Patent ID: 9742151
Date: 2017-08-22
CPC Classifications: H01S

Claim:
1. A terahertz quantum cascade laser device comprising: a substrate having a top substrate surface, a bottom substrate surface, and an exit facet extending between the top substrate surface and the bottom substrate surface at an angle θ a waveguide structure above the top substrate surface, the waveguide structure having a top surface, a bottom surface, a front facet extending between the top surface and the bottom surface and positioned proximate to the exit facet of the substrate, and a back facet extending between the top surface and the bottom surface and oppositely facing the front facet, the waveguide structure comprising a distributed feedback (DFB) grating layer above the quantum cascade laser structure, the DFB grating layer comprising one or more grating regions, each grating region comprising grating elements which periodically alternate in a longitudinal direction across the device, wherein adjacent grating elements have different indices of refraction, the DFB grating layer configured to provide optical feedback for one or both of the light of the first frequency ω a high-reflectivity coating on the front facet of the waveguide structure.