to previously reported MF sensors.
• Successfully corrected temperature-induced measurement errors for temperatures between 25°C and 35°C.

Conclusions:

• The developed ferrofluid-integrated fiber sensor offers a highly sensitive and cost-effective solution for weak MF measurements.
• The sensor effectively addresses and compensates for temperature cross-sensitivity.
• This technology holds promise for various applications requiring precise weak MF detection.