Monolithic Beam-Combined Mid-Infrared Laser Array

Maxion will develop a monolithic, beam combined array of phase-locked, buried heterostructure (BH) quantum cascade lasers (QCLs). The laser array will be designed to emit a low divergence optical beam in a direction normal to the array surface at a wavelength centered at 4.6 microns. The monolithic laser"s cw output power will exceed 15 Watts. Each ridge waveguide in the array of will contain a second order, buried grating etched close to its optical mode along its length, which will serve to out-couple the laser radiation in a direction normal to the array. The ends of the ridges will be highly reflecting - one end will be HR coated, and the other will have a distributed Bragg reflector (DBR), so that threshold currents are kept low. BH QCL laser radiation that is transmitted through the DBR will propagate in a special planar waveguide region located between the DBRs and a parallel, HR coated end facet separated from the DBR plane by a Talbot distance. This planar waveguide region will be specially designed to efficiently phase lock the QCLs in the array by coupling their radiation through the DBR reflectors.