Efficient, High-Data-Rate, Tapered Oxide-Aperture Vertical-Cavity Surface-Emitting Lasers

New advances in high-efficiency, high-speed 980-nm vertical-cavity surface-emitting lasers (VCSELs) are presented. The tapered oxide aperture was optimized to provide additional mode confinement without sacrificing its static low-loss performance. The pad capacitance was reduced by using benzocyclobutene, removing the n-contact layer, and shrinking the pad dimension. The mesa capacitance was also lowered by using a thicker oxide aperture and deep oxidation layers. With all these improvements, our devices demonstrated >20 GHz bandwidth, the highest for 980 nm VCSELs, and 35 Gb/s operation at only 10 mW power dissipation, corresponding to the highest reported data rate/power dissipation ratio of 3.5 Gb/(s.mW).