Optical Fiber Switch Index Matching Elastomeric Solid Layer

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Solution Overview

Problem

Optical fibers are difficult to couple together effectively due to discontinuities at connection points, leading to light reflection and signal loss, and existing solutions like mechanical fusion splicers are expensive and unsuitable for temporary connections, while index-matched materials are prone to contamination and maintenance issues.

Innovation Solution

An optical fiber switch with angled fibers and a first index matching elastomeric solid layer that chemically bonds to one end face and has a low-tack distal face for repeatable optical coupling, along with a second layer for enhanced mechanical and optical coupling, using acrylate polymers and actuators for precise alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If mechanical fusion splicers are used to join optical fibers, then connection loss is reduced, but cost increases and temporary connections become difficult

Engineering Contradiction:
Improvesignal lossVSAvoidcost and reconfigurability
Core Design Contradiction:
Loss of energyVSEase of manufacture

Solution Approach 1:

An index-matched gel material is introduced as an intermediary substance between the optical fiber end faces. This gel fills the gap and matches the refractive index of the fiber core, eliminating air gaps that cause reflection and signal loss. The gel allows for temporary, reconfigurable connections while maintaining low loss, avoiding the need for permanent fusion splicing.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The refractive index of the coupling material is changed to match that of the optical fiber core. By using a gel with an index of refraction approximately equal to the fiber core index (e.g., 1.46-1.48), the optical discontinuity at the interface is minimized, reducing reflection and improving signal transmission compared to air-gapped connections.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If index-matched liquid or gel materials are used for optical coupling, then alignment flexibility is improved, but contamination and maintenance problems increase

Engineering Contradiction:
Improvealignment flexibilityVSAvoidcontamination
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The physical state of the index-matched material is changed from liquid to solid gel. This gel formulation maintains the beneficial optical properties and alignment flexibility of liquid index-matched materials while eliminating the drawbacks of leakage, migration, and contamination. The solid gel structure provides stable, maintenance-free operation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

A composite gel material is used that combines the optical properties of index-matched materials with the structural stability of solid gels. This composite approach provides both the alignment flexibility needed for easy operation and the structural integrity needed to prevent contamination and maintenance issues.

Inventive Principle:
Principle #40Composite materials

3Loss of energy

If angled fiber end faces are used, then reflection is reduced, but mechanical coupling stability becomes difficult to maintain

Engineering Contradiction:
Improvereflection lossVSAvoidmechanical coupling stability
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The index-matched gel acts as a mediator that fills the gap between angled fiber end faces. This gel material allows the angled surfaces to maintain optical contact without requiring precise mechanical alignment, as the gel compensates for angular misalignment and maintains stable coupling through its conformable nature.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 provides durable, low-loss, and low-reflection optical coupling with reduced contamination risks, maintaining signal quality and allowing for repeatable, temporary connections without the need for excessive force or permanent deformation.

Implementation Method 1

The first index matching elastomeric solid layer has an index of refraction matching at least the index of refraction of the core

Methodology Applied
Scientific EffectIndex of refraction matching: Refraction

Implementation Method 2

the proximal end face is chemically bound to the first end face

Methodology Applied
Scientific EffectChemical bonding: Chemical Bonding

Implementation Method 3

the distal end face is low-tack to be repeatably directly mechanically coupled to the second end face

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 4

at least one actuator for relatively moving the first and second angled optical fibers between a coupled position and an uncoupled position

Methodology Applied
Scientific EffectMechanical actuation: Mechanical Force

Data Source

PatentEP2496979B1Optical fiber switch including an index matching elastomeric solid layer and related methods
Publication Date: 2014.12.17 HARRIS CORP
  • EP2496979B1 patent drawingFigure 1A~1B
  • EP2496979B1 patent drawingFigure 2A~2B
  • EP2496979B1 patent drawingFigure 3~4

AI summary

An optical fiber switch (230) which may include first and second angled optical fibers (231, 232) having respective first and second end faces (203, 204). Each of the first and second angled optical fibers (231, 232) may include a core (235, 236) having a core index of refraction (n1), and a cladding (237, 238) surrounding the core and having a cladding index of refraction (n2) less than the core index of refraction. The optical fiber switch (230) may further include a first index matching elastomeric solid layer (240) having a proximal face coupled to the first end face (203), and a distal face opposite the proximal face to be repeatably optically coupled to the second end face (204). The first index matching elastomeric solid layer (240) may have an index of refraction matching at least the index of refraction of the core (235, 236). The optical fiber switch (230) may also include at least one actuator (255) for relatively moving the first and second angled optical fibers (231, 232) between a coupled position and an uncoupled position.