Optical Fiber Bundle Segmentation for Access and Fire Resistance

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Solution Overview

Problem

Existing optical communication cables face challenges in supporting a large number of optical fibers within a small cross-sectional area while maintaining easy access and fire resistance, often requiring specialized tools to open the bundle jacket and compromising on burn performance as the fiber count and density increase.

Innovation Solution

The optical communication cable bundle features a thin, flexible outer bundle jacket made from a polymer material without fire-resistant additives, which is easily openable by hand, and stronger, fire-resistant subunit jackets that provide protection, allowing for a high-density fiber arrangement that passes fire rating tests without the need for tools.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a large number of optical fibers are packed into a small cross-sectional area, then fiber density and productivity are improved, but the bundle jacket becomes difficult to open without specialized tools

Engineering Contradiction:
Improvefiber densityVSAvoidaccessibility
Core Design Contradiction:
Quantity of substanceVSEase of operation

Solution Approach 1:

The cable structure is divided into multiple subunits, each containing a subset of optical fibers. This segmentation allows the overall cable to maintain high fiber density while enabling selective access to individual subunits without opening the entire cable jacket, thus preserving both high fiber count and ease of access.

Inventive Principle:
Principle #1Segmentation

2Reliability

If fire-resistant additives are included in the bundle jacket material, then fire resistance is improved, but the jacket becomes less flexible and more difficult to open

Engineering Contradiction:
Improvefire resistanceVSAvoidflexibility
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

Fire resistance functionality is segmented from the outer bundle jacket and assigned to the subunit jackets. The outer jacket can remain flexible and easy to open, while the inner subunit jackets incorporate fire-resistant properties, thus distributing the fire protection function without compromising the outer jacket's accessibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Fire-resistant properties are applied locally to the subunit jackets rather than uniformly to the entire cable structure. This allows different parts of the cable to have different properties: the outer jacket prioritizes flexibility and accessibility, while the inner subunit jackets provide fire resistance where needed.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If the bundle jacket is made thin and flexible for easy opening, then ease of operation is improved, but fire resistance is compromised

Engineering Contradiction:
Improveease of openingVSAvoidburn performance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The fire protection function is segmented from the outer bundle jacket and assigned to the inner subunit jackets. This allows the outer jacket to be thin and flexible for easy opening, while the inner subunit jackets provide the necessary fire resistance, thus resolving the contradiction between ease of operation and fire safety.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3702821B1Optical fiber bundle
Publication Date: 2023.04.19 CORNING OPTICAL COMMUNICATIONS LLC
  • EP3702821B1 patent drawingFigure 1~2
  • EP3702821B1 patent drawingFigure 3~4

AI summary

An optical communication cable bundle is provided. The cable bundle includes a bundle jacket having an inner surface defining a bundle passage and an outer surface defining an exterior surface of the cable bundle, and a plurality of optical fiber subunits located within the bundle passage and surrounded by the bundle jacket, each optical fiber subunit having a subunit jacket defining a subunit passage and a plurality of optical fibers located with the subunit passage. A thickness of the bundle jacket is less than a thickness of each of the subunit jackets and the bundle jacket is extruded tight around the subunit jackets to couple the subunits and the bundle jacket.