Efficient 2.96 µm dysprosium-doped fluoride fibre laser pumped with a Nd:YAG laser operating at 1.3 µm

A quasi-continuous wave Dy(3+)-doped ZBLAN fibre laser pumped by a ~1.3 microm Nd:YAG laser and operating at 2.96 microm with an emission linewidth of ~14 nm (FWHM) has been demonstrated. The (6)H(15/2) ? (6)H(9/2), (6)F(11/2) absorption band of Dy(3+)-doped ZBLAN centred at 1.3 microm has been used to pump the (6)H(13/2) ? (6)H(15/2) laser transition. For a 60 cm fibre length, a threshold of 0.5 W and a slope efficiency of ~20% with respect to the absorbed pump power was measured. The experimental slope efficiency was ~45% of the Stokes efficiency limit. The high efficiency relates to low pump ESA losses and an optimised output coupling as compared with previous demonstrations.