High-temperature continuous wave operation of strain-balanced quantum cascade lasers grown by metal organic vapor-phase epitaxy

The authors report the fabrication of high-power strained quantum cascade lasers working in continuous mode above $370\mathrm{K}$ . The devices, processed in narrow buried heterostructures, were grown by low-pressure metal organic vapor-phase epitaxy. Continuous wave output power as high as $312\mathrm{mW}$ at $300\mathrm{K}$ was obtained at a wavelength of $5.29\mu \mathrm{m}$ from a $3.25\mathrm{mm}$ long, $7.5\mu \mathrm{m}$ wide laser with a high-reflectivity back facet coating. The slope efficiency was in excess of $1.5\mathrm{W}∕\mathrm{A}$ and the power conversion efficiency reached almost 5%.