Two and four quantum-well (QW) GaInAsSb-AlGaAsSb lasers emitting at 2 mu m
are reported. In comparison to previously published data, it is found that
higher Al content in the QW barrier improves the internal efficiency,satura
ted modal gain, and characteristic temperature of the lasers, These results
are attributed to an increased valence band offset that provides superior
hole confinement in the GaInAsSb QW, A differential efficiency of 74% is ob
served at 25 degrees C under pulsed conditions for a 900-mu m cavity length
, 2-QW device, and a record characteristic temperature of 140 K is measured
for a 4-QW laser.