Properties of InxGa1−xAs-GaAs strained-layer quantum-well-heterostructure injection lasers

Abstract

Some of the properties of InxGa1−xAs-GaAs strained-layer quantum-well-heterostructure (SL-QWH) injection lasers are described. The laser structures are grown by molecular beam epitaxy on n+ GaAs substrates. Following the growth of a 0.5-μm n+ GaAs buffer layer, a 2-μm Al0.45Ga0.55As n-type cladding layer is grown. Next an undoped active region is grown, consisting of ∼1600 Å of GaAs with three ∼40-Å In0.35Ga0.65As quantum wells separated by two ∼30-Å GaAs barrier layers. Following the active region, a 2-μm Al0.45Ga0.65As p-type cladding layer and a 0.5-μm p+ GaAs cap layer are grown. Broad-area SL-QWH lasers operate under pulsed conditions at room temperature with threshold current densities as low as 465 A/cm2. The operating wavelength is near 1 μm. Lasers have operated for up to 1000 h with less than 25% increase in current density to maintain a constant output of 2 mW/facet. Data are also presented describing the temperature dependence of threshold current density. Values of T0 between 80 and 103 K are observed near room temperature, indicating that these SL-QWH lasers are somewhat more sensitive to temperature changes than conventional laser structures.