All-Fiber 2.05- m Continuous-Wave Ytterbium–Holmium Laser Pumped at 1.064 m

An Yb³⁺, Ho³⁺ codoped all-fiber laser oscillating at ~2.05 μm in continuous-wave, employing a novel pump version, 1.064 μm, is reported. Low threshold (~0.8 W) and moderate slope efficiency (~15.6%) of lasing are obtained in the simplest nonoptimized Fabry-Perot cavity, composed of a couple of spectrally adjusted fiber Bragg gratings. High brightness of ~2.05-μm output is an attractive laser´s feature, stemming from spatially single-mode operation and narrow optical spectrum (~70 pm at a 3-dB level), in the whole pumps´ range. The laser demonstrates high stability: during uninterrupted few-hours-perday operation its output power fluctuates within a 3% range.