Rare-Earth-Doped Fiber with Cladding Holes for Low-Loss Pump Efficiency

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Solution Overview

Problem

Existing cladding pumped multicore optical fiber amplifiers face challenges in optimizing excitation light power conversion efficiency while maintaining good connectivity with other optical fibers and combiners due to variations in core and cladding cross-sectional area ratios, leading to increased connection losses.

Innovation Solution

A rare-earth-doped fiber design that includes core and cladding regions with strategically placed holes to adjust the cross-sectional area ratio without altering the core size, optimizing the hole radius and number to achieve desired efficiency levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the cross-sectional area ratio of core and cladding is optimized to maximize excitation light power conversion efficiency, then power conversion efficiency is improved, but connection loss increases due to significant deviation from normal fiber dimensions

Engineering Contradiction:

Improveexcitation light power conversion efficiencyVSAvoidconnection loss

Core Design Contradiction:

Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The patent introduces air holes into the cladding region of the optical fiber to create a porous structure. This allows optimization of the effective cladding area without changing the physical outer dimensions of the fiber, thereby improving power conversion efficiency while maintaining standard fiber outer diameter for low connection loss

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The patent changes the structural parameters of the cladding by introducing holes with specific radii and arrangements. This modifies the effective area and numerical aperture of the cladding to optimize pump light absorption while keeping the overall fiber geometry compatible with standard connectors

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

Improves excitation light power conversion efficiency while ensuring good connectivity with other optical fibers and combiners, reducing power consumption per core.

Implementation Method 1

amplifies signal light propagating through a plurality of cores doped with a rare-earth element, by excitation light incident on cladding

Methodology Applied

Scientific EffectStimulated emission: Light

Implementation Method 2

excitation light source that emits excitation light for exciting rare-earth ions doped into the core region

Methodology Applied

Scientific EffectAbsorption: Absorption (EM radiation)

Data Source

PatentEP4686015A1Rare earth-doped fiber, optical amplifier, and design method of rare earth-doped fiber

Publication Date: 2026.01.28 NT T INC

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AI summary

The rare-earth-doped fiber includes at least one core region 11 doped with rare-earth ions, a cladding region 12 disposed around the core region 11, and a hole 13 formed in the core region 11 or the cladding region 12. The hole radius and the number of the holes 13 are determined such that the ratio Rcc of the cross-sectional area of the core regions 11 to the cross-sectional area of the cladding region 12 becomes a desired value.