All-Fiber 2.05- \(\mu \) m Continuous-Wave Ytterbium–Holmium Laser Pumped at 1.064 \(\mu \) m

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