Temperature-Stable 980-nm VCSELs for 35-Gb/s Operation at 85 °C With 139-fJ/bit Dissipated Heat

Energy-efficient oxide-confined 980-nm vertical-cavity surface-emitting lasers (VCSELs) operating at 35 Gb/s at 85 °C with only 139 fJ/bit of dissipated heat are reported. Oxide-aperture-dependent static characteristics and high-speed modulation properties at a high operation temperature of 85 °C are studied in detail. It is demonstrated that oxide-aperture diameters of ~3-4 μm are most suitable for energy-efficient and high bit rate operation at high temperatures. Data transmission experiments for ~3, 3.5, and 4 μm oxide-aperture diameter VCSELs are performed and the results are compared to formulate methods to minimize energy dissipation per bit. To date, our 980-nm VCSELs are the most energy-efficient VCSELs operating at 85 °C at any wavelength.