High-performance quantum cascade lasers in the 7.3- to 7.8-μm wavelength band using strained active regions

摘要

Abstract. We consider the use of strained quantum cascade (QC)nlaser designs in the 7.3- to 7.8-μm wavelength region to improve thencw operating characteristics of these lasers at room temperature. Wencompare the performance of a QC laser with a strain-balanced ac-ntive region with that of two similarly designed QC lasers with lattice-nmatched active-region layers, and we show that the strain-balancedndesign significantly outperforms the unstrained-layer designs in termsnof threshold-current density, power slope efficiency, and cw outputnpower at room temperature. A epi-side-down-mounted, double-channelnridge-geometry laser that was fabricated from the strained design withnaridgewidthof13 μm and a cavity length of 3 mm produced cw out-nput power in excess of 500 mW at room temperature. The characteristicntemperature T0 for the strained-layer design as determined from pulsednmeasurements between 25 and 80◦nC is 221.5 K, compared with a valuenof 194.0 K for one of the unstrained designs. C u00022010 Society of Photo-OpticalnInstrumentation Engineers. [DOI: 10.1117/1.3498758]