How can we accommodate the rapidly increasing power consumption of the internet? “Green” optical interconnects based on novel VCSELs

The rapidly growing demand for higher data rates in optical access networks, backplanes, memories, on-chip CPU, and chip-to-chip optical interconnects requires novel ultra-high bit rate sources, which are more energy efficient per bit than anything presently existing. A low-cost method to adjust the mirror reflectivity of vertical-cavity surface-emitting lasers (VCSELs) helps to optimize their cavity photon lifetime. The joint variation of photon lifetime and the oxide aperture diameter of our 980 nm VCSELs allows optimization procedures between the laser parameters. A new indicator helps to judge the optimum mirror reflectivity to enable increased bit rates in concert with reduced energy consumption, as well as temperature stability, and a smaller bias current density. Error-free back-to-back data transmission at 50 Gbit/s over a wide temperature range from 25°C to 75°C for completely unchanged driving conditions is presented amongst other progress, including a 400 fJ/bit data transmission energy efficiency at 50 Gbit/s.