Nested Undersea Cable Structure for High Fiber Count
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Solution Overview
Problem
Conventional undersea optical fiber cables are limited to a maximum of 74 fibers and scaling up their size to accommodate more fibers results in heavier and more costly cables, increasing installation and operational costs.
Innovation Solution
A compact cable design with a hollow buffer tube surrounded by layered strength members and a copper conductor, encapsulated by a polyethylene jacket, maintaining a consistent outer diameter while supporting up to 232 optical fibers, achieving low electrical resistance and optimal strength-to-weight ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the cable size is scaled up to accommodate more optical fibers, then the fiber count increases, but the cable weight increases significantly
Solution Approach 1:
The patent implements a nested structure where multiple buffer tubes containing optical fibers are placed inside a single outer buffer tube. This allows numerous fibers to be accommodated within a compact volume, significantly increasing fiber count without proportionally increasing cable weight. The nested arrangement optimizes space utilization and maintains a manageable cable diameter.
Solution Approach 2:
The patent transitions from a planar arrangement of fibers to a three-dimensional nested configuration. By organizing buffer tubes in multiple layers and positions within the outer buffer tube, the design efficiently utilizes vertical and radial dimensions, allowing high fiber density without increasing the cable's external footprint or weight.
2Quantity of substance
If the cable size is scaled up to accommodate more optical fibers, then the fiber count increases, but the installation and operational cost increases
Solution Approach 1:
The nested buffer tube configuration allows for standardized manufacturing processes to be applied to modular components. The outer buffer tube and inner buffer tubes can be manufactured separately and then assembled, enabling economies of scale and reducing per-fiber installation costs while maintaining high fiber counts.
Solution Approach 2:
The cable is divided into modular buffer tube segments that can be independently manufactured, tested, and assembled. This segmentation allows for standardized production techniques and simplifies installation procedures, reducing both manufacturing and operational costs while supporting high fiber counts.
3Strength
If additional strength members are added to withstand tensile and bending stresses, then the cable strength increases, but the cable weight increases
Solution Approach 1:
The outer buffer tube serves multiple functions simultaneously: it protects the inner buffer tubes from mechanical damage, provides structural strength to withstand tensile and bending stresses during installation, and maintains the compact nested configuration. This multi-functionality reduces the need for additional dedicated strength members, thereby limiting weight increase.
Solution Approach 2:
The patent employs composite material construction where the outer buffer tube is made from high-strength, low-density materials that provide both mechanical strength and buoyancy. This allows the cable to withstand installation stresses while minimizing weight increase, as the composite structure offers high strength-to-weight ratio.
Data Source
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AI summary
Disclosed are undersea cables having a high fiber count and low electrical resistance. In some embodiments, an optical cable includes a hollow buffer tube having a plurality of optical fibers therein, wherein the hollow buffer tube includes inner and outer buffer surfaces, and wherein the outer buffer surface of the hollow buffer tube defines an outer diameter. The optical cable may further include a first plurality of layered strength members surrounding the hollow buffer tube, and a conductor surrounding the first plurality of layered strength members. The optical cable may further include an outer jacket surrounding the conductor, wherein the outer jacket includes inner and outer jacket surfaces, wherein the outer jacket defines an outer diameter of the outer jacket, and wherein the outer diameter of the outer jacket is equal to or less than five times the outer diameter of the hollow buffer tube.