Perspectives and limitations of QKD integration in metropolitan area networks

Abstract

Quantum key distribution (QKD) systems have already reached a reasonable level of maturity. However, a smooth integration and a wide adoption of commercial QKD systems in metropolitan area networks has still remained challenging because of technical and economical obstacles. Mainly the need for dedicated fibers and the strong dependence of the secret key rate on both loss budget and background noise in the quantum channel hinder a practical, flexible and robust implementation of QKD in current and next-generation optical metro networks. In this paper, we discuss these obstacles and present approaches to share existing fiber infrastructures among quantum and classical channels. Particularly, a proposal for a smooth integration of QKD in optical metro networks, which implies removing spurious background photons caused by optical transmitters, amplifiers and nonlinear effects in fibers, is presented and discussed. We determine and characterize impairments on quantum channels caused by many classical telecom channels at practically used power levels coexisting within the same fiber. Extensive experimental results are presented and indicate that a practical integration of QKD in conventional optical metro networks is possible.

Quantum Key Distribution Secured Optical Networks: A Survey

“…The Off-MTP problem was addressed in [179] to improve cost efficiency by sharing a QKD network infrastructure among multiple tenant requests. An SDN-enabled metropolitan area QKD network [181] architecture was introduced, and various multi-tenancy operations for establishing multi-tenant requests over the new architecture were experimentally demonstrated. In the laboratory, an experimental testbed was established for demonstrating a workflow, protocol extension, and an ondemand secret key resource allocation strategy for providing multi-tenant services.…”

High Rate CV-QKD Secured Mobile WDM Fronthaul for Dense 5G Radio Networks

“…Coherent detection also contributes to narrowband opto-electronic filtering, which makes CV-QKD systems more robust to Raman scattering when classical channels co-exist on the same transmission span [16]. DV-based quantum systems reject Raman noise through the adoption of optical filters as they are applied in wavelength division multiplexing (WDM) architectures [17] such as they apply in 5G networks, whereas coherent detection enjoys a much steeper opto-electronic filtering response. For example, direct photodetection in the remote O-band is restricted to commercial standards such as coarse WDM or local area network (LAN) WDM, leading to reception bandwidths of ~500 GHz.…”

Multi-Tenant Provisioning for Quantum Key Distribution Networks With Heuristics and Reinforcement Learning: A Comparative Study

“…In recent years, the desire to reduce the capital expenditures of QKD network deployment has motivated the research of QKD integration with classical networks, where both of physical-layer performance and network-layer performance are taken into account. In order to improve the physical-layer performance such as secret-key rate and achievable distance, a number of analytical studies [30], [43], system experiments [31], [34], [36], and field trials [33], [44] have been carried out. On the other hand, several resource assignment strategies have been proposed to optimize the network-layer performance such as blocking probability and resource utilization when QKD coexists with the classical networks [32], [35].…”