Optical Fiber Grating Temperature And Tension Sensing System Based On Scanning Laser Source

Fiber Bragg Grating(FBG)as a new all-fiber passive components,with its unique advantages,in the field of optical fiber communication and sensing are playing a very important role.With the continuous mature and development of fiber grating sensors,multi-parameter measurement and demodulation technology has become the main research hotspot of fiber grating sensing system.Therefore,this paper studies the fiber Bragg grating temperature,axial tension sensing characteristics and demodulation technology.The paper mainly completed the following work.(1)In this paper,the definition and classification of fiber grating are introduced in detail;Based on the analysis of the axial strain,tension and temperature sensing mechanism of fiber Bragg gratings,the strain-temperature cross-sensitive problem of fiber Bragg grating is theoretically studied.(2)Aiming at the complicated part of the traditional broadband light source sensing system,a fiber grating sensing system based on linear swept light source is constructed.The demodulated signal can be swept by changing the time interval of the reflected signal of the sensing grating and the reference grating The sweep rate of the laser is obtained.(3)The temperature sensing characteristics and the tensile sensing characteristics in the water bath and in the air are experimentally studied with a single sensing grating.It is found that the temperature and tensile sensing properties of the fiber Bragg grating maintain a good linear relationship,but its temperature sensitivity coefficient in the water bath is larger than that in the air,and the factors influencing the system temperature and tensile sensitivity were analyzed.Finally,three fiber Bragg gratings are used to measure the temperature and axial tension and the experimental results are analyzed and compared.It is proved that the experimental system can measure the temperature and tension(strain)separately or simultaneously.