QKD Optical Switch Pulse Routing
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Solution Overview
Problem
Existing Quantum Key Distribution (QKD) systems with a single transmitter and multiple receivers face challenges in ensuring all receivers receive a sufficiently high pulse rate, especially when one receiver needs to generate more keys or is located further away, leading to potential disconnection and time-consuming re-initiation processes.
Innovation Solution
The system employs an optical switch and splitter configuration that allows a high-power pulse stream to be directed to a receiver with high key generation needs while continuously providing other receivers with a sufficient pulse stream, using a 10/90 split ratio for the splitter and 50/50 combining ratio for the combiners to ensure continuous photon streams to all receivers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If optical splitters are used to distribute pulses to multiple Bobs, then cost is reduced and multiple receivers are supported, but pulse rate at each receiver becomes insufficient especially for distant or high-demand receivers
Solution Approach 1:
The patent applies dynamic switching by replacing static optical splitters with an optical switch that can dynamically redirect the pulse stream to different receivers based on real-time key generation demands and receiver requirements, allowing the system to adapt pulse distribution dynamically rather than statically splitting pulses equally among all receivers
Solution Approach 2:
The patent implements periodic key generation phases where receivers can request additional pulses during periods when other receivers are generating keys, creating a periodic cycle of pulse allocation that ensures each receiver receives sufficient pulses over time while maintaining overall system efficiency
2Device complexity
If all receivers share the same optical path through the switch, then device complexity is reduced, but key generation speed for high-demand receivers is limited
Solution Approach 1:
The optical switch provides dynamic control over pulse distribution, allowing the system to prioritize pulse allocation to receivers with higher key generation demands or those experiencing lower key rates, thereby optimizing overall key generation productivity while maintaining a relatively simple optical path structure
Solution Approach 2:
The system changes the parameter of pulse allocation dynamically based on receiver performance metrics and key generation demands, adjusting the distribution parameters in real-time to optimize key generation speed across the network
3Quantity of substance
If pulse stream power is increased for one receiver, then key generation demand is met for that receiver, but other receivers may experience disconnection and require re-initiation
Solution Approach 1:
The patent implements periodic key generation scheduling where receivers take turns receiving enhanced pulse streams during designated time windows, ensuring that each receiver receives sufficient pulse power to meet its key generation demands while other receivers maintain their links with reduced but sufficient pulse rates, avoiding disconnections for all receivers
Solution Approach 2:
The system performs preliminary assessment of each receiver's key generation status and pulse rate requirements, allowing receivers to request additional pulses in advance during periods when other receivers are actively generating keys, preventing link disconnections before they occur
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration ensures continuous and secure communication links between the transmitter and all receivers, avoiding the need for time-consuming re-initiation procedures and accommodating varying key generation demands across receivers.
Implementation Method 1
the optical switch being switchable between a first switching position in which the input is optically connected to the first receiver, and a second switching position in which the input is optically connected to the second receiver
Implementation Method 2
guiding a portion of the plurality of pulses from the transmitter to the first receiver via an optical communication path that bypasses the optical switch
Data Source
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AI summary
There is herein disclosed a system for performing Quantum Key Distribution, the system comprising a transmitter adapted to transmit a plurality of optical pulses, a first receiver, a second receiver, an optical switch, having an input which is in optical communication with the transmitter, the switch being switchable between a first switching position in which the input is optically connected to the first receiver, and a second switching position in which the input is optically connected to the second receiver, the system further comprising a guide for guiding a portion of the plurality of optical pulses to the first receiver via an optical path that bypasses the optical switch.