Optical Fiber Coating Composition for Small-Radius Bending Reliability
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Solution Overview
Problem
Current methods fail to guarantee the mechanical reliability and failure time of optical fibers when bent around small radii, leading to potential failure during installation and handling in fiber-to-the-home networks.
Innovation Solution
A method of manufacturing optical fibers involves determining the failure strength and time of fibers when wound on a mandrel with a radius of 1.3 mm, selecting those with a failure strength of 5.5 kgf or more, and optimizing the fiber coating's composition, including OH concentration, resin moisture content, and pH, to ensure they do not fail under temporary excessive strain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an optical fiber is bent around a small radius during installation and handling, then the intrinsic strength of the glass is influenced, but the failure probability increases
Solution Approach 1:
The invention changes the chemical composition parameters of the glass fiber, specifically controlling the SiO2 content (92-99 wt%), Al2O3 content (0.1-5 wt%), and B2O3 content (0.1-5 wt%). By adjusting these compositional parameters, the glass achieves both high intrinsic strength and resistance to failure when bent around small radii, resolving the contradiction between reliability and failure probability under bending stress.
Solution Approach 2:
The invention creates a composite glass composition by combining multiple oxides (SiO2, Al2O3, B2O3) in specific proportions. This composite material structure provides both the intrinsic strength needed for reliability and the structural properties that prevent failure during small-radius bending, addressing the technical contradiction through material composition optimization.
2Strength
If the tetraethoxysilane content is increased in the primary coating to prevent strength reduction, then the basicity of the photo-cured primary coating increases, but the long-term reliability decreases
Solution Approach 1:
The invention optimizes the tetraethoxysilane content parameter within the range of 0.01-3.0 parts by mass and diethylamine content within 0.001-0.2 parts by mass. By precisely controlling these chemical parameters, the coating maintains appropriate basicity that prevents glass fiber strength reduction during cleaning while ensuring long-term reliability is not compromised. The balanced composition resolves the contradiction between strength retention and long-term reliability.
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
The method ensures optical fibers do not fail when temporarily bent around small radii, providing a guaranteed failure time and enhanced mechanical reliability by correlating failure strength and time through specific coating composition and processing conditions.
Implementation Method 1
disposing a fiber coating on the outer circumference of the glass fiber
Implementation Method 2
a resin for forming a primary coating which is a part of a fiber coating and is in contact with the outer circumference of a glass fiber, before being photo-cured
Data Source
AI summary
A method of manufacturing an optical fiber includes a first step of drawing an optical fiber preform into a glass fiber and disposing a fiber coating on the outer circumference of the glass fiber to form a parent optical fiber; a second step of cutting the parent optical fiber into a plurality of individual optical fibers; a third step of determining, at, at least, one spot of the parent optical fiber, a failure strength F1 and a failure time T; a fourth step of determining a failure strength F2 of each of the individual optical fibers; and a fifth step of selecting an optical fiber having a failure strength F2 of 5.5 kgf or more from the individual optical fibers cut from the parent optical fiber whose failure strength F1 and failure time T satisfy the inequality T>2.6×10−11×exp(4.736×F1).