Quantum Key Distribution Receiver Substrate Waveguide Alignment

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Solution Overview

Problem

Current optical receivers for quantum key distribution systems require precise manual alignment of optical components, making them time-consuming, expensive, and unsuitable for mass production due to mechanical robustness issues.

Innovation Solution

The use of hollow core waveguides formed in a substrate to optically couple and align optical components, allowing for a compact, robust, and cost-effective design that reduces alignment tolerances and enables mass production by integrating components within the substrate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If manual alignment of optical components is used, then alignment precision can be achieved, but production time increases and mechanical robustness deteriorates

Engineering Contradiction:
Improvealignment precisionVSAvoidproduction time
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent pre-forms alignment slots and hollow core waveguides in the substrate before inserting optical components. This preliminary structuring establishes precise geometric relationships between components, eliminating the need for time-consuming manual alignment during assembly while maintaining high alignment precision.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces the mechanical opto-mechanical mounting system with an integrated substrate-based positioning system. The hollow core waveguides and alignment slots provide inherent mechanical constraints that automatically position components with high precision, substituting complex mechanical adjustment mechanisms with a simplified integrated structure.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If opto-mechanical mounts are used for alignment, then alignment precision can be achieved, but device complexity and cost increase

Engineering Contradiction:
Improvealignment precisionVSAvoidstructural complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent merges the alignment structure, optical guiding (hollow core waveguides), and component mounting functions into a single integrated substrate. This consolidation eliminates separate opto-mechanical mounts and their associated alignment mechanisms, reducing device complexity while maintaining precision through the unified structural design.

Inventive Principle:
Principle #5Merging (Combining)

3Manufacturing precision

If manual alignment and gluing of optical components is used, then alignment precision can be achieved, but manufacturing cost increases

Engineering Contradiction:
Improvealignment precisionVSAvoidmanufacturing cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The alignment slots and hollow core waveguides are pre-formed in the substrate using automated fabrication processes before component insertion. This preliminary structuring enables subsequent automated assembly without requiring manual alignment or gluing operations, significantly reducing labor costs while maintaining precision through the pre-established geometric constraints.

Inventive Principle:
Principle #10Preliminary action

4Volume of moving object

If compact arrangement of optical components is implemented, then space efficiency improves, but alignment tolerance requirements increase

Engineering Contradiction:
Improvereceiver sizeVSAvoidalignment tolerance
Core Design Contradiction:
Volume of moving objectVSManufacturing precision

Solution Approach 1:

The hollow core waveguides act as intermediary structures that optically connect compactly arranged components while providing inherent alignment guidance through their geometric configuration. The waveguides tolerate smaller misalignments between components compared to direct free-space optical paths, enabling compact packaging without sacrificing optical performance.

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

This approach results in a mechanically robust, compact, and inexpensive optical receiver suitable for quantum key distribution, capable of mass production with reduced alignment requirements and improved productivity.

Implementation Method 1

hollow core waveguides formed in a substrate which guide radiation to optical components

Methodology Applied
Scientific EffectWaveguide (optics): Waveguide (optics)

Data Source

PatentEP2248284B1Optical transmitters and receivers for quantum key distribution
Publication Date: 2019.09.18 QUBITEKK
  • EP2248284B1 patent drawingFigure 1~2
  • EP2248284B1 patent drawingFigure 3
  • EP2248284B1 patent drawingFigure 4

AI summary

An optical receiver (100) for a quantum key distribution system comprises a plurality of optical components (103, 104, 106, 108, 110, 112, 114, 116, 118) mounted or formed in a substrate (122) and optically coupled by one or more hollow core waveguides (105, 123) formed in the substrate.