The access network portion of a telecommunications system in the last years demands ever-increasing bandwidth to serve not only residential and commercial customers but also other telecommunications operators, as is the case with back-haul in mobile infrastructure.To achieve this, technologies using fiber optics as a transmission medium are being developed.Passive Optical Network (PON) protocols such as ITU-T G.9804.1 provides new schemes of multiplexing that improve higher speed offered both in the downstream channel (operator to user) and in the upstream channel (user to operator).In some cases a symmetrical optical link is required to support new services, applications and terminals from users side because their profiles and demands has changed in the last decade with new challenges to maintain network parameters within the established contracted values.On the other hand, information security has also been a topic of interest in recent years, so quantum cryptography offers an alternative to increase robustness compared to the mechanisms available in electronic systems that could be vulnerable to the development of quantum computing.Although quantum cryptography protocols were defined in the last century, their application is of interest today, as they can exploit the properties of photons to make it more difficult for an intruder to obtain the private key of an information system that uses optical fiber as a transmission medium.This work shows the computational application of the BB84 quantum key distribution (QKD) protocol on an operating model of a 50G passive optical network, demonstrating both the cryptography performance and network quality parameters such as the bit error rate (BER) and the eye diagram.
The access network portion of a telecommunications system in the last years demands ever-increasing bandwidth to serve not only residential and commercial customers but also other telecommunications operators, as is the case with back-haul in mobile infrastructure.To achieve this, technologies using fiber optics as a transmission medium are being developed.Passive Optical Network (PON) protocols such as ITU-T G.9804.1 provides new schemes of multiplexing that improve higher speed offered both in the downstream channel (operator to user) and in the upstream channel (user to operator).In some cases a symmetrical optical link is required to support new services, applications and terminals from users side because their profiles and demands has changed in the last decade with new challenges to maintain network parameters within the established contracted values.On the other hand, information security has also been a topic of interest in recent years, so quantum cryptography offers an alternative to increase robustness compared to the mechanisms available in electronic systems that could be vulnerable to the development of quantum computing.Although quantum cryptography protocols were defined in the last century, their application is of interest today, as they can exploit the properties of photons to make it more difficult for an intruder to obtain the private key of an information system that uses optical fiber as a transmission medium.This work shows the computational application of the BB84 quantum key distribution (QKD) protocol on an operating model of a 50G passive optical network, demonstrating both the cryptography performance and network quality parameters such as the bit error rate (BER) and the eye diagram.
It is well known that optical access networks are able to provide high data rates over long distances and to a reasonable number of users. Security and privacy are always a challenge for public accessible network infrastructures. Especially in time-division multiplexing passive optical networks (TDM-PONs), in which the downstream signal is broadcasted to all users connected via the same wavelength channel in a shared fiber link, privacy can be a critical concern. Although encryption at the application layer can provide a high level of security, this can be achieved only if the encryption key distribution is perfectly save. On the other hand, encryption on the physical layer such as quantum cryptography or, more precisely, quantum key distribution (QKD) is a very promising approach to achieve secure communication. However, there remain several issues that have to be solved before the quantum cryptography reaches the maturity level needed for a cost effective implementation in practical networks. In this paper, we address quantum key distribution (QKD) over passive optical access networks, which is an enabling technology required to cost efficiently deploy practical quantum encrypted data communication in the access area. We study different methods to integrate QKD systems in conventional optical access networks and quantitatively evaluate their suitability for a potential implementation.
To achieve commercial scalability, fiber-based quantum key distribution (QKD) systems must be integrated into existing optical communication infrastructures, rather than deployed exclusively on dedicated dark fibers. Integrating QKD into optical access networks (OANs) would be particularly advantageous, as these networks provide direct connectivity to end users for whom security is critical. Such integration can address the inherent security vulnerabilities in current OANs, which are primarily based on time-division multiplexing passive optical networks (TDM-PONs). However, integrating QKD into PONs poses significant challenges due to Raman noise and other detrimental effects induced by PON signals, which intensify as the launched power of PONs increases to support higher transmission speeds. In this study, we review recent advancements in both QKD and access network technologies, evaluate the technical feasibility of QKD-OAN integration, and propose cost-effective strategies to facilitate the widespread deployment of QKD in future access networks.
Fiber-based quantum key distribution (QKD) systems are mature and commercialized, but their integration into existing optical networks is crucial for their widespread use, in particular in passive optical networks (PONs) if end-to-end quantum-secured communications are to be addressed. While discrete-variable QKD coexistence with classical channels is well-studied in point-to-point links, its performance in point-to-multipoint topologies like PONs has received less attention. We thus developed a numerical tool to estimate quantum-available bandwidth and maximum link lengths for QKD systems in single-fiber PON architectures in coexistence with GPON, XG-PON, NG-PON2, and HS-PON standards. The QKD channel performance is obtained by setting thresholds on the quantum bit error rate and the secret key rate, ultimately limited by spontaneous Raman scattering noise and high optical distribution network losses. We perform a comparison between the performance obtained assuming the asymptotic infinite-key generation rate or taking into account actual implementations in the finite-key regime. We evidence that proper design rules can be obtained as a function of both classical and quantum system parameters to support end-to-end quantum security services in existing optical networks.
Increasing incidents of cyber attacks and evolution of quantum computing poses challenges to secure existing information and communication technologies infrastructure. In recent years, quantum key distribution (QKD) is being extensively researched, and is widely accepted as a promising technology to realize secure networks. Optical fiber networks carry a huge amount of information, and are widely deployed around the world in the backbone terrestrial, submarine, metro, and access networks. Thus, instead of using separate dark fibers for quantum communication, integration of QKD with the existing classical optical networks has been proposed as a cost-efficient solution, however, this integration introduces new research challenges. In this paper, we do a comprehensive survey of the state-of-the-art QKD secured optical networks, which is going to shape communication networks in the coming decades. We elucidate the methods and protocols used in QKD secured optical networks, and describe the process of key establishment. Various methods proposed in the literature to address the networking challenges in QKD secured optical networks, specifically, routing, wavelength and time-slot allocation (RWTA), resiliency, trusted repeater node (TRN) placement, QKD for multicast service, and quantum key recycling are described and compared in detail. This survey begins with the introduction to QKD and its advantages over conventional encryption methods. Thereafter, an overview of QKD is given including quantum bits, basic QKD system, QKD schemes and protocol families along with the detailed description of QKD process based on the Bennett and Brassard-84 (BB84) protocol as it is the most widely used QKD protocol in the literature. QKD system are also prone to some specific types of attacks, hence, we describe the types of quantum hacking attacks on the QKD system along with the methods used to prevent them. Subsequently, the process of point-to-point mechanism of QKD over an optical fiber link is described in detail using the BB84 protocol. Different architectures of QKD secured optical networks are described next. Finally, major findings from this comprehensive survey are summarized with highlighting open issues and challenges in QKD secured optical networks.
The integration of quantum key distribution (QKD) into passive optical networks (PONs) poses new challenges due to the specific characteristics of the access network, as the high losses from passive splitters and the spontaneous Raman scattering noise generated by classical channels co-propagating in the same optical fiber. In this paper, different QKD technologies and implementations are compared, taking into account both discrete-variable and continuous-variable QKD systems to maximize the achievable secret key rate performance in single-fiber bidirectional PONs.
The access network segment represents the end point for the provision of quantum key distribution (QKD) services, offering secure communication to the end users. Yet the integration of QKD into legacy passive optical networks (PONs) is very challenging due to the high losses of the passive optical distribution network (ODN) and the presence of upstream and downstream classical channels belonging to many coexisting PON standards, which are the source of scattered Raman noise photons. In this study we evaluate the sustainability of discrete variable QKD services in access networks supporting one or more PON standards, evidencing the necessity of ODN architectures able to enhance the QKD performance and facilitate the key-exchange over the legacy PON links.