Energy-Efficient VCSELs for Interconnects

Vertical-cavity surface-emitting lasers (VCSELs) are particularly suited for energy- efficient optical interconnects in supercomputing. Consequently, several groups are developing VCSELs for energy-efficient interconnects with remarkable success. We give an overview over recent breakthroughs and present devices at the standard wavelength of 850 nm with record-low power consumption and heat dissipation per bit, achieving a value of only 69 mW/Tb/s at 17 Gb/s. This efficiency is exceeding the International Technology Roadmap for Semiconductors (ITRS) projection of 100 mW/Tb/s for 2015. If uncooled operation, ultradense arrays with smallest footprints, and highest ambient temperatures are required, the waveband around 1 μm is advantageous. At 980 nm, we could achieve an efficiency value in this waveband of 233 mW/Tb/s at an error-free 35 Gb/s.