Nanofilm-coated photonic crystal fiber long-period gratings with modal transition for high chemical sensitivity and selectivity

Shijie Zheng, Yinian Zhu, Sridhar Krishnaswamy

Research output: Chapter in Book/Report/Conference proceedingConference contribution

15 Scopus citations

Abstract

Using long-period gratings (LPGs) inscribed in an endless single-mode photonic crystal fiber (PCF) and coating nanostructure film into air channels in the PCF cladding with modal transition of the LPG, we have developed a fiber-optic sensing platform for detection of chemicals. PCF-LPG possesses extremely high sensitivity to the change in refractive index and chemical selectivity by localizing binding and/or absorption events in analyte solution. In this work, we numerically and experimentally investigate the behaviors of modal transition in the PCF-LPG where the air channels of PCF cladding are azimuthally coated with two types of nanostructure polymers as primary and secondary coatings by electrostatic self-assembly (ESA) deposition technique. The primary coating does not affect PCF-LPG parameters such as grating resonance wavelengths and its intensity that can be used for sensing, but it increases the sensitivity to refractive index of chemical analytes in the air channels. The secondary coating is for selective absorption of analyte molecules of interest. Those two coatings significantly modify the cladding mode distribution of PCF-LPG and enhance the evanescent wave interaction with the external environment, leading to a highly sensitive and selective chemical sensor. The integrated sensor has potential in a variety of applications, especially for nano-liter scale measurement in situ. The functional nanostructure films which respond to different parameters can be introduced into the air channels of the PCF-LPGs as transducers with chemical selectivity. In this paper, we demonstrate a fiber-optic humidity sensor with the proposed nanofilm-coated PCF-LPG for detection of corrosion in civil infrastructural health monitoring.

Original languageEnglish (US)
Title of host publicationSmart Sensor Phenomena, Technology, Networks, and Systems Integration 2012
PublisherSPIE
ISBN (Print)9780819490032
DOIs
StatePublished - 2012
EventSmart Sensor Phenomena, Technology, Networks, and Systems Integration 2012 - San Diego, CA, United States
Duration: Mar 12 2012Mar 14 2012

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume8346
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X

Other

OtherSmart Sensor Phenomena, Technology, Networks, and Systems Integration 2012
CountryUnited States
CitySan Diego, CA
Period3/12/123/14/12

Keywords

  • Fiber-optic sensors
  • fiber Bragg gratings
  • long-period gratings
  • modal transition.
  • photonic crystal fiber

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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