Lithium niobate nanoparticulate clad on the core of single mode optical fiber for temperature and magnetic field sensing

Lithium niobate with large non-linear optical coefficient and birefringence finds applications as varied optical devices. Nanoparticulate, polycrystalline LiNbO3 was synthesised and deposited on the core of the single-mode optical fiber and evaluated for their temperature and magnetic field sensing using C-band source. Temperature sensing was 30 pm/ °C with improved core-clad coupling at higher temperature. The magnetic field (0-30 mT) response was 131 pm/mT, with large hysteresis. The results have been correlated with the manipulation of core-clad modes due to strain induced in the core-deposited film and introduction of cation vacancies, resulting in induced ferromagnetism; thereby resulting in changed refractive index.