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Compact fiber Fabry–Perot sensors filled with PNIPAM hydrogel for highly sensitive relative humidity measurement

Lookup NU author(s): Dr Andrew Pike



This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND).


© 2022 Elsevier Ltd. A fiber-optic Fabry–Perot (FP) based relative humidity (RH) sensor was proposed and experimentally investigated by using Poly(N-isopropylacrylamide) (PNIPAM) hydrogel to connect two ends of single-mode optical fiber (SMF) to formulate a PNIPAM FP cavity. The water vapor will be absorbed by the PNIPAM hydrogel, which will alter both the refractive index (RI) and dimension of the PNIPAM FP cavity, resulting in the change of output resonance intensity in the reflective spectrum. The measure RH sensitivity is 1.634 nm/%RH within RH range from 45 to 75 % with good linearity of 0.9897 and excellent repeatability. The influence of PNIPAM hydrogel concentration on the RH sensitivity has been investigated - the higher the concentration of PNIPAM hydrogel, the higher the RH sensitivity of the sensor. The developed sensor can effectively monitor human respiratory with response and recovery time of 2.29 s and 1.90 s, respectively.

Publication metadata

Author(s): Xia R-L, Liu J, Shi J, He X-D, Yuan J, Pike AR, Chu L, Wu Q, Liu B

Publication type: Article

Publication status: Published

Journal: Measurement

Year: 2022

Volume: 201

Print publication date: 30/09/2022

Online publication date: 20/08/2022

Acceptance date: 16/08/2022

Date deposited: 09/11/2022

ISSN (print): 0263-2241

ISSN (electronic): 1873-412X

Publisher: Elsevier BV


DOI: 10.1016/j.measurement.2022.111781

ePrints DOI: 10.57711/g0ft-8m38


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