40 mW single-transverse-mode mid-IR (2.7 /spl mu/m) cw output from a simple mirror-free 780-nm diode-pumpable fiber laser

Summary form only given. We report over 40 mW of unsaturated single-transverse mode output power from an Er:ZBLAN fiber laser of relatively simple construction, enabled in part by the use of high Er concentrations (10,000 ppm) and in part by the choice of 780 nm (vs. 791 nm) as the pump wavelength. The output powers from this laser should be readily scalable to the watt-power level with commercially available 780-nm diode pumps. As such, we believe this work represents the first report of the use of a double-clad fiber for a mid-IR fiber laser.