Quantum-Aware Network Planning and Integration

TL;DR

This paper discusses the integration of quantum key distribution into existing optical networks, emphasizing quantum-aware planning techniques that enable coexistence with classical traffic without significant capacity loss.

Contribution

It introduces quantum-aware network planning methods that optimize wavelength assignment, facilitating the coexistence of quantum and classical signals in optical networks.

Findings

Quantum-aware planning improves coexistence of quantum and classical signals.

Naive planning can severely degrade classical capacity.

Heuristic methods enable minimal impact on network capacities.

Abstract

In order to broaden the adoption of highly-demanded quantum functionalities such as QKD, there is a need for having quantum signals coexist with classical traffic over the same physical medium, typically optical fibers in already-deployed networks. Beyond the experimental point-to-point demonstrations of the past few years, efforts are now underway to integrate QKD at the network level: developing interfaces with the software-defined-network ecosystem; but also network planning tools that satisfy physical-layer contraints jointly on the classical and quantum signals. We have found that in certain situations, na\"ive network planning prioritizing quantum traffic drastically degrades classical capacity, whereas a quantum-aware wavelength assignment heuristic allows coexistence with minimal impact on both capacities. More such techniques will be required to enable widespread deployment of QKD and other future quantum functionalities.