QKD Emitter Photon Mean Adjustment for High Channel Loss
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Solution Overview
Problem
Quantum Key Distribution (QKD) systems face limitations due to their weak loss resilience compared to classical communication systems, making them unsuitable for applications with channel losses exceeding their maximum budget, especially when using pre-installed optical fibers, which restricts the deployment of QKD over long distances.
Innovation Solution
The solution involves segmenting the quantum channel into sections with defined loss budgets, allowing users to adjust the mean number of photons emitted and detection probabilities based on these segments, enabling QKD systems to operate effectively in environments with higher losses by integrating user-defined loss values through interfaces at the emitter and receiver systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If QKD systems use pre-installed optical fibers for deployment, then ease of deployment is improved, but channel loss exceeds the maximum quantum channel loss budget making QKD inapplicable
Solution Approach 1:
The patent segments the quantum channel into multiple sections, each with its own loss budget. By dividing the total channel into segments (e.g., first section with loss L1, second section with loss L2), the system can independently optimize parameters for each segment. This allows the QKD system to operate over the entire segmented channel even when the total loss exceeds traditional single-budget limitations, enabling deployment over pre-installed optical fibers that would otherwise be unsuitable.
Solution Approach 2:
The patent changes the parameter of mean number of photons (μ) based on the segmented loss characteristics. By adjusting μ according to the specific loss budget of each segment rather than using a fixed value for the entire channel, the system optimizes key generation rate for each segment's conditions. This parameter adaptation enables the system to handle varying loss conditions across different fiber segments.
2Length of stationary object
If QKD systems operate over long distances, then operational distance is improved, but channel loss exceeds the maximum quantum channel loss budget
Solution Approach 1:
The patent divides the long-distance quantum channel into multiple sections, each with manageable loss characteristics. By segmenting the total distance into sections (first section, second section, etc.), each with its own loss budget, the system can process and optimize each segment independently. This segmentation allows operation over long total distances by breaking down the cumulative loss into manageable segmental losses that can be handled with appropriate parameter adjustments.
Solution Approach 2:
The patent implements dynamic adjustment of the mean number of photons based on the segmented loss characteristics of each channel section. Rather than using a static parameter setting, the system dynamically adapts μ to match the specific loss conditions of each segment, enabling flexible operation across varying distances and loss conditions.
3Device complexity
If QKD systems use traditional implementation with single loss budget, then device complexity is reduced, but adaptability to different loss conditions is limited
Solution Approach 1:
The patent introduces segmentation of the quantum channel into multiple sections, each with its own loss budget parameters. This segmentation approach enhances adaptability by allowing the system to configure different loss budgets for different segments, making it versatile for various deployment scenarios while maintaining manageable complexity through modular parameter configuration.
Solution Approach 2:
The patent implements dynamic parameter adjustment where the mean number of photons and loss budgets can be adapted based on the specific characteristics of each channel segment. This dynamic capability provides versatility for different loss conditions without requiring completely different system configurations, achieving adaptability through flexible parameter management rather than hardware complexity.
Data Source
AI summary
An apparatus for enhancing secret key rate exchange over quantum channel in QKD systems includes an emitter system with a quantum emitter and a receiver system with a quantum receiver, wherein both systems are connected by a quantum channel and a service communication channel. User interfaces within the systems allow to define a first quantum channel loss budget based on the distance to be covered between the quantum emitter and the quantum receiver and the infrastructure properties of the quantum channel as well as a second quantum channel loss budget associated to the loss within the realm of the emitter system. The emitter system is adapted to define the optimal mean number of photons of coherent states to be emitted based on the first and the second quantum channel loss budgets.