Researchers at Leibniz University Hannover have unveiled a pioneering technology that facilitates the transmission of entangled photons through optical fibers. This innovation holds the potential to seamlessly integrate quantum and conventional internet systems, promising unprecedented security enhancements and efficient utilization of existing telecommunications infrastructure.
A Breakthrough in Photonics
A team of four researchers from the Institute of Photonics at Leibniz University Hannover has successfully developed a state-of-the-art transmitter-receiver system. This system enables the transmission of entangled photons via optical fibers, a significant advancement towards realizing the quantum Internet. This next-generation technology promises encryption methods that are impervious to eavesdropping, even by future quantum computers, thereby safeguarding critical infrastructure.
Prof. Dr. Michael Kues, Head of the Institute of Photonics and Board Member of the PhoenixD Cluster of Excellence, emphasized the importance of this research. "To make the quantum Internet a reality, we need to transmit entangled photons via fiber optic networks," he stated. "Our research is a crucial step towards combining the conventional Internet with the quantum Internet."
Experimenting with Entangled Photons
In their experimental setup, the researchers demonstrated that photon entanglement is preserved even when transmitted alongside a laser pulse. Philip Rübeling, a doctoral student involved in the research, explained, "We can alter the color of a laser pulse with a high-speed electrical signal to match that of the entangled photons. This effect allows us to combine and later separate laser pulses and entangled photons of the same color within an optical fiber."
Advancing Hybrid Networks
This discovery could pave the way for integrating conventional and quantum Internet systems. Previously, utilizing both transmission methods simultaneously in an optical fiber was not feasible. "Entangled photons typically block a data channel in the optical fiber, hindering its use for conventional data transmission," noted Jan Heine, another doctoral student in the research group.
The experiment demonstrated for the first time that photons could be transmitted in the same color channel as laser light, allowing all color channels to remain available for conventional data transmission. "Our experiment illustrates how the practical implementation of hybrid networks can succeed," added Prof. Kues.
The study, titled "Quantum and coherent signal transmission on a single-frequency channel via the electro-optic serrodyne technique," was published on July 26, 2024, in Science Advances. DOI: 10.1126/sciadv.adn8907.
