Polarization stabilization for quantum key distribution in deployed fibre

李瑞雪 Li Ruixue, 马海强 Ma Haiqiang, Kejin Wei +2 more

Yicheng Shi, Hou Shun Poh, Alexander Ling +1 more

Quantum Key Distribution (QKD) using polarisation encoding can be hard to implement over deployed telecom fibres because the routing geometry and the birefringence of the fibre link can alter the polarisation states of the propagating photons. These alterations cause a basis mismatch, leading to an increased Quantum Bit Error Rate (QBER). In this work we demonstrate a technique for dynamically compensating fibre-induced state alteration in a QKD system over deployed fibre. This compensation scheme includes a feedback loop that minimizes the QBER using a stochastic optimization algorithm.

W. T. Buttler, Justin R. Torgerson, S. K. Lamoreaux

M. J. Clark, Obada Alia, Rui Wang +12 more

Quantum networks have been shown to connect users with full-mesh topologies without trusted nodes. We present advancements on our scalable polarisation entanglement-based quantum network testbed, which has the ability to perform protocols beyond simple quantum key distribution. Our approach utilises wavelength multiplexing, which is ideal for quantum networks across local metropolitan areas due to the ease of connecting additional users to the network without increasing the resource requirements per user. We show a 10 user fully connected quantum network with metropolitan scale deployed fibre links, demonstrating polarisation stability and the ability to generate secret keys over a period of 10.8 days with a network wide average-effective secret key rate of 3.38 bps.

Arka Mukherjee, Vivek Kumar, Prasanta Halder +6 more

Quantum key distribution (QKD) allows authenticated communicating entities to generate and distribute random keys with security guaranteed by the principles of quantum mechanics. Usually, the deployment of optical fibre-based QKD links requires a dark fibre for the quantum channel of the QKD link. However, the availability of dark fibre is scarce for field deployments and involves higher capital expenses. In this paper, we propose a QKD solution where the quantum channel and classical channel of the QKD link are multiplexed on the same fibre carrying a data traffic of 100 Gbps using wavelength division multiplexing (WDM). The solution will facilitate rapid upgradation of existing communication networks with quantum security, especially in metropolitan networks.

Chunyuan Zhou, Guang Wu, Xiuliang Chen +2 more