Optical Fiber Preform Boundary Detection With Polarized Light
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Solution Overview
Problem
Existing methods for measuring refractive index change positions in optical fiber preforms are inefficient, leading to increased measurement time and reduced accuracy, especially when dealing with minute differences in refractive index and large diameters.
Innovation Solution
A method and device using a polarizer and analyzer with orthogonal transmission axes to detect refractive index changes through photoelastic effects, combined with rotational alignment and parallel movement of the optical fiber preform, to enhance measurement accuracy while reducing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional measurement methods are used to measure refractive index change positions, then the measurement process can be completed, but the measurement time increases and accuracy decreases
Solution Approach 1:
The patent changes the optical parameters by introducing polarized light with specific polarization directions and using a polarizer-analyzer system. By adjusting the polarization state and using orthogonal transmission axes, the system enhances the contrast and detectability of refractive index boundaries, enabling faster and more accurate measurements without increasing measurement time.
Solution Approach 2:
The patent introduces a polarizer and analyzer as intermediary optical elements between the light source and the observation system. These intermediaries modify the light's polarization state to interact with the refractive index variations in the optical fiber preform, converting subtle refractive index changes into detectable intensity variations that can be measured quickly and accurately.
2Area of stationary object
If the optical fiber preform diameter is large, then the measurement coverage is improved, but the measurement accuracy for minute refractive index differences deteriorates
Solution Approach 1:
The patent changes the polarization parameter of the incident light and uses a polarizer-analyzer system with orthogonal transmission axes. This creates a high-contrast detection system where even minute refractive index differences produce significant intensity changes, maintaining measurement accuracy across large diameter preforms without sacrificing precision for small variations.
Solution Approach 2:
The patent applies local quality enhancement by using the polarizer-analyzer system to locally detect refractive index changes at specific positions along the optical fiber preform. The system can identify boundary positions between core and cladding regions with high precision, allowing accurate measurements even when the overall preform diameter is large.
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
Improves measurement accuracy of refractive index changes by detecting boundary positions clearly and efficiently, allowing for precise adjustment of core positions and reducing measurement time.
Implementation Method 1
A method and device using a polarizer and analyzer with orthogonal transmission axes to detect refractive index changes through photoelastic effects
Data Source
AI summary
The method for measuring the refractive index variation position of an optical fiber preform comprises: rotating the optical fiber preform about the central axis such that a straight line which is orthogonal to the central axis and which passes through two more refractive index variation positions of choice that are subject to measurement is orthogonal to the observation axis; irradiating a side surface of the optical fiber preform with light emitted from the light source, via the polarizer; receiving, with the camera and via the analyzer, the light that has been transmitted by the optical fiber preform, and acquiring a light intensity image; detecting a refractive index variation position of the optical fiber preform on the basis of the light intensity image; and moving the optical fiber preform or the observation axis parallel to the central axis.