Study On Heat Transfer Mechanism And Thermal Tuning Technology Of Metal Coated Fiber Grating

After 30 years of development,fiber grating has now become one of the mostimportant optical passive devices in the field of fiber-optic sensing and communication,it has formed a several hundred million dollar industry and a stable field of study.With the development of fiber-optic sensor technology and optical communicationnetwork, people committed to seeking a variety of fiber grating tuning techniqueswhich have wide tuning range, high stability, quasi-unchirp and well reusability, tomake the fiber grating can change in a specific wavelength range, this technique iswidely used to the field of tunable lasers, tunable filters, tunable dispersioncompensators, optical fiber amplifier gain flatness and so on.In this thesis, the theoretical analysis and experimental study of the thermaltuning techniques of fiber Bragg grating has been discussed, the main contentsinclude:combined with the research status, analyze and summarize the advantages anddisadvantages of fiber gratings thermal tuning methods based on semiconductorcooler/heater, coil heater, double-shoulder beam device and thin film heater; By theMaxwell electromagnetic theory, analysis of the coupled mode theory to describe thecharacteristics of fiber Bragg grating, and based on coupled mode theory, the uniformfiber grating reflectivity expressions is given, simulated and analyzed the spectra ofdifferent grating length;At the same time, the transfer matrix method which cananalyze the characteristics of non-uniform fiber grating and application in a morecomplex analysis of fiber grating Fourier transform has been researched;Through theanalysis of stress and thermal tuning characteristics of fiber grating, elaborating theprinciple of the fiber grating wavelength tuning, based on thermal tuningcharacteristics, optimize the design the thermal tuning device of the metal coated fibergrating;Focus on the heat transfer model of the metal coated fiber grating,one-dimensional heat transfer model and finite element analysis model are given,usingANSYS finite element analysis software, simulate and analyze the heat transfercharacteristics of the uniform metal coating of fiber Bragg grating tuning device, obtained the temperature rising curve of the metal coated fiber Bragg grating and theaxial thermal diffusion length which provide a basis for the geometric design of thedevice;Build an experimental optical path and achieve a thermal tuning rangemeasurement of metal coated fiber Bragg grating, gained 2.226nm thermal tuningrange.