We demonstrate GaSb-based vertical-external-cavity surface-emitting lasers (VECSELs) emitting multi-Watt output power and exhibiting a broad tuning range. A VECSEL gain structure comprising 15 In0.2Ga0.8Sb quantum wells grown on (100) n-doped GaSb substrate emitted a continuous-wave output power of over 4 W at 1970 nm wavelength operating near room temperature. Lasing was detected even at 50 degrees C. Optimized for high-power operation, the structure exhibited a tuning range of 75 turn. Using a modified VECSEL gain structure, comprising three different kinds of quantum wells, we achieved a spectral tuning of about 156 nm. (C) 2008 Elsevier B.V. All rights reserved.