Beam stability of buried-heterostructure quantum cascade lasers employing HVPE regrowth
Jae Ha Ryu, Jeremy Kirch, B. Knipfer, Zerui Liu, Morgan Turville-Heitz, Tom Earles, Robert Marsland, Axel Strömberg, Giriprasanth Omanakuttan, Yan‐Ting Sun, S. Lourdudoss, D. Botez, L. J. Mawst
Abstract
Measurements of beam stability for mid-infrared (IR)-emitting quantum cascade lasers (QCLs) are important for applications that require the beam to travel through air to remote targets, such as free-space communication links. We report beam-quality measurement results of narrow-ridge, 4.6 µm-emitting buried-heterostructure (BH) QCLs fabricated using ICP etching and HVPE regrowth. Beam-quality measurements under QCW operation exhibit M 2 < 1.2 up to 1 W for ∼5 µm-wide ridges. 5 µm-wide devices display some small degree of centroid motion with increasing output power (< 0.125 mrad), which corresponds to a targeting error of ∼1.25 cm over a distance of 100 m.