Routing and wavelength assignment in quantum key distribution networks: power control heuristics for quantum-classical multiplexing

TL;DR

This paper presents heuristics for routing and wavelength assignment in hybrid quantum-classical networks, focusing on power control to minimize interference and improve quantum channel integrity.

Contribution

It adapts classical heuristics to quantum networks and introduces power control strategies to mitigate nonlinear effects in quantum-classical multiplexing.

Findings

Power control reduces quantum channel interference.

Heuristics improve resource allocation efficiency.

Hybrid network performance varies with power settings.

Abstract

As quantum key distribution networks grow in size and complexity, resource assignment has become increasingly important. In passive optical networks without wavelength conversion, we need to assign a full route between origin and destination with the same wavelength from a finite set. This problem is computationally intensive and the common solution in classical optical networks is using heuristics. We adapt these heuristics to hybrid quantum networks where the quantum channel can share some of the optical links with classical channels. In this quantum-classical multiplexing, nonlinear effects can become the limiting factor in the range of the network. The signal in the classical channels can be subject to Raman Scattering or Four-Wave-Mixing and produce light in the quantum channels. While these processes are not efficient, even a single photon can ruin the quantum channel. We propose heuristics for the routing and wavelength assignment problem for hybrid quantum-classical networks with power control for the classical channels. By keeping the transmitted power to its bare functional minimum, we can reduce the interference to the quantum channels. We study their efficiency under different scenarios.