UBC scientists have built a quantum “translator” that bridges microwave and optical signals, potentially unlocking global quantum communication. The tiny silicon chip maintains delicate quantum links, opening a path to future quantum networks. (Artist’s concept.) Credit: SciTechDaily.com
Silicon breakthrough may provide the foundation for a global quantum internet.
UBC researchers have proposed a solution to a major challenge in quantum networking: a device that can convert microwave signals to optical signals and back again.
This technology could act as a universal translator for quantum computers, allowing them to communicate across long distances. It can convert up to 95 percent of a signal with almost no added noise, and it fits entirely on a silicon chip—the same material used in everyday computers.
“It’s like finding a translator that gets nearly every word right, keeps the message intact and adds no background chatter,” says study author Mohammad Khalifa, who conducted the research during his PhD at UBC’s faculty of applied science and the UBC Blusson Quantum Matter Institute.
UBC Professor Joseph Salfi. Credit: Paul Joseph/UBC
“Most importantly, this device preserves the quantum connections between distant particles and works in both directions. Without that, you’d just have expensive individual computers. With it, you get a true quantum network.”
How it works
Quantum computers use microwave signals to process information. However, to transmit that information across cities or continents, it must be converted into optical signals that can travel through fiber optic cables. These optical signals are extremely delicate, and even small disturbances during the conversion process can destroy them.
This creates a serious challenge for maintaining entanglement, the key phenomenon that quantum computers depend on, where two particles remain linked no matter how far apart they are. Einstein famously called it “spooky action at a distance.” If the entanglement is lost, so is the quantum advantage. The device developed by UBC researchers, described in npj Quantum Information, could support long-distance quantum communication while preserving entangled connections.
The silicon solution
The team’s model is a microwave-optical photon converter that can be fabricated on a silicon wafer. The breakthrough lies in tiny engineered flaws, magnetic defects intentionally embedded in silicon to control its properties. When microwave and optical signals are precisely tuned, electrons in these defects convert one signal to the other without absorbing energy, avoiding the instability that plagues other transformation methods.
Joseph Salfi lab at UBC’s Blusson Quantum Matter Institute. Credit: Paul Joseph/UBC
The device also runs efficiently at extremely low power—just millionths of a watt. The authors outlined a practical design that uses superconducting components, materials that conduct electricity perfectly, alongside this specially engineered silicon.
What’s next
While the work is still theoretical, it marks an important step in quantum networking.
“We’re not getting a quantum internet tomorrow—but this clears a major roadblock,” says the study’s senior author Dr. Joseph Salfi, an assistant professor in the department of electrical and computer engineering and principal investigator at UBC Blusson QMI.
“Currently, reliably sending quantum information between cities remains challenging. Our approach could change that: silicon-based converters could be built using existing chip fabrication technology and easily integrated into today’s communication infrastructure.”
Eventually, quantum networks could enable virtually unbreakable online security, GPS that works indoors, and the power to tackle problems beyond today’s reach, such as designing new medicines or predicting weather with dramatically improved accuracy.
Reference: “Robust microwave-optical photon conversion using cavity modes strongly hybridized with a color center ensemble” by M. Khalifa, P. S. Kirwin, Jeff F. Young and J. Salfi, 16 June 2025, npj Quantum Information.
