Performance Guarantees in Quantum Key Distribution Networks

Abstract

This paper aims to present a mathematical tool useful for quantum key distribution network configuration. In particular, the paper studies the throughput of secret key distribution in a quantum key distribution network with trusted repeaters. In addition, the backlog of secret keys at a trusted repeater is also investigated. The analysis is based on the queueing principle of secret keys in the trusted repeater, implied by that the transmission of secret keys in the network is store-and-forward. The obtained results are applied to a discrete-variable protocol with weak coherent pulse sources, where realistic system parameters are integrated in the analysis. It is shown that, if the secret key rates on the transmission path are different, the transient throughput of secret key distribution through the network also vary, located between an upper bound and a lower bound of the secrete key distribution rate.