Researchers Achieve Stable Quantum Links Over Kilometers of Fiber

New techniques help preserve quantum signals during long-distance transmission

Apr. 2, 2026 at 7:18am

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A highly structured abstract painting in muted tones of blue, green, and purple, featuring sweeping geometric arcs, concentric circles, and precise botanical spirals, conceptually representing the complex forces and structures underlying the stabilization of quantum signals transmitted over fiber optic networks.Innovative techniques to stabilize quantum signals over long-distance fiber networks could enable new breakthroughs in secure communications and distributed quantum computing.Boulder Today

Researchers have demonstrated that a single photon carrying quantum information can travel down kilometers of noisy real-world fiber and arrive at the far end with its quantum properties largely preserved. This breakthrough represents a key step toward building a fast and reliable quantum network that could support emerging technologies like distributed quantum computing and quantum sensor networks.

Why it matters

Scalable quantum networks are expected to enable secure communication protocols and improve measurement precision, but building a complete and practical quantum network requires overcoming challenges with fidelity and transmission rates. This work addresses how to send carefully prepared quantum states over messy, real-world optical fiber while preserving the quantum information.

The details

The researchers adapted fiber stabilization methods originally developed to compare optical atomic clocks to stabilize quantum network links. They send a bright reference laser through the same fiber to detect and correct environmental noise in real-time, allowing a quantum photon to travel 2 kilometers and arrive nearly identical to how it started. Experiments showed the separate photons traversing the fibers were more than 99% indistinguishable, with timing jitter canceled to less than 100 attoseconds.

  • The research was published in the Optica Publishing Group journal Optica Quantum on April 2, 2026.

The players

Nick Nardelli

Lead researcher from the National Institute of Standards & Technology (NIST).

Krister Shalm

Leads the quantum optics research at NIST.

Tara Fortier

Principal investigator and expert in optical frequency metrology at NIST.

Optica Publishing Group

The publisher of the Optica Quantum journal where the research was published.

University of Colorado, Boulder

Institution where some of the researchers are based.

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What they’re saying

“Scalable quantum networks could support several emerging technologies such as distributed quantum computing, where multiple quantum processors are connected to work together, and quantum sensor networks, where spatially separated sensors share quantum correlations to improve measurement precision.”

— Nick Nardelli, Researcher, National Institute of Standards & Technology (NIST)

“Our demonstration combines three capabilities that are rarely achieved together: highly stabilized fiber links, strong separation between the classical stabilization light and the quantum signal — also known as the co-existence challenge — and compatibility with high-bandwidth optical pulses.”

— Nick Nardelli, Researcher, National Institute of Standards & Technology (NIST)

What’s next

The researchers plan to use this stabilized fiber infrastructure to demonstrate the key components of a 'quantum repeater,' which is needed to extend quantum communication over long distances and lossy fibers. They are also developing additional components including reliable, identical single-photon sources and more efficient single-photon detectors.

The takeaway

This breakthrough in stabilizing quantum signals over long-distance fiber represents a significant step toward building a practical and scalable quantum network that could enable secure communications, distributed quantum computing, and enhanced measurement precision across a wide range of applications.