Optical Fiber Laser Cleaving Near the Ferrule End Face

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Solution Overview

Problem

The existing methods for laser cleaving of optical fibers secured to a ferrule are time-consuming and labor-intensive, requiring multiple mechanical polishing steps to achieve a precise optical surface within a few microns of the end face, and there is room for improvement in precision and efficiency.

Innovation Solution

A method involving a laser system that directs a low fluence laser beam, less than 100 J/cm², with a wavelength between 8.0 and 9.4 µm, to cleave the optical fiber less than 20 µm from the end face of a zirconia ferrule, using an elliptical beam spot positioned at least 5 µm from the ferrule bore edge, and reflecting the laser beam off the ferrule end face to minimize thermal absorption and debris impact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional mechanical polishing steps are used to form an optical surface within a few microns of the ferrule end face, then manufacturing precision is improved, but productivity deteriorates due to multiple time-consuming polishing steps

Engineering Contradiction:
Improveoptical surface position precisionVSAvoidconnectorization speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent replaces the conventional mechanical polishing system with a laser-based thermal processing system. The laser beam heats and melts the optical fiber material to form the optical surface, eliminating the need for multiple mechanical polishing steps while achieving the required precision within a few microns of the ferrule end face.

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

Solution Approach 2:

The patent changes the processing parameter from mechanical force (polishing) to thermal energy (laser heating). By controlling laser parameters such as power, pulse duration, and scanning speed, the optical surface is formed with precise control over its position relative to the ferrule end face, reducing the number of steps required.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If laser beam is directed directly to the optical fiber end portion for cleaving, then productivity is improved, but the ferrule may be damaged due to thermal absorption and debris impact

Engineering Contradiction:
Improvecleaving efficiencyVSAvoidferrule damage risk
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an intermediary approach where the laser beam is directed to first interact with the ferrule end face, which acts as a mediator to reflect the beam onto the optical fiber. This indirect path reduces direct thermal absorption by the ferrule while still enabling effective cleaving of the optical fiber.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

Instead of directly targeting the optical fiber with the laser beam, the patent inverts the approach by first directing the beam at the ferrule end face, utilizing the reflection to achieve the desired cleaving effect on the optical fiber with reduced thermal damage to the ferrule.

Inventive Principle:
Principle #13The other way round (Inversion)

3Manufacturing precision

If multiple mechanical polishing steps are used to form a high quality optical surface, then manufacturing precision is improved, but loss of time increases due to the multi-step process

Engineering Contradiction:
Improveoptical surface qualityVSAvoidpolishing process time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent merges multiple separate polishing steps into a single integrated laser processing step. The laser beam simultaneously performs material removal, surface smoothing, and precision positioning in one continuous operation, eliminating the sequential nature of conventional polishing and significantly reducing process time.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements continuous laser processing where the laser beam continuously acts on the optical fiber to form the optical surface without interruption. This continuous action replaces the intermittent mechanical polishing steps, maintaining useful action throughout the process and reducing total time while preserving surface quality.

Inventive Principle:
Principle #20Continuity of useful action

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 allows for precise and efficient cleaving of optical fibers close to the ferrule end face without damaging the ferrule, reducing the need for extensive mechanical polishing and minimizing debris-related issues, thus improving the speed and accuracy of the process.

Implementation Method 1

operating at least one laser to emit at least one laser beam; directing the at least one laser beam from the at least one laser to the end face of the holding member so that at least a portion of the at least one laser beam reflects off the end face of the holding member and is thereafter incident on the end portion of the optical fiber

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 2

The laser beam may be more readily reflected away from the ferrule instead of being absorbed within the ferrule and thereby causing ferrule damage

Methodology Applied
Scientific EffectThermal ablation: Laser Ablation

Implementation Method 3

directing the at least one laser beam from the at least one laser to the end face of the holding member so that at least a portion of the at least one laser beam reflects off the end face of the holding member

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP3704522B1Method for laser cleaving optical fibers
Publication Date: 2023.01.11 CORNING OPTICAL COMMUNICATIONS LLC
  • EP3704522B1 patent drawingFigure 1~2
  • EP3704522B1 patent drawingFigure 3~4
  • EP3704522B1 patent drawingFigure 5~6

AI summary

A method of cleaving an optical fiber comprises inserting the optical fiber through a bore of a holding member, securing the optical fiber to the holding member with a bonding agent, operating at least one laser to emit at least one laser beam, and directing the at least one laser beam from the at least one laser to the end face of the holding member. At least a portion of the at least one laser beam reflects off the end face of the holding member and is thereafter incident on an end portion of the optical fiber. The at least one laser beam has a laser fluence of less than 100 J/cm2 and cleaves the end portion of the optical fiber less than 20μm from the end face of the holding member. In an alternative method of cleaving an optical fiber at least one laser is operated so that it emits at least one laser beam that cleaves the end portion of the optical fiber by: (a) ablating some of the end portion of the optical fiber with the at least one laser beam emitted at a first wavelength; (b) tuning the at least one laser to a different wavelength; and (c) ablating an additional amount of the end portion of the optical fiber with the at least one laser beam emited at the different wavelength. Related systems are also disclosed.