High-energy, high-power ytterbium-doped Q-switched fiber laser

We report on a Q-switched, cladding-pumped, ytterbium-doped large-mode-area fiber laser operating at 1090 nm that is capable of generating 2.3 mJ of o utput pulse energy at a 500-Hz repetition rate and more than 5 W of average output power at higher repetition rates in a high-brightness beam (M-2 = 3 ). Using a similar fiber with a smaller core, we generated >0.5-mJ pulses i n a diffraction-limited beam. Our results represent a threefold increase in pulse energy over previously published values for Q-switched fiber lasers and firmly establish fiber lasers as compact, multiwatt, multimillijoule pu lse sources with large scope for both industrial and scientific application s. (C) 2000 Optical Society of America.