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Tunable Yb3+-doped Double-clad Fiber Lasers

Posted on:2010-04-20Degree:MasterType:Thesis
Country:ChinaCandidate:Y Y FanFull Text:PDF
GTID:2178360275494327Subject:Circuits and Systems
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Wavelength-tunable Yb3+-doped double-clad fiber(YDCF) lasers have great potential applications in many fields.In this thesis,theoretical and experimental investigations on wavelength-tunable YDCF lasers are reported.The research and development of the rare-earth doped fiber lasers and tunable fiber lasers are reviewed.The structures and principles of tunable YDCF lasers are introduced,including the structures and properties of YDCF,the pump and laser beam coupling,and optical resonant cavities.Then,the common methods for laser wavelength tuning are discussed.The diffraction effects of blazed gratings are analyzed,and the operation principles of blazed gratings in Littrow and Littman structures are compared.Numerical simulations of the YDCF lasers have been performed using the energy levels and spectrum properties of Yb3+ ions.The effects of reflectivities of cavity mirrors,scattering loss and fiber length on the output characteristics are analysed.The optimum fiber length of YDCF for maximizing laser output power is calculated.The characteristics of tunable YDCF lasers have been experimentally studied, and a YDCF laser prototype is successfully developed.Using a 975 nm high power multimode laser diode(LD) as the pump source,large-mode-area YDCF with an optimal length as the gain medium,and an external cavity based on Littrow configuration,a YDCF laser system was initially constructed on an optical table.The techniques for the YDCF end face polishing and the adjusting the optical components are presented.The demonstrated tunable YDCF laser has a wide tuning range from 1045 nm to 1125 nm,a good beam quality with M2x=1.23,M2y=1.20,a maximum output power of 30 W at 1089 nm,and the stable operation has been demonstrated.The performance specifications of the laser are in line with our expectations,and are at the national leading edge.The work reported in this paper has raised the national level of research and development in tunable YDCF lasers,and laid a good foundation for the further research and development.
Keywords/Search Tags:Fiber Laser, Yb3+ -doped Double-clad Fiber, Wavelength Tunable
PDF Full Text Request
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