Highly uniform, high quantum efficiency GaInAsSb/AlGaAsSb double heterostructure lasers emitting at 2.2 μm

GaInAsSb/AlGaAsSb double heterostructure lasers with low pulsed threshold current density were grown previously by liquid-phase epitaxy using a complicated five-layer structure to relieve the strain arising from graded cladding layers. Double heterostructures have now been grown over a narrower temperature range to minimise this grading. These simpler three-layer DH lasers have high room-temperature quantum efficiencies (5.4% per facet) and low broad-area threshold current densities (2.6 kA/cm2) which are uniform from chip to chip.