Simultaneous measurement of temperature and stain using LPFG and HBF loop mirror

A simultaneous measurement system of temperature and strain is proposed using a long period fiber grating(LPFG) and a high-birefringence fiber(HBF) loop mirror,based on their resonant wavelengths corresponding to different temperatures and strain sensitivities.Based on the theoretical analysis,the resonant wavelength response sensitivities to temperature and strain for long-period fiber grating and high-birefringence fiber loop mirror are experimentally determined,respectively.And then,the correlation coefficient matrix is constructed,so temperature and strain are discriminated.In the system,the temperature and strain measurement accuracies are ± 0.36 ℃ and ± 13.7 μe,respectively.With the experimental data of temperature and the simultaneous measured experimental data of temperature and strain,the analytical curve of the strain is calculated to verify the validity of the system.The results show that this system can solve the cross-sensitivity problem in the measurement of strain and temperature,and can effectively improve the system accuracy.