Routing Data with the Help of Silicon-Based Optical Switches

In the data centers that enable everything from AI models to video streaming, components called transceivers and switches do the vital work of transporting data within the facility.

Songli Wang, a PhD student in electrical engineering at Columbia Engineering, spent his summer at Intel designing a new generation of these components using technology he researches as a member of Keren Bergman’s Lightwave Research Group. Charles Batchelor Professor of Electrical Engineering and the director of CUbiC, Bergman and her team are developing a new class of nanoscale photonic interconnect technologies that seamlessly move data with extreme energy efficiency.

Wang’s project involves developing photonic integrated circuits that transmit and receive signals, known as transceivers. At Intel, he focused on optical switches, which route data from transceivers to the servers that make up a data center. 

The stint in industry allowed Wang to take a fresh look at the problems he’s trying to solve — and a chance to take advantage of the resources in an industrial research lab. Intel has been a leading industry expert in silicon photonics products. Some of the company’s research papers even inspired Wang’s own research.

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“There are different technologies for making optical switches, not just silicon photonics,” Wang says. “So the first thing I did was survey prototypes of state-of-the-art silicon photonic switches.” 

Silicon switches are more compact than commercial optical switches, but come with their own drawbacks like only being able to connect to a certain number of servers. Wang set out to design a silicon switch, hoping to reduce switch size while fitting as many server ports as he could into a single chip. He used simulations to design a switch, first designing components then putting the design into Intel’s simulation software to predict their performance. 

“It was incredibly rewarding to see my contributions directly align with the team’s objectives and make a tangible impact on the project,” Wang says. 

At Intel, Wang worked in the Silicon Photonics Research Team, where he got to see the close collaborations between the electronics circuits group and the photonic circuits group. 

“I learned a lot about how they collaborate,” he says. “It will help me in my future research at Columbia.”

Wang, who’s originally from Harbin, China, says he’s received a lot of support from Bergman, who is his advisor. “I really want to thank her because she’s helped me find these internship opportunities,” Wang says. 

In summer 2025, Wang will continue to develop skills in the industry applications of silicon photonics during an internship at NVIDIA. 

“I’m excited about the chance to collaborate with industry leaders and gain new insights that can shape the future of both my research and the broader field.”