New chip opens door to AI computing at light speed

A new silicon-photonic (SiPh) chip design from the lab of Nader Engheta, alongside Firooz Aflatouni, uses light waves, the fastest possible means of communication, rather than electricity, to perform mathematical computations.

Penn engineers have developed a new chip that uses light waves, rather than electricity, to perform the complex math essential to training AI. The chip has the potential to radically accelerate the processing speed of computers while also reducing their energy consumption.

Lit-up lights on a computer chip.
Image: iStock/yucelyilmaz

The silicon-photonic (SiPh) chip’s design is the first to bring together Benjamin Franklin Medal Laureate and H. Nedwill Ramsey Professor Nader Engheta’s pioneering research in manipulating materials at the nanoscale to perform mathematical computations using light—the fastest possible means of communication—with the SiPh platform, which uses silicon, the cheap, abundant element used to mass-produce computer chips.

The interaction of light waves with matter represents one possible avenue for developing computers that supersede the limitations of today’s chips, which are essentially based on the same principles as chips from the earliest days of the computing revolution in the 1960s.

In a paper published in Nature Photonics, Engheta’s team joined forces with Firooz Aflatouni, associate professor in electrical and systems engineering in Penn’s School of Engineering and Applied Sciences, whose research group has pioneered nanoscale silicon devices.

Their goal was to develop a platform for performing what is known as vector-matrix multiplication, a core mathematical operation in the development and function of neural networks, the computer architecture that powers today’s AI tools.

Instead of using a silicon wafer of uniform height, says Engheta, “you make the silicon thinner, say 150 nanometers,” but only in specific regions. Those variations in height—without the addition of any other materials—provide a means of controlling the propagation of light through the chip, since the variations in height can be distributed to cause light to scatter in specific patterns, allowing the chip to perform mathematical calculations at the speed of light.

This story is by Ian Scheffler. Read more at Penn Engineering Today.