Magnetic Field Sensor Based on Nano-Terbium-Oxide Coated Long-Period Fiber Grating

A novel magnetic field sensor based on long-period fiber gratings (LPFG) coated with terbium oxide nanofilms is proposed. Theoretical analysis and numerical simulation of the four-layer cylindrical waveguide's hybrid modes is investigated to achieve highly sensitive transition regions versus the thickness and refractive index of the film coated on LPFG. In this work, uniform and dense Tb<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>O<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> films are deposited on the LPFG using atomic layer deposition (ALD), and it shows that the sensor achieved an exceptional magnetic field sensitivity of 0.17 nm/mT when coated with 1200 layers of Tb<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>O<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub>. The combination of LPFG and terbium oxide materials appears to be highly promising for applications in magnetic field sensing.