Multi-mode optical fiber refractive index control via residual stress feedback
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Solution Overview
Problem
Multi-mode optical fibers experience deviations in refractive index distribution due to residual stress during the drawing process, leading to variations in bandwidth characteristics, which existing methods fail to adequately address.
Innovation Solution
A method involving the formation of a glass base material with controlled refractive index distribution, measurement of residual stress distribution, readjustment of the additive supply rate to correct refractive index deviations, and subsequent re-drawing of the glass base material to achieve a stable refractive index profile in multi-mode optical fibers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the refractive index distribution is controlled during glass base material formation, then the desired refractive index profile is achieved, but residual stress during drawing causes deviation from the desired distribution
Solution Approach 1:
The patent applies preliminary action by measuring the residual stress distribution before final product completion, and pre-correcting the refractive index distribution in the glass base material formation process. By measuring residual stress in the drawn optical fiber and using this information to adjust the additive supply rate in subsequent glass base material formation, the method proactively compensates for expected deviations rather than reacting after the fact.
Solution Approach 2:
The patent implements feedback by measuring the residual stress distribution in the drawn optical fiber and using this measurement to adjust the additive supply rate in the glass base material formation process. The measured residual stress serves as feedback information that directly influences the control parameters of the manufacturing process, creating a closed-loop system that continuously optimizes the refractive index distribution.
2Reliability
If multiple optical fibers are drawn at different drawing tensions to find optimal bandwidth characteristics, then the desired bandwidth can be achieved, but the manufacturing process becomes complex and yield decreases
Solution Approach 1:
The patent applies preliminary action by establishing the optimal refractive index distribution through controlled additive supply during glass base material formation, before the drawing process. This preliminary control of refractive index prevents the need for subsequent trial-and-error drawing experiments, directly improving yield by producing acceptable optical fibers in the first attempt.
Solution Approach 2:
The patent changes the control parameter from drawing tension to additive supply rate during glass base material formation. Instead of adjusting mechanical parameters during drawing, the method controls chemical composition parameters during pre-form creation, which fundamentally alters the refractive index distribution and eliminates the need for multiple drawing trials.
3Manufacturing precision
If the additive supply rate is adjusted to correct refractive index deviation, then the refractive index distribution is improved, but additional manufacturing steps are required
Solution Approach 1:
The patent merges the refractive index correction function into the existing glass base material formation process by adjusting the additive supply rate. Rather than adding a separate correction step after drawing, the method combines the refractive index control with the material formation process itself, integrating multiple functions into a single manufacturing stage.
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 effectively reduces refractive index deviations caused by residual stress, resulting in improved bandwidth characteristics and increased yield of multi-mode optical fibers with desired refractive index profiles.
Implementation Method 1
measuring a residual stress distribution in a radial direction of the drawn optical fiber
Data Source
AI summary
A method of manufacturing multi-mode optical fiber is disclosed. The method of manufacturing includes: a step of forming a first glass base material while controlling a supply rate of an additive for adjusting a refractive index to achieve a desired refractive index distribution; a step of drawing the first glass base material; a step of measuring a residual stress distribution in a radial direction of the multi-mode optical fiber after being drawn; a step of readjusting the supply rate of the additive in accordance with deviation of a refractive index, acquired from the residual stress distribution measured, from the desired refractive index distribution; a step of forming a second glass base material while supplying the additive at the supply rate after being readjusted; and a step of drawing the second glass base material.