Mid-IR type-II diode lasers

A 2.9 mu m superlattice diode laser with an InAs/GaSb/Ga0.75In0.25Sb/GaSb active region displayed high temperature operation and low current injection thresholds. The maximum operating temperature was 260 K, and at 200 K the threshold current density was 1.1 kA/cm(2) and the quantum efficiency > 15%. The peak output power per facet for this laser exceeded 800 mW at 100 K and 200 mW at 200 K for a 0.05% duty cycle. For two similar lasers, internal losses were extracted from optical pumping experiments. The first laser was designed to minimize Auger recombination by avoiding resonances between the bandgap and intervalence transitions Cat zone center), while the second was designed to maximize these resonances. Internal losses for the Auger minimized(maximized) laser diode were 14(10) cm(-1) at T = 100 K, and rose rapidly to 51(120) cm(-1) at 200 K. However, Auger coefficients were suppressed (less than or equal to 1.6x10(-27) cm(6)/s at T = 260 K) for both samples when compared to a type-I material with a similar bandgap. For optical pumping, peak output powers up to 6.5 W per facet at 100 K and 3.5 W per facet at 180 K were obtained for these samples at lambda approximate to 3.1 mu m.