Long wavelength VCSEL with tunnel junction and metamorphic AlAs/GaAs conductive DBR

Presents a novel VCSEL design which is monolithic, planar and combines the advantages of AlAs/GaAs DBRs and InP based active layers. The structure consists basically in the use of an active cavity sandwiched between two n doped semiconductor reflectors. A reverse biased n++/p++ tunnel junction is used for the hole injection in the p region of the gain medium. The top mirror is based on GaAs/AlAs metamorphic layers directly grown on the InP active cavity in a 2' compatible process. Current localization is achieved thanks to a simple proton implantation step that destroys locally the electrical conduction in the tunnel junction. Thermal, electrical and optical properties of n type binary GaAs/AlAs mirrors are therefore fully exploited in this simple design