NIST’s August report tested entanglement on exposed suburban fiber

NIST reported on August 5, 2026, that researchers had distributed entangled photons through 62 kilometers of commercial optical fiber between Gaithersburg and College Park, Maryland. The experiment took place in early 2025. August marks publication, rather than the experiment date. ^[1]

Much of the route used aerial cables exposed to temperature changes, wind and movement. Those disturbances can alter a photon’s polarization and disrupt the shared quantum state. The team used reference light and stabilization devices to measure the changing distortion and apply a compensating transformation. ^[1]

NIST reported 1,500 entangled photons per second and successful distribution during 92.8% of a 24-hour period, with the remaining time used for polarization correction. A statistical test supported the entanglement result. Those measures describe the demonstration, not the uptime or capacity of a commercial quantum internet. ^[1]

NIST noted that another group had previously achieved a longer underground-fiber link. The distinctive challenge here was noisy, exposed infrastructure. Improving transmission rates remained necessary for practical networks, while proposed applications in secure communications, linked quantum computers and distributed sensing were possibilities for further development. ^[1]

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