Tunable all PM ring-cavity multi-Watt Tm-doped fiber laser module for 1890–2050 nm

We report the design, optical architecture, and performance of a packaged tunable all polarization-maintaining (PM) Thulium-doped fiber laser (TDFL) with a continuous tuning range of 1890–2050 nm. It consists of a ring-cavity tunable fiber laser source followed with a booster stage which yields output power >3 W and a linewidth of <0.05 nm (4 GHz). Measured performance in terms of output power (up to 3.6 W), output OSNR (47–53 dB/0.1 nm), and long term power stability (<4% p-p) is presented as a function of wavelength over the full 160 nm tuning range. Applications to characterization of passive and active devices and components in the 2 µm band are demonstrated.