Tubular Hollow Waveguide for Single-Mode Low-Loss Transmission

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Solution Overview

Problem

Current hollow optical fibers face issues such as high linear losses, narrow bandwidth, high dispersion, and multimode operation, which limit their applications in nonlinear optics, frequency conversion, and high-resolution spectroscopy.

Innovation Solution

An electromagnetic waveguide with a hollow central part surrounded by a first set of primary tubes and a second set of secondary tubes, arranged in annular structures, to achieve single-mode guidance and reduced losses through inhibited coupling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If photonic band gap hollow fibers are used, then guidance is achieved, but linear losses increase rapidly for shorter wavelengths

Engineering Contradiction:
Improvelinear lossesVSAvoidwavelength range
Core Design Contradiction:
Loss of energyVSAdaptability or versatility

Solution Approach 1:

The waveguide structure is segmented into a hollow central part and multiple primary hollow tubes arranged in an annular manner. This segmentation creates a periodic structure that enables inhibited coupling guidance while maintaining low losses across a broad wavelength range, including shorter wavelengths where photonic band gap fibers fail.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a secondary hollow tube with a specific area ratio (0.35-0.50 times the central hollow part area) positioned at a specific location. This local modification optimizes the coupling inhibition between the central core and cladding modes, achieving low losses while maintaining broad wavelength adaptability.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If hollow core fibers are used, then bandwidth is improved, but dispersion becomes too high and structured

Engineering Contradiction:
ImprovebandwidthVSAvoiddispersion control
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The waveguide employs an asymmetric structure with a secondary hollow tube positioned off-center relative to the annular arrangement of primary tubes. This asymmetry breaks the structured dispersion pattern typical of symmetric hollow fibers, enabling smoother dispersion characteristics while maintaining broad bandwidth for applications like short laser pulses and high-resolution spectroscopy.

Inventive Principle:
Principle #4Asymmetry

3Adaptability or versatility

If current hollow optical fibers are used, then multimode operation occurs, but this limits applications in telecommunications

Engineering Contradiction:
Improvemode operationVSAvoidapplication suitability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent carefully controls geometric parameters including the area ratio between the secondary tube and central hollow part (0.35-0.50), the number of primary tubes (at least seven), and their annular arrangement. These parameter optimizations create a mode structure where the fundamental mode is well-confined while higher-order modes experience increased losses, enabling reliable single-mode operation for telecommunications applications.

Inventive Principle:
Principle #35Parameter changes

4Adaptability or versatility

If inhibited coupling mechanism is used, then wide transmission bands are achieved, but losses remain relatively high

Engineering Contradiction:
Improvetransmission band widthVSAvoidpropagation losses
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The secondary hollow tube acts as an intermediary element between the central hollow part and the annular primary tubes. It mediates the coupling between core and cladding modes, providing additional coupling paths that enhance mode confinement while maintaining the wide transmission bands characteristic of inhibited coupling guidance, thereby reducing propagation losses.

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 waveguide design minimizes losses for the fundamental mode while increasing losses for higher order modes, enabling efficient single-mode propagation and maintaining polarization, suitable for guiding waves from extreme ultraviolet to infrared, Tera-hertz, and microwaves.

Implementation Method 1

The present invention relates to an electromagnetic waveguide, based on the inhibited coupling mechanism

Methodology Applied
Scientific EffectInhibited coupling:

Data Source

PatentEP4008041B1Electromagnetic waveguide
Publication Date: 2025.07.09 UNIV DE LIMO
  • EP4008041B1 patent drawingFigure 1a~1c
  • EP4008041B1 patent drawingFigure 2~3
  • EP4008041B1 patent drawingFigure 4~5

AI summary

The present invention relates to the field of waveguides. The invention more precisely relates to a tubular electromagnetic waveguide (1) comprising a hollow central portion (2) defined by a first set of at least seven primary hollow tubes (8, 9, 10, 11, 12, 13, 14) that are distributed annually about the hollow central portion (2) and a second set of tubes comprising at least one secondary hollow tube (6); when there are a plurality thereof positioned annularly around the primary hollow tubes (8, 9, 10, 11, 12, 13, 14), the area of the at least one secondary hollow tube (6) is comprised between 0.35 and 0.50 times the area of the hollow central portion (2). The hollow tubes of the first set (8, 9, 10, 11, 12, 13, 14) are substantially of same size and distant from one another.