A team of computer engineers at the Aristotle University of Thessaloniki, has created the world’s fastest all-optical RAM cell, which uses light instead of electricity for storing and transmitting information.

In the paper published in the journals Optical Letters, the team noted that the proposed RAM operates at 10 Gb/s for both Write and Read functionalities at 6.2 dB and 0.4 dB power, respectively. And to achieve what seems to have put an end to the conundrum known as the “Memory Wall” , the team mounted InP optical Flip-Flop with interconnections integrated on a Semiconductor optical amplifier-Mach–Zehnder Interferometer. They also had On/Off switch parameterized to operate as a strongly saturated differentially-biased access gate.

In case you’re wondering what InP optical Flip-Flop is. It means the material is made out of indium phosphide, and a flip flop (or latch) type circuit made of optical parts – it has basic memory and can be connected to larger circuits to do more sophisticated stuffs. And now coming to the Mach-Zehnder interferometer, it determines the phase difference between two light inputs.

“Optical random access memories (RAMs) have been conceived as high-bandwidth alternatives of their electronic counterparts, raising expectations for ultra-fast operation that can resolve the ns-long electronic RAM access bottleneck,” the team wrote in the paper. “However, experimentally demonstrated optical RAMs have been limited to up to 5 GHz only, failing to validate the speed advantages over electronics.”

Members of the Wireless and Photonic Systems and Networks (WinPhoS) research group of the Aristotle University of Thessaloniki with their recent creation - the world's fastest optical RAM. [Image by Kathimerini via Ellines.com]
Members of the Wireless and Photonic Systems and Networks (WinPhoS) research group of the Aristotle University of Thessaloniki with their recent creation – the world’s fastest optical RAM. [Image by Kathimerini via Ellines.com]

One of the main challenges that computer technology faces is that the speed of the processors is evolving at a much rapid pace than does RAM speed. This increases performance gap between the two. And the result is the processor expecting to receive data from the much slower memory, and hence delaying the overall performance of the computer. However, the performance/speed of this newly built RAM is as twice as fast as that state-of-the-art optical RAM demonstrations.

10 Gb/s on a single RAM cell? That’s enormously huge. Well, the only downside is the size of this thing, and is currently proposed for supercomputers. Even better performance is expected by resorting to higher-capacity optical memories with multiple memory cells which use the different wavelengths of light.