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Proceedings Paper

Research on the demodulation techniques of long-period fiber gratings strain sensing with low cost
Author(s): Qingwei Wang; Yueming Liu; Weijian Tian; Guilan Feng
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Paper Abstract

The working principle of LPFG(Long-Period Fiber Grating) is based on coupling effect between propagating core-mode and co-propagating cladding-modes. The effective refractive index of cladding-modes could be obviously influenced by the environmental changes resulting in LPFG more sensitive than FBG (Fiber Bragg Grating) in sensing areas, such as temperature, strain, concentration, bending and etc. LPFG should have more potential in the field of sensors compared with FBG. One of the challenges in using LPFG for environmental sensing is how to interrogate the signal from the LPFG transmission spectrum, due to the large spectral range of the resonant dip. Nowadays the application of LPFG is normally limited in signal interrogation of FBG as optical edge filter. The signal interrogation of LPFG itself needs further research. Presently research on signal interrogation of fiber grating focuses on wavelength interrogation. The aim of wavelength interrogation is to get the wavelength shift caused by environmental change. To solve these problems, a kind of strain sensing interrogation technique for LPFG with low-cost based on tunable FBGs has been developed. Comparing with the method using Fabry-Perot cavity, tunable FBGs can lower the cost with the guarantee of sensing precision. The cost is further lowered without using expensive optical instruments such as optical switch. The problem of temperature cross-sensitivity was solved by using reference gratings. An experiment was performed to demonstrate the interrogation system. And in the experiment, the sensing signal of LPFG applied 0-1300με was successfully interrogated. The results of the interrogation system and OSA are similar.

Paper Details

Date Published: 15 October 2012
PDF: 6 pages
Proc. SPIE 8418, 6th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Design, Manufacturing, and Testing of Smart Structures, Micro- and Nano-Optical Devices, and Systems, 84181P (15 October 2012); doi: 10.1117/12.973670
Show Author Affiliations
Qingwei Wang, China JiLiang Univ. (China)
Yueming Liu, China JiLiang Univ. (China)
Weijian Tian, China JiLiang Univ. (China)
Guilan Feng, China JiLiang Univ. (China)


Published in SPIE Proceedings Vol. 8418:
6th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Design, Manufacturing, and Testing of Smart Structures, Micro- and Nano-Optical Devices, and Systems
Tianchun Ye; Song Hu; Yanqiu Li; Xiangang Luo; Xiaoyi Bao, Editor(s)

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