Abstract

Quantum-well lasers have been an attractive topic in recent years as the technologies of thin-film growth and device fabrication have advanced. The design of the layer structure is important in making a laser with low-threshold current, which is fundamentally required in constructing OEICs due to the reduction of heat generation. To this point, a graded-index waveguide and separate confinement heterostructure (GRIN-SCH) is one of the most effective layer structures in quantum-well lasers. The threshold current density, emission wavelength, and temperature sensitivity of AlGaAs/GaAs GRIN-SCH quantum-well lasers are discussed in detail as a function of well width. By optimizing the layer structure, a threshold current density of 290 A/cm² has been obtained at a well width of 6 nm.¹ Not only the design of layer structure but also crystal quality is a very important problem. By introducing a superlattice buffer layer, the minimum threshold current density of 175 A/cm² has been achieved.²

© 1987 Optical Society of America