Temperature Sensing Based On Chaotic Correlation Fiber Loop Ring-down System

Temperature is one of the most basic and important parameters in industrial production and system monitoring,and it is related to production safety,product quality and equipment life.Therefore,the real-time and accurate measurement of temperature is significant.However,the performance of traditional electronic temperature sensor will be weakened in some special circumstances,it is difficult to meet the measurement requirements.Thus,the interest of current research on temperature sensing is the exploration of a new type of temperature sensor,which has good insulation,reliability,and higher accuracy and is cheap.Optical sensors have been developed after the advent of lasers.Optical sensors utilize light as detection signal,it can be made into point or distributed temperature measurement system,and there are many different sensing mechanisms.Optical fiber sensor is highly chemical safety,coiling,anti-electromagnetic interference and can work in harsh environment.Fiber Bragg Grating(FBG)is an original optical fiber component and is the mainsensing elements in optical fiber sensing technology.In recent years,the fiber loop ring-down sensing which combines the advantages of optical fiber sensing and cavity ring-down technology has gradually become a new highly sensitive measurement technology.A novel sensor can be developed by integrating advanced optical fiber sensing technology and some optical fiber components.In this paper,a new type of temperature sensing system is designed,which combines FBG with fiber loop ring-down technology,chaotic laser is utilized as light source.The main work of this paper as follows:(1)The development of optical fiber temperature sensor is introduced.The principle of optical fiber temperature sensor is described and several common optical fiber temperature sensors are listed.Finally,the advantages of FBG temperature sensor are characterized and the development of FBG temperature sensor is introduced.(2)The sensing principle of fiber loop ring-down technology is presented,and the generation and characteristics of chaotic laser are introduced.Chaotic laser is utilized as the input light source of fiber loop ring-down technology instead of pulsed laser is proposed,and the decay time of chaotic autocorrelation peak is used as the sensing index.The theoretical analysis and simulation research in MATLAB of this method is conducted.In addition,the method is validated experimentally(3)A temperature sensor based on the combination of FBG and fiber loop ring-down technology based on chaotic autocorrelation is proposed.In order toverify the theoretical feasibility of the sensor,the method is deduced and validated mathematically,and the relevant numerical simulation is carried out in MATLAB.(4)A FBG temperature sensing system based on chaotic autocorrelation is built,and the temperature sensing experiment is carried out.The temperature measurement system achieves a sensitivity of 3.52ns/C and has good measurement stability.At the same time,the relationship between temperature and center wavelength of FBG is demodulated by this sensing system.