All-optical switching moves closer

An ultra-small and fast, electrically pumped all-optical memory on a silicon chip with record low power consumption has been produced by imec and its associated laboratory INTEC at the Ghent University.

The device paves the way for optical packet switching with reduced overall power consumption in high-speed, high-data-rate optical telecommunication systems.

Fibre-optic communication systems have revolutionised the telecommunications industry and play a crucial role in today’s information age where long-distance and high-data-rate communication is indispensable.

While the transportation of the data bits between different points in such networks normally makes use of light pulses, it is quite a different story for switching and routing data at the network nodes.

Due to the absence of good optical random access memories, up to now, the data needed to be converted from the optical to the electrical domain, and electronic switches with microelectronic processors were needed.

However, with the ever-increasing amount of data, the power consumption of such optoelectronic switches increases dramatically.

This latest development paves the way to switch in optical fiber networks or optical interconnect systems optically without reliance on optoelectronic conversions.

The optical random access memory has been achieved with ultra-compact micro-disk lasers with a diameter of 7.5 µm. The laser light can either propagate in the clockwise or counterclockwise direction and one can switch between these two laser modes using short optical pulses.

The lasers, implemented themselves in indium phosphide membranes, are heterogeneously integrated onto passive silicon waveguide circuits.