Interferometric and fibre Bragg grating sensor interrogation using an arrayed waveguide grating

David C.C. Norman, David J. Webb, Ralf D. Pechstedt

Research output: Chapter in Book/Published conference outputConference publication


We investigate the use of an arrayed waveguide grating (AWG) to interrogate both fibre Bragg grating (FBG) and interferometric sensors. A broadband light source is used to illuminate both the FBG and interferometric sensors. Reflected spectral information is directed to an AWG with integral photodetectors providing 40 electrical outputs. To interrogate interferometric sensors we investigated the dual wavelength technique to measure the distance of a Fabry-Perot cavity, which produced a maximum unambiguous range of 1440μm with an active sensor. Three methods are described to interrogate FBG sensors. The first technique makes use of the reflected light intensity in an AWG channel passband from a narrow bandwidth grating, giving a usable range of 500με and a dynamic strain resolution of 96nε/√Hz at 30Hz. The second approach utilises wide gratings larger than the channel spacing of the AWG; by monitoring the intensity present in corresponding AWG channels an improved range of 1890με was achieved. The third method improves the dynamic range by utilising a heterodyne approach based on interferometric wavelength shift detection providing a dynamic strain resolution of 17nε/√Hz at 30Hz.
Original languageEnglish
Title of host publicationOptical sensing
EditorsBrian Culshaw, Anna G. Mignani, Rainer Riesenberg
Number of pages8
ISBN (Print)978-0-8194-5381-5
Publication statusPublished - 2004
EventOptical Sensing - Strasbourg, France
Duration: 26 Apr 200427 Apr 2004

Publication series

NameSPIE proceedings
ISSN (Print)0277-786X


ConferenceOptical Sensing

Bibliographical note

David C. C. Norman ; David J. Webb and Ralf D. Pechstedt; "Interferometric and fibre Bragg grating sensor interrogation using an arrayed waveguide grating", Proc. SPIE 5459, Optical Sensing, 101 (September 1, 2004).

Copyright 2004 Society of Photo-Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.


  • arrayed waveguide grating
  • fibre Bragg grating
  • interferometric
  • Mach-Zehnder
  • Sensor


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