Strain sensing of modern composite materials with a spatial/wavelength-division multiplexed fiber grating network

A spatial/wavelength-division multiplexing topology with combination of a tunable-wavelength filter and an interferometric wavelength scanner is used to interrogate a range of fiber Bragg grating (FBG) strain sensors embedded in modern composite materials. A nine-element FBG sensor system based on this topology is demonstrated for quasi-static strain sensing of a carbon fiber reinforced plastic plate for aerospace applications. Preliminary experimental results show that a strain resolution of ~1.8micro rms with an ~30-Hz bandwidth (~0.32micro/ radicalHz) for quasi-static strain measurement has been achieved.