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Study On Double-clad Yb-doped Fiber Laser And Relaxation Oscillation In Solid-state Laser

Posted on:2004-12-25Degree:MasterType:Thesis
Country:ChinaCandidate:M ChenFull Text:PDF
GTID:2168360122467343Subject:Optics
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Fiber laser is an important kind of solid-state lasers. Double-clad pumped Yb-doped fiber laser has the advantages of compact structure, simple cooling, broad pumping wavelength, high efficiency, high power, long-life. There are many applications of fiber laser in optical communication, industry process, medical treatment, laser printing and label-making. Recently, the scientists go deep into the study on double-clad pumped fiber laser in both theory and experiment, such as high output power, Q-switching, mode-locking, CW tuning and nonlinear optics.We realize the first fiber laser of our lab. A laser diode with 976nm center wavelength and 2.03W maximum CW output power is pumping unidirectionally through the couple-imaging system on a double-clad Yb-doped silica fiber with a Yb-concentration 0.65 mol% circular inner core, a D-shaped inner clad, and 15m length by F-B cavity. The center wavelength of the fiber laser is 1130nm, and the maximum CW output power is 130.7mw. An optical-to-optical conversion efficiency of 42% and a slope efficiency of 63.4% are obtained. The character of fiber laser spectrum is measured by optical spectrum analyzer. The experiment approves the relationship of loss, threshold and lasing wavelength, which is that the higher loss, the higher threshold, and the shorter lasing wavelength. We have observed and recorded the relaxation oscillation of double-clad Ytterbium-doped fiber laser by a digital oscillograph. The relaxation oscillation frequency is 20.0kHz.The other work is the theory study on the relaxation oscillation of solid-state lasers. The relaxation oscillation in solid-state laser with relaxation oscillation pumping is studied theoretically by the rate equation. The undulation of the laser photon density contains relaxation oscillation frequency itself and that of pumping. When those two frequencies are close, the oscillation will be resonated. Especially, when the decay rates of the two frequency oscillations are same, the resonation will be strengthened greatly. PD feedback can restrain the relaxation oscillation effectively.
Keywords/Search Tags:double-clad pumped fiber laser, Yb-doped, solid-state laser, relaxation oscillation, PD feedback
PDF Full Text Request
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