GaAs-AlGaAs double heterostructure lasers with taper-coupled passive waveguides

Abstract

Taper‐coupled laser structures suitable for integrated optics applications were grown by a liquid phase epitaxy process. Reduced threshold current densities, j₀=6.3 kA/cm² μm, and external differential quantum efficiencies η_d as high as 28% were measured with nominally undoped n‐type active layers. Control units yielded j₀=5.3 kA/cm² μm with η_d as high as 37%. An internal quantum efficiency of 78% and a taper coupling efficiency ≳50% are deduced from the data.