Pressurized Optical Fiber Structure for Lower Rayleigh Scattering
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Solution Overview
Problem
Existing optical fibers face challenges in reducing Rayleigh scattering loss due to density fluctuations in the glass, which are not adequately addressed by current methods such as controlling viscosity and annealing processes.
Innovation Solution
The optical fiber design incorporates a pressurizing section between the inner and outer layers, allowing the inner portion to be pressurized during drawing, with a lower average viscosity than the outer layer, thereby suppressing density fluctuations and reducing transmission loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If pressure is applied to the glass during drawing to suppress density fluctuations, then transmission loss is reduced, but the glass structure may be damaged or deformation may occur
Solution Approach 1:
The patent applies pressure during the glass transition period when the glass is in a softened state, allowing the glass to be compressed and densified without structural damage. By controlling the timing of pressure application during the phase transition from molten to solidified state, the glass can accommodate pressure-induced densification while maintaining structural integrity, thereby reducing density fluctuations and transmission loss.
Solution Approach 2:
The patent utilizes the glass transition phase change to apply pressure effectively. During the drawing process, when the glass is in the transition zone between molten and solidified states, pressure is applied to suppress density fluctuations. The phase transition allows the glass to respond to pressure by densifying rather than deforming permanently, achieving reduced transmission loss while preserving structural strength.
2Loss of energy
If the inner portion has lower viscosity than the outer layer to enable pressure application, then density fluctuations are suppressed, but the structural stability during manufacturing may be compromised
Solution Approach 1:
The optical fiber structure is divided into distinct layers with different viscosity characteristics. The inner portion (core and inner cladding) has lower viscosity to allow pressure-induced densification, while the outer layer maintains higher viscosity for structural stability. This segmentation enables each layer to perform its specific function: the inner portion responds to pressure to reduce density fluctuations, while the outer layer provides mechanical support and shape stability during manufacturing.
Solution Approach 2:
Different viscosity properties are assigned to different regions of the optical fiber. The inner portion has locally optimized lower viscosity to enable effective pressure application and density control, while the outer layer has higher viscosity for overall structural stability. This local quality differentiation allows the system to achieve both pressure responsiveness and manufacturing stability simultaneously.
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 achieves a transmission loss of 0.15 dB/km or less for light at 1550 nm, effectively reducing density fluctuations and improving the optical fiber's performance.
Implementation Method 1
applying pressure to the glass during the glass transition, in the process of drawing the optical fiber from an optical fiber preform
Implementation Method 2
a pressurizing section being capable of applying pressure to the inner portion when being applied with pressure from external
Implementation Method 3
the inner portion has an average viscosity lower than an average viscosity of the outer layer
Implementation Method 4
The main factor of the transmission loss in optical fibers is Rayleigh scattering loss. A major factor of Rayleigh scattering loss is extremely small density fluctuations in the glass, mainly, in the glass forming the core portion
Data Source
AI summary
An optical fiber includes: an inner portion including a core portion and an inner cladding portion that surrounds the core portion and has a refractive index lower than a maximum refractive index of the core portion; and an outer layer surrounding the inner portion. A pressurizing section is provided between the inner portion and the outer layer, the pressurizing section being capable of applying pressure to the inner portion when being applied with pressure from external, and the inner portion has an average viscosity lower than an average viscosity of the outer layer.