Year: 2024
Type: article
Abstract: To establish a scalable and secure quantum network, a critical milestone is advancing from basic point-to-point quantum key distribution (QKD) systems to the development of inherently multi-user protocols designed to maximize network capacity. Here, we propose a quantum passive optical network (QPON) protocol based on continuous-variable (CV) systems, particularly the quadrature of the coherent state, which enables deterministic, simultaneous, and high-rate secret key generation among all network users. We implement two protocols with different trust levels assigned to the network users and experimentally demonstrate key generation in a quantum access network with 8 users, each with an 11 km span of access link. Depending on the trust assumptions about the users, we reach 1.5 and 2.1 Mbits/s of total network key generation (or 0.4 and 1.0 Mbits/s with finite-size channels estimation). Demonstrating the potential to expand the network's capacity to accommodate tens of users at a high rate, our CV-QPON protocols open up new possibilities in establishing low-cost, high-rate, and scalable secure quantum access networks serving as a stepping stone towards a quantum internet.
Source: Light Science & Applications
Institutions: Technical University of Denmark, Palacký University Olomouc
Language: English
Subfield: Artificial Intelligence
Field: Computer Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $4,190
Awards: G1373674157, Quantum non-Gaussian coherence, G434337789, G4446895428, G4470024446, G5032364540, Practical multi-user secure quantum communication, QuantERA ERA-NET Cofund in Quantum Technologies, G575169067, QuantERA II ERA-NET Cofund in Quantum Technologies, G6251103608, Center for Macroscopic Quantum States (bigQ), Quantum Secure Networks Partnership
OpenAlex ID: W4403476850