12-Core Optical Fiber Layout for Marker-Free Splicing

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Solution Overview

Problem

Conventional multi-core optical fibers require markers or polarity considerations for splicing, have small mode field diameters leading to high bending losses, and lack line symmetry, complicating splicing and increasing costs.

Innovation Solution

A 12-core optical fiber design with a circular cladding and line-symmetric core arrangement, allowing splicing without markers or polarity, and featuring a core structure that enables counter propagation and reduced crosstalk.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional multi-core optical fiber core arrangements are used, then splicing requires markers or polarity considerations, but this increases device complexity and splice costs

Engineering Contradiction:
Improvesplicing easeVSAvoidcore arrangement complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent applies asymmetry by deliberately designing a core arrangement that lacks rotational symmetry. The 12 cores are positioned at specific coordinates that create an asymmetric pattern, eliminating the need for markers or polarity considerations during splicing. This asymmetric arrangement simplifies the splicing process while maintaining manufacturability.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent creates a universal core arrangement that can be used for both bidirectional and unidirectional communication systems. The asymmetric 12-core configuration serves multiple functions: it enables simple splicing without markers, supports counter propagation, and maintains compatibility with standard optical fiber infrastructure, thereby reducing overall system complexity.

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

2Quantity of substance

If small mode field diameter cores are used, then core density increases, but bending losses increase

Engineering Contradiction:
Improvecore densityVSAvoidbending loss
Core Design Contradiction:
Quantity of substanceVSLoss of energy

Solution Approach 1:

The patent optimizes the mode field diameter parameter to achieve a balance between core density and bending loss. By carefully selecting the MFD value and adjusting the core spacing parameters, the design achieves high core density while maintaining acceptable bending loss characteristics. The specific coordinate positions of the 12 cores are optimized to maintain appropriate spacing.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent transitions from conventional 2D core arrangements to a optimized 3D spatial configuration within the cladding. The cores are positioned at specific (x, y) coordinates that create an asymmetric pattern, effectively utilizing the available cladding area in multiple dimensions to achieve high density while maintaining performance.

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

3Area of stationary object

If cores are arranged with adjacent relationships, then crosstalk increases, but space utilization improves

Engineering Contradiction:
Improvespace utilizationVSAvoidcrosstalk
Core Design Contradiction:
Area of stationary objectVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by creating different spatial relationships between different pairs of cores. The asymmetric arrangement ensures that no two cores have identical surrounding environments, which helps reduce coherent crosstalk. Each core's position is optimized to minimize its interaction with adjacent cores while maintaining overall space utilization.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent segments the 12 cores into distinct positional groups with specific coordination patterns. This segmentation creates controlled spacing relationships that reduce crosstalk while maintaining high density. The cores are distributed across different regions of the cladding cross-section rather than being clustered, reducing harmful interactions.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4400888B1Multi-core optical fiber and multi-core optical fiber cable
Publication Date: 2025.08.13 SUMITOMO ELECTRIC INDUSTRIES LTD
  • EP4400888B1 patent drawingFigure 1
  • EP4400888B1 patent drawingFigure 2
  • EP4400888B1 patent drawingFigure 3

AI summary

This disclosure relates to an MCF fiber being usable for short-haul O-band transmission, having a standard coating diameter in an MFD almost the same as that of a general-purpose SMF, being capable of splicing fibers without either a marker or a polarity, and including 12 cores usable for counter propagation. The MCF includes 12 cores and a common cladding, and the common cladding has an outer periphery with a circular cross-section, the 12 cores are arranged such that a plurality of cores, each having an adjacent relationship with a specific core that is not one of the plurality of cores, do not have an adjacent relationship with any of the other cores of the plurality of cores. The adjacent relationship is defined as a relationship between two cores having a center-to-center interval with a difference from a minimum center-to-center interval of 2 µm or less. On the cross-section, the 12 cores are arranged such that centers of the 12 cores are line symmetric with respect to a symmetry axis that intersects with the central axis and that passes through none of the centers of the 12 cores, and an arrangement of the centers of the 12 cores has rotational symmetry of order one.