Ultra high power fiber laser employing homemade (1+1) side-pumped fiber and tandem-pumping technique

With a homemade (1+1) side-pumped fiber and 1018 nm tandem-pumping strategy, we report an experimental demonstration of 17.4 kW power output, which is apparently a remarkable achievement. The (1+1) side-pumped fiber consists of an active core, highly doped with Ytterbium up to 2000 ppm, and a pump core to transport intensive pumping power through a homemade 5x1 combiner. Stimulated Raman scattering suppression ratio at maximum power is improved to 37.8 dB due to an array of connected tilted fiber Bragg gratings performance. So the experimental result clarifies the feasibility of combining side- and tandem- pumping in ultra high power scale of tens of kilowatts.