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Open AccessArticle
Balloon-Shaped Optical Fiber Humidity Sensor Based on PVA Coating for Respiratory Monitoring
by
Qingfeng Shi
Qingfeng Shi
Qingfeng Shi received a Master’s degree in physical education and training from Huaibei Normal in [...]
Qingfeng Shi received a Master’s degree in physical education and training from Huaibei Normal University, Huaibei, China, in 2013, and a Ph. D. degree in Physical education and training from Shinhan University, Gyeonggi-do, South Korea, in 2021. He is currently a Lecturer with the Sports Department, Taishan University, Taian, China. His research interests include exercise promotes health, smart sports and physical education.
Yunkun Cui
Yunkun Cui
Yunkun Cui received a Master’s degree in physical education and training from Fujian Normal China, [...]
Yunkun Cui received a Master’s degree in physical education and training from Fujian Normal University, Fuzhou, China, in 2007, and a Ph. D. degree in Physical education and training from Beijing Sport University, Beijing, China, in 2015. He is currently a Professor with the Sports Department, Taishan University, Taian, China. His research interests include exercise promotion of health, smart sports and fitness for all.
Wenyan Xu
Wenyan Xu
Wenyan Xu received a B.S. degree in optoelectronic information science and engineering, and an in of [...]
Wenyan Xu received a B.S. degree in optoelectronic information science and engineering, and an M.Eng. degree in electronic information from University of Jinan, Jinan, China, in 2021 and 2024, respectively. He is currently working towards a doctorate in optical engineering, Harbin Engineering University. His research interests include fiber-optic sensing and micro-nano fiber sensors.
Yu Zhang
Yu Zhang
Yu Zhang received a B.Eng. degree in electronic information science and technology from Yantai of in [...]
Yu Zhang received a B.Eng. degree in electronic information science and technology from Yantai Institute of Technology, Yantai, China, in 2024. He is currently working towards a Master’s degree in optoelectronic information engineering, University of Jinan. His research interests include fiber-optic sensing and micro-nano fiber sensors.
Feng Peng
Feng Peng
Feng Peng received a B.Eng. degree in Electronic Science and Technology, an M.Eng. degree in Optical [...]
Feng Peng received a B.Eng. degree in Electronic Science and Technology, an M.Eng. degree in Optical Engineering, and a Ph. D. in Optical Engineering from Harbin Engineering University, Harbin, China, in 2007, 2009, and 2012, respectively. He is currently an Associate Professor at the School of Physics and Technology, University of Jinan, Jinan, China. His research interests include fiber optic sensors and optic interferometers.
1
Sports Department, Taishan University, Taian 271021, China
2
College of Physics and Optoelectronic Engineering, Harbin Engineering University, Harbin 150001, China
3
School of Physics and Technology, University of Jinan, Jinan 250022, China
*
Authors to whom correspondence should be addressed.
Photonics 2026, 13(1), 2; https://doi.org/10.3390/photonics13010002 (registering DOI)
Submission received: 6 November 2025
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Revised: 18 December 2025
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Accepted: 18 December 2025
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Published: 19 December 2025
Abstract
A polyvinyl alcohol (PVA)-coated optical fiber humidity sensor for respiratory monitoring is proposed. The humidity sensor forms a fiber Mach–Zehnder interferometer (MZI) by bending the single-mode fiber (SMF) coated with PVA. The refractive index of PVA coatings varies with changes in relative humidity (RH), causing phase changes in higher-order modes and resulting in shifts in the transmission spectrum. The sensor exhibits excellent dynamic humidity response performance (92.8 ms for response time and 63.6 ms for recovery time), realizing a humidity sensitivity of −1.927 nm/%RH within the humidity range of 86.1% to 92.2%. Compared to the balloon-shaped fiber optic sensor based on polydimethylsiloxane (PDMS) coating previously proposed by our research group, the PVA coating facilitates easier surface composite on the fiber, exhibits faster response speed, and its humidity response range is more suitable for respiratory monitoring. Ultimately, the sensor was encapsulated within a mask to enable human respiration monitoring functionality.
Share and Cite
MDPI and ACS Style
Shi, Q.; Cui, Y.; Xu, W.; Zhang, Y.; Peng, F.
Balloon-Shaped Optical Fiber Humidity Sensor Based on PVA Coating for Respiratory Monitoring. Photonics 2026, 13, 2.
https://doi.org/10.3390/photonics13010002
AMA Style
Shi Q, Cui Y, Xu W, Zhang Y, Peng F.
Balloon-Shaped Optical Fiber Humidity Sensor Based on PVA Coating for Respiratory Monitoring. Photonics. 2026; 13(1):2.
https://doi.org/10.3390/photonics13010002
Chicago/Turabian Style
Shi, Qingfeng, Yunkun Cui, Wenyan Xu, Yu Zhang, and Feng Peng.
2026. "Balloon-Shaped Optical Fiber Humidity Sensor Based on PVA Coating for Respiratory Monitoring" Photonics 13, no. 1: 2.
https://doi.org/10.3390/photonics13010002
APA Style
Shi, Q., Cui, Y., Xu, W., Zhang, Y., & Peng, F.
(2026). Balloon-Shaped Optical Fiber Humidity Sensor Based on PVA Coating for Respiratory Monitoring. Photonics, 13(1), 2.
https://doi.org/10.3390/photonics13010002
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