Twisted Preform Bundle for Stable Microstructured Fiber Fusion
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Solution Overview
Problem
Existing methods for producing preforms for microstructured optical fibers often result in hollow or solid cylinders breaking during fusion, leading to unstable and non-reproducible fusions.
Innovation Solution
A preform is created by forming a bundle of sub-elements with a polygonal pattern that is twisted around the longitudinal axis, then sealed and heated with negative pressure to fuse the material-free spaces, ensuring a stable and reproducible fusion process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hollow or solid cylinders are fused to form an overall structure, then the preform structure is created, but the cylinders break during fusion leading to unstable and non-reproducible results
Solution Approach 1:
The patent applies asymmetry by introducing a predetermined twist angle to the bundle of sub-elements relative to the preform's longitudinal axis. This asymmetric arrangement prevents the hollow or solid cylinders from aligning in a way that creates stress concentration points during fusion, thereby eliminating the fracture tendency while maintaining structural integrity throughout the fusion process
Solution Approach 2:
The patent applies preliminary action by pre-twisting the bundle of sub-elements before the fusion process begins. This preliminary structural adjustment ensures that when heating and fusion occur, the cylinders are already in an optimized configuration that distributes thermal and mechanical stresses evenly, preventing breakage and ensuring reproducible fusion results
2Reliability
If the hollow cylinders are twisted at a predetermined angle, then fracture during fusion is prevented, but the manufacturing process becomes more complex
Solution Approach 1:
The predetermined twist angle is applied as a preliminary structural configuration to the bundle of sub-elements before fusion. This single preparatory step simplifies the overall manufacturing process by preventing fractures during fusion, eliminating the need for complex real-time monitoring and adjustment mechanisms, and ensuring reproducible results without significantly increasing device complexity
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 prevents fractures during fusion, allowing for a longitudinally stable and reproducible production of microstructured optical fibers with retained capillary patterns.
Implementation Method 1
the bundle is sealed at one end and then placed coaxially in a hollow glass cylinder as a cylindrical envelope... heated with negative pressure to fuse the material-free spaces
Implementation Method 2
heated with negative pressure to fuse the material-free spaces
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a preform and to a method for producing said preform for drawing a microstructured optical fiber, on which a core element (4) and a plurality sub-elements (5), which extend along the length of the preform, are arranged. In order to eliminate the high tendency to fracture during fusion and to ensure a fusion that is longitudinally stable and can be reproduced, according to the invention the sub-elements (5) and the core element (4) form a bundle (6) that is twisted at a specified angle around the longitudinal axis of the bundle (6a), wherein the pattern that is formed by the cross-sections of the sub-elements (5) and the cross-section of the core element (4) is maintained along the length of the preform (1), and subsequently, by heating beyond the transformation point of the materials thereof, is at least partially fused together, such that the material-free spaces (9, 10, 11) between the sub-elements (5), between the sub-elements (5) and the core element (4), and between the sub-elements (5) and the sheath (7) at least partially disappear.