Research On Q-Switched And Mode-Locked Fiber Lasers

Author: Li Zhaohui, born in 1975, Male, Graduate from the department of physics Nankai University in 1999. Now he is a master in the Institute of Modern Optics and he is interested in multi-wavelength fiber lasers, double-clad fiber lasers and short pulse fiber lasers.Today, fiber lasers and fiber amplifiers have many potential applications in optical measuring, tele-communication and sensor, but there is a problem in common fiber laser, which is the difficulty of coupling multi-mode, high power pump lasers into the single-mode fiber core, so it is difficult to make high power fiber lasers and high gain amplifiers. To solve this problem, cladding pump technologies are widely applied.We introduce the newest applications of cladding pump technology in optical communication in this paper, and expect the key technological problems to be resolved on cladding pump technology. We focus on experimental and theoretical research on Yb³⁺-doped double-clad fiber lasers and all-fiber Yb³⁺-doped single-mode lasers. The research works in detail is the following:1. Theoretical research on double-clad fiber lasers (1) Numerical analysis of laser performance of Yb³⁺-doped double clad fiber lasersUsing equations for forward and backward pumping lasers and signal lasers in double clad fiber, we numerically analysis the laser performance of Yb³⁺-doped double clad fiber lasers, including evolution of forward and backward pumping power along fiber under the different losses, evolution of forward and backward pumping power along fiber under the different structural cavity, evolution of gain factor along fiber under the different losses, output laser power versus fiber loss under different launched pump laser power, output laser power versus fiber loss under different launched pump power, output power versus fiber length under different launched pump powers and output power versus output and input mirror's reflectivity under different launched pump powers and losses. (2)Using new model, we discuss absorptive characteristics of double clad fiber lasers and derive the representation of effective absorption coefficient.