Adaptive fiber bragg grating demodulator for structural health monitoring applications

Yi Zhou*, Goutham Kirikera, Sridhar Krishnaswamy

*Corresponding author for this work

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

2 Scopus citations


An adaptive fiber Bragg grating demodulator is developed for structural health monitoring applications using two-wave mixing interferometer technology. This demodulator uses the photorefractive (PRC) InP: Fe crystal to demodulate the spectral shifts from the fiber Bragg grating (FBG) sensor. Any strains applied on the FBG sensors are encoded as wavelength shifts of the light reflected by the FBG sensor. The wavelength shift is converted into phase shifts and then demodulated by a TWM interferometer with unbalanced path in its reference and signal beam. The low frequency signals, such as signals caused by large quasi-static strain or large temperature drift applied on the FBG sensors, are automatically filtered by the demodulator. One of the structural health monitoring (SHM) applications, acoustic emission event detection and source location determination in a plate structure, will be demonstrated using this demodulator. In this application, a FBG sensor with large dynamic response range is glued on the surface of an aluminum plate. The demodulator actively monitors the FBG sensor. Once there is a dynamic spectral shift signal from the FBG sensor, the demodulator will be triggered to record the signal from the FBG sensor. The recorded signal is used to determine the source location of the acoustic emission event by wavelet transform technique.

Original languageEnglish (US)
Title of host publicationSAMPE '07
Subtitle of host publicationM and P - From Coast to Coast and Around the World; Conference Proceedings
StatePublished - 2007
EventSAMPE '07: M and P - From Coast to Coast and Around the World - Baltimore, MD, United States
Duration: Jun 3 2007Jun 7 2007

Publication series

NameInternational SAMPE Symposium and Exhibition (Proceedings)
ISSN (Print)0891-0138


OtherSAMPE '07: M and P - From Coast to Coast and Around the World
Country/TerritoryUnited States
CityBaltimore, MD


  • Fiber Bragg grating
  • Source location determination
  • Two-wave mixing
  • Wavelength demodulation

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering


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