High-power continuous-wave upconversion fiber laser at room temperature

We report cw laser emission of a Pr, Yb-doped ZrF4-BaF2-LaF3-AlF3-NaF fiber in the red spectral region. Laser emission was achieved on the transition P-3(0) --> F-3(2) (lambda(L) = 635 nm) with a Ti:sapphire pump laser tuned to lambda(p) = 850 nm. A maximum output power of P-out = 675 mW was obtained at an incident pump power of P-in = 3.37 W. The output power was increased to P-out = 1020 mW when pumping with P-in = 5.51 W was A photon avalanche process was found to contribute strongly to the population of the upper laser level. (C) 1997 Optical Society of America.