Liquid-cooled 24 W mid-infrared Er:ZBLAN fiber laser

A 24 W liquid-cooled CW 3 mu m fiber laser with a multimode-core Er-doped ZBLAN fiber has been developed. The output power of 24 W and an optical-to-optical efficiency of 14.5% (with respect to incident pump power) were obtained with 975 nm diode pumping. Efficient cooling was implemented by a combination of fluid cooling over the entire length of the fiber and conductive cooling at both end faces of the fiber. Consequently, stable high-power operation was demonstrated. To our knowledge, this is the highest output power obtained by a 3 mu m fiber laser. Furthermore, the high power can be further scaled up, since the output power in the present work is limited only by the available pump power. (C) 2009 Optical Society of America