Demodulation technique based on diffraction optical element for fiber Bragg grating sensing system

Zhongwei Feng; Li Zhang

doi:10.1117/12.870126

9 November 2010 Demodulation technique based on diffraction optical elements for fiber Bragg grating sensing system

Zhongwei Feng, Li Zhang

Proceedings Volume 7853, Advanced Sensor Systems and Applications IV; 78530I (2010) https://doi.org/10.1117/12.870126
Event: Photonics Asia 2010, 2010, Beijing, China

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.

Citation Download Citation

Zhongwei Feng and Li Zhang "Demodulation technique based on diffraction optical elements for fiber Bragg grating sensing system", Proc. SPIE 7853, Advanced Sensor Systems and Applications IV, 78530I (9 November 2010); https://doi.org/10.1117/12.870126

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