Low-Threshold Operation of GaAs-Based (GaIn)As/Ga(AsSb)/(GaIn)As „W"-Quantum Well Lasers Emitting at 1.3 μm

Abstract

The influence of the growth conditions as well as the device design on the device performance of (GaIn)As/Ga(AsSb)/(GaIn)As "W"-quantum well lasers is investigated. To this purpose, the epitaxy process is scaled to full two inch substrates for improved homogeneity while the growth process is carried out in a single run for an improved quality. Furthermore, the optical confinement factor is increased by increasing the aluminum concentration within the cladding layers to a value of 65 %. The procedure is carried out for devices with emission wavelengths of 1.26 µm as well as 1.30 µm. Differential efficiencies as high as 58 % and threshold current densities as low as 0.16 kA/cm 2 are observed in case of devices emitting at 1.26 µm at room temperature. Furthermore, excellent characteristic temperatures of T 0 = (72 ± 5) K and T 1 = (293 ± 16) K are recorded in the temperature range between 10°C and 100°C. Devices emitting at 1.30 µm exhibit differential efficiencies of 31 % and threshold current densities of 0.50 kA/cm 2 at room temperature. Further improvements of these properties and wavelength extension schemes are briefly discssused.