Flat Drop Optical Fiber Cable Asymmetry Wind Pressure

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Solution Overview

Problem

Conventional drop optical fiber cables, both circular and flat, face issues such as inequivalent stresses from wind pressure, increased width due to loose optical fibers, lower span length, longer installation time, and higher cable weight, making them unsuitable for aerial applications.

Innovation Solution

A flat drop optical fiber cable design featuring easily strippable buffer tubes, optical fiber ribbons, water blocking tapes, a cable sheath, strength members, and ripcords, optimized for aerial applications with a reduced weight and increased span length.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional circular drop optical fiber cables are used, then multiple buffer tubes can encapsulate multiple optical fibers, but the cable experiences inequivalent stresses from wind pressure and is unsuitable for aerial application

Engineering Contradiction:
Improveaerial application suitabilityVSAvoidwind pressure stress
Core Design Contradiction:
ReliabilityVSStress or pressure

Solution Approach 1:

The patent applies asymmetry by transitioning from a conventional circular cable cross-section to a flat cable cross-section with a width-to-height ratio of 1.5:1 or greater. This asymmetric flat shape provides more equitable stress distribution when subjected to wind pressure during aerial installation, resolving the technical contradiction between aerial application suitability and wind pressure resistance.

Inventive Principle:
Principle #4Asymmetry

2Shape

If loose optical fibers are arranged in flat structure, then the cable becomes flat shaped, but the width of the drop optical fiber cable increases drastically

Engineering Contradiction:
Improveflat shapeVSAvoidcable width
Core Design Contradiction:
ShapeVSArea of stationary object

Solution Approach 1:

The patent applies merging by combining multiple individual optical fibers into compact ribbon assemblies, where fibers are closely spaced and bound together. Multiple ribbons are then bundled within buffer tubes to form the flat cable structure. This merging approach achieves the desired flat shape while minimizing the overall cable width by efficiently packing the optical fibers in a consolidated arrangement.

Inventive Principle:
Principle #5Merging (Combining)

3Quantity of substance

If multiple optical fibers are included in flat and circular drop optical fiber cables, then the cable can carry more data, but the installation time increases

Engineering Contradiction:
Improvenumber of optical fibersVSAvoidinstallation time
Core Design Contradiction:
Quantity of substanceVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-organizing multiple optical fibers into ribbon assemblies during manufacturing, where fibers are precisely aligned and bound in fixed patterns. Buffer tubes are pre-configured to contain specific ribbon bundles. This preliminary organization eliminates the need for time-consuming field splicing and routing of individual fibers, allowing installers to simply connect pre-assembled units and significantly reducing overall installation time while maintaining high fiber counts.

Inventive Principle:
Principle #10Preliminary action

4Strength

If conventional drop optical fiber cables are used, then the cable structure is established, but the cable weight becomes higher

Engineering Contradiction:
Improvecable structureVSAvoidcable weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent applies parameter changes by modifying the cable's cross-sectional geometry from circular to flat, with specific width-to-height ratio parameters of 1.5:1 or greater. This geometric parameter change allows for optimized material distribution and reduced overall cable dimensions while maintaining structural strength. The flat configuration enables more efficient packing of strength members and buffer tubes, reducing redundant material and achieving lower cable weight without compromising structural integrity.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3663825B1Flat drop optical fiber cable
Publication Date: 2025.02.12 STERLITE TECHNOLOGIES LTD
  • EP3663825B1 patent drawingFigure 1
  • EP3663825B1 patent drawingFigure 2

AI summary

The present disclosure provides a flat drop optical fiber cable. The flat drop optical fiber cable includes one or more buffer tubes. The one or more buffer tubes extend substantially along a longitudinal axis of the flat drop optical fiber cable. The flat drop optical fiber cable includes a plurality of optical fiber ribbons. The flat drop optical fiber cable includes one or more water blocking tapes. The one or more water blocking tapes are positioned in the flat drop optical fiber cable in one or more arrangements. The flat drop optical fiber cable includes a cable sheath. The cable sheath encapsulates the one or more buffer tubes and the one or more water blocking tapes. The flat drop optical fiber cable includes a plurality of strength members.