Elastic Optical Network (EON) is a promising solution to address the high capacity, low latency, and flexibility requirements of the upcoming 5th-generation (5G) networks. Furthermore, Multi-Core Fibers (MCFs) and Space Division Multiplexing (SDM) technique can be utilized to overcome the capacity limitation of the conventional Single Mode Fibers (SMFs). On the other hand, Quantum Key Distribution (QKD) is an effective solution to address the security issues in 5G transport networks. In this paper, we investigate the performance of QKD over elastic optical networks with multi-core fibers and address the resource allocation problem for quantum and classical channels of QKD (QChs and CChs) and conventional data channels (DChs). To do so, we calculate the background noise caused by different noise sources and accordingly calculate the Secret Key Rate (SKR) in quantum channels. Then, we propose an Integer Linear Programming formulation and a heuristic algorithm to allocate network resources (spectrum, core, and links) to QChs, CChs, and DChs, with the objective of maximizing the secret key rate and minimizing the number of utilized frequency slots (FSs). Finally, we evaluate the proposed ILP and heuristic algorithm in terms of SKR and the number of utilized FSs. In our simulations, we consider core and metro topologies, fixed and distance adaptive launch power for classical signals, different fiber specifications, and different assumptions regarding the relative locations of quantum and classical channels in a multi-core fiber.
Elastic Optical Network (EON) is a promising solution to address the high capacity, low latency, and flexibility requirements of the upcoming 5th-generation (5G) networks. Furthermore, Multi-Core Fibers (MCFs) and Space Division Multiplexing (SDM) technique can be utilized to overcome the capacity limitation of the conventional Single Mode Fibers (SMFs). On the other hand, Quantum Key Distribution (QKD) is an effective solution to address the security issues in 5G transport networks. In this paper, we investigate the performance of QKD over elastic optical networks with multi-core fibers and address the resource allocation problem for quantum and classical channels of QKD (QChs and CChs) and conventional data channels (DChs). To do so, we calculate the background noise caused by different noise sources and accordingly calculate the Secret Key Rate (SKR) in quantum channels. Then, we propose an Integer Linear Programming formulation and a heuristic algorithm to allocate network resources (spectrum, core, and links) to QChs, CChs, and DChs, with the objective of maximizing the secret key rate and minimizing the number of utilized frequency slots (FSs). Finally, we evaluate the proposed ILP and heuristic algorithm in terms of SKR and the number of utilized FSs. In our simulations, we consider core and metro topologies, fixed and distance adaptive launch power for classical signals, different fiber specifications, and different assumptions regarding the relative locations of quantum and classical channels in a multi-core fiber.
Quantum key distribution (QKD) is considered as a promising solution for secure communications. Nevertheless, challenges such as the elevated cost of dark-fibers used for QKD, quantum transceivers (Q-TRx), and security issues with QKD trusted nodes impede its widespread deployment. This paper explores a multi-band elastic optical network (MB-EON) for implementing QKD on the existing fiber infrastructure, augmenting network capacity without the need for new fiber installations. The careful transmission of classical and quantum channels in MB-EON necessitates impairment-aware algorithms to shield quantum channels from potential disruptions caused by classical channels. To tackle this, we conduct an in-depth analysis of various noise sources to pinpoint the optimal key transfer scenario. Our study further includes calculations for the upper bound of the public interaction channel (PICh) bit rate in the BB84-Decoy protocol and the secret key rate (SKR). Furthermore, a time division multiplexing technique is proposed to allocate bit-rate of each Q-TRx and PICh-TRx among received demands and grooming them as a one connection. Furthermore, we delve into the QKD trusted node placement method as a robust solution for long-distance QKD, effectively minimizing Q-TRx usage and selecting less QKD trusted nodes to bolster network security by proposing the hot-links algorithm (HLA). Finally, three routing, modulation format, spectrum, and time slot assignment (RMSTA) algorithms are proposed and compared. The simulation results reveal that the proposed HLA trusted node placement method with flexible routing of classical channels and QKD channels demonstrates significant improvements in key transfer efficiency, network security, and blocking probability compared to the fixed-distance trusted node placement with joint routing of CChs and QKD channels.
To ensure the security of optical networks in the future, integrating quantum key distribution (QKD) with optical networks is one of the solutions. Moreover, the optical network based on multi-core fiber (MCF) is also one of the ways to improve the transmission capacity. Therefore, we study the integration of QKD into MCF-enabled optical networks. Aiming at the resource allocation problem of MCF-enabled wavelength division multiplexing optical networks, this paper proposes a resource allocation scheme which is suitable for independent-core-transmission of classical signals and quantum signals. For core resource, we propose the alternate core allocation algorithm. For wavelength resource, we propose the iteration-based wavelength allocation algorithm. The overall scheme uses the proposed two algorithms to first allocate the core and then allocate the wavelength. The simulation results show that the proposed scheme has a great improvement in secret key rate (SKR) compared with the benchmark scheme on the regular hexagonal 7-core fiber and 19-core fiber. And the proposed scheme still has good performance under long transmission distance and high classical signal power.
Quantum-key-distribution (QKD) enabled optical networks can provide secure keys for different kinds of applications to ensure the high security of communication processes. As the number of wavelength channels in a single-core fiber is limited, space division multiplexing (SDM) has been considered to be a valuable technique to provide more wavelength resources, which solves the problem of insufficient channel capacity. Due to the rapid expansion of data volume, the SDM-based QKD network has been regarded as an important paradigm. At the same time, resource allocation in multi-core optical networks is a problem worthy of studying. In this work, four routing, core, and wavelength allocation (RCWA) algorithms are proposed in the multi-core optical network for quantum service requests and classical service requests, which are referred to as RCWA without perception (RCWA-WP), RCWA with crosstalk perception (RCWA-XTP), RCWA with spectrum perception (RCWA-SP), and RCWA with core perception (RCWA-CP). Simulations are carried out to evaluate the network performance in terms of blocking probability, key utilization, and average crosstalk intensity. The comparative results indicate that the RCWA-SP algorithm can improve network performance and reduce the blocking probability, while the RCWA-XTP algorithm can reduce inter-core crosstalk during transmission.
Data transmission with optical fiber is vulnerable to eavesdropping. Moreover, conventional key distribution technology suffers from increasing computational power and upgraded attack algorithms. To address these issues, quantum key distribution (QKD), a quantum technology that secures secret information (such as a cryptographic key) exchange between two parties, can be used to guarantee secure data transmission. Integrating QKD into existing wavelength division multiplexing optical networks has been verified through a series of experiments, which contribute to ensuring network security and saving fiber resources. This paper addresses the resource assignment problem in QKD-enabled optical networks. First, a QKD-enabled optical network architecture is introduced. A small fraction of wavelength channels are segmented into multiple time slots with optical time division multiplexing technology to construct quantum key channels (QKChs) and measuring-basis channels, and then the remaining wavelengths can construct traditional data channels. Second, a static routing, wavelength, and time-slot assignment (RWTA) strategy is proposed and verified by the integer linear programming formulation and a heuristic algorithm. In the RWTA, QKChs are assigned for service requests according to the security levels specified by relevant key-updating periods. Thus, the secret keys for data encryption can update periodically to enhance security. Simulation results indicate that there is a trade-off between security (i.e., security levels and security-level types) and resource utilization.
The integration of Quantum Key Distribution (QKD) into optical networks has emerged as a promising solution for securing sensitive data transmission in mobile fronthaul applications. However, implementing QKD typically requires dedicated dark fibers, which increases network complexity and deployment costs. This paper explores an approach that leverages Multi-Core Fibers (MCF) to integrate both classical and quantum channels within the same optical fiber, utilizing Space Division Multiplexing (SDM). By dedicating separate cores for quantum and classical channels, the proposed system minimizes the need for additional infrastructure while ensuring secure and efficient communication. Crosstalk between cores, a critical factor in MCF design, is analyzed through simulations, considering parameters such as core pitch and operating spectrum. Results demonstrate the feasibility of achieving minimal inter-core crosstalk for reliable quantum and classical channel coexistence. This study underscores the potential of MCF-based SDM as a cost-effective and scalable solution for future quantum-secured mobile networks.
Quantum key distribution over optical networks has been noted as a state-of-the-art approach to next-generation secure communication. We propose two approaches to manage the signal for quantum key exchange between two trusted nodes; in the first approach, the quantum channel (QCh) uses distinct fiber whereas the classic channel (CCh) and public interaction channel (PICh) use another fiber to be transmitted on C-band (C+L band), and in the second approach CCh and PICh are transmitted over C+L band and QCh only uses O-band, both routed on the same fiber. In this context, two variations of the initial approach have been put forth, namely scenario 1 and scenario 2. In scenario 1, the CChs are positioned within the extended C-band, while in scenario 2, they find their place within the extended C+L-band. Concerning the secondary approach, denoted as scenario 3, the CChs+PIChs and QChs are situated in the extended C+L-band and low-loss O-band with consideration of noises over QChs, respectively. We propose a heuristic resource allocation with a time-division multiplexing technique in quan-tum resource allocation to compare the resource utilization of the mentioned approaches. The simulation outcomes demonstrate the advantages of adopting scenario 3 in relation to fiber deployment. This is highlighted by an 86 % (34 %) enhancement in fiber efficiency when compared to scenario 1 (2), all while employing an equal count of quantum transmitters and receivers over the initial eight years. As per the specifications of scenario 3, during the concluding year, there has been a notable 44 % surge in quantum transmitter and receiver utilization for both scenarios 1 and 2. This upsurge is accompanied by a substantial reduction in fiber utilization, amounting to a 117 % (34 %) reduction concerning scenario 1 (2).