Highly sensitive fiber-optic temperature sensor based on Lyot filter cascaded with Fabry-Perot interferometer

• Published in: Optical fiber technology 2023-10, Vol.80, p.103451, Article 103451
• Main Authors: Wu, Kaiyang, Zuo, Cheng, Zhao, Siyang, Shi, Jinhui, Guang, Dong, Yu, Benli
• Format: Article
• Language: English
• Subjects: Fabry-Perot interferometer; Lyot filter; Optical fiber temperature sensor; Ultra-fine polarization-maintaining fiber; Vernier effect
• ISSN: 1068-5200; 1095-9912
• DOI: 10.1016/j.yofte.2023.103451

•A highly sensitivity temperature sensor based on Lyot filter with Vernier effect has been demonstrated.•Because the interference spectra of Fabry-Perot interferometer and the Lyot filter are both relatively uniform, it is easy to achieve the Vernier effect.•By adjusting the length of the Ultra-fine polarization maintaining fiber (UFPMF) in the Lyot filter, it is easy to achieve higher magnification based on Vernier effect.•The reference interferometer used is insensitive to temperature.•Ultra-fine polarization maintaining fiber (UFPMF) in sensing interferometers features a high birefringence (B), which effectively reduces the size of the sensor. A highly sensitive fiber-optic temperature sensor based on a Lyot filter cascaded with a Fabry-Perot interferometer (FPI) is proposed and demonstrated in this study. The FPI consists of a segment of hollow-core photonic crystal fiber (HCPCF) spliced between two single-mode fibers (SMFs), which is insensitive to temperature and strain and is an ideal reference interferometer. The Lyot filter is composed of two polarizers with an uiltra-fine polarization maintaining fiber (UFPMF) of a certain length for temperature sensing. By adjusting the length of the UFPMF, the free spectral range (FSR) of the Lyot filter is close to FPI, resulting in an optical Vernier effect and improved sensitivity. Experimental results show that with the Vernier effect, the temperature sensitivity is enhanced from −1.145 nm/℃ to −59.31 nm/℃, and the sensitivity amplification factor is about 51.8. The proposed sensor with the Vernier effect has good performance in temperature sensing and is suitable for applications fields where high sensitivity temperature measurement is required.