[Show abstract][Hide abstract] ABSTRACT: Multicore quantum cascade lasers with large cavities show low optical losses, high saturation intensity, and low beam divergence. We present a four active core laser based on InGaAs–AlInAs material system emitting at 10.5 μ m . To improve thermal conductance, InP interstacks were used to separate active regions. Selective lateral etching of the active regions was used to reduce optical losses. Peak powers up to 4.6 W, average powers up to 310 mW, and wall-plug efficiencies up to 4.6% were measured at 300 K. A far field with full width at half maximum of 18.7° and 49.8° in the lateral and in the growth direction, respectively, was observed.
[Show abstract][Hide abstract] ABSTRACT: Continuous-wave operating singlemode quantum-cascade lasers with a threshold current of 75 mA and total power consumption of less than 2 W are presented. The lasers are grown by metal-organic vapour- phase epitaxy; they function up to temperatures higher than 50degC and the emission wavelength is 5.25 mum.