Quantum cascade lasers with low-loss chalcogenide lateral waveguides

Quantum cascade lasers have been fabricated with chalcogenide lateral waveguide claddings. Several-micrometer thick Ge/sub 0.25/Se/sub 0.75/ glass has been deposited by pulsed laser ablation onto the sidewalls of narrow, deep etched laser ridges. Due to the intrinsically low mid-infrared attenuation of the chalcogenide material, the waveguide loss of the lasers is significantly reduced, by up to /spl sim/50%, depending on the ridge width, when compared to conventional ridge waveguides. This resulted in an improved overall laser performance, such as a reduction of the threshold current density, an increase in slope efficiency, and an improved temperature performance.