Glass Microstructured Fiber Tip Assembly for Thermal Alignment Stability

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Solution Overview

Problem

Existing methods for assembling microstructured or nanostructured optical and photonic components on optical fibers face challenges such as poor adhesion, thermal instability, and misalignment due to thermal shrinkage, especially in high-temperature and vibrational environments, and existing adhesion layers are insufficiently robust.

Innovation Solution

A method involving a support made of vitreous material, assembled with the optical fiber using localized fusion, where the component is first formed on a photosensitive material transformed into glass through multi-photon photopolymerization, followed by thermal annealing to prevent shrinkage, and aligned with the fiber before assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If two-photon polymerization is used to create high-resolution microstructures, then manufacturing precision is improved, but thermal stability deteriorates due to polymer material limitations

Engineering Contradiction:
Improvemicrostructure resolutionVSAvoidthermal stability
Core Design Contradiction:
Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The patent transforms the material state from polymer to glass through controlled thermal treatment parameters. By heating the polymer microstructure to temperatures above its glass transition temperature and holding it for a specific duration, the material undergoes a parameter change that converts it into a thermally stable glassy state while preserving the high-resolution features created by two-photon polymerization.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite structure where the original polymer material is transformed into a glass-polymer composite through partial vitrification. This composite material combines the high-resolution capability of polymer-based two-photon polymerization with the thermal stability of glass, achieving both fine feature resolution and thermal resistance.

Inventive Principle:
Principle #40Composite materials

2Loss of substance

If high-temperature heat treatment is applied to remove organic fraction, then purity is improved, but manufacturing precision deteriorates due to dimensional shrinkage

Engineering Contradiction:
Improveorganic fraction removalVSAvoiddimensional accuracy
Core Design Contradiction:
Loss of substanceVSManufacturing precision

Solution Approach 1:

The patent performs preliminary dimensional compensation before the high-temperature heat treatment. By calculating the expected shrinkage based on the polymer-to-glass transformation and adjusting the initial 3D model dimensions accordingly, the final vitrified structure achieves the desired dimensional accuracy. This preliminary action prevents the need for post-processing adjustments.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent incorporates a cushioning factor in the design phase to compensate for the inevitable shrinkage during vitrification. The initial structure is designed with slightly larger dimensions that account for the expected contraction, ensuring that after heat treatment and organic fraction removal, the final dimensions match the target specifications.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Strength

If adhesion layers are introduced to improve assembly strength, then strength is improved, but device complexity increases

Engineering Contradiction:
Improveassembly adhesionVSAvoidstructure complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent merges the adhesion function into the support structure itself by making the support and component from the same polymer material. This material unity creates inherent adhesion through molecular bonding when the materials are in contact, eliminating the need for separate adhesion layers. The merging of material types simplifies the overall device structure while maintaining strong assembly bonds.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses homogeneous polymer material for both the support structure and the microcomponent. This material homogeneity ensures compatible thermal expansion coefficients, similar processing requirements, and natural adhesion through molecular entanglement and bonding, eliminating the need for heterogeneous adhesion layers and reducing device complexity.

Inventive Principle:
Principle #33Homogeneity

4Ease of manufacture

If friction-based attachment is used to assemble component on fiber, then ease of manufacture is improved, but reliability deteriorates in high-temperature and vibrational environments

Engineering Contradiction:
Improveassembly simplicityVSAvoidenvironmental stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent replaces the mechanical friction-based attachment system with a thermal-field-based bonding system. By using controlled heating during assembly, the polymer materials undergo localized melting and re-solidification, creating strong molecular bonds between the support and the optical fiber. This substitution of mechanical bonding with thermal-field bonding provides superior reliability in high-temperature and vibrational environments.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes phase transition of the polymer material from solid to molten state and back during the assembly process. By heating the polymer to its melting point, the material becomes fluid and can flow into the interface between the support and fiber, creating strong adhesion upon cooling. This phase transition mechanism provides reliable bonding that withstands environmental stresses better than friction-based attachment.

Inventive Principle:
Principle #36Phase transitions

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

Ensures strong and precise attachment of the component to the fiber, maintaining alignment and optical properties, while avoiding post-assembly misalignment and deformation.

Implementation Method 1

produce on a first end of said support, by photopolymerization with several photons, in particular with two photons, a micro-structured or nano-structured component

Methodology Applied
Scientific EffectPhotopolymerization with several photons: Photopolymerisation

Implementation Method 2

carry out one or more heat treatments so as to transform the first material of said support and the second material of said micro- or nano-structured component into a glassy material

Methodology Applied
Scientific EffectThermal annealing: Annealing

Implementation Method 3

assemble and join, a region of a second end of said support opposite said first end with an area of ​​an end or a lateral surface of said structure

Methodology Applied
Scientific EffectLocalized fusion: Welding

Data Source

PatentEP4519726B1Process for producing, at the end of a structure, a micro- or nano-component made of vitreous material produced by multi-photon photopolymerization
Publication Date: 2026.04.15 SAFRAN AIRCRAFT ENGINES SAS
  • EP4519726B1 patent drawingFigure 1~4
  • EP4519726B1 patent drawingFigure 5A~5B
  • EP4519726B1 patent drawingFigure 6~7

AI summary

The invention relates to a process for producing an optical device equipped with a nano-structured or micro-structured component (21) joined to one end of an optical fibre (30), the process comprising steps of: - providing a carrier (10) based on a photosensitive material (12) that is convertible into a vitreous material, and producing on one end (10A) of said carrier, by two-photon photopolymerization, a micro-structured or nano-structured component (21) based on a photosensitive material (22) that is convertible into a vitreous material; - carrying out one or more heat treatments so as to convert the material (12) of said carrier and the material (22) of said micro- or nano-structured component into vitreous material; subsequently, - joining and securing a region of a second end (10B) of said carrier (10), which end is opposite said first end (10A), to a zone of an end of the optical fibre (30), through localized fusion of said region and of said zone, of said carrier and of said optical fibre (30), respectively.