Infrared semiconductor laser modules for DIRCM applications

We report on the concept, realization and performance data of infrared semiconductor laser modules serving as compact and robust laser sources for a Directed Infrared Countermeasures (DIRCM) system. While the 2-2.5 µm atmospheric transmission window is covered by a GaSb-based optically pumped semiconductor disk laser (OPSDL), delivering a continuous-wave (cw) or temporally modulated output of => 1 W with a high beam quality (M2 < 3), an external cavity (EC) quantum cascade (QC) laser module is used to cover the 4.5-5 µm spectral range. The EC-QC laser concept allows efficient spectral beam combining of the output of several QC laser located side-by-side on the same semiconductor chip, while preserving the high-quality output beam of a single emitter. Both the OPSDL and the EC-QC laser have been integrated into rugged laser modules, comprising also all necessary power supply and control electronics, ready for use in field trials.