Broadband tunable PM holmium doped ring fiber laser for the 2000–2100 nm band

We report the experimental performance of a tunable polarization-maintaining (PM) holmium-doped fiber ring laser, followed by a single-clad single-stage holmium-doped fiber amplifier. An average output power of 1.6 W over a tuning range of 100 nm (from 2000 to 2100 nm) was obtained for 6.5 W of total launched pump power at 1860 nm, corresponding to an optical-to-optical efficiency of 32 %. We measured an optical signal-to-noise ratio (OSNR) larger than 42 dB/0.05 nm and a polarization extinction ratio (PER) larger than 19.6 dB. The long-term power stability exhibited a peak-to-peak variation of 1.2 % over 2 h, and the experimentally measured spectral width of the laser was 530 MHz.