Quantum Optical Network Planning for Lower-Cost QKD Deployment

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Solution Overview

Problem

Existing methods for planning quantum optical networks, such as QKD networks, are not sufficiently efficient in optimizing the distribution of quantum optical systems, leading to high costs and suboptimal security in telecommunications networks.

Innovation Solution

A method and system for planning quantum optical networks using an optimization procedure to determine an optimal number of quantum optical systems, specifically QKD systems, distributed across network nodes via quantum channels, minimizing costs while ensuring secure key exchange and redundancy, utilizing both classical and quantum annealing methods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If QKD systems are deployed to secure data traffic in telecommunications networks, then network security is improved, but the cost increases significantly due to the high price of individual QKD systems

Engineering Contradiction:
Improvenetwork securityVSAvoidcost
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent combines multiple QKD system functions into shared infrastructure components, particularly quantum random number generators (QRNGs) that can serve multiple network nodes. By merging redundant functions and utilizing shared resources across the network, the overall system cost is reduced while maintaining security requirements.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements universal quantum optical systems that can perform multiple functions - serving as quantum repeaters, trusted nodes, or end-point QKD systems depending on network configuration needs. This multi-functionality allows a single system type to replace multiple specialized components, reducing total cost.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Productivity

If QKD systems are distributed across all network nodes, then key exchange rate is improved, but the number of systems required increases leading to higher costs

Engineering Contradiction:
Improvekey exchange rateVSAvoidnumber of QKD systems
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The patent introduces quantum repeaters and trusted nodes as intermediary components that enable key exchange between network nodes without requiring direct QKD system pairs between all nodes. These intermediaries extend the reach and capacity of the quantum key distribution network, improving overall key exchange rates while reducing the total number of expensive QKD systems needed.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent transitions from point-to-point QKD connections to a multi-dimensional network architecture where quantum keys can be distributed through multiple paths and routed dynamically. This dimensional expansion of the network topology allows higher aggregate key exchange rates without proportionally increasing the number of QKD systems.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If redundant QKD paths are implemented for network reliability, then security is improved, but the number of quantum optical systems increases

Engineering Contradiction:
Improvenetwork redundancyVSAvoidnumber of quantum optical systems
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent merges redundant QKD paths by implementing shared quantum infrastructure that can serve multiple security paths. Quantum random number generators and other quantum optical components are shared across redundant paths, allowing the network to maintain multiple secure routes without proportionally increasing the total number of quantum systems.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements dynamic path selection where quantum key material is generated and distributed along active paths, then recovered and reused when paths become inactive or when switching between redundant routes. This allows the same quantum systems to serve multiple redundant paths sequentially rather than requiring dedicated systems for each path.

Inventive Principle:
Principle #34Discarding and recovering

Data Source

PatentEP4106263B1Method and system for planning a quantum optical network
Publication Date: 2025.10.15 DEUTSCHE TELEKOM AG
  • EP4106263B1 patent drawingFigure 1~2
  • EP4106263B1 patent drawingFigure 3~4

AI summary

The present invention relates to a method for planning a quantum optical network with an optimal number of quantum optical systems (130) for at least one defined application case, wherein the optimal number of quantum optical systems (130) is distributed and implemented on network nodes (110, 111-116, 410) of a telecommunications network, and the quantum optical systems (130) are operationally assigned in pairs to a respective network connection of a selection of network connections (120, 420) connecting the respective network nodes (110, 111-116, 410), wherein the pairwise assigned quantum optical systems (130) are interconnected via quantum channels on their respective assigned network connections, and wherein the optimal number of quantum optical systems (130) and the selection of network connections (120, 420) are determined by applying a cost function (200,300) as a function of at least the number of quantum optical systems (130) as a first reference variable, a global extremum, in particular a global minimum, is determined using an optimization method. Furthermore, the present invention relates to a corresponding system for carrying out the method according to the invention and a quantum optical network planned using the method according to the invention.