Monolithic Beam Steerer for High Power Mid-infrared Quantum Cascade Lasers

In this SBIR program, Omega Optics, University of Texas, Austin and Adtech Photonics propose a complete monolithic epitaxial device, with no wafer bonding, for surface emitting 2D non-mechanical optical beam steering at 4.6 micron wavelength. Two methods will be investigated: first, with slant etch normal emitters for azimuthal and elevation steering at a single wavelength using thermal phase shifting; second, with grating arrays for thermal phase shifting for azimuthal steering and wavelength tuning based elevation steering. In each case, an unequally spaced grating array with emitter spacing limited by optical crosstalk between adjacent elements, results in a single far field lobe with narrow beam width and large side lobe reduction to achieve 20degree by 15degree steering. The monolithic epitaxial structure comprises a quantum cascade laser (QCL) active region grown on top of a passive underlying InGaAs waveguide. The dual waveguide structure adiabatically transfers the QCL mode to the passive waveguiding section where light is split among emitter elements for antenna emission to free space. Thermal modeling will be done for epi-up and epi-down configurations to emit more than 1W room temperature continuous wave emission demonstrated in Adtech QCLs. Efficient phase shifters and compact subwavelength waveguides will achieve compact steering demonstration.