Vapor-phase Axial Deposition Burner Gradient Control for Optical Fiber Porous Glass
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Solution Overview
Problem
The existing Vapor-phase Axial Deposition (VAD) method for fabricating porous glass base materials for optical fibers often results in cracking during the initial stage of deposition, leading to unstable outer diameters and reduced productivity due to the formation of low-density portions.
Innovation Solution
A fabrication method and apparatus that adjust the gradient of the clad forming burner during the deposition process, starting with a downward gradient and transitioning to an upward gradient, to ensure continuous flame alignment and controlled gas ejection, preventing initial-stage cracks and stabilizing the outer diameter of the porous glass base material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a fixed gradient burner is used during deposition, then the fabrication process is simple, but initial-stage cracks occur and outer diameter stability deteriorates
Solution Approach 1:
The burner gradient is changed dynamically during the deposition process. Specifically, the gradient is adjusted from an initial state to a final state during the deposition of glass fine particles. This dynamic adjustment prevents initial-stage cracks and stabilizes the outer diameter of the porous glass base material, resolving the contradiction between manufacturing precision and device complexity by implementing a time-varying parameter rather than a fixed complex mechanism
Solution Approach 2:
The gradient parameter of the burner is changed during the deposition process. The gradient transitions from an initial value to a final value as deposition progresses. This parameter change approach allows the system to adapt to different stages of deposition, preventing cracks and stabilizing outer diameter without requiring complex additional hardware
2Productivity
If deposition continues without gradient adjustment, then the process is continuous and simple, but low-density portions form and productivity decreases
Solution Approach 1:
The burner gradient is adjusted periodically during the deposition process. The gradient changes at specific stages: initially maintaining a first gradient, then switching to a second gradient during continued deposition. This periodic adjustment prevents the formation of low-density portions while maintaining continuous deposition, thereby improving both productivity and reliability
3Stability of the object's composition
If the clad forming burner maintains a downward gradient, then the initial deposition is stable, but outer diameter control deteriorates during continued deposition
Solution Approach 1:
The burner gradient is preliminarily set to a downward gradient at the beginning of deposition to ensure stable initial deposition. After the initial stable deposition is achieved, the gradient is then adjusted to improve outer diameter control during continued deposition. This preliminary action approach resolves the contradiction by sequencing the gradient settings according to deposition stages
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 effectively reduces the occurrence of initial-stage cracks and stabilizes the outer diameter of the porous glass base material, increasing yield and productivity by ensuring a consistent effective portion with a target outer diameter, while minimizing foams and agglomerated soot.
Implementation Method 1
According to the Vapor-phase Axial Deposition (VAD) method, a plurality of synthesizing burners are used to concurrently form a core-corresponding portion and a clad-corresponding portion of a porous glass base material for optical fiber
Data Source
AI summary
According to a fabrication method for fabricating a porous glass base material for optical fiber, the orientation of a clad forming burner used to form the outermost layer of a clad-corresponding portion is changed further upward while glass fine particles are deposited during the period between a first timing and a second timing. At the first timing, the outer diameter of the porous glass base material for optical fiber has not reached a target outer diameter. The second timing is later than the first timing, and either a timing at which the outer diameter of the porous glass base material for optical fiber reaches the target outer diameter for the first time, or a timing prior to this timing.