Multiplexed adaptive two-wave mixing wavelength demodulation of fiber Bragg grating sensor for monitoring both dynamic strains and quasi-static drifts

Yi Qiao, Sridhar Krishnaswamy*

*Corresponding author for this work

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

Abstract

A multiplexed 4-channel version of two-wave mixing (TWM) wavelength demodulator using InP:Fe photorefractive crystal (PRC) in the C-band (1530-1570nm) is demonstrated. The system can be used as a wavelength demodulator for use with Fiber Bragg Grating (FBG) sensors to monitor both dynamic strains and quasi-static strains. In this configuration, the FBG is illuminated with a broadband source, and any strain in the FBG is encoded as a wavelength shift of the light reflected by the FBG. The reflected light from the FBG is spilt into two unbalanced paths and both beams (pump and signal) mix in the PRC. Any wavelength shift of the reflected light results in an equivalent phase shift between the pump and signal beams as they travel unbalanced path lengths. Since TWM is an adaptive process, the two interfering beams are naturally in quadrature and remain in quadrature even in the presence of large quasi-static strains. In this paper, the demonstrated 4-channel TWM wavelength demodulator is able to demodulate dynamic strains from four FBG sensors simultaneously in the presence of quasi-static drifts. And with the aid of a spectrum analyzer, the quasi-static shifts caused by static strains or temperature changes are obtained by monitoring the spectral shift of the transmitted light through the FBG sensors.

Original languageEnglish (US)
Title of host publicationSmart Structures and Materials 2006
Subtitle of host publicationSmart Sensor Monitoring Systems and Applications
Volume6167
DOIs
StatePublished - Jul 17 2006
EventSmart Structures and Materials 2006: Smart Sensor Monitoring Systems and Applications - San Diego, CA, United States
Duration: Feb 27 2006Mar 1 2006

Other

OtherSmart Structures and Materials 2006: Smart Sensor Monitoring Systems and Applications
CountryUnited States
CitySan Diego, CA
Period2/27/063/1/06

Keywords

  • Fiber bragg grating
  • Photorefractive
  • Two-wave mixing
  • Wavelength demodulation

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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