Photonic switches used for routing the optical signals reaching data centers have been hindered by a fundamental tradeoff between size and speed: Larger switches can handle higher speeds and more data but also consume more energy, occupy more physical space, and drive up costs.
Now, in a new paper in Nature Photonics, researchers at Penn’s School of Engineering and Applied Science describe the creation of a novel photonic switch that overcomes this size-speed tradeoff. And at just 85 by 85 micrometers, the new switch’s units are smaller than a grain of salt.
By manipulating light at the nanoscale with unprecedented efficiency, the new switch speeds up the process of getting data on and off the literal information superhighway of fiber-optic cables that encircles the globe. “This has the potential to accelerate everything from streaming movies to training AI,” says senior author Liang Feng, a professor in materials science and engineering (MSE) and in electrical and systems engineering.
The new switch relies on non-Hermitian physics, a branch of quantum mechanics that explores how certain systems behave in unusual ways, giving researchers more control over light’s behavior. “We can tune the gain and loss of the material to guide the optical signal toward the right information highway exit,” says Xilin Feng, a doctoral student in ESE and the paper’s first author. In other words, the unique physics at play allows the researchers to tame the flow of light on the tiny chip, enabling precise control over any light-based network’s connectivity.
The upshot is that the new switch can redirect signals in trillionths of a second with minimal power consumption. “This is about a billion times faster than the blink of an eye,” says Shuang Wu, a doctoral student in MSE and co-author of the paper. “Previous switches were either small or fast, but it’s very, very difficult to achieve these two properties simultaneously.”
Read more at Penn Engineering Today.
