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| The Measurement of the Refractive Index and Concentration of Solutions Based on Long-period Gratings |
| HU Xing-liu1,2,LIANG Da-kai1,ZENG Jie1,LU Guan1 |
1. The Aeronautical Science Key Laboratory for Smart Material and Structures, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangshu 210016, China
2. College of Information and Electric Engineering,Anhui University of Technology, Ma’an Shan, Anhui 243002,China |
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Abstract The resonant peaks of long-period grating pair are sensitive to external refractive index.According to this characteristic, on-line and real-time measurement of liquids refractive index and concentration can be realized. NaCl and sugar solutions which are of different refractive index are studied. The relationships among refractive index, concentration and resonant peaks are obtained. The experimental results show that the LPGP is sensitive to the external refractive index which is in the range of 1 to 1.4513, when the external refractive index increase, the amplitude of loss peak decrease gradually and the central wavelength has a blue shift.This sensor is quite useful for chemical, pharmaceutical, biological, and process control sensing applications and it has very high practical value.
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2011, Vol. 32 
