Optical Fiber Ribbon Design for High Density Cable
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Solution Overview
Problem
Optical fiber ribbons with small core diameters (<250 µm) in optical fiber cables experience increased bending strain and transmission loss when bent, particularly at the ends, due to low rigidity and meandering, which worsens with higher fiber densities.
Innovation Solution
An optical fiber ribbon configuration with 16 to 48 fibers, each with a core diameter of 160-220 µm, connected by a resin with a Young's modulus of 200 MPa or less and a breaking elongation of 30% or more, arranged in an intermittent connection type to reduce bending strain, and coated with primary and secondary resins for improved shell effect and lateral pressure resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If optical fiber ribbons with smaller core diameter are used to increase cable density, then cable density is improved, but bending strain and transmission loss increase due to low rigidity
Solution Approach 1:
The patent changes the physical parameters of the optical fiber by specifying a core diameter range of 160-220 µm and controlling the outer diameter within 200-280 µm. This parameter optimization balances the rigidity needed to prevent meandering with the compact size required for high cable density, directly resolving the contradiction between cable density and transmission loss
Solution Approach 2:
The patent employs composite material structures including the optical fiber core, cladding, and coating layers with specific material properties. The fiber is embedded in a ribbon structure with tension members and surrounded by buffer materials, creating a composite system that enhances rigidity while maintaining small dimensions, thus preventing meandering and reducing transmission loss in high-density cables
2Productivity
If the number of optical fiber ribbons is increased to increase cable capacity, then cable capacity is improved, but transmission loss significantly increases due to cumulative bending strain
Solution Approach 1:
The patent divides the optical fiber into segmented structures within the ribbon, with individual fibers positioned in specific patterns and separated by buffer materials. This segmentation allows each fiber to maintain its mechanical integrity independently while being part of a larger high-capacity cable system, preventing cumulative bending strain effects
Solution Approach 2:
The patent optimizes geometric parameters including the number of ribbons (2-12), fibers per ribbon (12-48), ribbon width (3.0-4.5 mm), and overall cable dimensions. These parameter changes enable high cable capacity through increased fiber count while controlling the physical layout to minimize bending strain accumulation across multiple ribbons
3Volume of moving object
If thin optical fibers are used to reduce cable size, then cable size is reduced, but rigidity decreases causing fiber meandering
Solution Approach 1:
The patent precisely controls the outer diameter parameter within 200-280 µm and core diameter within 160-220 µm ranges. This parameter optimization ensures the fiber is thin enough for compact cable size but maintains sufficient rigidity to prevent meandering, directly resolving the contradiction between cable size and fiber rigidity
Solution Approach 2:
The patent creates a composite structure where the optical fiber is embedded in a ribbon with tension members, buffer materials, and protective coatings. This composite construction provides external mechanical support that compensates for the inherent low rigidity of thin fibers, preventing meandering while maintaining compact cable dimensions
Data Source
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AI summary
An optical fiber ribbon that includes 16-48 parallel optical fiber core wires and a connecting resin that connects adjacent optical fiber core wires. The outer diameter D of the optical fiber core wires is 160-220 µm, and when N is the number of optical fiber core wires and S is the bending strain of the optical fiber core wires, S=0.167×N/2 (%) or less.