Five-stage interband cascade lasers grown by solid-source molecular-beam epitaxy were processed into ridges of varying width and electroplated with An for improved epitaxial-side-up heat sinking. A 22-mu m ridge emitted 264 mW per facet cw at 80 K (lambda = 3.4 mu m) and 100 mW per facet at 200 K (lambda = 3.6 mu m). A 12-mu m ridge operated cw to a maximum temperature of 257 K (lambda = 3.7 mu m). Beam qualities for the narrowest ridges approach the diffraction limit. (c) 2006 Elsevier B.V. All rights reserved.