Fiber Splice Encapsulation With Cladding Light Strippers

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Solution Overview

Problem

High-power fiber laser systems face significant losses and performance degradation due to cladding light at fiber splices, particularly when transitioning between fibers with different core and cladding dimensions, leading to uncontrolled dissipation and potential overheating.

Innovation Solution

Encapsulating fiber splices with cladding light strippers (CLS) on both sides to systematically remove cladding light, utilizing high-index materials and structured surfaces to guide and convert cladding light into heat, thereby maintaining beam quality and thermal management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If fiber splices are used to join separate fiber lengths, then fiber system continuity is achieved, but splice losses increase and beam quality deteriorates due to uncontrolled cladding light dissipation

Engineering Contradiction:
Improvesplice lossesVSAvoidbeam quality
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

A cladding light stripper (CLS) is introduced as an intermediary component between spliced fiber sections. The CLS actively removes cladding light that would otherwise cause uncontrolled dissipation and beam quality degradation, while allowing the splice to maintain mechanical and optical continuity. This mediator resolves the contradiction by controlling the harmful cladding light without preventing the useful fiber joining function.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention extracts and removes the harmful cladding light component from the fiber system at splice locations using the CLS. By selectively removing only the cladding light (not the core signal), the system maintains splice functionality while eliminating the source of energy loss and beam quality deterioration.

Inventive Principle:
Principle #2Taking out (Extraction)

2Device complexity

If cladding light is allowed to propagate through fiber splices, then fiber system simplicity is maintained, but overheating occurs due to uncontrolled energy dissipation

Engineering Contradiction:
Improvesystem simplicityVSAvoidthermal management
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The CLS serves as a thermal management intermediary by intercepting cladding light before it can cause uncontrolled heating at splice points. The device converts optical energy to heat in a controlled manner, preventing the accumulation of excessive thermal energy that would occur without such an intermediary component.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention converts the harmful uncontrolled dissipation of cladding light into a beneficial controlled process. The CLS intentionally converts cladding light energy to heat through a managed mechanism, transforming what was previously a harmful thermal issue into a controllable and manageable process.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Power

If high-power beams are conveyed through optical fiber, then system power capability increases, but sensitivity to fiber length increases due to stimulated Raman scattering

Engineering Contradiction:
Improvebeam powerVSAvoidenergy loss sensitivity
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The CLS converts the harmful cladding light (which causes SRS and energy loss) into a beneficial controlled heating process. By removing cladding light at splice points, the system can maintain higher power levels in the core without the compounding energy losses that would otherwise occur through SRS mechanisms.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 effectively reduces splice losses and prevents overheating, enhancing beam quality and thermal management in high-power fiber systems by controlled dissipation of cladding light.

Implementation Method 1

utilizing high-index materials and structured surfaces to guide and convert cladding light into heat

Methodology Applied
Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 2

utilizing high-index materials and structured surfaces to guide and convert cladding light into heat

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP3850408B1Optical fiber splice encapsulated by a cladding light stripper
Publication Date: 2026.03.04 NLIGHT INC
  • EP3850408B1 patent drawingFigure 1A~1C
  • EP3850408B1 patent drawingFigure 2A~3B
  • EP3850408B1 patent drawingFigure 4A~4B

AI summary

Spliced multi-clad optical fibers with a cladding light stripper (CLS) encapsulating the splice. The splice may facilitate conversion between two optical fibers having different architectures, such as different core and/or cladding dimensions. The CLS may comprise a first length of fiber on a first side of the splice, and a second length of fiber on a second side of the splice, encapsulating the splice within the lengths of the CLS. The splice may abut one or more of the lengths of the CLS, or may be separated from one or more lengths of the CLS by an intermediate length of a first and/or second fiber joined by the splice.