  Dynamic and flexible optical networking enabled by NFV and SDN are the key
technology enablers for supporting the dynamicity and bandwidth requirements of
emerging 5G network services. To achieve the objective of 5G, Network Services
(NSes) must be often deployed transparently over multiple administrative and
technological domains. Such case often presents security risks since a typical
NS may comprise a chain of network functions, each executed in different remote
locations, and tampering within the network infrastructure may compromise their
communication. To avoid such threats, QKD has been identified and proposed as a
future-proof method immune to any algorithmic cryptanalysis based on
quantum-physics mechanisms. The maturity of QKD has enabled the R&D of quantum
networks coexisting with optical networks using telecom equipment. This makes
the QKD a suitable candidate for the security of distributed and virtualised
network services.
  In this paper, for the first time, we propose a dynamic quantum-secured
optical network for supporting network services that are dynamically created by
chaining VNF over multiple network domains. This work includes a new
quantum-ROADM, extensions to SDN-enabled optical control plane, and extensions
to NFV orchestration to achieve quantum-aware, on-demand chaining of VNFs. The
experimental results verify the capability of routing quantum and classical
data channels both individually and dynamically over shared fibre links.
Moreover, quantum secured chaining of VNFs in 5G networks is experimentally
demonstrated via interconnecting four autonomous 5G islands simultaneously
through the q-ROADM with eight optical channels using the 5GUK Exchange
orchestration platform. The experimental scenarios and results confirm the
benefit of the proposed data plane architecture and control/management plane
framework.
