Multicore Fibre Preform Marker Rod for Precise Core Alignment

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Solution Overview

Problem

The production of multi-core fibers is challenged by the difficulty in maintaining precise alignment and minimizing attenuation between cores, which is exacerbated by the need for marker elements that introduce additional risks of damage and deformation, particularly in the 'stack-and-draw' and OVD processes.

Innovation Solution

A method involving a glass filler rod with a recess for a marker element, allowing for precise alignment and insertion without modifying the outer glass, ensuring high accuracy and reducing the risk of damage during fiber production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If marker elements are inserted into the hollow cylinder in the 'stack-and-draw' process, then alignment reference is provided, but the risk of damage and deformation increases

Engineering Contradiction:
Improvealignment precisionVSAvoidrisk of damage
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent introduces a filler rod as an intermediary component that integrates the marker element within its structure. The filler rod acts as a mediator between the hollow cylinder and the marker element, providing mechanical support and protection while maintaining alignment functionality. This resolves the contradiction by shielding the marker element from direct exposure to damage risks during stacking and drawing operations.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The marker element is nested within the filler rod, which itself is inserted into the hollow cylinder. This nested structure protects the vulnerable marker element by embedding it within the more robust filler rod, reducing the risk of damage during handling and processing while preserving its alignment reference function.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Measurement precision

If the hollow cylinder is modified to accommodate marker elements, then alignment is enabled, but the complexity and risk of deformation increase

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

Solution Approach 1:

The patent divides the system into separate functional components: the hollow cylinder maintains its simple structural role, while the filler rod serves as a separate module that integrates both the marker element and structural support functions. This segmentation avoids modifying the hollow cylinder, reducing complexity and deformation risk while enabling precise alignment through the filler rod's integrated marker.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The filler rod acts as an intermediary that carries the marker element without requiring modifications to the hollow cylinder. This mediator approach enables alignment functionality while preserving the simplicity and structural integrity of the original hollow cylinder design.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Quantity of substance

If multiple components are stacked for multi-core fiber production, then core density increases, but dimensional errors and contamination risk increase

Engineering Contradiction:
Improvecore densityVSAvoiddimensional accuracy
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent merges the marker element and structural support functions into a single integrated filler rod component. This consolidation reduces the number of separate parts that need to be stacked and handled, thereby minimizing cumulative dimensional errors and contamination risks while maintaining the necessary core density through proper component arrangement.

Inventive Principle:
Principle #5Merging (Combining)

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 reduces the risk of rejects and fiber curl, maintaining high accuracy and alignment, thereby enhancing the production efficiency and quality of multi-core fibers.

Implementation Method 1

a rod made of a low-viscosity glass with a polygonal cross-section is inserted into the remaining open central opening, and a marker rod is inserted into a void next to this rod. In a later stage of the process, all components of the assembly are heated, with the rod made of the low-viscosity glass softening first and filling the gaps.

Methodology Applied
Scientific EffectGlass softening: Melting

Data Source

PatentEP4466236B1Method and preform for producing a multicore fibre
Publication Date: 2026.03.11 HERAEUS QUARZGLAS GMBH & CO KG
  • EP4466236B1 patent drawingFigure 1~3
  • EP4466236B1 patent drawingFigure 4~5

AI summary

Known methods for producing a multicore fibre comprise a method step in which a component group is reshaped to form the multicore fibre or to form a pre-form for the multicore fibre, comprising a hollow cylinder having a central hole and a hollow cylinder longitudinal axis, and having a glass casing region made of casing glass and multiple glass core regions provided with a core glass, wherein at least one part of the central hole is provided with a glass filling material having a filling rod longitudinal axis and a filling rod outer casing surface. In order to provide a method, on this basis, for producing multicore fibres without a central signal core, in which the risk of rejects is reduced in the finishing of the glass casing hollow cylinder, according to the invention, a recess extending in the direction of the filling rod longitudinal axis is generated in or on the filling rod, into which a marker element made of marker glass is introduced or which forms the marker element.