Optical Receiver Transmitter Beamsteering Satellite QKD

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Solution Overview

Problem

Current quantum key distribution (QKD) systems face limitations in communication capacity and latency, especially over long distances, due to finite block length effects and low-capacity classical communication links, which restrict the rate of secure key generation and transmission in satellite-based QKD networks.

Innovation Solution

An optical system with beamsteering capabilities that separates incoming optical signals into multiple optical bands, allowing for high-capacity communication through the use of near-infrared, infrared, and visible light spectra, and employs a tracking subsystem to maintain precise alignment and minimize misalignment losses, enabling real-time and secure key distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If quantum key distribution is performed over long distances via satellite, then communication range is improved, but communication capacity and key generation rate deteriorate due to finite block length effects and low-capacity classical communication links

Engineering Contradiction:
Improvecommunication rangeVSAvoidkey generation rate
Core Design Contradiction:
Length of stationary objectVSProductivity

Solution Approach 1:

The patent segments the optical signal into multiple wavelength channels using wavelength division multiplexing. Each wavelength channel carries independent quantum or classical information, allowing parallel key generation processes that overcome the limited capacity of classical communication links and enable higher key generation rates over long satellite distances.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements a multi-functional optical system that can simultaneously handle quantum key distribution, classical communication, and wavelength multiplexing operations. This universal system processes multiple optical bands (visible, near-infrared, infrared) through a single integrated platform, maximizing communication capacity while maintaining long-distance satellite connectivity.

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

2Productivity

If multiple optical bands are used for high-capacity communication, then communication capacity is improved, but device complexity increases

Engineering Contradiction:
Improvecommunication capacityVSAvoidsystem complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent merges multiple wavelength division multiplexing channels and optical processing functions into a single integrated optical system. By combining quantum and classical communication channels across multiple optical bands in one unified device, the system achieves high communication capacity while minimizing the complexity that would arise from separate systems for each wavelength channel.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If beamsteering and tracking subsystems are implemented, then alignment precision is improved, but device complexity and component size increase

Engineering Contradiction:
Improvealignment precisionVSAvoidsubsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses a beacon signal as an intermediary to facilitate precise tracking and beamsteering. The beacon provides reference information that enables the tracking subsystem to maintain accurate alignment without requiring complex active control mechanisms, thereby achieving high alignment precision while keeping the tracking subsystem relatively simple and compact for satellite deployment.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

The optical system enhances communication capacity and latency, facilitating faster quantum key generation and secure communication over long distances, while minimizing data storage requirements and optimizing satellite component size.

Implementation Method 1

the optical beam separator is adapted to separate the incoming optical signal into a first signal in a first optical band, a second signal in a second optical band, and an input beacon signal in a third optical band

Methodology Applied
Scientific EffectWavelength-dependent beam splitting: Dispersion (of waves)

Data Source

PatentEP4440003A1An optical receiver/transmitter with beamsteering
Publication Date: 2024.10.02 KK TOSHIBA
  • EP4440003A1 patent drawingFigure 1
  • EP4440003A1 patent drawingFigure 2
  • EP4440003A1 patent drawingFigure 3

AI summary

An optical system comprising an optical beam separator; a beam-steering device adapted to receive an incoming optical signal and to output the incoming optical signal to the optical beam separator; a plurality of subsystems comprising a first communication subsystem, a second communication subsystem and a tracking subsystem; wherein the optical beam separator is adapted to separate the incoming optical signal into a first signal in a first optical band, a second signal in a second optical band, and an input beacon signal in a third optical band, and is adapted to output the first optical signal to the first communication subsystem, to output the second signal to the second communication subsystem and to output the input beacon signal to the tracking subsystem; and wherein the tracking subsystem is adapted to determine an alignment of the input beacon signal based on a first portion of the input beacon signal, and to control the beam-steering device to adjust the beacon signal alignment based on the determination.