Experimental Study Of Yb³⁺ Doped Double-clad Mode-locked Fiber Laser

In this thesis , theoretical and experimental study of Yb³⁺ doped double-clad mode-locked fiber laser was presented . The main contents are as follows:First , the development and merits of Yb³⁺ doped double-clad fiber laser was introduced . A brief introduction on the application of fiber laser was presented.Then , the characteristics of Yb³⁺ doped double-clad fiber was introduced . It included the following parts: the energy structure and spectrum of Yb³⁺ ions , the structure of double-cald fiber , the pumping design of fiber laser and the nonlinear effect in fiber. At last , the basic mode-locked theory was presented.Next , a F-P cavity fiber laser was constructed . And the output laser was studied , which implied the characteristics of the fiber. A Q-switched fiber laser was performed .The reason of Q-switched operation was analysed.At last , the study of passive mode-locked Yb³⁺ doped double-clad fiber laser was performed . The mode-locked operation was related to semiconductor saturable absorber (SESAM) and nonglinear polarization evolution (NPE) . The phenomena and results of the experiment were reported. Q-Switching mode-locked operation was realized , but cw operation failed.All in all , on the base of the theory about Yb³⁺ doped double-clad fiber laser, the experimental study was performed. The best result was Q-Switching mode-locked operation .In order to realize cw operation , more research is needed.