High Power MOCVD-Grown Quantum Cascade Lasers

High-CW-power (i.e., watt-range), mid-infrared (IR) (λ= 3-15 μm) quantum cascade lasers (QCLs) are needed for a wide range of applications, from remote sensing to infrared countermeasures. Many of these applications require single-spatial-mode operation with beam stability to multi-watt-range output powers. Scaling the CW single-mode output power requires optimization of the QCL active region, as well as device architectures allowing for scaling the lateral width. Single-element, edge-emitting QCLs operating in the 4.5-5.0 μm wavelength region generally requires a relatively narrow element width (~ 5 microns) to maintain stable, single-spatial-mode CW operation up to the 1.5-2.0 watt-range output power levels. Larger width devices operate to high CW output powers (~ 5W), but suffer from multi-mode operation as well as beam instabilities with drive current [1].