Two-Dimensional Surface Emitting Mid-Wave Infrared (MWIR) Interband Cascade Laser Arrays for High-Power Applications

We propose achieving high power mid-infrared arrays with interband cascade vertical cavity surface emitting lasers (VCSEL). Unlike quantum cascade lasers, optical selection rules in interband cascade lasers allow vertical emission. The massive parallelism of a VCSEL array will allow small, low power lasers to achieve high total output power with no speckle due to spatial incoherence across the array. Mid-infrared VCSELs have already achieved room temperature, continuous wave operation. We propose improving on state-of-the-art using several innovative approaches: growth on Si for improved thermal management; lower absorption cavity design; improved quantum well design; an oxide aperture to reduce loss by moving the optical mode and the pumped active region away from sidewalls, and improving their overlap; and electroplating with the very high thermal conductivity copper. To extract the heat, we propose modelling of heat pipes to spread the heat over a larger area, then a cold plate to extract heat from the heat pipe. To combine beams from different VCSELs, we propose using COMSOL ray matrix to model microlens arrays combined with macroscopic lenses.