Optical Fiber Primary Coating Curing Stability
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Solution Overview
Problem
Conventional optical fiber coatings do not fully cure during the fiber draw process, leading to increased primary-coating in situ modulus (P-ISM) when exposed to additional UV radiation, which results in sensitivity to micro-bending and adverse effects on attenuation characteristics.
Innovation Solution
The optical fibers are cured to at least 85% of their fully cured P-ISM value by exposing them to additional UV radiation and heat during the draw process, using added UV lamps and inline heaters, while maintaining high manufacturing draw speeds, thereby stabilizing the coatings and reducing P-ISM increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the primary coating is cured to a higher extent during fiber draw, then the P-ISM stability is improved, but the manufacturing draw speed is reduced
Solution Approach 1:
The patent applies parameter changes by modifying the curing parameters of the primary coating through the addition of UV lamps and adjustment of draw tower temperature. These parameter changes enable the coating to cure to at least 85% of its fully cured P-ISM value during the draw process, achieving stable P-ISM while maintaining high draw speeds of at least 10 meters-per-second.
Solution Approach 2:
The patent implements preliminary action by initiating the curing process during the fiber draw operation itself, rather than allowing the coating to remain uncured. By exposing the coating to UV radiation and heat during draw, the coating begins curing in advance, ensuring that when the fiber is completed, the coating has achieved sufficient cure level (at least 85% of fully cured P-ISM) to provide stability without requiring post-draw curing that would reduce productivity.
2Stability of the object's composition
If additional UV radiation is applied to cure the coating, then the P-ISM stability is improved, but the device complexity is increased
Solution Approach 1:
The patent merges the curing function with the existing fiber draw process by integrating UV lamps into the draw tower structure. This combination allows the coating to be cured during the draw operation without requiring a separate, standalone curing system. The UV lamps are positioned to expose the coating as the fiber passes through the draw tower, effectively merging curing with the drawing process and minimizing additional device complexity.
Solution Approach 2:
The patent applies self-service by enabling the coating to cure using the existing thermal environment of the draw tower and UV radiation from the UV lamps. The coating utilizes the draw tower's temperature and the UV light to initiate and progress the curing reaction, reducing the need for external curing equipment or processes. This self-service approach minimizes additional complexity while achieving the desired P-ISM stability.
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
This approach results in optical fibers with stable P-ISM values that increase by less than 15% when exposed to additional UV, reducing microbending sensitivity and improving optical fiber performance in rollable ribbon fiber-optic cables.
Implementation Method 1
The primary coating is cured during draw to at least eighty-five percent (85%) of the coating's fully cured primary-coating in situ modulus (P-ISM) value
Implementation Method 2
using added UV lamps and inline heaters
Data Source
AI summary
An optical fiber comprising a core, a cladding disposed about the core, and a primary coating disposed about the cladding. The primary coating is cured during draw to at least eighty-five percent (85%) of the primary coating's fully cured primary-coating in situ modulus (P-ISM) value.