Abstract
We report on an ytterbium-doped fiber laser (FL) remotely pumped by a commercial Yb:YAG thin-disk laser with a beam parameter product of 4 mm mrad and an emission wavelength of 1030 nm. The pump light absorption is 1.4 dB/m, which is 77 times lower than the peak value at 976 nm. The high-brilliance pumped fiber laser with a double pass of the pump light yielded a maximum output power of 1008 W out of 1264 W pump power. Despite the low pump absorption at 1030 nm, this kW-fiber laser reaches an excellent optical-to-optical efficiency of 80%. This concept of high-brilliance pumping enables to overcome the nonlinear effects limiting high-power high-brightness beam delivery over long distances and offers a power scalability fiber lasers paired with flexibility in the application.