Employees of the Leibniz University of Hannover have proven that quantum information and classical data can be transmitted over a single optical fiber.
Quantum computers will become much more powerful when they are connected to networks. If such networks are used on the basis of existing fiber optic channels, it will be economical and increase the security of data transmission. However, the combination of quantum and ordinary signals in one channel causes difficulties: quantum states are very sensitive to interference and easily destroyed. German scientists managed to find a solution.
Researchers from the Leibniz University of Hannover have proven that quantum information and classical data can be transmitted over a single optical fiber. This opens up the possibility of creating an Internet protected from hacking and combining quantum computers into powerful clusters for solving complex tasks.
“To create a quantum Internet, it is necessary to transmit entangled photons through fiber optic networks, – explains physicist Michael Kus from Hannover. – At the same time, we want to preserve the possibility of transmitting ordinary data through the same channels. Our research – an important step towards the unification of the traditional and quantum Internet.
To combine quantum and ordinary signals, scientists used a modulator with a linear phase change (serrodin). This device shifts the phases of an optical signal in a single frequency channel, which makes it possible to simultaneously transmit quantum and classical data without disturbing photon entanglement. At the output, the streams are split and each goes to its own receiver.
It is important to note that this all happens in one frequency channel, not just one fiber, where there can be many channels. This minimally reduces the bandwidth of the regular Internet and accelerates the emergence of the quantum Internet.