Temperature insensitive torsion sensor based on ring-core fiber orthogonal core-offset structure

• Published in: Measurement : journal of the International Measurement Confederation 2023-06, Vol.215, p.112868, Article 112868
• Main Authors: Zhang, Qishuang, Chen, Yao, Wang, Ying, Ling, Qiang, Gu, Zhengtian, Chen, Daru, Jiang, Xiuli
• Format: Article
• Language: English
• Subjects: Mach-Zehnder interferometer; Optical fiber sensors; Ring-core fiber; Temperature-insensitive; Torsion
• ISSN: 0263-2241
• DOI: 10.1016/j.measurement.2023.112868

•A novel temperature-insensitive torsion sensor based on ring-core fiber orthogonal core-offset structure has been proposed and discussed in detail.•The sensor exhibits high linear torsion sensitivity of −0.2 nm/(rad/m) in the range of 0 rad/m to 28.5599 rad/m and low cross-sensitivity from temperature.•The sensor is compact and easy to make. We have proposed a temperature-insensitive fiber-optic torsion sensor based on ring-core fiber (RCF). The sensor is fabricated by orthogonal core-offset splicing between the RCF and single-mode fiber. Due to the core-offset structure, the Mach-Zehnder interference is enhanced, and the torsion sensing is realized. The sensor is fabricated and tested, exhibit high linear torsion sensitivity of −0.2 nm/(rad/m) in the range of 0–28.5599 rad/m and −0.079 nm/(rad/m) in the range of −25.3866–0 rad/m. The torsion increasing and decreasing process proves the good reliability of our sensor. Besides, through the temperature sensing, it is found that our sensors show a low temperature sensitivity of 26.4 pm/°C in the temperature range from 30 °C to 90 °C, which reduces the cross-sensitivity between torsion and temperature. Thus, the sensor can be used in structural conventional health monitoring, biomechanics due to many advantages such as sample size, low-cost and high sensitivity.