Management of the electrical injection uniformity in broad-area top-emitting VCSELs

The electrical properties of broad-area 850 nm top emitting VCSELs have been investigated in order to improve carrier injection uniformity in their active zone. First, we have demonstrated using an electrical simulation tool that a multi-point localized injection design associated with a spreading layer at the top of the device (ITO) can lead to a significant improvement of carrier injection and on its spatial distribution. Secondly, the electrical contrast achievable by applying this method with localized etchings has been experimentally measured. Finally, stripe-shaped devices with output power up to 50 mW in a continuous-wave operation at room temperature have been demonstrated.