The latest result at the Center for Quantum Devices about high power, high wall plug efficiency, mid-infrared quantum cascade lasers (QCLs) is presented. At an emitting wavelength of 4.8 μm, an output power of 3.4 W and a wall plug efficiency of 16.5% are demonstrated from a single device operating in continuous wave at room temperature. At a longer wavelength of 10.2 μm, average power as high as 2.2 W is demonstrated at room temperature. Gas-source molecular beam epitaxy is used to grow the QCL core in an InP/GaInAs/InAlAs material system. Fe-doped semiinsulating regrowth is performed by metal organic chemical vapor deposition for efficient heat removal and low waveguide loss. This accomplishment marks an important milestone in the development of high performance midinfrared QCLs.© (2009) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.