For the last four years, Qunnect has been focused on one idea—taking entanglement-based quantum networks out of the lab and into the real world.

We’ve had meaningful successes in that work. Our Carina hardware has been deployed on underground metro fiber in places like New York City and Berlin, and that footprint is growing. We’ve shown that Carina can meaningfully deliver high-performing entanglement distribution on active underground networks—the kind of fiber that runs beneath busy cities, carries real data traffic, and comes with all the unpredictability of real operations.

But in the United States, underground fiber is only one part of the story. Two years ago, NIST and Qunnect signed a collaborative partnership agreement (CRADA) for an entirely different kind of test: Could we make entanglement work on aerial fibers—the cables strung on telephone poles and high power electrical lines across most of the country?

If you live outside a dense city center, you already know the answer to why this matters. In much of the United States, aerial fibers—cables strung along utility poles—are everywhere. It’s significantly faster and less expensive to deploy than buried fiber, which requires trenching, permits, and complex construction. For classical internet traffic, the difference between aerial versus underground is negligible: Data moves either way because classical signals tolerate a lot of variation without falling apart.

Entanglement is different. It depends on extremely stable optical conditions. To operate on aerial fiber—which is constantly moving and changing temperature—the entanglement network has to compensate for unpredictable drifts within every second of operation. Historically, sustained entanglement on aerial fiber has been difficult, if not impossible to maintain at infrastructure-grade reliability.

But if quantum networking is going to scale across the U.S., it can’t be limited to places where underground fiber dominates. It has to operate on the infrastructure America already has—including above ground.

So Qunnect partnered with NIST to test Carina on a live, deployed aerial link: a 62 km fiber connection between NIST and the Joint Quantum Institute, where roughly 70% of the route is aerial.

Today, we’re excited to share the result.

In a collaborative paper with Qunnect, NIST and UMD researchers, we demonstrated stable, validated entanglement distribution across that 62 km link—and increased usable entanglement uptime to nearly 93%. In practical terms, it means existing aerial fiber can now support entanglement distribution for more than 22 hours per day—nearly 20x more than what was possible before! It also reflects the extraordinary work of the NIST and UMD scientists who helped make this breakthrough possible.

This milestone shows that entanglement-based quantum networking can operate above ground as well as below it, using deployed infrastructure that already exists. It means nationwide scale doesn’t require a rebuild of America’s communications footprint—only the right hardware, system design, and scientific rigor to validate performance in real-world conditions.

Most of all, it reinforces the guiding idea we’ve had at Qunnect since the very beginning: The quantum internet won’t arrive through a new, pristine greenfield rollout. It will be layered onto the infrastructure we already use—link by link, city by city—until entanglement becomes as dependable as the networks it runs on.

Nationwide scale requires that entanglement be able to operate on the infrastructure America already has. NIST and Qunnect just proved it can.