Speakers
Description
Demonstrating the distribution of entangled photon pairs is a key step toward large-scale quantum networks, which could interconnect future quantum computers and form the foundation of a quantum internet. A major challenge in long-distance quantum communication is coping with varying conditions in deployed optical fibers. When a classical signal co-propagates with single photons in the same fiber, it experiences identical transmission conditions and can therefore serve as a real-time probe of the link.
Within CERN’s Quantum Technology Initiative, we extend the role of the White Rabbit Precision Time Protocol beyond sub-nanosecond synchronization, which is critical for coordinating distributed physics experiments and for linking future quantum computers. By using wavelength division multiplexing, classical White Rabbit signals are co-propagated with single photons and used to monitor the fiber conditions such as polarization drifts and timing fluctuations.
Here, we demonstrate the distribution of polarization-entangled photon pairs in the telecom O-band coexisting with a White Rabbit signal in the C-band over a 30 km internal CERN fiber.
In collaboration with partners from the Geneva Quantum Network (UniGe, HEPIA, ID Quantique, and Rolex), this work will be extended to a deployed metropolitan fiber link between CERN and Geneva, exploring multiple White Rabbit wavelengths across the C-band. These results show that precise time synchronization and quantum entanglement distribution can coexist in the same optical fiber, supporting the integration of quantum communication with existing telecommunication infrastructure and enabling the interconnection of future quantum computing nodes.