Microbundle Optical Cable with Elongated Cross-Section for Conduit Installation

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Solution Overview

Problem

Existing optical cables face challenges in achieving a reduced outer diameter with high fiber count and modularity, while also being easily bendable for installation in conduits, especially in existing buildings where space is limited and bends are common.

Innovation Solution

The optical cable features microbundles with an elongated cross-section and ellipticity ratio of 0.5 to 1, loosely housed in an outer jacket, allowing for movement and rotation, and a cable filling ratio of 0.25 to 0.55 to facilitate bending and extraction, with strength members and a lubricant to reduce friction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the outer diameter of the optical cable is reduced to fit in limited conduit spaces, then the cable can be installed in existing buildings with occupied conduits, but the fiber count and modularity are compromised

Engineering Contradiction:
Improveouter diameterVSAvoidfiber count
Core Design Contradiction:
Volume of moving objectVSQuantity of substance

Solution Approach 1:

The optical cable is segmented into multiple microbundles, each containing a limited number of optical fibers (e.g., 2-12 fibers per microbundle). This segmentation allows the overall cable to achieve high fiber count while maintaining a compact outer diameter, as each microbundle is individually sized and can be efficiently packed within the cable structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple microbundles are nested within a common outer jacket, with each microbundle containing its own set of optical fibers. This nested arrangement allows efficient space utilization, enabling high fiber density while maintaining a reduced outer diameter suitable for installation in existing conduits.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Strength

If the optical cable is made rigid to protect fibers from mechanical damage, then fiber strength is improved, but the cable becomes difficult to bend for installation in conduits

Engineering Contradiction:
Improvefiber strengthVSAvoidbendability
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The cable is divided into multiple independent microbundles that can move relative to each other within the outer jacket. This segmentation allows the cable to bend flexibly during installation while each microbundle maintains its structural integrity and protects the optical fibers from mechanical damage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The microbundles are arranged to be loosely housed in the outer jacket, allowing them to move and rotate relative to each other. This dynamic arrangement enables the cable to adapt to bending requirements during installation while maintaining fiber protection, and the microbundles can self-arrange to optimize bending characteristics.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If multiple optical fibers are provided to a single costumer for competition among providers, then service versatility is improved, but the cable complexity and extraction difficulty increase

Engineering Contradiction:
Improveservice versatilityVSAvoidcable complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Optical fibers are organized into discrete microbundles, each containing a specific number of fibers. This segmentation provides natural modular units that can be independently extracted and assigned to different customers or service providers, enabling versatile service allocation while maintaining manageable cable complexity through standardized microbundle structures.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The loose housing of microbundles in the outer jacket allows them to move and rotate, facilitating easy extraction of specific microbundles for customer assignment. This dynamic arrangement enables flexible service configuration where microbundles can be independently managed without increasing overall cable complexity.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2517059B1Microbundle optical cable
Publication Date: 2018.11.21 PRYSMIAN SPA
  • EP2517059B1 patent drawingFigure 1~3

AI summary

It is disclosed a microbundle optical cable such as, for instance, a riser cable. The optical cable comprises: an outer jacket and a plurality of microbundles housed in the outer jacket. At least one of said microbundles comprises an optical fiber ribbon enclosed in a microbundle coating. The at least one microbundle comprises a longitudinal axis and a cross-section taken on a plane substantially perpendicular to the longitudinal axis. The cross-section may comprise a first dimension and a second dimension. The first dimension is higher than the second dimension. Therefore, the cross-section shape is an elongated cross shape.