A highly-sensitive temperature sensor based on GeO2–SiO2 long period fiber grating. (18th November 2020)

• Record Type: Journal Article
• Authors: Lotfi, Mohammad; Noori, Mina
• Is Part Of: Physica scripta. Volume 96:Number 1(2021)
• Publication Date: 2020-11-18
• Subjects: long period grating -- temperature sensor -- sensitivity -- phase matching conditions; Physics -- Periodicals; 530.05
• DOI: 10.1088/1402-4896/abc8a2
• Languages: English
• ISSNs: 0031-8949

Abstract

Abstract: A highly-sensitive long period grating temperature sensor has been introduced here, which is composed of GeO2 in the core and SiO2 in the cladding. Due to high thermo-optic coefficient contrast of the core and the cladding, the proposed sensor provides high temperature sensitivity of S = Δ λ /ΔT = −2.3871 nm/°C in the temperature range of 71 °C to 406 °C. The grating period and the length of the sensor are 445.4 nm and ∼25 mm, respectively and the operating wavelength range is λ ∼1.48–2.28 μ m. The proposed sensor has been investigated considering material dispersion for the core and the cladding at different temperatures. Also, the conditions required for coupling of the fundamental core mode to the higher order cladding modes with respect to lattice constant have been regarded. The phase matching curves has been considered in the design of the proposed sensor and the structure has been optimized to present the maximum sensitivity, achievable in the regarded temperature range. The presented optical temperature sensor is feasible with low cost which benefits the high sensitivity, large detection range, and large operating wavelength range and it can find potential applications in the measurement of temperature in toxic, unreachable, and far distant environments such as in temperature control of lasers, and in oil or gas industries.