IBM Engineers Use Light To Speed Up Chip Communications

Every so often, an idea comes along that really strikes us as amazing. This is definitely one of those. IBM has a team of scientists with IQs that we can't even fathom, and those very people have created an ultra-fast device that can use light for communication between chips. The goal here? It's to find a way to replace electrical signals that communicate via copper wires between computer chips with tiny silicon circuits that communicate using pulses of light. Even more importantly, this creation could advance the way computer chips talk to each other, and if new efficiencies are discovered, we can obviously expect even faster PCs in our future.


The device is called a nanophotonic avalanche photodetector, and it is the fastest of its kind. It could enable breakthroughs in energy-efficient computing that can have significant implications for the future of electronics, with Dr. T.C. Chen noting that this invention "brings the vision of on-chip optical interconnections much closer to reality." It can receive optical information signals at 40Gbps (billion bits per second) and simultaneously multiply them tenfold.

Moreover, the device operates with just a 1.5V voltage supply, 20 times smaller than previous demonstrations. Thus many of these tiny communication devices could potentially be powered by just a small AA-size battery, while traditional avalanche photodetectors require 20-30V power supplies. We know all of this just might be over your heads (we're already spinning just trying to figure it all out), so save yourself the trouble and check out the video below for some much-needed explaining.

“This dramatic improvement in performance is the result of manipulating the optical and electrical properties at the scale of just a few tens of atoms to achieve performance well beyond accepted boundaries,” said Dr. Assefa, the lead author on the paper. “These tiny devices are capable of detecting very weak pulses of light and amplifying them with unprecedented bandwidth and minimal addition of unwanted noise.” 

In IBM’s device, the avalanche multiplication takes place within just a few tens of nanometers (one-thousandths of a millimeter) and that happens very fast. The tiny size also means that multiplication noise is suppressed by 50% - 70% with respect to conventional avalanche photodetectors. The IBM device is made of Silicon and Germanium, the materials already widely used in production of microprocessor chips. Moreover it is made with standard processes used in chip manufacturing. Thus, thousands of these devices can be built side-by-side with silicon transistors for high-bandwidth on-chip optical communications. 

The Avalanche Photodetector achievement, which is the last in a series of prior reports from IBM Research, is the last piece of the puzzle that completes the development of the “nanophotonics toolbox” of devices necessary to build the on-chip interconnects.