Multi-core Optical Fiber with Segmented Inner Cladding for Pumping Efficiency

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Solution Overview

Problem

Current multi-core erbium-doped optical fiber amplifiers face challenges in reducing power consumption and improving pumping efficiency, which is essential for enhancing communication capacity in optical communication systems.

Innovation Solution

The design incorporates a double-cladding multi-core optical fiber with a triangular lattice arrangement of core portions, featuring an inner cladding with different refractive index regions and an outer cladding with a lower refractive index, optimizing the refractive index profile to increase the scattering of pumping light and enhance its absorption by the rare earth elements, thereby improving pumping efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a double-cladding multi-core optical fiber with uniform refractive index in the inner cladding is used, then the structure is simple and easy to manufacture, but the pumping efficiency is insufficient and power consumption is high

Engineering Contradiction:

Improveease of manufactureVSAvoidpumping efficiency

Core Design Contradiction:

Ease of manufactureVSLoss of energy

Solution Approach 1:

The inner cladding portion is divided into multiple regions with different refractive indices. Specifically, the inner cladding includes a first region with a first refractive index and a second region with a second refractive index that is lower than the first. This local variation in refractive index creates optimal conditions for pumping light scattering and absorption in different areas, thereby improving pumping efficiency without complicating the overall manufacturing process.

Inventive Principle:

Principle #3Local quality

2Reliability

If the refractive index of the inner cladding is increased to improve light confinement, then optical confinement is enhanced, but pumping light scattering is reduced and pumping efficiency decreases

Engineering Contradiction:

Improveoptical confinementVSAvoidpumping efficiency

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

Different regions of the inner cladding are assigned different refractive indices to fulfill different functions. The first region maintains higher refractive index for optimal optical confinement, while the second region has lower refractive index to enhance pumping light scattering. This spatial differentiation resolves the contradiction between confinement and scattering requirements.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The inner cladding is segmented into multiple functional regions with distinct refractive index characteristics. This segmentation allows each region to optimize for its specific purpose - some areas for confinement, others for scattering - thereby achieving both goals simultaneously rather than forcing a compromise in a uniform structure.

Inventive Principle:

Principle #1Segmentation

3Productivity

If multi-core optical fiber amplifiers are used to increase communication capacity, then bandwidth is expanded, but power consumption increases

Engineering Contradiction:

Improvecommunication capacityVSAvoidpower consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

By changing the refractive index parameter distribution within the inner cladding - specifically creating regions with different refractive indices - the pumping efficiency is improved. This parameter optimization reduces the amount of pumping power required to achieve the same amplification effect, thereby reducing overall power consumption while maintaining the multi-core configuration's high communication capacity.

Inventive Principle:

Principle #35Parameter changes

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 configuration leads to improved pumping efficiency and reduced power consumption, allowing for more effective optical amplification and increased communication capacity while maintaining desired optical characteristics.

Implementation Method 1

optimizing the refractive index profile to increase the scattering of pumping light and enhance its absorption by the rare earth elements

Methodology Applied

Scientific EffectScattering: Scattering

Implementation Method 2

an optical coupler configured to optically couple the pumping light to the inner cladding portion of the optical amplifying fiber

Methodology Applied

Scientific EffectOptical coupling:

Implementation Method 3

erbium (Er), a rare earth element, included in its core portions is optically pumped

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentUS20230123319A1Optical amplifying fiber, optical fiber amplifier, and optical communication system

Publication Date: 2023.04.20 FURUKAWA ELECTRIC CO LTD

AI summary

An optical amplifying fiber includes: at least one core portion including a rare earth element added therein; an inner cladding portion surrounding the at least one core portion, the inner cladding portion having a refractive index lower than a maximum refractive index of the at least one core portion; and an outer cladding portion surrounding the inner cladding portion, the outer cladding portion having a refractive index lower than the refractive index of the inner cladding portion, the inner cladding portion including different refractive index regions each having a refractive index different from a refractive index of a region adjacent to that different refractive index region.