The Research Of Distributed Optical Fiber Temperature Measurement System Based On Raman Scattering Principle

The Distributed Optical Fiber Temperature Measurement System Based on Raman Scattering Principle utilizes the temperature-sensitive characteristic of spontaneous Raman scattering combined with the positioning principle of optical time-domain reflection to achieve the distributed measurement of temperature.Distributed optical fiber temperature measurement technology,which was first proposed in the 1970 s,after 40 years of research and development,is widely used in Aerospace,power,petroleum,military and other fields with its advantage of anti-electromagnetic interference,small size,light weight and longdistance temperature measurement,etc.Based on the deep research on the theory of distributed optical fiber temperature measurement,this thesis designed and developed a distributed optical fiber temperature measurement system based on Raman scattering.In this thesis,the traditional temperature demodulation method had been improved and optimized to improve the accuracy of temperature measurement and position location.This thesis is divided into six parts,the main contents are as follows:The first part is introduction,the current situation of distributed Raman temperature measurement system at home and abroad,and research background,significance as well as the main research content in this thesis were introduced briefly.The second part described the theory of distributed optical fiber temperature measurement system and the principle of temperature measurement.The third part introduced the overall design of distributed optical fiber Raman temperature measurement system,selected and developed the system components through the analysis of system performance indicators.The fourth part is the focus of this thesis.In this part,the key technologies of the system were analyzed,including temperature calibration,weak signal extraction and demodulation algorithm optimization,and a new compensation algorithm for fiber dispersion and loss was proposed,greatly improving the temperature accuracy of the system measurement.A software of the system was designed and a detailed performance test was carried on the distributed Raman temperature measurement system.The design process and test result analysis were presented in the fifth part.Quantitative analysis shows that the distributed fiber Raman temperature measurement system can reach the performance of temperature measuring distance of 9km,spatial resolution of 2.2m,temperature resolution of2°C,temperature measurement accuracy of 1.5°C and positioning accuracy of 0.1m.The sixth part is the summary and prospect of this thesis.