Interrogation of Fibre Bragg Grating Sensors Using an Arrayed Waveguide Grating
نویسندگان
چکیده
We experimentally investigate the use of an arrayed waveguide grating (AWG) to interrogate fibre Bragg grating (FBG) sensors. A broadband light source is used to illuminate the FBG sensors. Reflected spectral information is directed to the AWG containing integral photodetectors providing 40 electrical outputs. Three methods are described to interrogate FBG sensors. The first technique makes use of the wavelength dependent transmission profile of an AWG channel passband, giving a usable range of 500με and a dynamic strain resolution of 96nε/√Hz at 13Hz. The second approach utilises wide gratings larger than the channel spacing of the AWG; by monitoring the intensity present in several neighbouring 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 an improved dynamic strain resolution of 17nε/√Hz at 30Hz.
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