IEEE Access (Jan 2020)

Investigation of Relative Humidity Sensing Using Tapered No-Core Fiber Coated With Graphene Oxide Film

  • Hua Yang,
  • Juan Liu,
  • Bin Liu,
  • Chaowei Luo,
  • Zhen Yi,
  • Lichun Ma,
  • Sheng-Peng Wan,
  • Andrew R. Pike,
  • Yong Qing Fu,
  • Qiang Wu,
  • Xingdao He

DOI
https://doi.org/10.1109/ACCESS.2020.3041507
Journal volume & issue
Vol. 8
pp. 220755 – 220761

Abstract

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A microfiber interferometer based on a single-mode tapered-no-core single-mode (STNCS) fiber structure coated with a thin layer of graphene oxide (GO) was proposed and demonstrated as a relative humidity (RH) sensor. The STNCS fiber structure has a strong evanescent field, which can sensitively response to changes in the surrounding refractive index. The moisture-sensitive material GO was used to form the film on the no-core fiber by a dip impregnation method. The effects of GO concentration and the tapered waist diameter on RH sensitivity were studied experimentally. The experimental results showed that a thinner waist diameter provides higher RH sensitivity. When the concentration of GO solution is 0.01 mg/mL, the STNCS fiber structure with a waist diameter of 2.9 μm performs better in RH sensing; a high sensitivity of 0.461 nm/%RH in the range of 40-98% was achieved. The sensor has good stability with wavelength fluctuations of ±0.009 nm and ±0.008 nm over 60 mins at RHs of 50% and 80%, respectively. The proposed fiber optic humidity sensor has a high sensitivity over a wide measurement range and offers good stability showing promising potential application in the field of RH sensing.

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