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Proceedings Paper

Demodulation technique based on diffraction optical element for fiber Bragg grating sensing system
Author(s): Zhongwei Feng; Li Zhang
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Paper Abstract

A new demodulation technique based on diffraction grating is proposed for high speed application. Compared with tunable filter method, the diffraction grating method has the advantages of potential high interrogation speed, high energy efficiency, no sweeping movements, which makes it a competitive interrogation method in certain field such as dynamic strain monitoring. The optical layout is crucial to guarantee the required performance of the interrogator. A structure which consists of two diffraction gratings, a fiber collimator, a reflection mirror, and a detector is adopted in the consideration of spectrum resolution, optical aberration, and geometrical size. The initial parameters for the structure are figured out by the optical path calculation involving the coefficient of the employed optical elements. The optimized procedure is following sequentially in order to minimize the aberration and obtain the pre-defined specifications theoretically. As the central wavelength for the interrogator is 1550nm, the InGaAs linear array sensor is introduced as the photoelectrical detector. Experiment of demodulation for FBG sensing system is carried out to verify the feasibility of this technique. The wavelength resolution for the interrogator is 1pm, and the demodulation speed is about 2kHz.

Paper Details

Date Published: 9 November 2010
PDF: 9 pages
Proc. SPIE 7853, Advanced Sensor Systems and Applications IV, 78530I (9 November 2010); doi: 10.1117/12.870126
Show Author Affiliations
Zhongwei Feng, Changcheng Institute of Metrology and Measurement (China)
Li Zhang, Changcheng Institute of Metrology and Measurement (China)

Published in SPIE Proceedings Vol. 7853:
Advanced Sensor Systems and Applications IV
Brian Culshaw; Yanbiao Liao; Anbo Wang; Xiaoyi Bao; Xudong Fan; Lin Zhang, Editor(s)

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