Fiber Laser Ferrule and Housing for Compact Heat Dissipation

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Solution Overview

Problem

Conventional fiber laser apparatuses face challenges in achieving a small, compact design due to heat accumulation issues when shortening the length of the gain fiber, which limits their downsizing potential and efficiency.

Innovation Solution

The use of ferrules and housing materials with high thermal conductivity (such as metals) and thermal expansion coefficients matching those of the fiber, to reduce heat accumulation and stress on the fiber ends, allowing for effective heat dissipation and preventing damage from thermal expansion differences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the gain fiber length is shortened to achieve compact apparatus size, then the apparatus volume is reduced, but heat accumulation in the fiber increases causing damage

Engineering Contradiction:
Improveapparatus volumeVSAvoidheat accumulation in fiber
Core Design Contradiction:
Volume of moving objectVSTemperature

Solution Approach 1:

A heat dissipation member is introduced as an intermediary component between the gain fiber and the housing. This member has high thermal conductivity and is in thermal contact with the gain fiber, serving as a heat transfer mediator that conducts heat away from the fiber without requiring the fiber to be in direct contact with the housing or cooling fluid

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The thermal conductivity parameter of the heat dissipation member is optimized to be higher than conventional materials. By changing the material parameter (using materials with superior thermal conductivity), the heat dissipation capability is enhanced, allowing the fiber to operate at higher powers without damage even in a compact configuration

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If conventional materials (zirconia ferrules, aluminum housing) are used, then manufacturing is easy, but thermal conductivity is insufficient leading to heat accumulation

Engineering Contradiction:
Improvemanufacturing easeVSAvoidheat dissipation efficiency
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The system uses a composite structure combining different materials with complementary properties: the heat dissipation member is made from materials with high thermal conductivity (such as copper, aluminum, or their alloys), while the ferrules may use conventional ceramics like zirconia. This composite approach allows each component to be optimized for its specific function while maintaining ease of manufacture

Inventive Principle:
Principle #40Composite materials

3Volume of moving object

If fiber length is reduced for compact design, then apparatus size decreases, but stress from thermal expansion differences increases causing fiber damage

Engineering Contradiction:
Improveapparatus volumeVSAvoidthermal expansion stress on fiber
Core Design Contradiction:
Volume of moving objectVSStress or pressure

Solution Approach 1:

The patent explicitly considers thermal expansion effects by selecting materials for the heat dissipation member and housing whose thermal expansion coefficients are matched to minimize differential expansion. This prevents excessive stress from being applied to the gain fiber during temperature changes, allowing the compact design to operate reliably

Inventive Principle:
Principle #37Thermal expansion

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 approach enables the downsizing of fiber laser apparatuses by minimizing heat accumulation and stress, enhancing thermal conductivity and expansion coefficient matching, thus improving output efficiency and preventing damage from thermal expansion differences.

Implementation Method 1

The use of ferrules and housing materials with high thermal conductivity (such as metals) and thermal expansion coefficients matching those of the fiber, to reduce heat accumulation and stress on the fiber ends

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

thermal expansion coefficients matching those of the fiber, allowing for effective heat dissipation and preventing damage from thermal expansion differences

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP4007089B1Fibre laser device
Publication Date: 2024.09.04 KIMMON KOHA CO LTD
  • EP4007089B1 patent drawingFigure 1
  • EP4007089B1 patent drawingFigure 2A~2B
  • EP4007089B1 patent drawingFigure 3

AI summary

A fiber laser apparatus to use a fiber of short length type to which an active element is added with high concentration, includes a ferrule inserted on an end of the fiber, and a housing to accommodate the fiber and to support the fiber with the ferrule, wherein each of the housing and the ferrule is constituted by a metal material having a thermal expansion coefficient approximate to a thermal expansion coefficient of a raw material of the fiber.