The Theoretical And Experimental Study On High Power Tm-doped Fiber Laser

In recent years, with the study on rare ion-doped fiber lasers deepen increasingly,Tm-doped fiber laser has been focused on by a great deal of countries and scientists dueto its important applications on remote sensing, lidar, medicine and optical parameteroscillator and so on. Compared to the conventional Yb-doped fiber laser, Tm-dopedfiber laser possesses a wider tunable range, works at eye-safe wavelengths, and hashigher thresholds for various nonlinear effects, which makes Tm-doped fiber lasers havemore advantages on high power output. On the base of these advantages, we study theTm-doped fiber laser theoretically and experimentally in this paper.At first, this paper reviews the recent development on CW Tm-doped fiber laser,presents the development and applications of Tm-doped fiber laser on coherent andspectrum combinations, and elucidates the important applications of Tm-doped fiberlaser on remote sensing, lidar, medicine and optical parameter oscillator.In allusion to the complex energy levels of Tm3+ions and various cross-relaxationprocesses involved in the process of laser oscillation, we propose the space-propagationmodel for the Tm-doped fiber laser. Compared to the conventional models, this modelhas significant advantage in reducing the required computing resources and improvingthe computing efficiency significantly.We deduce the three-order approximation of electromagnetic waves in the slightlyperturbed optical waveguide, and propose the modal coupling equations applicable inthe multimode fiber under the one-order approximation of electromagnetic waves. Thenwe analyze the impacts of various factors on the index distribution in the Tm-dopedfiber amplifier, and perform numerical simulation with the modal coupling equation inorder to elucidate the impacts of various factors on the modal interaction in the fiber.Based on the theoretical studies mentioned above, this paper has performed a greatdeal of experiments on Tm-doped fiber laser. We have realized a hectowatt-level2μmCW Tm-doped fiber laser in all-fiber format successfully, which makes goodpreparation for higher2μm CW Tm-doped fiber laser in the future. In the same time, wealso have done the experiment about coherent combination of two ways of2μm CWTm-doped fiber laser, from which we have learned a great deal of experience so as tocomplete the coherent combination of more ways of2μm CW Tm-doped fiber laser infuture.