Researchers develop quantum communications network

Researchers at the University of Rochester and Rochester Institute of Technology have made a significant breakthrough by connecting their campuses with an experimental quantum communications network using two optical fibers. The experimental network, known as the Rochester Quantum Network or RoQNET, utilizes single photons to transmit information over 11 miles along fiber-optic lines at room temperature using optical wavelengths.

Quantum communications networks have the potential to revolutionize information security, making messages impossible to clone or intercept without detection. While qubits can be created using various physical systems, such as atoms, superconductors, and defects in materials like diamond, individual particles of light are considered the most suitable qubits for long-distance quantum communications.

Although different types of qubit sources like quantum dots or trapped ions may be utilized in the future for specific applications in quantum computing or sensing, photons are particularly attractive due to their potential for transmission over fiber-optic telecommunications lines.

According to Nickolas Vamivakas, the Marie C. Wilson and Joseph C. Wilson Professor of Optical Physics at the University of Rochester, “This is a step towards creating quantum networks that can secure communications and enable new approaches to distributed computing and imaging.” The RoQNET stands out for its use of integrated quantum photonic chips for quantum light generation and solid-state based quantum memory nodes.

The collaboration between the University of Rochester and RIT teams has resulted in the development of technology with photonic-integrated circuits that could pave the way for a functional quantum network. Current efforts to utilize fiber-optic lines for quantum communication rely on bulky and expensive superconducting-nanowire single-photon detectors (SNSPDs), a barrier that the researchers aim to overcome.

Stefan Preble, a professor in the Kate Gleason College of Engineering at RIT, highlights the advantages of photons in quantum communication, stating, “Photons move at the speed of light and their wide range of wavelengths enable communication with different types of qubits. Our focus is on distributed quantum entanglement, and RoQNET serves as a test bed for this purpose.”

In the future, the researchers plan to expand the RoQNET quantum communications network to connect with other research facilities across New York State, including Brookhaven National Lab, Stony Brook University, Air Force Research Laboratory, and New York University. This expansion could lead to further advancements in quantum communication and networking technologies.

Image: A photonic chip coupled to a highly nonlinear crystal and a fiber array unit. The crystal produces entangled visible-telecom photon pairs, which are processed on silicon nitride and silicon photonic integrated circuits enabling a compact and versatile platform to link visibly accessed quantum nodes over existing telecommunications infrastructure. Credit RIT.

Paper: https://doi.org/10.1364/OPTICAQ.546774