Beyond 3 μ m Dy^{3 +} /Er^{3 +} co-doped ZBLAN fiber lasers pumped by 976 nm laser diode

Dysprosium-erbium (Dy3+/Er3+) co-doped ZBLAN (ZrF4-BaF2-LaF3-AlF3-NaF) fiber lasers operating at 3.2-3.35 μm were demonstrated by pumping at the 980 nm Er3+ absorption band. A maximum output power of 260 mW at 3.27 μm with a slope efficiency of 5.73% was achieved with 3.6 m 0.25 mol. % Dy3+/4 mol. % Er3+ co-doped ZBLAN fiber. Lasers operating at 3.23 μm and 3.35 μm were also demonstrated with 2 m and 9 m gain fibers, respectively, but with lower slope efficiencies. Our experiments confirm the possibility of pumping the Dy3+/Er3+-doped ZBLAN fiber laser with a low-cost high efficiency diode laser at 976 nm.