Ultra-high sensitivity SPR temperature sensor based on a helical-core fiber

Abstract

A novel compact ultra-high sensitivity optical fiber temperature sensor based on surface plasmon resonance (SPR) is proposed and demonstrated. The sensor is fabricated by employing a helical-core fiber (HCF), which is polished as a D-type fiber on the helical-core region and coated with a layer of Au-film and polydimethylsiloxane (PDMS). The theoretical and experimental results show that the resonant wavelength and sensitivity of the proposed sensor can be effectively adjusted by changing the twisting pitch of HCF. Due to the high refractive index sensitivity of the sensor and the high thermo-optic coefficient of PDMS, the maximum sensitivity can reach -19.56 nm/°C at room temperature when the twist pitch of HCF is 2.1 mm. It is worth noting that the sensitivity can be further improved by using a shorter pitch of HCF. The proposed SPR temperature sensor has adjustable sensitivity, is easy to realize distributed sensing, and has potential application prospects in biomedical, healthcare, and other fields.

Improving Temperature-Sensing Performance of Photonic Crystal Fiber via External Metal-Coated Trapezoidal-Shaped Surface

“…The λres peak decreases with increasing temperature from 10 °C to 60 °C. According to Equation (3), the CL peak is related to the permittivity of Ag and the real part of the RI of the temperature analyte, which is also temperature dependent [20]. Figure 4a shows the CL as a function of the wavelength of the core-guided mode at temperatures ranging from 10 • C to 60 • C, using the structural parameters listed in Table 1.…”

“…This decrease in λ res peak is associated with a reduction in CL on the Ag surface. The λ res peak decreases with increasing temperature from 10 • C to 60 • C. According to Equation (3), the CL peak is related to the permittivity of Ag and the real part of the RI of the temperature analyte, which is also temperature dependent [20].…”

“…The SPR effect is sensitive to changes in the refractive index (RI) of the surrounding medium. This property is advantageous for different SPR sensors and has broad applications and research impacts [8][9][10][11][12][13][14][15][16][17][18][19][20][21].…”

High-precision and long-range optical fiber Fabry–Perot interferometer for high temperature measurement

“…In the field of high-temperature sensing, commonly used optical-fiber sensing structures include fiber Mach-Zehnder interferometer (MZI) [17,18], fiber Bragg grating (FBG) [19][20][21][22], fiber blackbody cavity [23], fiber Michelson [24,25], white light interferometric sensors with sapphire fibers [26], composite materials [27][28][29][30], Raman [31], plasmonic sensors [32], and fiber Fabry-Port interferometer (FPI). In response to the actual needs of aeroengine temperature measurement [33], the MZI is a transmissive type, which has problems such as inconvenience to make probes and that its dynamic range is limited to around 10 nm.…”

“…The single-crystal sapphire opticalfiber sensing element [26] can accomplish the ultrahigh temperature measurement of 1600 • C, but sapphire is expensive. The optical-fiber temperature sensor with Al 2 O 3 -MgO nanocomposite as cladding material [28] has an excellent optical response and can measure temperatures from 35 • C to 80 • C. Similarly, Al 2 O 3 nanopowders [30] and surface plasmon resonance fiber-optic sensors [32] are also mostly used for temperature measurements below 100 • C, and there are still some limitations in high-temperature measurement fields such as aeroengines. The optical-fiber FPI has high-temperature resistance, high sensitivity, low production cost, and a cheap and small structure.…”