Research On Key Technology Of High-speed Multi-channel Fiber Bragg Grating Sensing Demodulation

The Internet of Things technology,as a significant force to accelerate human society to a smart society,has been fully developed,especially the sensors,which are an important means of sensing the Internet of Things,and its development is changing with each passing day.Fiber Bragg grating sensor is a new type of sensor with passive,electrical insulation and strong anti-electromagnetic characteristics,which provides the possibility for sensing and detection under various complex and harsh environmental conditions,and has received extensive attention and use.However,in high-speed dynamic fields such as aerospace and industrial measurement,one must realize high-speed demodulation of high-frequency sensor information,and two must realize multi-point monitoring of physical quantities.Due to the limitation of demodulation frequency,traditional fiber grating demodulation instruments cannot fully utilize the advantages of fiber grating sensors in the field of dynamic measurement.However,most systems capable of high-speed demodulation are often expensive and sensitive to environmental changes,and cannot meet monitoring requirements.demand.In view of the above situation,this article has carried out the research of high-speed multi-channel demodulation technology and realized the demodulation system,which is of great significance for further promote the application of optical fiber sensing in the high-frequency field.The content is as follows:1.The high-speed multi-channel fiber grating sensor demodulation system is designed as a whole,which is divided into the hardware system of the lower computer and the software of the upper computer.The communication and data transmission between the two is realized and the optical device is selected.Then,focusing on the two aspects of high-speed and multi-channel,the key technology of the sensor demodulation system is studied,and the peak finding algorithm based on the centroid algorithm is proposed.Then the temperature compensation is used to eliminate wavelength drift and realize multi-channel acquisition,and finally optimize the performance of wavelength data persistence.2.Design and complete the host computer software of the fiber grating demodulation system.According to the software development process,the development of the upper computer software is divided into four stages:demand analysis,scheme design,detailed implementation,and system testing.The software realizes the functions of sensor demodulation system initialization,wavelength demodulation,wavelength information display,and wavelength data persistence.3.Performance test of the fiber grating demodulation system.Through temperature experiments,it is analyzed that the wavelength accuracy of the demodulation system is ±2pm,the wavelength stability is ±1pm,and the linearity can reach 0.99994.The dynamic demodulation capability of the demodulation system is verified through vibration experiments and the maximum demodulation frequency measured is up to 10kHz.