Non-Adiabatically Tapered Optical Fiber Humidity Sensor with High Sensitivity and Temperature Compensation

We demonstrate an all-fiber, high-sensitivity, dual-parameter sensor for humidity and temperature. The sensor consists of a symmetrical, non-adiabatic, tapered, single-mode optical fiber, operating at the wavelength near the dispersion turning point, and a cascaded fiber Bragg grating (FBG) for temp...

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Main Authors: Zijun Liang, Chao Wang, Yaqi Tang, Shoulin Jiang, Xianjie Zhong, Zhe Zhang, Rui Dai
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Sensors
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Online Access:https://www.mdpi.com/1424-8220/25/14/4390
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author Zijun Liang
Chao Wang
Yaqi Tang
Shoulin Jiang
Xianjie Zhong
Zhe Zhang
Rui Dai
author_facet Zijun Liang
Chao Wang
Yaqi Tang
Shoulin Jiang
Xianjie Zhong
Zhe Zhang
Rui Dai
author_sort Zijun Liang
collection DOAJ
description We demonstrate an all-fiber, high-sensitivity, dual-parameter sensor for humidity and temperature. The sensor consists of a symmetrical, non-adiabatic, tapered, single-mode optical fiber, operating at the wavelength near the dispersion turning point, and a cascaded fiber Bragg grating (FBG) for temperature compensation. At one end of the fiber’s tapered region, part of the fundamental mode is coupled to a higher-order mode, and vice versa at the other end. Under the circumstances that the two modes have the same group index, the transmission spectrum would show an interference fringe with uneven dips. In the tapered region of the sensor, some of the light transmits to the air, so it is sensitive to changes in the refractive index caused by the ambient humidity. In the absence of moisture-sensitive materials, the humidity sensitivity of our sensor sample can reach −286 pm/%RH. In order to address the temperature and humidity crosstalk and achieve a dual-parameter measurement, we cascaded a humidity-insensitive FBG. In addition, the sensor has a good humidity stability and a response time of 0.26 s, which shows its potential in fields such as medical respiratory dynamic monitoring.
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spelling doaj-art-c595e5caad164013bb9bdf17b8bfd4c72025-08-20T02:47:06ZengMDPI AGSensors1424-82202025-07-012514439010.3390/s25144390Non-Adiabatically Tapered Optical Fiber Humidity Sensor with High Sensitivity and Temperature CompensationZijun Liang0Chao Wang1Yaqi Tang2Shoulin Jiang3Xianjie Zhong4Zhe Zhang5Rui Dai6Future Technology School, Shenzhen Technology University, Shenzhen 518118, ChinaFuture Technology School, Shenzhen Technology University, Shenzhen 518118, ChinaFuture Technology School, Shenzhen Technology University, Shenzhen 518118, ChinaFuture Technology School, Shenzhen Technology University, Shenzhen 518118, ChinaFuture Technology School, Shenzhen Technology University, Shenzhen 518118, ChinaCollege of Engineering Physics, Shenzhen Technology University, Shenzhen 518118, ChinaFuture Technology School, Shenzhen Technology University, Shenzhen 518118, ChinaWe demonstrate an all-fiber, high-sensitivity, dual-parameter sensor for humidity and temperature. The sensor consists of a symmetrical, non-adiabatic, tapered, single-mode optical fiber, operating at the wavelength near the dispersion turning point, and a cascaded fiber Bragg grating (FBG) for temperature compensation. At one end of the fiber’s tapered region, part of the fundamental mode is coupled to a higher-order mode, and vice versa at the other end. Under the circumstances that the two modes have the same group index, the transmission spectrum would show an interference fringe with uneven dips. In the tapered region of the sensor, some of the light transmits to the air, so it is sensitive to changes in the refractive index caused by the ambient humidity. In the absence of moisture-sensitive materials, the humidity sensitivity of our sensor sample can reach −286 pm/%RH. In order to address the temperature and humidity crosstalk and achieve a dual-parameter measurement, we cascaded a humidity-insensitive FBG. In addition, the sensor has a good humidity stability and a response time of 0.26 s, which shows its potential in fields such as medical respiratory dynamic monitoring.https://www.mdpi.com/1424-8220/25/14/4390optical fiber sensorsdispersion turning pointrelative humidity sensordual-parameter sensors
spellingShingle Zijun Liang
Chao Wang
Yaqi Tang
Shoulin Jiang
Xianjie Zhong
Zhe Zhang
Rui Dai
Non-Adiabatically Tapered Optical Fiber Humidity Sensor with High Sensitivity and Temperature Compensation
Sensors
optical fiber sensors
dispersion turning point
relative humidity sensor
dual-parameter sensors
title Non-Adiabatically Tapered Optical Fiber Humidity Sensor with High Sensitivity and Temperature Compensation
title_full Non-Adiabatically Tapered Optical Fiber Humidity Sensor with High Sensitivity and Temperature Compensation
title_fullStr Non-Adiabatically Tapered Optical Fiber Humidity Sensor with High Sensitivity and Temperature Compensation
title_full_unstemmed Non-Adiabatically Tapered Optical Fiber Humidity Sensor with High Sensitivity and Temperature Compensation
title_short Non-Adiabatically Tapered Optical Fiber Humidity Sensor with High Sensitivity and Temperature Compensation
title_sort non adiabatically tapered optical fiber humidity sensor with high sensitivity and temperature compensation
topic optical fiber sensors
dispersion turning point
relative humidity sensor
dual-parameter sensors
url https://www.mdpi.com/1424-8220/25/14/4390
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AT shoulinjiang nonadiabaticallytaperedopticalfiberhumiditysensorwithhighsensitivityandtemperaturecompensation
AT xianjiezhong nonadiabaticallytaperedopticalfiberhumiditysensorwithhighsensitivityandtemperaturecompensation
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