Arc-Cladding Hollow-Core Fiber for Low-Loss Compact Coupling

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Solution Overview

Problem

Anti-resonant hollow-core fibers face challenges in reducing size without increasing transmission loss, making them incompatible with conventional fibers for normal connections.

Innovation Solution

A hollow-core fiber structure is designed with a cladding layer formed by single-layer or multi-layer arcs, using tubular units with specific angular arrangements and spacings to confine light propagation, ensuring low loss and compatibility with conventional fibers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the microstructure complexity is increased to reduce transmission loss, then the transmission loss is reduced, but the overall size of the fiber increases

Engineering Contradiction:
Improvetransmission lossVSAvoidfiber size
Core Design Contradiction:
Loss of energyVSVolume of moving object

Solution Approach 1:

The fiber structure is divided into multiple tubular units (first and second tubular units) arranged in a specific pattern. Each tubular unit contains air holes that segment the cladding layer, creating a modular microstructure that reduces transmission loss while controlling overall fiber size through systematic arrangement rather than increasing complexity indiscriminately

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from conventional circular fiber cross-sections to a structured arrangement of tubular units with specific geometric patterns. The cladding layer is designed with air holes positioned at specific distances from the fiber core, creating a two-dimensional pattern that optimizes light confinement while maintaining manageable fiber dimensions

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Loss of energy

If the microstructure complexity is increased to reduce transmission loss, then the transmission loss is reduced, but the compatibility with conventional fibers deteriorates

Engineering Contradiction:
Improvetransmission lossVSAvoidcompatibility with conventional fibers
Core Design Contradiction:
Loss of energyVSAdaptability or versatility

Solution Approach 1:

The fiber is segmented into distinct functional regions: a fiber core for light propagation and a cladding layer with specific microstructure for confinement. This segmentation allows the core to maintain compatibility with conventional fibers while the cladding provides advanced loss-reduction features through its structured air hole pattern

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the fiber are assigned different structural qualities: the fiber core maintains a simple, conventional structure for compatibility, while the cladding layer incorporates complex air hole patterns specifically where needed for light confinement and loss reduction, creating local optimization without compromising overall compatibility

Inventive Principle:
Principle #3Local quality

3Volume of moving object

If the fiber size is reduced for better compatibility, then the compatibility with conventional fibers is improved, but the transmission loss increases

Engineering Contradiction:
Improvefiber sizeVSAvoidtransmission loss
Core Design Contradiction:
Volume of moving objectVSLoss of energy

Solution Approach 1:

The patent uses thin-walled tubular units with air holes positioned at specific distances from the fiber core. These thin-walled structures provide effective light confinement through the anti-resonant mechanism while maintaining a compact overall fiber size, achieving low transmission loss without requiring large fiber dimensions

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent optimizes specific geometric parameters including the distance d1 from the fiber core to air holes, the distance d2 between adjacent air holes, and the wall thickness of tubular units. By carefully controlling these parameters within specific ranges, the fiber achieves low transmission loss while maintaining a compact size suitable for compatibility with conventional fiber infrastructure

Inventive Principle:
Principle #35Parameter changes

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 design effectively reduces fiber size while maintaining low loss, enabling wider application scenarios and compatibility with conventional fibers.

Implementation Method 1

An anti-resonant hollow-core fiber uses a light-guiding mechanism of anti-resonant reflection to form a cladding layer by simply arranging geometric microstructure units

Methodology Applied
Scientific EffectAnti-resonant reflection: Reflection

Data Source

PatentEP4692872A1Hollow-core optical fiber and optical transmission system
Publication Date: 2026.02.11 HUAWEI TECH CO LTD
  • EP4692872A1 patent drawingFigure 1(a)~3(b)
  • EP4692872A1 patent drawingFigure 4~5
  • EP4692872A1 patent drawingFigure 6~7

AI summary

This application provides a hollow-core fiber, including N first tubular units, N second tubular units, and a protection sleeve. The N first tubular units are arranged circumferentially and abut against the protection sleeve. The N second tubular units are in one-to-one correspondence with the N first tubular units, and each of the N first tubular units is nested in a corresponding second tubular unit, to form, together with the second tubular unit, a cladding layer that confines light beam propagation within a fiber core. A cross section of the second tubular unit includes at least one arc structure, and a central angle of the arc structure is 180 degrees to 340 degrees. The cladding layer is constructed by using a microstructure unit including a single-layer arc or multi-layer arcs, to confine light beam propagation within the fiber core. In this case, a size of the fiber is effectively reduced while ensuring a low loss of the fiber, so that a hollow-core fiber structure in this application has good compatibility, and is applicable to wider application scenarios.