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

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/degrees 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. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

The proposed compact ultra-high sensitivity optical fiber temperature sensor based on surface plasmon resonance can effectively adjust sensitivity by changing the twisting pitch of the helical-core fiber. The sensor has adjustable sensitivity, is easy to realize distributed sensing, and has potential application prospects in biomedical, healthcare, and other fields.