Bottom-Emitting Coherently Coupled Vertical Cavity Laser Arrays

Two-dimensional coherently coupled photonic crystal ion-implanted bottom emitting vertical cavity surface emitting laser arrays are demonstrated. Subthreshold luminescence shows uniform current injection below threshold, benefiting from the improved contact alignment compared with the top emitting arrays. In-phase operation has been achieved in 2×2 and 3×3 arrays at lasing threshold. A remaining challenge is achieving uniform current distribution above lasing threshold for larger arrays due to the variation of series resistance through each of the elements of the arrays.