Multicore Fiber Polygonal Array Crosstalk Reduction

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Solution Overview

Problem

Current optical communication systems face challenges in increasing bandwidth capacity while maintaining low cost and reducing crosstalk and loss in high-density multicore fiber cables, especially in long-haul and data center applications, where conventional single-core solutions are costly and inefficient.

Innovation Solution

A multicore fiber design with a polygonal array configuration, where cores are positioned at vertices to minimize crosstalk, using a stack-and-draw technique with refractive index variations and cladding to form waveguides, and employing tapered multicore connectors for low-loss and low-crosstalk signal transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If cores are positioned closer together to increase fiber density, then the number of cores per fiber increases, but crosstalk between cores increases

Engineering Contradiction:
Improvefiber densityVSAvoidcrosstalk
Core Design Contradiction:
Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by creating a heterogeneous core structure where one core has a different refractive index profile than the others. This local differentiation allows the system to maintain high core density while the distinct optical properties of the heterogeneous core reduce crosstalk interactions, enabling closer core spacing without proportionally increasing interference

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs asymmetry by designing a multicore fiber where at least one core differs from the others in refractive index, core diameter, or positioning. This asymmetric configuration breaks the symmetry of uniform core arrays, allowing optimized core spacing and reduced crosstalk while maintaining high overall core density in the fiber

Inventive Principle:
Principle #4Asymmetry

2Productivity

If more cores are added to increase bandwidth capacity, then spectral efficiency increases, but cable size and duct congestion worsen

Engineering Contradiction:
Improvebandwidth capacityVSAvoidcable size
Core Design Contradiction:
ProductivityVSArea of stationary object

Solution Approach 1:

The patent merges multiple optical channels into a single multicore fiber cable, combining the functionality of what would traditionally require multiple separate single-core fibers. This consolidation achieves high bandwidth capacity while reducing the overall cable size and number of ducts required, as multiple cores share a common cladding and protective structure

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent transitions from one-dimensional single-core fiber arrangements to two-dimensional multicore arrays within a single fiber cross-section. This dimensional change allows multiple data channels to be transmitted simultaneously through spatial division multiplexing, dramatically increasing bandwidth capacity without proportionally increasing cable outer diameter

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

3Reliability

If conventional single-core solutions are used to provide bandwidth, then reliability is maintained, but cost increases with N times deployment cost for N-fold capacity increase

Engineering Contradiction:
Improveconnection reliabilityVSAvoiddeployment cost
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent creates a universal multicore fiber platform that can provide multiple data channels simultaneously while maintaining compatibility with existing optical communication infrastructure. The fiber design allows standard splicing, connectorization, and signal processing techniques to be applied to each core, enabling reliable multi-channel transmission without requiring entirely new deployment methodologies

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

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 achieves low crosstalk and loss, enabling high-density, high-speed parallel data transmissions over long distances with compatibility with existing single-core fiber infrastructure, supporting multiple channels and users, and demonstrating effective performance in passive optical networks and data centers.

Implementation Method 1

The plurality of cores and surrounding cladding provide respective index variations, so as to form a respective plurality of waveguides for conducting parallel data transmissions

Methodology Applied
Scientific EffectTotal Internal Reflection: Total Internal Reflection

Implementation Method 2

form a respective plurality of waveguides for conducting parallel data transmissions from a first end of the fiber to a second end

Methodology Applied
Scientific EffectWaveguide: Waveguide (optics)

Data Source

PatentEP2545400B1Multicore fibers and associated structures and techniques
Publication Date: 2017.12.06 OFS FITEL LLC
  • EP2545400B1 patent drawingFigure 1~2
  • EP2545400B1 patent drawingFigure 3~4
  • EP2545400B1 patent drawingFigure 5~6

AI summary

A multicore fiber comprises a plurality of cores extending along the length of a fiber body. Each of the cores is surrounded by a cladding. The plurality of cores and surrounding cladding provide respective index variations, so as to form a. respective plurality of waveguides for conducting parallel data transmissions from a first end of the fiber to a second end. The plurality of cores has a cross-sectional geometry in which the plurality of cores is configured in a polygonal array, in which at least some of the cores are positioned at the vertices of the array. The polygonal array is configured such that neighboring cores in the array are separated from each other by a distance that Is sufficient to prevent crosstalk therebetween.