The capability to fabricate two-dimensional (2D) semiconductor diode laser array is one of the most important steps towards making wafer-scale low-cost lasers. The recent emergence of vertical cavity surface emitting laser (VCSEL) facilitates the fabrication of such large 2D arrays. In this paper, we review the recent progress on a novel largeaperture single-mode VCSEL and a 2D multiple-wavelength VCSEL array for ultra-high bandwidth applications. We demonstrate a passive antiguide region (PAR) VCSEL which emits a stable single mode with very low threshold, a large aperture, and a fixed polarization. We also demonstrate multi-wavelength VCSEL arrays with repeatable wavelength spans over 20 nm, grown by Molecular Beam Epitaxy. The wavelength shift is achieved by varying the GaAs growth rate across the wafer using a patterned backing wafer to induce a temperature profile. Such multiple wavelength laser arrays are promising for ultrahigh bandwidth optical transmission and switching systems using wavelength division multiplexing (WDM).
