High-speed interferometric FBG interrogator with dynamic and absolute wavelength measurement capability

Perry, Marcus and Orr, Philip and Niewczas, Pawel and Johnston, Michael (2013) High-speed interferometric FBG interrogator with dynamic and absolute wavelength measurement capability. Journal of Lightwave Technology, 31 (17). pp. 2897-2903. ISSN 0733-8724 (https://doi.org/10.1109/JLT.2013.2276391)

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Abstract

A passive, interferometric wavelength demodulation technique has been extended to measure the absolute wavelengths of a multiplexed array of fiber Bragg grating sensors. The scheme retains its original strain resolution of 10 nε/√{Hz}. A proof-of-concept interrogation system was able to determine the absolute wavelength of Bragg peaks to within 20 pm (17 με). Static and dynamic Bragg grating strains were accurately demodulated in both absolute and relative wavelength measurement modes. This demonstration indicates that interferometric techniques are able to provide absolute, static and dynamic measurements of strain within a single platform.