Optical Cable Load-Bearing Core Slot Design
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Solution Overview
Problem
Existing optical cables face challenges in providing protection against microbending while allowing easy access to optical fibers, especially in small ducts, and have complex manufacturing processes due to large sizes and multiple layers.
Innovation Solution
An optical cable with a load-bearing core having a slot with a width that provides a low clearance fit for the optical fibers, ensuring they are not stuck, and a depth equal to or lower than the core radius, made of high elastic modulus material, allowing for a small diameter cable with easy installation and manufacturing through continuous processes like extrusion or pultrusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a deep longitudinal cavity is used in the cylindrical support to house optical fibres, then fibre protection and access are improved, but the solid area of the support is reduced, requiring additional bearing elements and increasing device complexity
Solution Approach 1:
The cylindrical support is segmented into functional zones: a load-bearing outer ring and an inner cavity region for fibre housing. This segmentation allows the support to provide both mechanical strength and fibre access without requiring additional bearing elements, as the outer ring maintains structural integrity while the inner cavity accommodates fibres loosely.
2Reliability
If multiple layers including tape and non-extruded layers are used between the cylindrical support and outer sheath, then fibre protection is improved, but the manufacturing process becomes slow and cannot be carried out in a single shot
Solution Approach 1:
The tape layer and non-extruded layers are merged into a single extruded sheath layer. This integrated sheath provides both mechanical protection and structural function in one continuous manufacturing step, eliminating the need for separate tape winding and layering operations, thereby enabling single-shot extrusion production while maintaining fibre protection.
Solution Approach 2:
The manufacturing process is made continuous through single-shot extrusion, where the sheath is formed in one continuous operation without interruption for adding tape or other layers. This continuous extrusion process maintains production efficiency while ensuring consistent fibre protection through the integrated sheath design.
3Strength
If a large diameter cable is used to provide sufficient solid area in the cylindrical support, then mechanical strength is improved, but installation in small ducts becomes difficult
Solution Approach 1:
The cylindrical support employs local quality optimization by concentrating material in the outer load-bearing ring where mechanical strength is needed, while the inner region is configured as a cavity for fibre housing. This non-uniform distribution of material provides sufficient structural strength with a reduced overall cable diameter, enabling installation in small ducts while maintaining mechanical integrity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables easy installation in small ducts, reduces fiber stress, maintains optimal transmission properties, and simplifies the manufacturing process by allowing self-supporting cables with reduced diameter and enhanced mechanical performance.
Implementation Method 1
The load bearing core is made of a material having an elastic modulus of at least 40 GPa
Data Source
Figure 1a~1b
Figure 2a~2b
Figure 3a~3b
AI summary
It is disclosed an optical cable comprising a load bearing core comprising a longitudinally and radially extending slot housing at least one optical fibre, wherein the slot has a width providing a low clearance for the optical fibre(s) housed therein and preventing two optical fibres being stuck one another; and the slot has a depth equal to or lower than a radius of the core.