Elimination of Thermal Strain Interference in Mechanical Strain Measurement at High Temperature Using an EFPI-RFBG Hybrid Sensor With Unlimited Cavity Length

Recent advances in optical fiber high-temperature sensors and encapsulation technique [Invited]

“…7, and the cavity length of the sensor was measured to be 30 μm by scanning electron microscopy (SEM), with an ablation depth of ∼72 μm. Its interference [62] Microstructured fiber (MF) 24°C-1000°C 17.7 pm/°C 2013 [63] Double-core photonic crystal fiber (DC-PCF) 30°C-900°C 13.9 pm/°C 2014 [64] PCF 17°C-1200°C 10 pm/°C 2015 [65] Microfiber (MF) 25°C-1000°C 13.6 pm/°C 2018 [66] No-core fiber (NCF) 100°C-1100°C 16.36 pm/°C (400°C) 0-2000 με 2019 [67] Polarization-maintaining PCF 100°C-1000°C 15.34 pm/°C 2020 [68] PCF 25°C-1000°C 16.12 nm/°C 2021 [69] Polarization-maintaining PCF 50°C-900°C 17.52 pm/°C (400°C) 2021 [70] EFPI 100°C-700°C 0.98 pm/°C 0-800 με 2012 [71] 20°C-800°C 0.59 pm/°C 0-3700 με 2014 [72] 23°C-600°C 12.3 pm/°C 0-2104 με 2016 [73] 20°C-1000°C 15.41 pm/°C 0-1 000 με 2019 [74] 100°C-800°C 10.74 pm/°C 0-900 με 2020 [75] 26°C-1000°C 6.98 pm/°C (800°C) 0-350 με 2022 [76] 26°C-700°C 12.715 pm/°C 2022 [77] 24°C-900°C 12.8 pm/°C 0-210 με 2023 [78] spectrum had an extinction ratio greater than 14 dB, and tests showed that the sensor could achieve temperature sensing up to 1100°C, with a sensitivity of 0.074 pm/°C. In 2014, Kaur et al [72] micromachined an FPI microcavity on the end face of an SMF using femtosecond laser micromachining technology to achieve temperature sensing at 800°C, and performed a strain measurement at room temperature up to 3700 με.…”

Vernier Effect Based Temperature Sensor Revealed Ultra-Sensitivity With High-Detection Resolution

“…Over the past decade, numerous optical fiber-based temperature sensing architectures have been developed. Mach Zehnder Interferometers (MZIs) [1][2][3][4], Sagnac Interferometers [5][6][7][8], Fabry-Perot interference (FPI) Sensors [9][10][11][12], Surface Plasmon Resonance (SPR) Sensors [13][14][15][16][17], Silicon On Insulator (SOI) sensor [18], Fiber Bragg Gratings (FBGs) Sensor [19][20][21], and Long-Period Fiber Gratings (LPFGs) [22][23][24] are popular in temperature measuring devices. Most interferometers, including conventional FBGs, are shown to have low-temperature sensitivities due to the low thermaloptical coefficient (TOC) and thermal-expansion coefficient (TEC) of silica.…”

A Composite Fabry-Perot Interferometric Sensor with the Dual-Cavity Structure for Simultaneous Measurement of High Temperature and Strain

“…At present, the most widely used high-temperature strain sensors are high-temperature strain gauges, which operates based on gauge resistance as a function of strain. However, they suffer from the inherent disadvantages of vulnerability to electromagnetic interference (EMI), mechanical hysteresis and creep [ 5 ] and drift in response due to oxidation [ 3 ], which diminish their reliability and accuracy in the above-mentioned environments. Therefore, it is a pressing demand to develop robust strain sensors capable of operating in environments with targeted high temperatures while maintaining a stable strain response.…”

“…When used for high-temperature strain measurement, total deformation including strain induced by thermal expansion as well as forces applied to the structure will be measured [ 13 ]. This temperature-strain cross-sensitivity may be a problem in practical applications, especially in high-temperature strain measurement which requires the discrimination of thermal strain and pure force-induced strain of the sensing point [ 5 ]. In order to overcome this issue, a number of techniques have been proposed before, such as the combination use of two FBGs [ 14 , 15 ], hybrid configuration of Bragg grating and long-period gratings [ 16 ], polarization-rocking filter [ 17 ].…”