Room-temperature, electrically-pumped multiple-active-regionVCSELs with high differential efficiency at 1.55 µm

Abstract
All-monolithic, single-step grown, room-temperature, electrically-pumped vertical cavity lasers based on III-As compounds are presented witha threshold current density 570 A/cm2, a differential efficiency greater than 50% and a threshold voltage of 3 V. The lasers employ three active regions, epitaxially stacked in series with Esaki junctions to increase the gain and the differential efficiency.