Study on the Temperature Characteristics of Fiber Grating

In recent years , fiber grating temperature sensor in the measurement of the actual project has been widely used. However , current research on fiber grating temperature sensing properties mostly uniform temperature throughout fiber grating resonant wavelength with temperature change characteristics . In some areas , you need to get real-time fiber grating local temperature changes , such as fiber grating transient temperature measurement and its temperature study of the dynamic response characteristics , when suffered rapid temperature changes , the fiber grating material has thermal inertia , suffered temperature change information can not be obtained in real time . Therefore , a local transient temperature characteristics of the fiber grating research has important implications . Based on this, by the the moderate linear temperature under fiber grating reflection spectrum of the fiber grating local transient characteristics . The specific contents include : First, the system introduces the basic theory of fiber grating fiber grating mode coupling theory and transfer matrix method and the scope of application of the two methods . Analysis of the characteristics of the reflection spectrum of the fiber grating , fiber grating stress and temperature sensing model . Secondly , a detailed analysis of the characteristics of the the fiber gratings local transient affected by temperature . Based on the transfer matrix method to establish a of fiber gratings local transient affected by temperature reflection spectrum model found its reflection spectrum split when the the fiber gratings local short transient affected by temperature , through theoretical study and simulation , and the split point linear the cyclical movement, the reflectance of the split point and subject to temperature relationship of the position of the approximate hyperbolic tangent relationship . Obtained on this basis the parameters and the bandwidth of the reflection spectrum , reflection spectrum of the relationship between the amount of the symmetric wavelength drift . Then, the analysis of the reflection spectrum of the fiber grating linear function of temperature characteristics . Fiber grating by a linear function of temperature , is proportional to the slope of the reflection spectrum bandwidth ; temperature of the initial value , the slope of the reflection spectrum symmetry found through theoretical study and simulation based on the transfer matrix method to establish the model of a linear function of temperature fiber grating reflection spectrum proportional to the wavelength drift . Finally, the experimental study of the fiber gratings local transient affected by temperature characteristics . The results verify the correctness of theoretical analysis and simulation study provides a theoretical basis for the application of fiber grating temperature sensor field .