Thin-Wall Optical Core Subunit With Bonded Rip Cord Access
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Solution Overview
Problem
Existing optical fiber cables face challenges in providing easy access to subunits without damaging the optical fibers, especially when using membranes with embedded or loosely positioned access features, and they suffer from dimensional instability due to thermal cycling.
Innovation Solution
The integration of an attached access feature, such as a rip cord, with a thin membrane that is securely bonded to the subunit, using materials with low shrinkage and high modulus to maintain flexibility and strength, and tactile locator features for easy access without applying force directly to the fibers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an access feature is embedded in or loosely positioned within the membrane, then access to optical fibers is provided, but the optical fibers may be damaged during access operations
Solution Approach 1:
A rip cord is introduced as an intermediary element between the user and the optical fibers. The rip cord extends through the membrane and provides a mechanical interface for opening the membrane without direct contact with the optical fibers. This mediator allows the membrane to be opened while keeping the optical fibers stationary and protected from damage.
Solution Approach 2:
The membrane opening function is segmented from the optical fiber handling function. The rip cord is separated as a distinct component that performs the membrane-opening action, while the optical fibers remain isolated within their protective positioning. This segmentation allows independent optimization of each function.
2Adaptability or versatility
If a thin membrane is used to provide flexibility and ease of access, then the subunit is more flexible, but dimensional stability during thermal cycling deteriorates
Solution Approach 1:
The membrane is constructed from composite materials that combine the benefits of thinness with dimensional stability. The membrane includes a base layer providing flexibility and additional layers or treatments that provide thermal stability and resistance to dimensional changes during thermal cycling.
Solution Approach 2:
The membrane's physical parameters are optimized by controlling its thickness, material composition, and structural properties. The membrane is designed with specific thickness ranges and material characteristics that balance flexibility with thermal dimensional stability, allowing it to accommodate thermal expansion and contraction without excessive deformation.
3Ease of operation
If force is applied directly to optical fibers for access, then the membrane can be opened, but the optical fibers may be damaged or displaced
Solution Approach 1:
The rip cord serves as a mechanical intermediary that transfers the opening force from the user to the membrane without requiring direct force application to the optical fibers. The rip cord is specifically designed to engage and open the membrane while maintaining clear separation from the optical fiber bundle.
Solution Approach 2:
The force application point is extracted from the optical fiber region and relocated to the rip cord. This extraction allows the opening action to be performed at a location and in a manner that does not involve or threaten the optical fibers, separating the force application function from the fiber handling function.
Data Source
AI summary
An optical fiber cable is provided. Embodiments of the disclosure relate to an optical fiber subunit for an optical fiber cable. The optical fiber subunit includes a membrane having an inner surface and an outer surface in which the inner surface defines a central passage. The subunit further includes an access feature disposed in the central passage and attached to the inner surface of the membrane. In various embodiments, the access feature includes a coating to provide enhanced attachment to the membrane. Also disclosed are embodiments of an optical fiber subunit having one or more subunits disposed within a central bore of a cable jacket and embodiments of a method of manufacturing a subunit for an optical fiber cable.