Development Of FBG Demodulator Based On Tunable Laser And Its Application In Strain Detection Technology

Fiber Bragg Grating(FBG)is an optical fiber sensor with the advantages of high sensitivity,light weight,and strong anti-interference ability.It is widely used in aerospace,petrochemical and other sensing fields.Strain detection is one of the most widely used applications of fiber grating sensors.Fiber gratings are wavelength-modulated fiber-optic sensors,and the accurate demodulation of wavelengths is the basis for sensor applications.In recent years,it is a research hotspot to develop the fiber grating demodulator based on tunable semiconductor lasers.Firstly,on the basis of analyzing the principle of fiber grating strain sensing,the surface paste fiber grating strain sensor of metal packaging is designed and calibrated.The structure and transfer model of the sensor are simulated and analyzed by ANSYS software,and the transmission efficiency and precision of the sensor are improved.Secondly,based on the analysis of the working principle of the demodulator,a design scheme of demodulator based on tunable semiconductor laser is proposed,the hardware and software design of the demodulator is completed,and four channels of synchronous high-precision demodulation are realized.The design of hardware includes the module design of power supply,laser drive,photoelectric conversion and data acquisition.In the aspect of software design,the C language code is written,including all drivers module and peak finding algorithms.And it is realized to display and save the central wavelength and spectrum of the sensor on the computer.Finally,the system test platform is built.The performance of fiber grating strain sensor and demodulator is tested.And the experimental results shows that the designed sensor can complete the high precision strain measurement on the surface of the object,and the demodulator can accurately demodulate the wavelength of the FBG sensor.In summary,this paper researched the status of strain detection and fiber Bragg grating demodulator.On the basis of the research,a kind of surface pasted FBG strain sensor is developed,and the structure design of the sensor is completed.Furthermore,a fiber grating demodulator are developed,which is based on tunable semiconductor laser.The hardware and software design of the demodulator is completed and the strain high precision detection is realized.These has laid a foundation for deepening the application of FBG sensors and the development of more accurate and faster fiber Bragg grating demodulator.