Optical Fiber Core Rod Stabilization via Glass Holding Members
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Solution Overview
Problem
Conventional optical fiber manufacturing methods face challenges in achieving a stable core diameter along the longitudinal direction due to excessive fluctuations, which affect yield ratios and are difficult to resolve, especially when using glass rods held in a glass matrix, where thermal contraction differences lead to core diameter variations outside permissible ranges.
Innovation Solution
An optical fiber manufacturing method involving a glass pipe with a core rod and holding members, where glass particles are filled between the core rod and the pipe's inner wall, and the holding members are used to sandwich the core rod, with controlled bulk densities and dehydroxylation processes to stabilize the core diameter, ensuring consistent core diameter throughout the fiber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If glass rods are held in a glass matrix during manufacturing, then the structure provides support and stability, but thermal contraction differences cause excessive core diameter fluctuation outside permissible ranges
Solution Approach 1:
The patent introduces a holding member as an intermediary component between the glass rods and the glass matrix. This holding member has a bulk density matched to the glass particles (within 0.8-1.2 times range), allowing it to act as a thermal buffer during heat-melting. The holding member prevents direct thermal interaction between the glass matrix and glass rods, thereby eliminating the harmful thermal contraction differences that cause core diameter fluctuation.
Solution Approach 2:
The patent changes the bulk density parameter of the holding member to match the glass particles within a specific range (0.8-1.2 times). This parameter optimization ensures that the holding member undergoes similar thermal contraction as the surrounding glass particles during heat-melting, preventing differential stress and core diameter variation. The bulk density becomes a critical control parameter for maintaining manufacturing precision.
2Ease of manufacture
If glass particles are used to fill the gap between glass rod and glass tube, then the filling is simplified, but thermal contraction differences lead to core diameter fluctuation
Solution Approach 1:
The holding member serves as an intermediary layer between the glass particles and the glass rods. While glass particles maintain their simplicity for filling, the holding member buffer prevents their thermal contraction from directly affecting the core rod, thus maintaining both ease of manufacture and manufacturing precision.
Solution Approach 2:
By controlling the bulk density of the holding member to match the glass particles (0.8-1.2 times range), the patent ensures thermal contraction compatibility. This allows the use of simple glass particle filling while preventing the harmful effects of thermal mismatch, thereby maintaining both manufacturing simplicity and core diameter stability.
3Strength
If the bulk density of holding members differs significantly from glass particles, then the holding members provide strong structural support, but thermal contraction differences cause excessive core diameter fluctuation
Solution Approach 1:
The patent optimizes the bulk density parameter of the holding member to be within 0.8-1.2 times that of glass particles. This parameter range maintains sufficient structural support strength while ensuring thermal contraction compatibility with the surrounding glass particles during heat-melting, thereby preventing core diameter fluctuation.
Solution Approach 2:
The patent applies the principle of thermal expansion/contraction matching by selecting holding member materials and densities that undergo similar thermal dimensional changes as the glass particles. This thermal compatibility ensures that during heat-melting, the holding member and glass particles contract uniformly, preventing differential stress that would cause core diameter variation while maintaining structural integrity.
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 method enables the production of optical fibers with a stable core diameter along the longitudinal direction, reducing yield losses and improving manufacturing efficiency by controlling thermal contraction and core diameter consistency.
Implementation Method 1
it becomes difficult to eliminate the excessive fluctuation in the core diameter... there occurs a non-negligible difference in the thermal contraction at the time of heat-melting
Implementation Method 2
performing dehydroxylation of the filled glass particles using the reducing gas
Data Source
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AI summary
An optical fiber manufacturing method includes placing, inside a glass pipe constituting a cladding portion, a first holding member, which is one of a pair of holding members made of glass and having a plurality of holes formed thereon, and a core rod, which includes a core forming portion serving as the core portion and includes a cladding forming portion constituting the cladding portion, in such a way that the core rod is supported by the first holding member; includes filling glass particles in the gap between the inner wall face of the glass pipe and the core rod; includes placing a second holding member of the pair of holding members inside the glass pipe and holding the core rod in a sandwiched manner in between the first holding member and the second holding member; includes sealing one end portion of the glass pipe and manufacturing an intermediate object; and includes manufacturing an optical fiber using the intermediate object. The bulk density of the first holding member and the second holding member is set to be within a predetermined range with reference to the bulk density of the filling portion filled with the glass particles, and the predetermined range is determined according to the permissible variation range for the core diameter in the longitudinal direction of the optical fiber.