Researchers from the Leibniz University of Hanover have developed a method for transmitting entangled photons and laser pulses of the same color through a single optical fiber.
A team of scientists from the Leibniz University of Hanover has achieved a significant breakthrough in quantum communications by creating a new method for transmitting entangled photons via optical fiber. This advancement could be a pivotal step towards establishing a quantum internet, promising secure encryption resistant to eavesdropping, even by future quantum computers.
For the first time, four researchers from the Institute of Photonics at the Leibniz University of Hanover have demonstrated the transmission of entangled photons and laser pulses of the same color through a single optical fiber. Professor Michael Kues, head of the Institute of Photonics, emphasized the importance of this achievement: “To make the quantum internet a reality, we need to transmit entangled photons over optical fiber networks. We also aim to continue using optical fiber for conventional data transmission. Our research is a crucial step towards integrating the traditional internet with the quantum internet.”
In their experiment, the researchers demonstrated that the entanglement of photons is preserved even when transmitted together with a laser pulse. Philipp Rubeling, a PhD student at the Institute of Photonics, explained the method: “We can change the color of the laser pulse using a high-speed electrical signal to match the color of the entangled photons. This effect allows us to combine laser pulses and entangled photons of the same color in the optical fiber and then separate them again.”
Until now, it has not been possible to use the same color channel in an optical fiber for transmitting both entangled photons and laser light, which led to blocking the data channel for conventional transmission. However, the new concept demonstrated in the experiment allows photons to be sent in the same color channel as the laser light, preserving all color channels for conventional data transmission.
Jan Heine, a PhD student in Kues’ group, noted: “Entangled photons block the data channel in the optical fiber, preventing its use for conventional data transmission. Our concept resolves this issue, enabling all color channels to be used for traditional data transmission.”
Professor Michael Kues added: “Our experiment demonstrates how the practical implementation of hybrid networks can be successful.” The research results were published in the journal Science Advances, underscoring the significance of this achievement for the advancement of quantum communications and the creation of the quantum internet.
