Already today, quantum communications networks are being actively deployed and created in Russia and around the world, and standards in the field of quantum technologies are being developed. As part of the roadmap for the development of quantum communications in Russia, the length of quantum networks is more than 7 thousand km, and by 2030 it is planned to be more than 15 thousand km. Quantum communications today are, in fact, a technology of quantum key distribution, which is at the stage of intensive scientific research and development. With regard to backbone quantum networks, the technology of secret key distribution requires new approaches to implementation, since the use of equipment from various vendors and the length of fiber-optic communication lines impose surmountable restrictions on the topology of backbone networks. An important aspect in the design of quantum networks is the calculation of losses in optical communication channels. Attenuations introduced by various passive and active elements are usually calculated individually for each section of the network and ultimately form a comprehensive energy model. The article considers several topologies of backbone quantum networks and presents the calculation of optical losses for fiber-optic communication channels of these topologies. In general, a method for detecting an optical signal in quantum communication networks is presented. The purpose of the article is a comparative analysis of energy models of backbone quantum networks and a presentation of a variant of implementing a section of an urban quantum network. The work describes a generalized principle of operation of a quantum key distribution system both in a two-pass version and in a single-pass configuration. The results of the analysis of the energy model and the calculation of average losses in a quantum channel are presented. In conclusion, we propose for consideration a possible variant of the topology of a quantum network.
Already today, quantum communications networks are being actively deployed and created in Russia and around the world, and standards in the field of quantum technologies are being developed. As part of the roadmap for the development of quantum communications in Russia, the length of quantum networks is more than 7 thousand km, and by 2030 it is planned to be more than 15 thousand km. Quantum communications today are, in fact, a technology of quantum key distribution, which is at the stage of intensive scientific research and development. With regard to backbone quantum networks, the technology of secret key distribution requires new approaches to implementation, since the use of equipment from various vendors and the length of fiber-optic communication lines impose surmountable restrictions on the topology of backbone networks. An important aspect in the design of quantum networks is the calculation of losses in optical communication channels. Attenuations introduced by various passive and active elements are usually calculated individually for each section of the network and ultimately form a comprehensive energy model. The article considers several topologies of backbone quantum networks and presents the calculation of optical losses for fiber-optic communication channels of these topologies. In general, a method for detecting an optical signal in quantum communication networks is presented. The purpose of the article is a comparative analysis of energy models of backbone quantum networks and a presentation of a variant of implementing a section of an urban quantum network. The work describes a generalized principle of operation of a quantum key distribution system both in a two-pass version and in a single-pass configuration. The results of the analysis of the energy model and the calculation of average losses in a quantum channel are presented. In conclusion, we propose for consideration a possible variant of the topology of a quantum network.
The analysis of the performance indicators fiber-optic communication lines (FOCL) using quantum technology based on the architectural concept of NGN (Next Generation Network) and future networks FN (Future Networks) for the construction highly efficient optical telecommunication networks supporting a wide range cryptographic resistance. Threats of unauthorized access, denial of service, loss information, cryptographic methods and algorithms for information protection are considered. Complex criteria of FOCL efficiency using such quantum technologies as network performance using WDM (Wavelength Division Multiplexing) technology, information security characteristics when using quantum cryptography protocols, taking into account resistance to various threats, informative characteristics photon sources are selected. A new approach is proposed for the study and assessment of complex indicators complex optical information protection systems and effective control of a set quantum key distribution systems for fiber-optic communication lines. The functioning of the investigated FOCL using quantum technology based on the principles "Point-to-point" network topology, which allows organizing a quantum information and service channel, is considered. On the basis of the proposed approach, the efficiency quantum key distribution, the capabilities quantum cryptography protocols under the influence of photon number splitting attack (PNS-Photon Number Splitting Attack) and the information entropy of the characteristics of sources of optical photon qubit fluxes are investigated. Analytical expressions are obtained for assessing the complex indicators of the information security system when using quantum key distribution (QKD) for FOCL. On the basis of the new approach, a numerical analysis was carried out and a graphical dependence of the information entropy of the packet on the packet length in qubits was constructed for the given transfer characteristics of the FOCL. It was found that an increase in the limited packet length in bits, which meets the requirements reliability and efficiency of the operation FOCL system, leads to an increase in the value information entropy as a fraction of the packet, at a given bit rate of the network.
This paper presents a comprehensive analysis of the application of quantum key distribution technology in atmospheric optical communication lines to ensure the information security of transmitted information in urban infrastructure conditions and between critical infrastructure industrial facilities. The necessity of applying quantum key distribution technology in atmospheric optical communication channels is substantiated. The results of numerical modeling of quantum key distribution performance indicators confirm the need for their preliminary numerical analysis taking into account regional meteorological statistical data when designing network segments including atmospheric quantum key distribution systems. The developed software package enables optimization of system parameters for specific climatic conditions and channel topology which increases the efficiency of deploying secure networks including atmospheric optical channels for energy, financial and industrial facilities. The developed software package, implementing a physically based methodology for accounting for cumulative losses in such a communication channel, enables a comprehensive assessment of the effectiveness of quantum key distribution taking into account turbulence, absorption, scattering, geometric losses, meteorological conditions and the characteristics of the detection equipment. The practical significance of the complex lies in the ability to optimize system parameters (wavelength, aperture diameter, transmitter power, etc.) for specific climatic conditions and channel topology, which is critical when designing secure networks that include atmospheric optical channels.
The purpose of the article was to theoretically determine harmonised criteria for the applicability of quantum key distribution for the protection of critical infrastructure, taking into account the long-term risk of decryption by adversaries possessing quantum computational resources and traffic archiving capabilities. The methodology relied on a theoretical systems analysis of three Quantum Key Distribution subsystems – sources, detectors, and channels (fibre/free space) – complemented by simplified models of the link budget and bit error probability. A concise scenario analysis was conducted for banking networks, energy systems, and government communications, taking into account scalability, compatibility, and cost. The main results showed that laser intensity stability of 1-2% and higher detector efficiencies – 60-70% for Avalanche Photodiodes and 80-90% for Superconducting Nanowire Single-Photon Detectors – extended practical distances and reduced errors. Without trusted nodes in fibre, 150-200 km was achievable; for urban Free-Space Optics lines, 5-20 km was optimal, while longer distances required network segmentation or satellite segments. Architecturally, it was justified that: for banks – rings with trusted nodes and Free-Space Optics reserve; for energy systems – dual fibre channels “control centre-substation” with a local key cache; for government communications – segmented domains with interagency gateways and satellite redundancy. In all scenarios, a Quantum Key Distribution + Post-Quantum Cryptography hybrid with short key rotation and operational countermeasures against attacks on detectors and channels was appropriate, confirming practical suitability for urban and regional networks. The practical significance lay in providing engineering teams in banking, energy, and government communications with ready-made architectural profiles – from rings and dual fibre channels to segmented domains – with Key Management System/Hardware Security Module integration, definition of Service Level Objective/Service Level Agreement, and phased roadmaps. For regulators and operators, this formed a basis for updating requirements and audits, as well as for planning redundancy (Free-Space Optics/satellite) and Total Cost of Ownership categories
The article analyzes the main trends in the field of optimization of information transmission processes using quantum methods. It is shown that numerical modeling of satellite optical communication systems is necessary in order to determine the most effective modes and parameters of communication equipment. This article is devoted to the problem of developing a software package for calculating the characteristics of a communication channel between a ground station and an artificial Earth satellite. A detailed description of the basic functions of the developed software package for calculating the characteristics of an Earth-satellite optical communication channel protected by QKD technology is presented. Based on numerical modeling using the developed software package, a comprehensive study of the influence of atmospheric losses, as well as various parameters of the receiving and transmitting equipment of both the ground station and the satellite, is carried out. In particular, when modeling the efficiency of satellite quantum key distribution and an optical communication channel, atmospheric phenomena such as refraction, absorption, aerosol scattering, as well as the parameters of the QKD equipment were taken into account. Modeling revealed the need to take into account many aspects to achieve maximum efficiency of the QKD in real conditions. It is shown that the developed software for flexible modeling of various scenarios for using atmospheric optical communications opens up new opportunities for research and practical application of quantum technologies in the field of information security, which is important for data protection in the face of growing cybersecurity threats. It is shown that the capabilities of the developed software package can contribute to the creation of standardized approaches to assessing and improving quantum key distribution systems.
In today’s digital era, the need for communication systems that are both faster and more secure continues to grow, pushing innovation toward the development of the Quantum Internet. This paper investigates how advancements in optical switching and networking technologies are shaping this evolution by combining classical optical communication with the principles of quantum mechanics. It begins by reviewing how optical fiber systems have advanced to support high speed, low loss data transmission, forming the backbone for quantum communication infrastructure. The study explains the working principles of qubits, entanglement, and Quantum Key Distribution (QKD), which allow the transfer of data with unparalleled security through photon based signaling. Furthermore, it explores modern optical switching methods such as all optical, electro optic, and MEMS based switches, emphasizing their role in managing quantum signals efficiently while reducing energy consumption and transmission latency. The paper also highlights key network components like quantum routers, repeaters, and photonic integrated circuits that enable seamless interaction between classical and quantum networks. In addition, it reviews emerging technologies such as AI-assisted routing, low noise photon detectors, and nanophotonic materials that enhance the scalability and performance of quantum systems. The research identifies persistent challenges, including photon loss, decoherence, fabrication cost, and standardization issues, while outlining strategies to overcome them through advanced design and material innovation. Overall, this work provides a comprehensive understanding of how optical switching advancements are paving the way for a reliable, large scale, and globally connected Quantum Internet capable of transforming future communication and information security.
Quantum key distribution protocols are easily the most advanced quantum information technology up to date, driving the whole field of quantum communications towards actual systems implementations and flourishing theoretical advances and experimental demonstrations. Exploiting the consolidated telecommunications industry knowledge, optimized equipment and already existing broad infrastructure, fiber-based quantum key distribution schemes are in particular a promising direction in which the scientific research efforts are addressed, for the final goal of building a quantum network. However, three main challenges are still preventing the large-scale industrial deployment of fiber-based quantum key distribution schemes: the limited achievable secret key generation rate, when compared to those reached by classical communications; the bounded propagation distances, due to intrinsic channel losses; and the struggle of the integration with classical data rates, which are additional sources of noise from the point of view of a quantum channel. During my Ph.D., we have focused on two of these problems, proposing new efficient designs for fiber-based high-dimensional protocols and space division multiplexing schemes to increase the secret key rate of quantum systems, and investigating the optimization of wavelength multiplexing setups for the integration with classical communications.