Study On High-speed GaAs Optical Fiber Temperature Sensing Technology And Its Application

Temperature is one of the main physical quantities of non-electricity measurement in power transmission equipment.It is played an important role in maintaining the normal operation of power system and improving the reliability of power supply.Accurate control of temperature is become an indispensable part of social production practice.Traditional temperature measurement methods such as thermocouples,infrared temperature measurement have become a conventional method for measuring the surface temperature of objects in power equipment.However,in the complex environment of strong magnetic field,large current and high voltage inside the electrical equipment,the traditional temperature measurement method is greatly limited.Optical fiber temperature sensor based on optical principle is an effective measurement tool in these occasions.Fiber has the characteristics of good electrical insulation,small size,light weight,corrosion resistance and electromagnetic interference resistance.With the rapid development of optical fiber manufacturing technology and optical fiber sensing technology,optical fiber temperature sensor and optical fiber sensing temperature measurement technology will become one of the important development directions.In this paper,combined with the research status at home and abroad,the technical characteristics of optical fiber temperature measurement has been analyzed by comparing with the traditional temperature measurement technology,and the optical properties of Ga As crystal is further studied.Firstly,the principle of gallium arsenide temperature sensing technology is explored,and a simplest temperature measurement model is built for experiments.Then the fabrication and packaging process of gallium arsenide optical fiber temperature sensor has been studied.Then the fabrication and packaging process of gallium arsenide optical fiber temperature sensor has been studied.The material selection of optical fiber temperature sensor,the design of temperature probe structure and the design of the overall sensor have been described in detail,and the stability and accuracy of its work is tested by experiments.Finally,a high-speed temperature measurement system based on spectral analysis is designed.The principle and function of the system have been introduced in detail from two aspects of hardware and software,and the practicability and effectiveness of the temperature measurement system is tested by using PC software.The reflection spectrum of gallium arsenide material has absorption edge,and the absorption edge will have moved to longer wavelength with the increase of temperature.In this paper,a concept of equivalent wavelength based on the local area of the reflection spectrum,and a new temperature demodulation method and data processing flow have been prepossessed based on this principle.The temperature measurement error caused by spectral jitter and superposition effect caused by high-speed acquisition can be avoided by this method.The experimental results show that the temperature measurement error of the high-speed Ga As multi-channel optical fiber temperature monitoring system designed in this paper is less than ± 0.2 °C in the temperature range of-20 °C?60 °C.The temperature measurement error is less than ± 0.5 °C in the temperature range of 60 °C ?250 °C.And the accuracy and reliability of the whole temperature measurement system is verified.