Complex Spatial Structures in the Optically Driven VCSELs

This study investigates the spatiotemporal dynamics of broad-area vertical-cavity surface-emitting lasers (VCSELs) under external optical injection. Using a semiconductor-adapted Maxwell-Bloch model, we demonstrate that weak optical injection effectively suppresses modulation instability—a major constraint to achieving coherent VCSEL emission. Through linear stability analysis and numerical simulations, we found and showed the dependence of spatial patterns on pump current and injection amplitude. Our results reveal that controlled optical injection transforms chaotic emission into ordered structures, including stripes, hexagons, labyrinths, and their hybrid forms, with the pattern scale governed by the wavenumber of maximum growth increment. Notably, reducing the laser aperture size promotes the formation of defect-free patterns. These findings offer key insights for stabilizing VCSEL emission and leveraging self-organized patterns for advanced photonic applications, such as optical computing and on-chip communication systems.