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Study On Clad-Pumped Tm~(3+)-Doped Fiber Laser

Posted on:2007-01-16Degree:DoctorType:Dissertation
Country:ChinaCandidate:Y J ZhangFull Text:PDF
GTID:1118360212970122Subject:Physical Electronics
Abstract/Summary:PDF Full Text Request
Using cladding-pumped method and high-power multimode laser diode as pumping sources, the fiber laser maximum output power has been increased greatly at room-temperature. The lasing threshold, slope efficiency and output scaling power of Tm3+-doped crystals host is sensitive to the host material temperature. The Tm3+-doped silica fiber laser can operate high efficiently with only passive cooling. The dissertation focuses on the Tm3+-doped double clad fiber laser.The absorption and fluorescent spectrums of Tm3+-doped four kind of popular laser crystals, ZBLAN fiber and silica fiber are reviewed and compared in the chapter 2. The absorption and fluorescent spectrums of Tm3+-doped in the fiber host are wider than those of crystals host. Based on a rate equation model, the lasing threshold and output power approximate analytical and quasi-analytical expression are present. The theory of mode analysis to calculate the absorption efficiency for the double-clad optical fibers is present, and the simplified expression of calculating the effective absorption coefficient is given. From the Tm3+ rates equations, pumped at CW 793nm laser, the Tm3+-doped silica fiber laser threshold characteristics, laser output characteristics, that correlated to parameters of cavity are discussed. The mechanics of 3H6,3H4→3F4,3F4 cross relaxation process due to low the lasing threshold and increase the slope efficiency. The 3H6,3H4→3F4,3F4 cross relaxation process can make the fiber laser quantum efficiency get to 2. The theoretical analysis results show that the heavily Tm3+-doped silica fiber can boost the cross relaxation probability. At the same time, relevant energy levels parameters are variable.The experimental courses and results of Tm3+-doped silica fiber laser are described in details using the single end-pumping method. It is also investigated that the fiber length, cavity structure and fiber temperature influence on the lasing threshold, slope efficiency and laser spectrum. The single-pass pump and double-pass pump results, including the lasing threshold and slope efficiency, are compared using the LMA Tm3+-doped silica fiber. Pumped the LMA Tm3+-doped silica fiber at 807.5nm output from LD,the fiber lasers acquire high efficient...
Keywords/Search Tags:fiber laser, Tm3+-doped, clad-pumped, 2μm laser, gain-switched
PDF Full Text Request
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