CNT-Armoured Submarine Optical Cable for Lower Weight
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Solution Overview
Problem
Submarine optical cables face challenges with high weight due to metallic armour layers and copper conductors, which compromise tensile strength and increase attenuation, necessitating heavier payoff systems and frequent repeaters.
Innovation Solution
Incorporating carbon nanotube (CNT) bundles as strength and conductive components to replace or supplement metallic armour wires and copper conductors, enhancing tensile strength while reducing weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metallic armour layers and copper conductors are used, then tensile strength and electrical conductivity are improved, but cable weight increases
Solution Approach 1:
The patent uses carbon nanotube bundles as a composite material that combines both mechanical strength and electrical conductivity in a single component. These CNT bundles replace the traditional separate metallic armour layers and copper conductors, providing the necessary tensile strength while significantly reducing the cable weight due to the exceptional strength-to-weight ratio of carbon nanotubes.
Solution Approach 2:
The carbon nanotube bundles perform multiple functions simultaneously: they provide mechanical reinforcement (tensile strength) like the metallic armour layers, and they conduct electricity like the copper conductors. This multi-functionality eliminates the need for separate components, reducing overall cable weight while maintaining both structural integrity and electrical conductivity for powering repeaters.
2Reliability
If copper conductor is used, then electrical conductivity is improved, but cable weight increases
Solution Approach 1:
Carbon nanotubes possess exceptional electrical conductivity comparable to or exceeding copper, combined with even higher strength-to-weight ratios. The patent utilizes this property to replace copper conductors with CNT bundles that can carry electrical current to power repeaters while dramatically reducing the conductor weight.
3Length of stationary object
If deeper deployment is required, then cable length is improved, but cable weight increases
Solution Approach 1:
For deep-sea and long-distance cable deployments, the patent employs carbon nanotube bundles that provide the necessary tensile strength to withstand the stresses of deep water deployment while maintaining minimal weight. This is critical because lighter cables require less powerful payoff systems and experience less cumulative weight over long deployment lengths.
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
CNT bundles provide superior strength-to-weight ratio and conductivity, resulting in a lighter, more efficient submarine optical cable with reduced diameter and lower environmental impact.
Implementation Method 1
CNT bundles can be used as strength members and/or as electric conductors depending on the position in the cable
Implementation Method 2
CNT bundles can be used also as electrically conductive components in substitution or in combination with a conductor, e.g. a copper layer optionally joined to a semiconductive layer
Data Source
Figure 1
Figure 2a~2b
Figure 3
AI summary
The present disclosure relates to a repeatered submarine optical cable (1) comprising: - one or more optical fibres (2); - a metallic tubular buffer element (3) housing the one or more optical fibres (2); - an electrically conductive layer (6) surrounding the tubular buffer element (3), and - at least one armour (4, 10), wherein the at least one armour (4, 10) and/or the electrically conductive layer (6) comprise carbon nanotube (CNT) bundles (7).