Temperature insensitive air-cavity Fabry-Perot gas pressure sensor based on core-offset fusion of hollow-core fibers

Mao qing Chen, He ming Wei*, Yong Zhao, Xiao hua Lei, Sridhar Krishnaswamy

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

A temperature insensitive air-cavity Fabry-Perot Interferometer (FPI) based on core-offset fusion (FPI-CFH) of hollow-core fibers with different inner diameters was developed. This sensing structure consists of input single mode fiber (SMF), two short sections of hollow-core fibers (HCF1 and HCF2), and a gold film. The HCF1 with an inner diameter of 70 μm is used to construct air-cavity FPI, and the HCF2 with an inner diameter of 10 μm is offset spliced with HCF1 to provide a flat reflective surface of air-cavity FPI, which can increase the reflection to enhance the fringe contrast, and meanwhile the microfluidic channel of HCF2 is used for the gas inlet. The left end-face of HCF2 is coated with gold film (the thickness of ∼50 nm) to improve the light reflectivity, so that, increasing the fringe contrast of air-cavity FPI spectrum. The experimental results show that the proposed FPI-CFH sensor has a high gas pressure sensitivity of 4.314 nm/MPa with a good linear response (the value of R-Square is 0.9987) when the gas pressure increases from 400 to 1000 kPa, and what's more, the proposed sensor has a negligible temperature cross-sensitivity (0.0051nm/°C) in the range of 20–80 °C due to the structure of all-fiber and the essential characteristics of air-cavity FPI. The maximal relative error of the proposed sensor in the measurement process of gas pressure decrease is less than 1%, which illustrates the sensor has good precision and repeatability. Moreover, the proposed sensor has good stability in a long-term gas pressure testing. Therefore, the proposed FPI-CFH sensor can achieve high precision gas pressure sensing but is insensitive to the variation of temperature.

Original languageEnglish (US)
Article number111589
JournalSensors and Actuators, A: Physical
Volume298
DOIs
StatePublished - Oct 15 2019

Keywords

  • Core-offset fusion
  • Fabry-Perot interferometer
  • Gas pressure sensor
  • Hollow-core fiber
  • Optical fiber sensor

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Instrumentation
  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Electrical and Electronic Engineering

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