Performances of PMMA-Based Optical Fiber Bragg Grating Sensor in Extended Temperature Range

Abstract

PMMA based optical fiber Bragg grating (POFBG) sensors are investigated in an environmental chamber with controlled temperature and relative humidity at temperature extended to 70 °C. At below a critical temperature of 50 °C the POFBG sensor exhibits good linearity and sensitivity for both temperature and humidity sensing. Nonlinear responses are observed at higher temperature, giving rise to varying, reduced magnitudes of sensitivities. An important feature of POFBG humidity sensing is observed at above critical temperature where the POFBG humidity sensitivity turns from positive to negative. A theoretical model based on Lorentz–Lorenz equation is presented to estimate the dependence of POFBG refractive index on temperature and relative humidity. The experimental results qualitatively agree with the theoretical analyses.

Direct Bragg Grating Inscription in Single Mode Step-Index TOPAS/ZEONEX Polymer Optical Fiber Using 520 nm Femtosecond Pulses

“…In addition to FBGs in silica fibers, FBGs in polymer optical fibers (POFs) have been more and more popular since the first fabrication in 1999 [ 8 ] due to their unique advantages compared to silica fibers, such as lower Young’s modulus, larger negative thermo-optic coefficients, higher elastic strain limits, and higher bending flexibility [ 9 , 10 , 11 ]. FBGs in POFs have been used for a variety of sensing applications, such as temperature [ 12 , 13 ], strain [ 14 ], humidity [ 15 , 16 ], liquid level [ 17 ], plantar pressure [ 18 ], gas pressure [ 19 ] and soil water content [ 20 ]. Meanwhile, researchers have tried to improve FBG reflectivity and inscription efficiency by different techniques.…”

Special Issue on “Advancements in Fiber Bragg Grating Research”

“…An FBG can also be written in polymer optical fibers, showing distinct features of negative thermo-optic coefficients and an affinity for water. A comprehensive study of sensing performance of polymer optical fiber gratings at an extended temperature range is presented [6]. The uniform-period FBG is one of the earliest and most widely used gratings.…”

Projeto de um relé de gás com análise de gás livre em transformadores de potência refrigerados a óleo

“…A Figura 12 relaciona a cor do óleo com o seu estado [18]. Outro fator importante no processo de degradação da qualidade do óleo é a presença de água [19] que, dentre outros problemas, reduz sua rigidez dielétrica e aumenta as chances de ocorrerem falha severas e desligamento do transformador.…”