Fiber Optic Cable Design for Subscriber Networks

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Solution Overview

Problem

Conventional fiber optic cables face challenges in maintaining optical performance and reliability during installations, particularly in aerial and buried applications, due to the need for robust designs that accommodate slack storage and varying installation lengths, while avoiding damage from pressure clamps that can cause optical attenuation.

Innovation Solution

A fiber optic cable design with a smaller cross-sectional footprint, featuring strength members aligned on either side of the optical fiber and a cable jacket with a medial height less than the end height, allowing for efficient slack storage and reduced optical attenuation, along with preconnectorized assemblies using hardened connectors for plug-and-play connectivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional fiber optic cables with larger cross-sectional footprint are used, then they provide robust protection for optical fibers, but they require larger storage spaces and increase material handling costs

Engineering Contradiction:

Improveoptical fiber protectionVSAvoidstorage space requirement

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent applies this principle by using a thin-film optical protector that directly contacts and protects the optical fiber without requiring a bulky buffer tube. The flexible thin film provides sufficient protection while minimizing the cable's cross-sectional footprint, enabling compact storage and handling.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent changes the structural parameters of the cable by eliminating the traditional buffer tube and using a thinner cable jacket configuration. The strength members are positioned to provide protection while maintaining a smaller overall cable diameter, thus reducing storage space requirements while preserving fiber protection.

Inventive Principle:

Principle #35Parameter changes

2Strength

If pressure clamps are used to secure aerial fiber optic cables, then they prevent cable sag and provide mechanical support, but they can cause optical attenuation and damage to the fiber

Engineering Contradiction:

Improvemechanical supportVSAvoidoptical attenuation

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an intermediary protective layer or modified cable structure between the pressure clamp and the optical fiber. This intermediary element distributes the clamping force away from the fiber, providing mechanical support while preventing direct contact that would cause attenuation or damage.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies local quality by creating a cable structure where different regions have different properties - the region contacting the pressure clamp is designed to withstand compression, while the region containing the optical fiber is protected from compressive forces. This localized differentiation allows the cable to receive mechanical support without transmitting damaging forces to the fiber.

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If multiple cable lengths are used to accommodate varying installation distances, then installation flexibility is improved, but device complexity and inventory management increase

Engineering Contradiction:

Improveinstallation flexibilityVSAvoidinventory management

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent creates a universal cable assembly design that can be used for various installation distances and configurations. By standardizing the cable construction with protectors and strength members positioned to handle different tension and slack conditions, a single cable type can serve multiple installation scenarios, eliminating the need for multiple specialized cable lengths.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Strength

If robust cable designs with larger cross-sections are used for buried and duct applications, then they withstand rough terrain and handling, but they reduce slack storage capacity

Engineering Contradiction:

Improveroughness resistanceVSAvoidslack storage capacity

Core Design Contradiction:

StrengthVSVolume of moving object

Solution Approach 1:

The patent uses flexible thin-film protectors and a streamlined cable jacket that provides sufficient protection for rough handling and buried installation while maintaining a compact cross-section. The thin-film approach provides the necessary durability without the bulk of traditional protective structures, preserving slack storage capacity.

Inventive Principle:

Principle #30Flexible shells and thin films

Data Source

PatentUS7796853B2Fiber optic cables and assemblies for fiber toward the subscriber applications

Publication Date: 2010.09.14 CORNING OPTICAL COMMUNICATIONS LLC

AI summary

Disclosed are fiber optic cables and assemblies for routing optical networks closer to the subscriber. The fiber optic cables have a robust design that is versatile by allowing use in aerial application with a pressure clamp along with use in buried and/or duct applications. Additionally, the fiber optic cables and assemblies have a relatively large slack storage capacity for excess length. Assemblies include hardened connectors such as plugs and/or receptacles suitable for outdoor plant applications attached to one or more ends of the fiber optic cables for plug and play connectivity.