Optical Preform Soot Pressing for Complex Refractive Index Profiles
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Solution Overview
Problem
Conventional methods for forming optical preforms from silica glass soot are limited in creating complex refractive index profiles and are not suitable for forming preforms with multiple layers of different compositions and morphologies, as they often result in low yield and contamination issues.
Innovation Solution
A method involving a mold body with an elastically deformable bladder that rotates to compress silica glass soot radially, allowing for the formation of multiple layers with controlled refractive index profiles by varying the composition and morphology of each layer, enabling the creation of optical preforms with complex refractive index profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional outside vapor deposition (OVD) process is used to form cladding layer, then high yield manufacturing is achieved, but the rate limiting step occurs and only 50% of pyrolysis product is deposited
Solution Approach 1:
The patent converts the previously wasted pyrolysis product (silica glass soot collected in baghouse) into a valuable resource by using it as feedstock for forming optical preform cladding layers through the soot pressing process, thereby eliminating waste and improving overall deposition efficiency
Solution Approach 2:
The patent changes the physical and chemical parameters of the silica glass soot by controlling particle size distribution, morphology, and composition to optimize the soot pressing process and achieve high-quality cladding layers with desired refractive index profiles
2Manufacturing precision
If soot pressing process with strenuous chemistry process is used to remove impurities, then purity improvement is attempted, but mixed results are achieved
Solution Approach 1:
The patent performs preliminary purification of silica glass soot through controlled particle size classification and selective dissolution processes before the soot pressing operation, removing impurities in advance to prevent contamination during cladding formation and eliminate the need for complex post-processing chemistry
Solution Approach 2:
The patent extracts and removes specific impurities from the silica glass soot feedstock through selective dissolution and filtration processes, separating unwanted contaminants from the valuable silica particles before they are pressed into cladding layers
3Ease of manufacture
If vertical pressing technique is used to form cladding layer, then single layer formation is achieved, but complex refractive index profile cannot be constructed
Solution Approach 1:
The patent divides the cladding formation process into multiple sequential soot pressing operations, where each operation forms a distinct layer with specific composition and morphology, allowing construction of complex multi-layer structures with tailored refractive index profiles
Solution Approach 2:
The patent extends the manufacturing capability from single-layer to multi-layer formation by adding the dimension of layer stacking in the radial direction, enabling construction of complex optical preforms with concentric layers of different compositions around the core
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 allows for the efficient formation of optical preforms with precise refractive index profiles and improved purity, enabling the production of high-quality optical fibers by effectively utilizing silica glass soot that would otherwise be considered waste.
Implementation Method 1
The mold body may be rotated at a rotational speed sufficient to force the silica glass soot towards an inner wall of the mold body
Implementation Method 2
The elastically deformable bladder may be disposed within and lines the mold cavity adjacent to an inner wall of the mold body
Implementation Method 3
the silica glass soot is compressed in an inward radial direction as the mold body is rotated to form a soot compact layer
Data Source
AI summary
Methods and apparatuses for forming optical preforms from silica glass soot are disclosed. According to one embodiment, a method for forming an optical preform may include loading silica glass soot in a mold cavity of a mold body. The mold body may be rotated at a rotational speed sufficient to force the silica glass soot towards an inner wall of the mold body. Thereafter the silica glass soot is compressed in an inward radial direction as the mold body is rotated to form a soot compact layer.