Grapefruit photonic crystal fiber sensor for gas sensing application

Chuanyi Tao, Heming Wei, Yinian Zhu, Sridhar Krishnaswamy*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


Use of long period gratings (LPGs) formed in grapefruit photonic crystal fiber (PCF) with thin-film overlay coated on the inner surface of air holes for gas sensing is demonstrated. The finite-element method was used to numerically simulate the grapefruit PCF-LPG modal coupling characteristics and resonance spectral response with respect to the refractive index of thin-film inside the holey region. A gas analyte-induced index variation of the thin-film immobilized on the inner surface of the holey region of the fiber can be observed by a shift of the resonance wavelength. As an example, we demonstrate a 2,4-dinitrotoluene (DNT) sensor using grapefruit PCF-LPGs. The sensor exhibits a wavelength blue-shift of ∼820 pm as a result of exposure to DNT vapor with a vapor pressure of 411 ppbv at 25°C, and a sensitivity of 2 pm ppbv-1 can be achieved.

Original languageEnglish (US)
Article number057103
JournalOptical Engineering
Issue number5
StatePublished - May 1 2016


  • gas sensing
  • long period grating
  • photonic crystal fiber
  • sensor

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Engineering(all)


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