A resonantly diode-pumped high-power continuous-wave Er
3+:YAG laser with a crystalline fiber geometry based on total-internal-reflection pump guiding is reported. Up to 9.4 W of output
power could be generated and a slope efficiency of 46.8% was achieved. Intrinsic efficiencies reached up to 48.8% and an optimum
outcoupling of ∼20% was found. A strong thermal lens was observed and cavity stability and hysteresis effects were studied.
PACS 42.55.-f - 42.55.Xi - 42.60.-v