Optical Fiber Preform Manufacturing Using Induction Heating
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Solution Overview
Problem
The existing methods for manufacturing optical fibers are costly and inefficient, with mature technologies offering little room for cost reduction, and outdated manufacturing facilities pose a significant barrier to reducing production costs, particularly due to the challenges of forming large-diameter muffle tubes that are prone to deformation at high temperatures.
Innovation Solution
A method involving the formation of a porous silica-based glass layer around a core rod, followed by dehydration, sintering under decreased pressure, and vitrification in an inert gas atmosphere, excluding helium, to create a translucent glass cladding layer, which allows for the production of optical fiber preforms and fibers with reduced manufacturing costs and extended facility lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a large-diameter muffle tube is used to manufacture large-size optical fiber preform, then the manufacturing capability is improved, but the muffle tube is softened at high temperature and deformed, reducing reliability
Solution Approach 1:
The patent extracts the harmful function of the muffle tube (which softens and deforms at high temperature) by replacing it with a susceptor that can withstand the processing temperature. The muffle tube is removed from the heating system, and the porous layer is directly heated by electromagnetic induction using the susceptor as the heating element, eliminating the reliability issue of large-diameter muffle tubes
Solution Approach 2:
The patent replaces the conventional thermal conduction heating system (which requires a muffle tube) with an electromagnetic induction heating system. The susceptor absorbs electromagnetic energy and converts it to heat directly, eliminating the need for a mechanical muffle tube structure that is prone to deformation
2Manufacturing precision
If conventional vitrification method is used with helium gas, then the porous layer is converted to transparent glass layer, but the manufacturing cost increases due to expensive helium gas
Solution Approach 1:
The patent replaces the expensive helium gas with inexpensive nitrogen gas as the atmosphere for the vitrification process. The nitrogen gas serves the same function of providing an inert atmosphere to prevent oxidation while being much more economical, directly reducing manufacturing costs
Solution Approach 2:
The patent changes the atmospheric composition parameter from helium to nitrogen, and adjusts the heating method from conventional thermal conduction to electromagnetic induction. These parameter changes maintain the vitrification effect while reducing costs
3Duration of action of stationary object
If outdated manufacturing facilities are used, then existing investment is protected, but the manufacturing cost cannot be reduced and productivity is limited
Solution Approach 1:
The patent makes the susceptor serve multiple functions: it acts as both the heating element (replacing the muffle tube's heating function) and as a support structure for the porous layer. This multi-functionality allows existing facility components to be reused while achieving new manufacturing capabilities
Solution Approach 2:
The patent introduces a dynamic heating system where the susceptor can be selectively heated by electromagnetic induction. The heating is not static but can be controlled dynamically, allowing for more flexible and efficient processing that improves productivity while using existing facility infrastructure
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 efficient manufacturing of optical fiber preforms and fibers with improved refractive-index profiles and low transmission loss, suitable for broadband wavelength division multiplexing, while avoiding the use of expensive helium gas and extending the life of existing manufacturing equipment.
Implementation Method 1
dehydrating the porous layer under at least one condition of a decreased pressure, an ambient atmosphere with an inert gas and a halogen gas, and an ambient atmosphere with an inert gas and a halogen-based compound gas
Implementation Method 2
sintering the dehydrated porous layer under a decreased pressure until the dehydrated porous layer becomes a translucent glass layer containing a closed pore
Implementation Method 3
vitrifying the translucent glass layer under an ambient atmosphere including an inert gas other than a helium gas, to make the translucent glass layer into the cladding layer
Implementation Method 4
drawing the translucent glass preform formed with the core rod and the translucent glass layer in such a manner that the translucent glass layer becomes a transparent glass layer
Data Source
AI summary
A porous layer is formed by depositing a silica glass particle around a core rod. The porous layer is dehydrated. The dehydrated porous layer is sintered under a decreased pressure until the dehydrated porous layer becomes a translucent glass layer containing a closed pore. The translucent glass layer is vitrified under an ambient atmosphere including an inert gas other than a helium gas.