Power Scaling of Multiple Single-mode Laser Bundles in All-Fiber Configuration

We have demonstrated a novel approach to obtain high power narrow-linewidth fiber laser radiation by incoherent beam combination of three single-mode fiber lasers utilizing a laser combiner. The central wavelength of the fiber laser is 1080 nm with an optical bandwidth narrower than 0.3 nm. Each fiber laser channel is based on a direct pumped oscillator. In every laser channel, a 976 nm wavelength, 105 mu m fiber pigtailed laser diodes of 9-W maximal power are employed, and the pump power is directly launched into the double-clad Yb-doped fiber. The three single-mode fiber lasers are then incoherently combined by a 4x1 laser combiner. More than 14 W total output power is obtained with a combining efficiency of 90% above.