TU/e develops efficient nano-LED for optical interconnects

TU/e researchers have integrated a light channel on a nano-LED that is a thousand times more efficient than previous combinations. Partly because of this, the combination has good credentials to be able to serve as a light source for optical connections in chips.

The LED with integrated waveguide is several hundred nanometers in size. The way in which the scientists have linked the LED to the light channel ensures that a relatively large amount of light is retained. In previous attempts by researchers to integrate LED and channel, a lot of light was lost.

The Eindhoven invention now achieves an efficiency of between 0.1 and 1 percent, but the scientists expect that percentage should be significantly higher with new production techniques. According to TU/e, the efficiency is already at least 1000 times better ‘than the best variants developed elsewhere’.

An additional advantage of the nano-LED is that it is processed on a silicon substrate. Silicon is not suitable for integration of light sources, but the researchers have placed the LED on a membrane of indium phosphide. Processing this on silicon makes the technology theoretically compatible with chips.

The researchers are still cautious about this; A lot of research still needs to be done before actual production. However, the first tests are promising. The nano-LED could convert electrical signals into optical signals so quickly that data rates of several gigabits per second would be within reach. Optical interconnects should thus become an alternative to electronic data connections at chip and system level.

The researchers publish their work under the name Waveguide-coupled nanopillar metal-cavity light-emitting diodes on silicon in the scientific journal Nature Communications.