| Coherently-coupled vertical cavity surface-emitting laser (VCSEL) arrays offer a unique approach to beam steering and high-radiance applications, and have many advantages such as small size, low cost, high speed, durability and manufacturing ease. Previous work on coherently-coupled VCSEL arrays has left unfinished the tasks of determining the beam steering mechanism within the arrays and achieving current uniformity across large arrays without resorting to overly-complicated fabrication procedures. This work fulfills the former by establishing a full theoretical connection between the differential current injected into the array elements and the observed steering of the far-field beam. Record high beam-steering speed and phase responsivity are also demonstrated, showing promise for applications in high-speed modulation. The first in-phase emission from a coherently-coupled bottom-emitting VCSEL array is also demonstrated, along with significantly improved current uniformity across larger arrays. |
