Optical fiber glass preform and method for drawing optical fiber glass preform
AssigneeShin-Etsu Chemical Co., Ltd.
InventorRyo Mitta
Life of this patent
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Abstract
Provided is an optical fiber glass preform, in a preliminary step of a final drawing step, in which the optical fiber glass preform is undergone one or more drawing steps to be drawn to a final target diameter, wherein as an outer diameter of an effective portion of the glass preform is continuously measured in a longitudinal direction, and from outer diameter measurement results obtained, a regression line of y=ax+b is obtained using the least squares method with y as the outer diameter and x as a length, an absolute value of a slope a is less than or equal to 0.005 mm/mm; and a maximum value of an obtained absolute value of a curvature of the outer diameter at any given point, in the outer diameter measurement results obtained, is 0.003 or less.
Claims5
An optical fiber glass preform, in a preliminary drawing step of a final drawing step, in which the optical fiber glass preform undergoes one or more further drawing steps to be drawn to a final target diameter, wherein
- an outer diameter of an effective portion of the optical fiber glass preform continuously measured in a longitudinal direction has an inclined regression line of y=ax+b obtained using a least squares method with y as an outer diameter and x as a length, wherein an absolute value of the slope a of the inclined regression line is between 0.004 mm/mm and 0.005 mm/mm, and a maximum value of an absolute value of a curvature of the outer diameter at any given point over the longitudinal direction is 0.003 mm−1 or less.
A drawing method of an optical fiber glass preform for drawing processing the optical fiber glass preform, by a plurality of drawing steps, to a final target diameter, wherein
- the optical fiber glass preform in a preliminary step of a final drawing step is drawn so that
- when an outer diameter of an effective portion of the optical fiber glass preform is continuously measured in a longitudinal direction, and from outer diameter measurement results obtained, a regression line of y=ax+b is obtained using the least squares method with y as the outer diameter and x as a length, an obtained absolute value of a slope a is less than or equal to 0.005 mm/mm;
- and a maximum value of an absolute value of a curvature of the outer diameter at any given point, in the outer diameter measurement results obtained, is 0.003 or less.
Dependencies are inferred from the claim text.