Fiber Pump Combiner With Tapered Coupling Device

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Solution Overview

Problem

High power fiber laser systems face challenges in combining multiple optical fibers to achieve high power output without reducing beam efficiency or quality, often resulting in structural defects and handling difficulties due to extensive physical manipulation of fibers.

Innovation Solution

An optical fiber combiner with a coupling device featuring a gradual taper and a hollow structure to secure and align optical fibers, reducing physical manipulation and minimizing imperfections, while using methods like plasma heating or fusion splicing for coupling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If optical fibers are extensively manipulated (fused, twisted, tapered) to achieve high coupling efficiency, then beam combination efficiency is improved, but structural defects such as micro-bends are introduced that degrade beam quality and reliability

Engineering Contradiction:
Improvebeam combination efficiencyVSAvoidbeam quality
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The device separates the coupling function from the fiber bundle, using a multi-faceted input surface to receive light from multiple fibers independently while maintaining their structural integrity. This avoids the need to manipulate the fibers themselves for coupling.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The tapered coupling device acts as an intermediary between the fiber bundle and output, providing a gradual transition that couples light without requiring direct physical manipulation of the fibers. The intermediary structure protects fibers from damage while achieving efficient coupling.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Power

If optical fibers are twisted to achieve high coupling efficiency, then power combination is improved, but handling difficulty increases

Engineering Contradiction:
Improvecombined power outputVSAvoidfiber handling
Core Design Contradiction:
PowerVSEase of operation

Solution Approach 1:

Instead of twisting fibers to achieve coupling, the invention inverts the approach by using a multi-faceted input surface that naturally receives and couples light from multiple fibers in their normal, untwisted orientations. The coupling geometry is reversed from fiber-manipulation-based to surface-geometry-based.

Inventive Principle:
Principle #13The other way round (Inversion)

3Ease of manufacture

If fiber bundle cross-sectional area is narrowed during tapering, then coupling to single output fiber is achieved, but physical manipulation increases causing structural defects

Engineering Contradiction:
Improvecoupling fabricationVSAvoidfiber structural integrity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The input surface is segmented into multiple facets, each corresponding to a specific fiber or group of fibers. This segmentation allows independent positioning and coupling of each fiber without requiring the entire bundle to be tapered or manipulated, preserving fiber structural integrity while achieving precise coupling.

Inventive Principle:
Principle #1Segmentation

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 solution enhances beam quality and efficiency by reducing physical manipulation of fibers, minimizing structural defects, and improving handling, thereby maintaining high power output with improved reliability.

Implementation Method 1

a plurality of optical fibers each having an input surface and an output surface, wherein the output surfaces of the plurality of optical fibers are optically coupled to the coupling device, wherein the coupling device combines optical power emitted by the plurality of optical fibers

Methodology Applied
Scientific EffectOptical coupling: Optical Fibre

Implementation Method 2

a hollow structure configured to encase the plurality of optical fibers and to secure the plurality of optical fibers in place for coupling to the coupling device

Methodology Applied
Scientific EffectMechanical constraint: Mechanical Force

Data Source

PatentEP3391110B1Fiber pump combiner
Publication Date: 2019.11.20 NLIGHT INC
  • EP3391110B1 patent drawingFigure 1
  • EP3391110B1 patent drawingFigure 2
  • EP3391110B1 patent drawingFigure 3

AI summary

An optical fiber combiner comprising a coupling device having an input surface area, and you Ain, and an output surface area, Aout, wherein the input surface area Ain is greater than the output surface Aout, and a plurality of optical fibers each having an input surface and an input surface and an output surface, wherein the ouput surfaces of the plurality of optical fibers are coupled to the copuling device, wherein the coupling device combines optical power emitted by the plurality of optical fibers.