High-power, low-noise, Yb-doped, cladding-pumped, three-level fiber sources at 980 nm.

We present results on a high-power, cladding-pumped, Yb-doped fiber emitting at 977 nm in laser and ampllified-spontaneous-emission source configurations. We obtained up to 1.4 W of fiber-coupled, single-mode output power and slope efficiency as high as 68%.