Abstract
The recent progress of high-power fiber lasers is remarkable. Advantages of a fiber laser in characteristics such as efficient cooling property, high-damage threshold, ultra-low loss, and waveguide structure enable the outstanding high-power operation with excellent beam quality. In this paper, the advances of fiber lasers are reviewed. The power limitation of Yb-doped double-clad fiber laser is discussed, which clarifies the importance of scaling the fiber mode-field diameter and the launching capability of pump power for higher power operation. Key techniques of side-pumping geometry and photonic-crystal fibers are discussed. For further power and brightness scaling, the research on beam combining of many fiber lasers is also getting activated and briefly introduced.
