On-Chip Passive Phase-Locking for High Coherent Power, Mid-IR Quantum Cascade Lasers

The technical objectives of this proposal are: 1) Implement the design developed in Phase I for the realization of 8 micron-emitting active-photonic-crystal (APC) quantum-cascade (QC) lasers of 3 W average, diffraction-limited power and 15 % wallplug efficiency in quasi-CW operation; 2) Design and realize 4.6 micron-emitting APC QC lasers of 3 W CW diffraction-limited power and 15 % wallplug efficiency; 3) Identify commercial partners/customers and additional commercial markets; and 4) Perform studies for scaling the coherent power at 4.6 micron to the 50-100 W range. Tapered-active, deep-well QC lasers will be used, since they suppress carrier leakage out of active regions, resulting in electro-optic characteristics much less temperature sensitive than for conventional QC devices; thus allowing for significant increases in average power and wallplug efficiency. The APC-QC devices to be used have a built-in refractive-index step an order of magnitude higher than that for conventional APC-QC devices, and thus will be able to achieve stable, diffraction-limited beam operation in quasi-CW or CW operation to watt-range coherent powers with high wallplug efficiency.