Simultaneous Discriminating Measurement of Temperature and Strain Based on a Long Period Grating’s Spectrum
HU Xing-liu1,2, LIANG Da-kai1*, LU Guan1, ZENG Jie1
1. The Aeronautical Science Key Laboratory for Smart Material and Structures, Nanjing University of Aeronautics and Astronautics, Nanjing 210016，China 2. College of Information and Electric Engineering，Anhui University of Technology, Maanshan 243002，China
Abstract：The new scheme of using a long period grating for simultaneous discriminating measurement of temperature and strain is proposed. The scheme is based on the long period grating’s spectrum characteristics. The spectrum is composed of multiple and different loss peak. The resonant wavelength of the first and fourth-order loss peak with different temperature and strain sensitivity was selected in this experiment. The wavelength shift resulting from parameter variation can be obtained by observing its corresponding spectrum. The temperature was acquired by a study on the temperature characteristic of a LPG. The strain sensitivity was obtained by the research on the strain characteristic of a LPG. The standard matrix equation was set up and solved according to the corresponding parameter. The authors know by calculating the standard matrix equation that the cross-sensitivity has little influence on the measurement of the parameter. As the effect of cross-sensitivity is lower than the resolution of the LPG in this case, we can eliminate the deviation due to the cross-sensitive by appropriate compensation. The errors of temperature and strain were calculated to be ±0.92 ℃ and ±22 με respectively. The cross-sensitivity between temperature and strain was decreased and the measuring precision of the system was improved by using this scheme in which a single long period grating was used to test two measurands. By comparison between the applied and the calculated temperature and strain of a LPG, the experiment results showed that the methods are feasible.The experimental system is small and the cost is relatively low. The experimental device is simple and practical and has good application prospect.
Key words：Long period fiber grating;Temperature sensing;Pressure sensing;Simultaneous measurement;Fiber
胡兴柳1,2，梁大开1*，陆 观1，曾 捷1 . 基于单长周期光纤光栅光谱特性的温度和应变同时区分测量[J]. 光谱学与光谱分析, 2010, 30(03): 851-854.
HU Xing-liu1,2, LIANG Da-kai1*, LU Guan1, ZENG Jie1 . Simultaneous Discriminating Measurement of Temperature and Strain Based on a Long Period Grating’s Spectrum . SPECTROSCOPY AND SPECTRAL ANALYSIS, 2010, 30(03): 851-854.
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