High power asymmetrical InAsSb/InAsSbP/AlAsSb double heterostructure lasers emitting at 3.4 mm

Midinfrared lasers with an asymmetrical InPAsSb/InAsSb/AlAsSb double heterostructure are reported. Using the asymmetrical double heterostructure, pand n-cladding layers are separately optimized; high energy-gap AlAsSb (Eg'1.5 eV! for the p-type cladding layer to reduce the leakage current, and thus to increase To , and low energy-gap InPAsSb (Eg'0.5 eV! for the n-cladding layer to have low turn-on voltage. 100-mm-width broad-area lasers with 1000 mm cavity length exhibited peak output powers of 1.88 W in pulse and 350 mW in continuous wave modes per two facets at T580 K with To of 54 K and turn-on voltage of 0.36 V. Maximum peak output powers up to 6.7 W were obtained from a laser bar of total aperture of 400 mm width and cavity length of 1000 mm, with a differential efficiency of 34% and far-field beam divergence narrower than 40° at 80 K. © 1999 American Institute of Physics. @S0003-6951~99!00909-2#