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Tag: Quantum Internet

  • Quantum Internet Breakthrough: Scientists Route Entanglement on Demand with $100 Optical Fiber

    Scottish researchers have unveiled a prototype quantum network that merges two independent networks into a single, flexible system of eight users, capable of routing and even teleporting entanglement on demand. The work sets a new benchmark for scalable quantum networking and marks a tangible step toward a future quantum internet.

    The team built the network not on expensive quantum chips, but on ordinary optical fiber costing less than £100 (roughly $100). The physicists exploited the chaotic scattering of light inside the fiber as a resource, transforming it into a programmable router of quantum entanglement. As the researchers explain, light in a multimode fiber ricochets through hundreds of internal pathways, and this apparent “chaos” was converted into computational advantage. By shaping the light at the input, the researchers effectively program the fiber, turning its intricate structure into a high-dimensional optical circuit.

    The resulting device can flexibly distribute quantum entanglement among users in a range of configurations — local, global, or hybrid. Crucially, the system supports multiplexing, meaning it can serve multiple users in parallel rather than only a single pair at a time. The principle is familiar from classical telecommunications, where different channels coexist on one line by using distinct wavelengths, but here it is realized in the quantum domain.

    The most striking achievement of the experiment was the simultaneous transmission — or teleportation — of entanglement between four remote users across two channels at once. Entanglement teleportation has been demonstrated before, but never in such a versatile, multi-user architecture. By controlling the input light, the researchers can steer entanglement wherever they choose — and even relocate it — using nothing more than a piece of inexpensive fiber.

    The authors note that this demonstration may prove pivotal for future quantum computers. One of the most promising paths toward powerful quantum computing is to interconnect many small quantum processors into a unified computational cluster. The Heriot-Watt prototype showcases a network capable of distributing and exchanging entanglement among numerous nodes, making it a potential foundation for scalable quantum machines. Though still a laboratory demonstration, its principles can be expanded, Malik emphasizes.

  • A Breakthrough for the Quantum Internet: New Photonic Router Directs Entangled Photons with Over 99% Accuracy

    Scientists at Tohoku University have unveiled a next-generation photonic router capable of directing quantum information with an accuracy exceeding 99%—a milestone regarded as crucial in the development of the future quantum internet. The device achieves record-low losses of just 0.06 dB (around 1.3%) while remaining fully compatible with existing telecommunications infrastructure, addressing a long-standing challenge of creating practical components for scalable quantum communication.

    The system operates at nanosecond speeds and, for the first time, has demonstrated the ability to reroute entangled photon pairs without breaking their quantum correlation. During testing, interference visibility reached 97%, confirming that the router processes complex states while preserving the information encoded within them. Importantly, the device is designed to integrate seamlessly with current fiber-optic networks.

    Entanglement remains a cornerstone resource for quantum technologies, essential for distributed computing, high-precision sensing, and secure data transmission. Thus, the ability to maintain entanglement during routing is a fundamental prerequisite for real-world applications. The high interference visibility observed in the Tohoku experiments demonstrates that the new device meets these stringent demands.

    The vision of a quantum internet is built upon transmitting information via individual photons. The primary engineering challenge lies in designing components capable of rerouting these fragile particles without distortion. To be universally applicable, such devices must function reliably across a variety of states, with polarization—the orientation of a photon’s electric field—being the most common encoding method.

    Until recently, no component could route photons of arbitrary polarization at standard wavelengths with both low loss and high fidelity. The research team led by Professor Fumihiro Kaneda has solved this problem with an electro-optical router. In their experiments, polarization was preserved with greater than 99% accuracy, producing an output signal nearly indistinguishable from the original.

    This breakthrough was made possible by an innovative design centered on a parallelogram-shaped interferometer, which preserves polarization while reducing the number of optical components. Fewer elements mean lower losses and greater stability. The result is a device that combines minimal distortion, nanosecond-scale performance, negligible noise, and compatibility with existing networks.

    Researchers emphasize that earlier prototypes suffered from noise, distortion, and significant loss, rendering them unsuitable for practical use. By overcoming these limitations in a single solution, the Tohoku University team has taken a decisive step toward building a full-scale quantum network infrastructure, bringing the long-anticipated quantum internet closer to reality.