Not only do current on chip interconnects limit data rates, they also account for most of the energy consumed. Photonic interconnects are generally considered to be the solution, but the light source must be small enough, and with sufficient output and efficiency.
The research team has developed an LED of ‘some hundred nanometres’ with an integrated waveguide. The nano LED consists of a metal-coated III–V semiconductor nanopillar which is said to funnel ‘a large fraction’ of spontaneous emission into the fundamental mode of an InP waveguide bonded to a silicon wafer.
Progress has also been made in the quality of the integrated coupling of the light source to the waveguide, meaning less light is lost. According to the team, while the efficiency of the nano LED is currently less than 1%, that figure is expected to increase with the development of a new production method.