While the idea of ​​a quantum internet has huge potential, connecting it to the regular old internet has its challenges, and new research is now providing clues about how current and future networks could be connected.

An experiment by researchers at Leibniz University of Hannover in Germany demonstrates how quantum information and the classical 1s and 0s of ordinary data can be transmitted through the same optical fiber.

This means the ability to use existing infrastructure to network multiple quantum computers, potentially providing a virtually hack-proof Internet and an unparalleled means of computing power that could one day solve challenging computational tasks.

Quantum communication requires tightly coupled light waves to be sent in isolation to maintain their delicately entangled connections, which means they must be transmitted separately from ordinary light waves that carry data, making it difficult to send everything down the same pipe.

“To make the quantum internet a reality, we need to transfer entangled photons via fiber-optic networks,” says physicist Michael Kues of Leibniz University in Hanover. “We also want to continue using optical fibers for conventional data transmission.”

“Our research is an important step in bridging the gap between the traditional internet and the quantum internet.”

The team used a specially designed device to implement a technique called the seroroid technique, which changes the phase of signals in an optical fiber to accommodate quantum and classical data in the same frequency channel.

However, this is done in a way that the data streams do not interfere with each other, preserving the entangled state of the quantum stream. At the other end of the network, the streams can be split again so that both types of data can be sent and received; this is a hybrid approach to communication.

This is the first time that scientists have succeeded in sending entangled light as unentangled data using the same frequency channel in an optical fiber. Since these optical fibers already form the backbone of our internet, this means that quantum technologies could be adopted more quickly.

“Entangled photons block the data channel in the optical fiber, preventing it from being used for normal data transmission,” says physicist Jan Heine from the Leibniz University of Hannover.

There are still many challenges to overcome, with ongoing research aimed at finding ways to transmit quantum information over longer distances without gaps and to manage traffic on existing networks. However, if we can make a quantum internet work, it promises to add a unique layer of super-secure protection on top of the internet we know today—data that simply gets shredded when attackers try to compromise it.

“Our experiment demonstrates how practical implementation of hybrid networks can be successful,” says Kues. The study was published on Science Developments.