Angled cavity broad area quantum cascade lasers

Angled cavity broad area quantum cascade lasers (QCLs) are investigated with surface grating-based distributed feedback (DFB) mechanisms. It is found that an angled cavity incorporating a one dimensional DFB with grating lines parallel to the laser facet offers the simplest solution for single mode and diffraction limited emission in the facet normal direction. A room temperature single mode QCL with the highest output power for wavelengths longer than 10 μm is demonstrated. This structure could be applied to a wide range of laser structures for power scaling along with spectral and spatial beam control.