Microstructured Optical Fiber Core for Supercontinuum Reliability

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Solution Overview

Problem

Microstructured optical fibers used in supercontinuum generation systems suffer from material degradation due to high-intensity seed beams, leading to increased transmission loss and reduced beam quality, particularly for visible wavelengths, which affects the long-term reliability and performance of the system.

Innovation Solution

The use of a microstructured optical fiber with a core comprising two different silica materials, where the first region is more resistant to photo-induced defect creation and has a higher refractive index than the second region, providing a high degradation resistance while maintaining low transmission loss, thereby supporting a Gaussian mode for extended periods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a high-intensity seed beam is launched into the fiber core to generate strong supercontinuum, then the supercontinuum power and broadness is improved, but material degradation and transmission loss increase significantly

Engineering Contradiction:
Improvesupercontinuum powerVSAvoidtransmission loss
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The patent applies local quality by creating a core with non-uniform refractive index distribution through controlled doping. The dopant concentration varies spatially within the core, with higher doping in the central region and lower doping toward the periphery. This local variation in material composition creates regions with different optical properties, allowing the fiber to maintain low transmission loss while supporting high-intensity beams for strong supercontinuum generation.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent utilizes parameter changes by modifying the refractive index profile through controlled dopant distribution. The refractive index is changed as a function of radial position within the core, creating a graded-index structure. This parameter variation allows optimization of both transmission characteristics and non-linear optical effects, enabling high-power supercontinuum generation with reduced transmission loss.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If high-intensity seed beam is used for supercontinuum generation, then the generation efficiency is improved, but material permutation and defect creation increase

Engineering Contradiction:
Improvesupercontinuum generation efficiencyVSAvoidfiber reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies local quality by creating a core with non-uniform refractive index distribution through controlled doping. The dopant concentration varies spatially within the core, with higher doping in the central region and lower doping toward the periphery. This local variation in material composition creates regions with different optical properties, allowing the fiber to maintain low transmission loss while supporting high-intensity beams for strong supercontinuum generation.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses composite materials by combining silica base material with dopants (such as germanium, fluorine, or other oxide dopants) in varying concentrations. This creates a composite structure where different material components contribute different properties: the silica provides the base optical matrix, while the dopants modify refractive index and resistance to photo-induced defects. The composite nature allows optimization of both generation efficiency and reliability.

Inventive Principle:
Principle #40Composite materials

3Loss of energy

If the fiber core structure is optimized for low transmission loss, then the beam quality is maintained, but resistance towards photo-induced defects decreases

Engineering Contradiction:
Improvetransmission lossVSAvoidphoto-induced defect creation
Core Design Contradiction:
Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by creating a core with non-uniform refractive index distribution through controlled doping. The dopant concentration varies spatially within the core, with higher doping in the central region and lower doping toward the periphery. This local variation in material composition creates regions with different optical properties, allowing the fiber to maintain low transmission loss while supporting high-intensity beams for strong supercontinuum generation.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent utilizes parameter changes by modifying the refractive index profile through controlled dopant distribution. The refractive index is changed as a function of radial position within the core, creating a graded-index structure. This parameter variation allows optimization of both transmission characteristics and non-linear optical effects, enabling high-power supercontinuum generation with reduced transmission loss.

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 enables the generation of a broad, high-power supercontinuum with improved durability and reduced transmission loss, maintaining high beam quality and supporting a Gaussian mode for longer operational hours, even under high-intensity light exposure.

Implementation Method 1

the first region is more resistant to photo-induced defect creation

Methodology Applied
Scientific EffectPhoto-induced defect creation resistance:

Implementation Method 2

a seed beam is launched from a pump source into a fiber core of a microstructured optical fiber for generation of supercontinuum light through non-linear processes

Methodology Applied
Scientific EffectNon-linear optical processes:

Data Source

PatentEP3198313B1Optical fiber with microstructured core
Publication Date: 2022.03.09 NKT PHOTONICS AS
  • EP3198313B1 patent drawingFigure 1A~1B
  • EP3198313B1 patent drawingFigure 2~3
  • EP3198313B1 patent drawingFigure 4

AI summary

The invention relates to a micro-structured optical fiber suitable for supercontinuum generation a preform therefor, a method of production thereof and a supercontinuum light source. The optical fiber comprises a core microstructured length section Lcm, which comprises: a micro-structured core region comprising at least a first region forming a central part of the core region and a second region surrounding the first region; and a cladding surrounding the core region; wherein the first and second regions are of a first and second silica material, respectively, which differs with respect to composition, and wherein the core region in at least a length part of the core microstructured length section Lcm has a cross sectional diameter Dcm perpendicular to the longitudinal axis which is about 8 μm or less.