Shared Cable Use: The experiment combined quantum and classical data in one fiber.
Reduced Noise: Researchers identified a wavelength region and filters to minimize interference.
Teleportation Method: Only the quantum state travels, which helps avoid fragile particles traversing long distances.
Northwestern University engineers accomplished quantum teleportation on a 30 kilometer-long fiber optic cable carrying large volumes of Internet traffic. Published in Optica, their findings highlight the possibility of integrating quantum communication into existing networks. The team identified a specific optical channel to help photons carrying quantum data avoid intense classical data streams.
Quantum teleportation uses entanglement to share information between particles across long distances without requiring a physical transfer. By measuring two photons destructively—one that bears quantum data and another entangled photon—the quantum state is effectively passed to a remote photon. This avoids sending fragile quantum particles through an entire network, relying instead on the entanglement link.
Before these results, researchers assumed that combining entangled photons with ordinary Internet data would be too noisy. The Northwestern team studied the scattering of light within the cable to locate an underused band, then employed specialty filters to reduce collisions with classical signals. They confirmed the process by checking the integrity of quantum data at the receiving node.
"This is incredibly exciting because nobody thought it was possible. Our work shows a path towards next-generation quantum and classical networks sharing a unified fiber optic infrastructure. Basically, it opens the door to pushing quantum communications to the next level."
— Prem Kumar, Professor of Electrical and Computer Engineering, Northwestern University
In the lab setup, the fiber carried normal Internet traffic while the researchers teleported quantum information. The experiment suggests conventional cables can support both types of signals by placing sensitive photons in a quiet zone. With better hardware for detection and advanced protocols for error mitigation, engineers expect to extend quantum teleportation over greater distances.
Kumar’s team anticipates future demonstrations on real-world underground lines instead of in-lab spools. The group also plans to investigate multi-photon experiments to accelerate progress in quantum connectivity. By harmonizing quantum data with classical communications, researchers foresee simpler deployment of quantum sensors, cryptographic systems, and eventually, quantum computing architectures.
