Diode pumped dysprosium fiber laser

We present preliminary results relating to laser emission at 3:16 µm from a Dy fiber laser that is diode pumped at 800 nm. To allow strong diode pump absorption and to capture improved quantum efficiencies resulting from cross relaxation, the Dy:ZBLAN fiber was co-doped with Tm ions in a 10 to 1 concentration ratio to Dy. A resonant energy transfer from Tm to Dy provides an inversion on the 6H13/2 to 6H15/2 transition. Maximum output power of 5.5 mW at a slope efficiency of 1.3 % was produced from a highly non-optimal arrangement. System performance is bench marked against well established resonant pumping of the Dy upper state. Measurement of fluorescence lifetimes of both dopants allows for qualitative assessment of the energy transfer efficiency. A potentially detrimental energy transfer mechanism is identified and discussed.