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.
|Title of host publication||Optical sensing|
|Editors||Brian Culshaw, Anna G. Mignani, Rainer Riesenberg|
|Number of pages||8|
|Publication status||Published - 2004|
|Event||Optical Sensing - Strasbourg, France|
Duration: 26 Apr 2004 → 27 Apr 2004
|Period||26/04/04 → 27/04/04|
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