High temporal and spatial resolution distributed fiber Bragg grating sensors using time-stretch frequency-domain reflectometry

Ahmad, Eamonn J and Wang, Chao and Feng, Dejun and Yan, Zhijun and Zhang, Lin (2016) High temporal and spatial resolution distributed fiber Bragg grating sensors using time-stretch frequency-domain reflectometry. IEEE/OSA Journal of Lightwave Technology, 35 (16). pp. 3289-3295. ISSN 0733-8724. E-ISSN 1558-2213. (doi:https://doi.org/10.1109/JLT.2016.2605401) (Full text available)

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Abstract

A novel interrogation technique for fully distributed linearly chirped fiber Bragg grating (LCFBG) strain sensors with simultaneous high temporal and spatial resolution based on optical time-stretch frequency-domain reflectometry (OTS-FDR) is proposed and experimentally demonstrated. LCFBGs is a promising candidate for fully distributed sensors thanks to its longer grating length and broader reflection bandwidth compared to normal uniform FBGs. In the proposed system, two identical LCFBGs are employed in a Michelson interferometer setup with one grating serving as the reference grating whereas the other serving as the sensing element. Broadband spectral interferogram is formed and the strain information is encoded into the wavelength-dependent free spectral range (FSR). Ultrafast interrogation is achieved based on dispersion-induced time stretch such that the target spectral interferogram is mapped to a temporal interference waveform that can be captured in real-time using a single-pixel photodector. The distributed strain along the sensing grating can be reconstructed from the instantaneous RF frequency of the captured waveform. High-spatial resolution is also obtained due to high-speed data acquisition. In a proof-of-concept experiment, ultrafast real-time interrogation of fully-distributed grating sensors with various strain distributions is experimentally demonstrated. An ultrarapid measurement speed of 50 MHz with a high spatial resolution of 31.5 µm over a gauge length of 25 mm and a strain resolution of 9.1 µε have been achieved.

Item Type: Article
Uncontrolled keywords: chromatic dispersion, fiber Bragg grating, Fourier transforms, optical interferometry, frequency-domain reflectometry, time stretch
Subjects: T Technology > TK Electrical engineering. Electronics Nuclear engineering > TK5101 Telecommunications > TK5103.59 Optical communications, Fibre-optics
T Technology > TK Electrical engineering. Electronics Nuclear engineering > TK8300 Optoelectronic devices
Divisions: Faculties > Sciences > School of Engineering and Digital Arts > Broadband & Wireless Communications
Depositing User: Chao Wang
Date Deposited: 01 Sep 2016 09:35 UTC
Last Modified: 15 Aug 2017 15:43 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/57038 (The current URI for this page, for reference purposes)
Wang, Chao: https://orcid.org/0000-0002-0454-8079
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