Optical Fiber Preform Manufacturing via Self-Hardening Cladding
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Solution Overview
Problem
The manufacturing of optical fibers with special structures, such as hole-assisted, photonic crystal, and multi-core fibers, requires complex and costly processing steps, leading to increased optical loss factors due to surface roughness and impurities, and challenges in achieving high precision in core and outer diameters, as well as structural parameters.
Innovation Solution
A method involving the arrangement of SiO2 glass rods in a container, followed by pouring a hardening-resin-containing SiO2 glass raw material solution and a hardener, solidifying through a self-hardening reaction, and heating in chlorine gas to form optical fiber base materials with a SiO2 cladding layer and optional empty holes, eliminating the need for mechanical drilling and polishing, thereby reducing surface roughness and enhancing dimensional precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If mechanical cutting is used to open through-holes in the optical fiber base material, then the special structure (hole-assisted, photonic crystal, multi-core) can be formed, but the surface roughness increases and optical loss factors are added
Solution Approach 1:
The patent forms the through-holes and empty holes during the base material formation process itself, before the drawing process. By using a rod with pre-formed holes as the core material and forming the cladding layer around it, the special structure is created in advance, eliminating the need for subsequent mechanical cutting and polishing operations that would increase surface roughness.
Solution Approach 2:
The patent replaces the mechanical cutting system (drills, ultrasonic waves, polishing equipment) with a chemical/thermal formation process. The through-holes are formed by creating a rod with holes and depositing cladding material around it, then fusing everything together in a heat treatment process, substituting mechanical operations with a unified thermal-chemical process.
2Shape
If multiple processing steps (mechanical cutting, washing, dehydration, drying, heating) are used to manufacture special structure optical fibers, then the desired structure can be achieved, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent merges multiple separate processing steps into a single integrated process. Instead of separately performing mechanical cutting, washing, dehydration, drying, and heating, the invention combines these operations by forming the base material with pre-existing holes and then performing a single fusion heat treatment that completes the structure formation, significantly reducing process complexity.
Solution Approach 2:
The patent performs preliminary formation of the through-holes and empty holes in the rod material before the main base material formation process. This preliminary action allows the special structure to be established early, eliminating the need for subsequent complex processing steps to create or modify these features.
3Shape
If through-holes are opened by mechanical cutting, then the special structure can be formed, but the optical loss increases due to surface roughness and impurities
Solution Approach 1:
The patent replaces mechanical cutting operations with a thermal-chemical formation process. By forming the through-holes in the rod material and then fusing the cladding layer around them through heat treatment, the method eliminates mechanical contact that would create surface roughness and impurities, thereby reducing optical loss.
Solution Approach 2:
The patent changes the physical state and parameters of the materials during processing. The rod material and cladding material are heated to high temperatures during fusion, changing their physical state to enable bonding without mechanical contact. This parameter change (temperature, physical state) allows formation of smooth surfaces with low optical loss.
4Ease of manufacture
If conventional VAD method is used to manufacture base material, then the base material can be formed, but achieving high precision in core and outer diameters becomes difficult
Solution Approach 1:
The patent uses a rod with pre-formed through-holes as the core material, establishing the precise geometry of the core and hole structures before base material formation. This preliminary action allows precise control of core diameter and hole positions, which are then maintained during the base material formation and fusion processes.
Solution Approach 2:
The patent segments the base material formation process into distinct components: the rod with pre-formed holes, the cladding layer material, and the fusion process. This segmentation allows independent optimization and precise control of each component's dimensions, enabling high precision in the final core and outer diameters.
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 low scattering loss, high mechanical strength, and precise dimensional control, reducing production costs and complexity while achieving high reproducibility and optical performance.
Implementation Method 1
pouring a hardening-resin-containing SiO2 glass raw material solution for cladding layer and a hardener, solidifying through a self-hardening reaction
Implementation Method 2
drying the solidified material and heating the solidified material in chlorine gas, to manufacture an optical fiber base material
Data Source
Figure 1A~2
Figure 3A~4B
Figure 5A~6B
AI summary
The present invention provides a method for manufacturing an optical fiber base material and an optical fiber base material, the method including: arranging a rod containing SiO2 family glass for core, in a container; pouring a SiO2 glass raw material solution for cladding layer and a hardener into the container, the glass raw material solution containing a hardening resin; solidifying the glass raw material solution through a self-hardening reaction; and then drying the solidified material and heating the solidified material in chlorine gas, to manufacture an optical fiber base material in which a SiO2 cladding layer is formed in an outer periphery of the rod containing SiO2 family glass for core.