Efficient large-scale multiplexing of fiber Bragg grating and fiber Fabry-Perot sensors for structural health monitoring applications

Cranch, Geoffrey A. and Flockhart, G. M. H. and Kirkendall, C. K.; Meyendorf, N and Baaklini, GY and Michel, B, eds. (2006) Efficient large-scale multiplexing of fiber Bragg grating and fiber Fabry-Perot sensors for structural health monitoring applications. In: Advanced Sensor Technologies for Nondestructive Evaluation and Structural Health Monitoring II. Proceedings of the Society of Photo-Optical Instrumentation Engineers (SPIE), 6179 . SPIE, USA. ISBN 0819462322 (https://doi.org/10.1117/12.657416)

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Abstract

Fiber Bragg gratings have been demonstrated as a versatile sensor for structural health monitoring. We present an efficient and cost effective multiplexing method for fiber Bragg grating and fiber Fabry-Perot sensors based on a broadband mode-locked fiber laser source and interferometric interrogation. The broadband, pulsed laser source permits time and wavelength division multiplexing to be employed to achieve very high sensor counts. Interferometric interrogation also permits high strain resolutions over large frequency ranges to be achieved. The proposed system has the capability to interrogate several hundred fiber Bragg gratings or fiber Fabry-Perot sensors on a single fiber, whilst achieving sub-microstrain resolution over bandwidths greater than 100 kHz. Strain resolutions of 30n epsilon/Hz(1/2) and 2 n epsilon/Hz(1/2) are demonstrated with the fiber Bragg grating and fiber Fabry-Perot sensor respectively. The fiber Fabry-Perot sensor provides an increase in the strain resolution over the fiber Bragg grating sensor of greater than a factor of 10. The fiber Bragg gratings are low reflectivity and could be fabricated during the fiber draw process providing a cost effective method for array fabrication. This system would find applications in several health monitoring applications where large sensor counts are necessary, in particular acoustic emission.

ORCID iDs

Cranch, Geoffrey A., Flockhart, G. M. H. ORCID logoORCID: https://orcid.org/0000-0002-8777-7511 and Kirkendall, C. K.; Meyendorf, N, Baaklini, GY and Michel, B
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