Multi-core optical fiber with fluorine-doped cladding

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Solution Overview

Problem

Conventional multi-core optical fibers face issues with transmission loss and nonlinearity, which are not adequately addressed, posing challenges for large-capacity and long-haul transmission applications.

Innovation Solution

A multi-core optical fiber design featuring cores made of silica glass doped with chlorine or pure silica, surrounded by a cladding of fluorine-doped silica glass, with varying chlorine doping between cores to adjust refractive index differences and include leakage reduction portions to minimize crosstalk and transmission loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If conventional multi-core optical fibers are used, then the number of cores can be increased, but transmission loss and nonlinearity increase

Engineering Contradiction:
Improvenumber of coresVSAvoidtransmission loss
Core Design Contradiction:
Quantity of substanceVSLoss of energy

Solution Approach 1:

The patent changes the chemical composition parameters of the optical fiber by doping the cladding with fluorine and cores with chlorine or making them pure silica. This parameter change reduces transmission loss and nonlinearity while enabling higher core counts.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite material structure with fluorine-doped silica glass cladding and chlorine-doped or pure silica cores. This composite approach optimizes the optical properties to reduce transmission loss and nonlinearity.

Inventive Principle:
Principle #40Composite materials

2Quantity of substance

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

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

Solution Approach 1:

The patent changes the refractive index parameters through specific doping concentrations (fluorine in cladding, chlorine in cores) to optimize the balance between core density and crosstalk reduction.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies different doping concentrations locally - fluorine doping in the cladding region and chlorine doping in the core regions - to create optimal local optical properties that reduce crosstalk while maintaining high core density.

Inventive Principle:
Principle #3Local quality

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 design effectively reduces transmission loss and nonlinearity, maintains crosstalk at a certain level, and prevents polarization mode dispersion, while allowing for a higher number of cores with reduced core interval without increasing crosstalk, enhancing the fiber's performance for high-capacity applications.

Implementation Method 1

The cladding is comprised of silica glass doped with fluorine, and each of the plural cores is comprised of silica glass doped with chlorine or pure silica glass

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP2369376B1Multi-core optical fiber
Publication Date: 2016.11.02 SUMITOMO ELECTRIC INDUSTRIES LTD
  • EP2369376B1 patent drawingFigure 1
  • EP2369376B1 patent drawingFigure 2
  • EP2369376B1 patent drawingFigure 3

AI summary

The present invention relates to a multi-core optical fiber having a structure for reducing transmission loss and nonlinearity. The multi-core optical fiber comprises plural cores (111-113) extending along a center axis direction, and a cladding surrounding the peripheries of the plural cores. The cladding is comprised of silica glass doped with fluorine, and each of the plural cores is comprised of silica glass doped with chlorine or pure silica glass.