Small-sized lithographic single-mode VCSELs with high-power conversion efficiency

Abstract

Small, single mode VCSELs have been pursued almost since the inception of the device, but have been difficult to realize. Here we present data on lithographic and oxide-free VCSELs as small as 2 μm in diameter that produce single transverse mode powers of 8 mW and have high efficiency. The efficiencies reach 46% power conversion with greater than 73 % slope efficiency, with threshold current as low as 300 μA. Smaller VCSELs of 1 μm diameter produce 37 % power conversion efficiency with greater than 79 % slope efficiency, and single mode power over 5 mW. The keys to the high performance are the lithographic control and oxide elimination that reduce the electrical and thermal resistances.