Optical-Electric Composite Cable Gap Design for Microbending Loss Reduction
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Solution Overview
Problem
Existing optical-electric composite cables face issues where high-tensile fibers can transmit lateral pressure to optical fibers, leading to increased microbending-induced optical loss, and strengthening the protective tube to prevent bending reduces flexibility.
Innovation Solution
The design includes an optical fiber enclosed by an inner tubular cover, surrounded by electric wires bundled with a binding member and covered by an outer tubular cover, with a gap between the binding member and the outer cover, featuring a helical winding and specific material properties to absorb and distribute external forces, reducing pressure on the optical fiber while maintaining flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high-tensile fiber is filled at high density to disperse external force, then external force dispersion is improved, but lateral pressure on optical fiber increases causing microbending loss
Solution Approach 1:
The patent applies different material properties to different regions: the inner tubular cover uses high elastic modulus (0.01-1 GPa) to provide structural support and disperse external forces, while the gap region provides cushioning space. This local differentiation allows force dispersion without transmitting excessive lateral pressure to the optical fiber.
Solution Approach 2:
The inner tubular cover acts as an intermediary between the optical fiber and the binding member with electric wires. It absorbs and distributes external forces before they reach the optical fiber, preventing direct transmission of lateral pressure while maintaining overall structural integrity.
2Object-affected harmful factors
If protective tube is strengthened to prevent bending and twisting, then optical fiber protection is improved, but cable flexibility decreases
Solution Approach 1:
The patent specifies an elastic modulus range (0.01-1 GPa) for the outer tubular cover, balancing protection and flexibility. This parameter optimization ensures the cover provides sufficient mechanical protection against bending and twisting while maintaining adequate cable flexibility for installation and handling.
Solution Approach 2:
The cable employs a composite structure combining the inner tubular cover, outer tubular cover, binding member, and gap space. This composite design distributes mechanical stresses across multiple components, providing protection without requiring any single component to be excessively rigid, thus preserving flexibility.
3Strength
If gap is reduced between binding member and outer cover to improve structural integrity, then cable strength is improved, but microbending loss increases due to force transmission
Solution Approach 1:
The gap between the binding member and outer tubular cover serves as a pre-designed cushioning space. When external forces are applied, this gap absorbs shocks and prevents direct force transmission to the optical fiber, cushioning against potential microbending before it occurs.
Data Source
AI summary
An optical-electric composite cable includes an optical fiber, an inner tubular cover enclosing the optical fiber, a plurality of electric wires arranged outside the inner tubular cover, a binding member collectively bundling the plurality of electric wires, and an outer tubular cover covering an outer periphery of the binding member. A gap exists between the binding member and the outer tubular cover.