A Temperature-Insensitive Cladding-Etched Fiber Bragg Grating Using a Liquid Mixture with a Negative Thermo-Optic Coefficient

Abstract

To compensate for the temperature dependency of a standard FBG, a cladding-etched FBG immersed with a liquid mixture having a negative thermo-optic coefficient is presented, and its characteristics are investigated. The Bragg wavelength of the cladding-etched FBG is shifted counter to the direction of the Bragg wavelength shift of a conventional FBG according to the mixing ratio of glycerin to water; thus, the temperature-dependent Bragg wavelength shift was almost compensated by using a liquid mixture of water (50%) and glycerin (50%) having the negative thermo-optic coefficient of −5 × 10−4 °C−1.

Stack of PECVD silicon nitride nano-films on optical fiber end-face for refractive index sensing

“…Different optical properties of the films were obtained by varying flow of SiH 4 and pressure in the chamber during the deposition, which were 150 cccm and 0.9 Torr or 500 sccm and 1.2 Torr for low (n 1 ) -0000. 1 [wu] UoualaneAA 0091 0991 0091 structure is described by Eq. 2.…”

“…The probes are often based on fiber bragg gratings (FBGs) [1] or Fabry-Perot (FP) [2] resonator. When the refractive index (RI) sensing is discussed, the cladding of the FBG structure needs to be significantly etched in order to let the guiding mode interact with external medium [1]. The effective application of FP resonator requires, in turns, the measured liquid to penetrate the FP cavity [2].…”

Plasmonic Optical Fiber-Grating Immunosensing: A Review

“…Hence, in practice, unclad optical fibers are used, with the core exposed to the surrounding medium so that an evanescent wave can extend in this medium. This is usually obtained through a chemical etching process, most often with hydrofluoric acid (HF) [ 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ] or through a side-polishing process [ 31 , 32 , 33 , 34 , 35 ]. The latter configuration has strong similarities with the use of Bragg gratings produced in D-shaped optical fibers [ 36 ].…”

Sensing properties of periodic stack of nano-films deposited with various vapor-based techniques on optical fiber end-face

“…The probes based on stacked structures are often identified with fiber bragg gratings (FBGs) [1], but they need to be significantly etched in order to be used as a refractive index (RI) sensor. This modification of fiber's structure affects its integrity and makes it very fragile.…”