Researchers at the University of Twente solved a long-standing problem: trapping optically-generated sound waves in a standard silicon photonic chip. This discovery, published as a Featured Article in APL Photonics, opens new possibilities for radio technology, quantum communication, and optical computing.
-
-
-
-
Delen
Scalable way to generate and control sound in silicon photonic chips
Light travels extremely fast, while sound waves move much more slowly. By manipulating the interaction between light and sound —a physical phenomenon known as stimulated Brillouin scattering (SBS) — researchers can find new ways to store and filter information in a compact chip. This is useful in applications such as ultra-fast radio communication and quantum technology. But doing this in silicon photonic chips, one of the most important integrated photonics technologies today, was a major challenge.
Rethinking silicon photonics
Silicon photonics is emerging as an important solution to the bandwidth and energy bottlenecks faced by the ever-increasing datacentres industry. Introducing sound waves into these chips can unlock an even larger performance boost.
However, conventional silicon photonic structures, known as waveguides, struggle to keep sound waves confined. Sound tends to escape into the silicon oxide layer underneath the silicon structures, reducing efficiency. Previous solutions involved suspending the silicon structures but this approach was difficult to manufacture and not mechanically stable.
Trapping sound waves
To overcome this issue, the team led by David Marpaung, took a new approach: increasing the size of the silicon structures. The researchers used waveguides that were 100 times larger than traditional silicon nanowires. They successfully trapped sound waves while maintaining a compact chip design.
“These waveguides from VTT Finland are exactly what we needed to finally trap sound in silicon chips. Their size makes all the difference, allowing us to control sound waves in a way that simply wasn’t possible before.”, said Kaixuan Ye, the leading author of this work, who is currently pursuing a PhD in David’s group.
Scalability for real-world applications
Despite the increased waveguide size, the new silicon photonic chips remain compact and practical. Entire circuits, including meter-long waveguides, fit within a 1 cm² chip. This makes the technology scalable and compatible with the existing semiconductor industry, ensuring feasibility for large-scale production.
“This achievement took nearly ten years of research and collaboration,” said Marpaung. “By working with VTT Finland and refining our techniques, we finally succeeded in demonstrating this effect in a standard silicon platform.”
Future impact
This discovery brings new functionality to silicon photonics, which is already widely used in optical computing and communication. The ability to guide sound waves at ultra-high frequencies of nearly 40 GHz makes this technique promising for next-generation wireless communication and quantum applications.
Source: utwente.nl
