Wavelength Assignment in Quantum Access Networks with Hybrid Wireless-Fiber Links

TL;DR

This paper introduces a low-complexity wavelength allocation method for hybrid wireless-fiber quantum access networks, enabling efficient secret key exchange under realistic noise conditions within limited time frames.

Contribution

It presents a near-optimal wavelength assignment technique tailored for quantum networks with hybrid links, accounting for environmental noise and Raman effects, improving key exchange efficiency.

Findings

Secret keys can be exchanged in tens of seconds with proper system parameters.

The proposed algorithm enhances quantum key rates in high noise and loss scenarios.

The method is feasible for realistic quantum communication scenarios.

Abstract

We propose a low-complexity near-optimal wavelength allocation technique for quantum key distribution access networks that rely on wavelength division multiple access. Such networks would allow users to send quantum and classical signals simultaneously on the same optical fiber infrastructure. Users can be connected to the access network via optical wireless or wired links. We account for the background noise present in the environment, as well as the Raman noise generated by classical channels, and calculate the secret key generation rate for quantum channels in the finite-key setting. This allows us to examine the feasibility of such systems in realistic scenarios when the secret key exchange needs to be achieved in a limited time scale. Our numerical results show that, by proper choice of system parameters for this noisy system, it is possible to exchange a secret key in tens of seconds. Moreover, our proposed algorithm can enhance the key rate of quantum channels, especially in high noise and/or high loss regimes of operation.