Multi-Core to Single-Core Fiber Coupling Using Gradient-Index Lens

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Solution Overview

Problem

Existing interconnection methods between multi-core and single-core optical fibers are not compact or easy to implement, often requiring glass spacers and microlens arrays that complicate alignment and increase complexity.

Innovation Solution

A coupling system using gradient-index lenses and fiber sections with radial offsets, allowing for precise control of beam angles and diameters, facilitating alignment and compact assembly by eliminating the need for glass spacers and microlens arrays.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a glass spacer and microlens array are used to redirect optical beams from multi-core fiber to single-core fiber array, then the optical signals can be transferred between different fiber types, but the system becomes less compact and alignment becomes more difficult

Engineering Contradiction:

Improveoptical signal transfer capabilityVSAvoidsystem compactness and alignment difficulty

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the functions of the glass spacer and microlens array into a single integrated gradient-index lens component. This gradient-index lens simultaneously performs beam redirection and focusing, eliminating the need for separate glass spacers and microlens arrays, thereby reducing system complexity while maintaining optical signal transfer capability between multi-core and single-core fibers

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The gradient-index lens serves multiple functions within the coupling system: it acts as both a beam redirecting element and a focusing element, replacing the specialized functions of separate glass spacers and microlens arrays. This multi-functional component simplifies the overall system structure while maintaining the ability to transfer optical signals between different fiber types

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Ease of manufacture

If a microlens array is used to redirect optical beams, then beam redirection is achieved, but alignment problems arise and implementation becomes difficult

Engineering Contradiction:

Improvebeam redirection functionVSAvoidalignment ease

Core Design Contradiction:

Ease of manufactureVSEase of operation

Solution Approach 1:

The patent combines the beam redirection function of the microlens array with the focusing function of the gradient-index lens into a single integrated component. This eliminates the alignment issues associated with separate microlens arrays while maintaining effective beam redirection and optical signal coupling

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent employs a gradient-index lens with specific refractive index profiles (parabolic or other gradient distributions) to achieve both beam redirection and focusing effects. By carefully selecting the gradient index parameters and lens geometry, the system achieves effective optical coupling without the alignment sensitivity of traditional microlens arrays

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If a glass spacer is used to increase beam spacing, then beam separation is achieved, but the solution is not compact

Engineering Contradiction:

Improvebeam spacing capabilityVSAvoidsystem compactness

Core Design Contradiction:

Ease of manufactureVSVolume of moving object

Solution Approach 1:

The patent integrates the beam spacing function into the gradient-index lens structure itself, eliminating the need for separate glass spacers. The gradient-index lens achieves beam separation through its refractive index profile and geometry, providing the same beam spacing capability in a more compact form factor without requiring additional spacer components

Inventive Principle:

Principle #5Merging (Combining)

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 system enables easier alignment and more compact integration of multi-core and single-core fibers, improving the efficiency of optical signal transmission while reducing alignment errors and system complexity.

Implementation Method 1

a gradient-index lens, positioned between said multi-core fiber and said at least one single-core fiber

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 2

a first gradient-index fiber section coupled at the end of the multi-core fiber to form a first microlensed end

Methodology Applied

Scientific EffectGradient-index refraction: Refraction

Data Source

PatentUS20250004204A1System for coupling a multi-core optical fiber with at least one single-core optical fiber, and corresponding coupling method

Publication Date: 2025.01.02 ORANGE SA

AI summary

The disclosed technology relates to a coupling system between a multi-core optical fiber (MCF) and a set of at least one single-core optical fiber (SCF), each single-core fiber of the set being coupled with a separate core of the multi-core fiber, the coupling system comprising: a gradient-index lens (GRIN-L), positioned between the multi-core fiber and the at least one single-core fiber; a first gradient-index fiber section coupled at the end of the multi-core fiber to form a first microlensed end (GRIN-MCF); for each single-core fiber of said set, a second gradient-index fiber section coupled at the end of the single-core fiber to form a second microlensed end (GRIN-SCF); the first and second microlensed ends being coupled on either side of the lens with a radial offset of one relative to the other defined according to a core parameter of the multi-core fiber.