Open AccessFiber Bragg gratings for low-temperature measurement
Author(s) -
Elton Soares de Lima Filho,
Mohamad Diaa Baiad,
Mathieu Gagné,
Raman Kashyap
Publication year - 2014
Publication title -
optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.22.027681
Subject(s) - fiber bragg grating , materials science , optics , phosfos , optical fiber , fiber optic sensor , refractive index , thermal expansion , thermal , photonic crystal fiber , fiber , temperature measurement , optoelectronics , polarization maintaining optical fiber , composite material , wavelength , physics , quantum mechanics , meteorology
We demonstrate the use of fiber Bragg gratings (FBGs) as a monolithic temperature sensor from ambient to liquid nitrogen temperatures, without the use of any auxiliary embedding structure. The Bragg gratings, fabricated in three different types of fibers and characterized with a high density of points, confirm a nonlinear thermal sensitivity of the fibers. With a conventional interrogation scheme it is possible to have a resolution of 0.5 K for weak pure-silica-core FBGs and 0.25 K using both boron-doped and germanium-doped standard fibers at 77 K. We quantitatively show for the first time that the nonlinear thermal sensitivity of the FBG arises from the nonlinearity of both thermo-optic and thermal expansion coefficients, allowing consistent modeling of FBGs at low temperatures.