Researchers at Northwestern University successfully achieved quantum teleportation over a 30-kilometer fiber optic cable while simultaneously handling 400 Gbps of classical internet traffic. The details of the study were published recently in the journal Optica, according to Observador.
Led by Professor Prem Kumar, the team transmitted quantum information over existing fiber optic cables that were also carrying traditional data traffic. This marked the first time quantum teleportation was demonstrated under such conditions. "It's incredibly exciting because nobody thought it was possible," said Kumar, the study's leader, according to ABC Color.
Quantum teleportation relies on the phenomenon of quantum entanglement, where particles become linked and can share information instantaneously over vast distances. Instead of particles physically traveling to deliver information, entangled particles exchange information without physically carrying it, enhancing both speed and security in data transfer. This principle was used by the researchers to transmit quantum information alongside classical data in the same infrastructure.
Prior to this study, many researchers doubted that quantum teleportation could work in cables carrying regular internet traffic. It was believed that delicate quantum signals would be overwhelmed by the millions of photons carrying classical data. However, the Northwestern team overcame this challenge by identifying specific wavelengths that minimize interference from classical signals. By carefully studying how light scatters within fiber optic cables, the researchers pinpointed a less crowded wavelength of light where they could place the photons, which receives less interference from other signals and facilitates the passage of photons, as reported by Digital Journal.
"We discovered that we could perform quantum communication without the interference of the classical channels that are present simultaneously," said Kumar, according to ABC Color. The team used advanced filters to manage noise from traditional communications, which helped reduce noise caused by regular internet traffic, as mentioned by Jomfruland.net.
To confirm the success of their method, the researchers measured the quality of the quantum information at the receiving end. The results showed that quantum information could be successfully transmitted even in a high-traffic environment, addressing the challenge of interference between classical and quantum signals.
The achievement suggests that quantum communication could potentially be implemented using existing telecommunications infrastructure. "Our work shows a path toward the next generation of quantum and classical networks that share a unified fiber optic infrastructure. Basically, it opens the door to take quantum communications to the next level," said Kumar, as reported by Observador.
Encouraged by these results, the team plans to extend their experiments over greater distances and test under real-world conditions using existing underground fiber optic cables. "Many people thought that special infrastructures would not be built for quantum communication. But if we choose the right wavelengths, we don't need to build new infrastructures. Classical and quantum communication can coexist," added Kumar, according to Jomfruland.net.
This article was written in collaboration with generative AI company Alchemiq