Research On Temperature Measurement Calibration Technology Of Fiber Bragg Grating Temperature Sensor

As fiber Bragg grating(FBG) temperature sensor has the characteristic of intrinsic wavelength coding, resisting of electromagnetic and light-intensity fluctuation interference, and can realize quasi-distributed measurement by using division multiplex technologies, it’s widely used in temperature or stress monitoring in fields like electricity, oil, aerospace, and medicine and so on. But FBG temperature sensor is not in temperature measurement system and there’s no calibration specification for it at home and abroad, which is not helpful to the further popularization and application of FBG temperature sensor. In this paper, the quasi-distributed temperature measurement performance of FBG temperature sensor has been studied.First, the sensing and demodulation technology of FBG temperature sensor has been analyzed, the status of the development and application of FBG has been introduced and put forward a new application scenarios which has already obtained the authorization of national practical new-type patent, and the status of calibration research of FBG system has been summarized and the existing problems has been analyzed.Then, combined with laboratory temperature measuring instruments, laboratory calibration system has been designed including the hardware and software function design and realization. The equipment selection of hardware system has been discussed in detail. By using the C++ combining with SQL Server and My SQL database technology, software has been designed to acquire and process data and generate the report to improve the efficiency.To verify the theoretical results several experiments have been done. By analyzing the change of sensitivity coefficient with temperature under linear heating(-20~120) ℃ condition of FBG sensor the conclusion can be obtained that the linear relationship of sensitivity coefficient and the temperature is hold only if the temperature is below 100 ℃, when used at a higher temperature range the relationship is approximately quadratic. The method to test the temperature measurement accuracy of the beginning and the end sensors connected with fiber of 50 km shows that the distance will not affect the accuracy of quasi-distributed system. The test under linear heating(20~90) ℃ condition of 4 FBG temperature sensors shows that the temperature measurement range and the temperature sensitivity coefficient should be considered in FBG sensors layout to ensure the accuracy of all sensors in single channel. The method of uncertainty evaluation has been discussed in this paper to appraise the system.Finally, the conclusion for the research on this topic has been made. And by summarizing the existing deficiency, the next phase of the research work has been prospected. According to the analysis of experimental results, combining with existing standards and calibration standards, the draft specification of the FBG system has been established.