Optical Fiber Preform Deposition Control for Core Eccentricity
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Solution Overview
Problem
The existing methods for manufacturing optical fiber glass preforms, such as the OVD method, face challenges with core eccentricity and non-circular cladding due to biased glass particle deposition, especially as preform sizes increase and deposition rates accelerate.
Innovation Solution
A method involving the controlled reciprocation of a burner relative to a rotating base material, adjusting the angle and thickness of glass particle deposition to specific conditions (excluding angles of 0°, 120°, 240°, 72°, 144°, 216°, and 288°) to achieve uniform deposition and prevent core eccentricity and cladding non-circularity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If glass particles are deposited at high speed to increase productivity, then the deposition amount per unit time increases, but core eccentricity and cladding non-circularity occur due to biased deposition
Solution Approach 1:
The patent applies dynamics by making the burner reciprocate (move back and forth) during the deposition process. The burner moves in the axial direction of the base material while the base material rotates, creating a dynamic deposition pattern that prevents localized over-deposition. This reciprocating motion distributes glass particles more uniformly across the deposition surface, maintaining manufacturing precision even at high deposition speeds.
Solution Approach 2:
The patent utilizes asymmetric reciprocation patterns where the burner's forward and backward motion paths or speeds are deliberately made different. This asymmetric motion prevents the formation of symmetric deposition patterns that could lead to non-circular cladding. By introducing controlled asymmetry in the burner trajectory, the patent achieves more uniform radial deposition and prevents core eccentricity while maintaining high productivity.
2Loss of time
If the base material rotation speed and burner reciprocation speed are increased to improve efficiency, then manufacturing time is reduced, but deposition uniformity deteriorates causing core eccentricity
Solution Approach 1:
The patent employs dynamic speed control where the burner reciprocation speed is coordinated with the base material rotation speed. By synchronizing these speeds and adjusting their ratio, the patent ensures that glass particles are deposited uniformly across different angular positions. This dynamic coordination allows high rotation and reciprocation speeds to be maintained while preserving deposition uniformity, thus reducing manufacturing time without sacrificing precision.
Solution Approach 2:
The patent implements periodic reciprocation of the burner in sync with the periodic rotation of the base material. This periodic action creates a regular deposition pattern that ensures each region of the base material receives glass particles at appropriate intervals. By maintaining the right periodic relationship between reciprocation and rotation, the patent achieves uniform deposition even at high speeds, preventing core eccentricity while minimizing manufacturing time.
3Device complexity
If a single burner is used to simplify the device, then device complexity is reduced, but deposition control capability is insufficient to prevent core eccentricity
Solution Approach 1:
The patent achieves precise deposition control with a single burner by making it dynamic rather than static. The burner reciprocates in the axial direction while the base material rotates, creating a scanning motion that distributes deposition uniformly. This dynamic single-burner approach replaces the need for multiple stationary burners, reducing device complexity while maintaining or improving core eccentricity control through coordinated motion between the burner and base material.
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 effectively reduces core eccentricity and cladding non-circularity, ensuring the production of optical fiber glass preforms with improved circularity and reduced connection loss, suitable for optical fibers with mode field diameters less than 9.1 μm.
Implementation Method 1
glass particles being generated by glass making feedstock gas being supplied while a burner and the base material that is rotating are reciprocated relatively to each other
Implementation Method 2
depositing glass particles on a base material
Data Source
AI summary
A method of manufacturing an optical fiber glass preform, the method comprising depositing glass particles on a base material, the glass particles being generated by glass making feedstock gas being supplied while a burner and the base material that is rotating are reciprocated relatively to each other, wherein when a portion corresponding to an outer diameter equal to or more than 0.80 L and equal to or less than L is deposited, wherein L represents a final outer diameter of a part of the optical fiber glass preform manufactured, the part being formed by the deposition of the glass particles, the deposition is performed under a first condition where an angle formed by a first line extending from a center O of a cross section of the base material to a rotational position r0 at which one round trip of the relative reciprocation starts and a second line extending from the center O to a rotational position r1 at which the one round trip of the relative reciprocation ends is an angle excluding 0°, 120°, 240°, 72°, 144°, 216°, and 288°; or the deposition is performed under a second condition where the angle is 120° or 240°, thereby to deposit the glass particles to a thickness corresponding to a thickness equal to or less than 0.03 L; or the deposition is performed under a third condition where the angle is 72°, 144°, 216°, or 288°, thereby to deposit the glass particles to a thickness corresponding to a thickness equal to or less than 0.02 L; or the deposition is performed under a fourth condition where the angle is 0°, thereby to deposit the glass particles to a thickness corresponding to a thickness equal to or less than 0.01 L.