Imagine a device so tiny that a hundred of them could fit across a single human hair. That's the scale of new light-powered computer parts just developed by researchers in Erlangen, Germany, and Cambridge, Massachusetts.
A team at the Max Planck Institute for the Science of Light and Harvard University has created three tiny components for photonic microchips — the technology that moves data using light instead of electricity. These new parts, designed by artificial intelligence algorithms, are up to 500 times smaller than parts made using traditional methods.
Photonic chips already power many technologies around us, from telecom equipment to large AI data centers. They work by guiding light through channels thinner than a human hair on a chip smaller than a fingernail. The challenge has been making the individual parts small enough to pack more onto each chip.
Traditionally, engineers designed each component by hand, starting with a basic shape and tweaking it until it worked. This took a lot of time and limited how tiny the parts could become.
The new research took a different approach. The team told a computer what they wanted each part to do — like splitting different colors of light — and then let the algorithm search through millions of possible shapes to find the best one. The shapes the computer came up with looked strange: irregular patterns of holes and ridges. But they worked.
"Inverse design lets us define what we want light to do, and the optimization finds a structure that does it, often one no human would have drawn," said Toby Bi, a doctoral researcher at the Max Planck Institute and co-lead author of the study.
The team used thick silicon nitride as their material, which keeps light loss low and can produce clean, laser-like light in many colors. The smallest component they built — a device that separates light by color — fits into a space just five micrometers wide, 50 to 300 times smaller than older designs doing the same job.
Some tiny mirrors the algorithm designed reflect up to 98.5 percent of incoming light. When placed in pairs, they form tiny cavities where light bounces back and forth more than 100 times before escaping — enough to enable powerful interactions between light and matter.
The findings, published in the journal Nature Communications, could eventually help pack more components onto photonic chips, making data centers faster and more efficient. They could also advance fields like quantum computing and precision sensing, where squeezing more functionality onto tiny chips matters.
"These compact, computer-designed components are an important step toward more densely integrated nonlinear and quantum photonic circuits," said Dr. Pascal Del'Haye, who led the research team at the Max Planck Institute.