High-efficiency broad-area single-quantum-well lasers with narrow single-lobed far-field patterns prepared by molecular beam epitaxy

Broad-area single-quantum-well graded-index waveguide separate-confinement heterostructure lasers were fabricated by molecular beam epitaxy. A high external quantum efficiency of 79% and stable, single-lobed far-field patterns with a beam divergence as narrow as 0.8° (1.9 times diffraction limit) for a 100 μm-wide laser were obtained under pulsed conditions.