Continuous-wave operation of distributed-feedback quantum cascade laser with ultra-low threshold current density

Abstract

Continuous-wave operation of a distributed-feedback quantum cascade laser emitting at around 4.6 µm grown by solid source molecular beam epitaxy combined with metal organic vapour phase epitaxy is presented. These devices display an ultra-low threshold current density of 0.85 kA/cm2 at 30 °C. The low threshold characteristics resulted in continuous-wave operating temperature up to 100 °C for thermoelectrically cooled devices and room-temperature continuous-wave output power in excess of 8.5 mW for uncooled devices.