08/05/2026
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Researchers from Northwestern University have achieved the first real-world demonstration of quantum entanglement over an active commercial fiber-optic network, marking a major milestone toward building a practical quantum internet. Instead of using a dedicated laboratory fiber, the team successfully transmitted quantum signals through the same telecom cable that simultaneously carried normal internet traffic.
Quantum communication relies on entanglement, a phenomenon in which two particles remain linked even when separated by long distances. Because these quantum states are extremely fragile, scientists have long believed they would be disrupted by the noise generated from conventional internet data. The new experiment shows that quantum and classical communications can coexist on the same fiber without interfering with each other.
To make this possible, the researchers carefully selected wavelengths where quantum photons experience minimal interference from high-speed internet traffic. They also developed filtering and routing techniques that protected the delicate quantum signals while allowing ordinary data to flow uninterrupted through the network.
The breakthrough could significantly reduce the cost of deploying a future quantum internet. Instead of building entirely new fiber-optic infrastructure, quantum communication systems may be added to existing telecommunications networks, making large-scale deployment faster and more economical.
A future quantum internet would enable capabilities beyond today's internet, including virtually unbreakable quantum encryption, secure communication between quantum computers, distributed quantum computing, and highly precise synchronization for scientific instruments and advanced sensors. These technologies could benefit cybersecurity, finance, healthcare, defense, and scientific research.
Although this demonstration represents a major step forward, researchers emphasize that a global quantum internet is still years away. Important challenges remain, including extending communication distances, developing scalable quantum repeaters, and integrating large numbers of quantum devices. Nevertheless, the successful operation over a busy real-world telecom network shows that practical quantum networking is moving from laboratory experiments toward real-world deployment.
Sources:
Northwestern University - Illinois