Vertical cavity surface emitting lasers (VCSELs) present the basis for large data rate optical interconnects in data centers. Presently VCSELs have replaced edge-emitting lasers for distances below 500 m due to their advantages such as on-wafer test possibility. The demand for VCSELs and in particular, arrays has most recently significantly increased due to the trend for wavelength multiplexing in data centers and the development of automobile applications like short-range LIDAR.