An optimum design of high sensitivity PMMA-coated FBG sensor for temperature measurement

Abstract

Fiber Bragg grating (FBG) with silica material has limitations in measuring mechanical quantities such as strain and temperature, this happens because silica fibers are easy to break at higher transverse or axial strains. This deficiency can be overcome in several ways, one of which is by coating the silica FBG with a coating material made of metal or polymer. In this research, the FBG sensor has been designed by poly methyl methacrylate (PMMA)-coated FBG and silica. The finite element method (FEM) is used to analyze the electric field distribution on the surface of PMMA coated FBG with a coating thickness of 20 µm. Furthermore, the sensitivity of each coated FBG as a temperature sensor was measured in the range of 25 ℃ to 85 ℃ using coupled mode theory (CMT). From the design and analysis of coated FBG, it was found that FBG coated with PMMA material had the highest sensitivity of 395.73pm/℃. However, the FBG sensor coated with silica material has a sensitivity of 13.73 pm/℃. the shift obtained is also linear along with the temperature of 25 ℃ to 85 ℃.

Ultra low loss and dual polarized SPR-PCF sensor based on refractive index

“…The need for optical sensors continues to increase, this is due to the extraordinary capabilities of optical sensors such as high sensitivity wide sensing range, resistance to electromagnetic wave interference, and very small size [1], so it can be designed with a portable size and working based on wavelength. Several optical sensors have reached the commercialization process while some are still in the development stage, various types of optical based sensors including optical fiber, multi-mode fiber, fiber Bragg grating (FBG) [2], [3], tapered FBG, and optical fiber based surface plasmon resonance-photonic crystal fiber (SPR-PCF) [4], [5]. Also, several sensing techniques have been reported by many researchers, including the Mach Zehnder interferometer technique.…”

“…COMSOL-based FE is used in investigating the performance of sensor components, in COMSOL we define fused silica material using the Sellmeier as in (6). Meanwhile, the values for each symbol in (6) A1=0.696163, A2=0.4079426, A3=0.897479400, B1=0.0046791486 𝜇𝑚 2 , B2=0.0135120631 𝜇𝑚 2 , B3=97.9340025 𝜇𝑚 2 .…”