Research On Demodulation Scheme Of Long Distance Fiber Bragg Grating Sensor System

Since the 21st century,IoT technology has made great progress as an important pillar to promote the progress of intelligent society.Among them,the sensor technology that supports the Internet of Things is developing most rapidly.At present,many new types of sensors have emerged.Among them,FBG sensors,which are typical representatives,have been widely concerned due to their small electromagnetic interference,small size,and stable and reliable under high temperature and high corrosion conditions.The agency has conducted a large-scale pilot application.As the scale of the power grid continues to increase,the demand for long-distance line monitoring appears one after another,but due to the limitations of fiber loss,light source power,and noise interference in long-distance environments,the fiber grating sensing system under long-distance transmission conditions The application is caught in a bottleneck.It is of great value to study the fiber grating demodulation technology suitable for long-distance transmission environment,which is the key to promote the further engineering application of fiber Bragg grating sensing system.In this paper,the research on the demodulation scheme of the long-distance fiber Bragg grating sensing system is carried out.The scheme improves the transmission distance of the system and effectively eliminates the noise interference,and realizes the monitoring of the reflected signal of the fiber grating outside 100 km.The main research contents are as follows:1.Carry out research on the current five mainstream fiber grating demodulation schemes,and further analyze the advantages and disadvantages of each demodulation scheme according to the possible problems under long-distance engineering conditions,and optimize two demodulation schemes as long-distance demodulation prototypes.Program.2.Two long-distance fiber grating demodulation schemes are designed.Both schemes use the Raman amplifier to increase the input optical power,and the acousto-optic modulator reduces the average power of the input optical power,which effectively suppresses the noise interference while increasing the optical transmission distance.The performance of the two schemes is further discussed,and a set of schemes is preferred as the final scheme.3.Designed a long-distance fiber Bragg grating demodulator software based on Lab VIEW language and MYSQL database.According to the requirements of long-distance demodulation,four aspects of requirements analysis,system design,function development,and software testing were completed.