[Objective]In order to solve the problem of cross sensitivity of temperature and strain in Fiber Bragg Grating(FBG)sensing,the response characteristics of temperature and strain in each mode of Few Mode Fiber(FMF)-FBG were studied in this paper.A four-mode FBG temperature and strain dual parameter sensor was also proposed.[Methods]The basic mode and a few higher modes can be transmitted simultaneously in the low-mode fiber,taking into account the advantages of low mode dispersion of Single Mode Fiber(SMF)and low nonlinearity of multi-mode fiber,which can be used for sensing multiple physi-cal quantities at the same time.By analyzing the different optical power sensitivity of the LP01 mode in the FMF-FBG at differ-ent temperatures,and considering the good linearity of wavelength,temperature and strain under this mode.Thus,the tem-perature and strain dual parameter sensing of FMF-FBG is realized.[Results]The results show that the sensor can better solve the problem of cross sensitivity of temperature and strain.[Conclusion]Compared with SMF-FBG,the FMF-FBG has several reflection peaks of different modes at the same time,which can not only solve the cross-sensitivity problem of temperature and strain,but also greatly improve the accuracy and stability of sensing,which may have a good application prospect in the field of new type of sensing.
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