	US 12,448,317 B2
	Method of manufacturing optical fiber and apparatus for manufacturing optical fiber
Hiroshi Kohda, Osaka (JP); Takaharu Sato, Osaka (JP); and Katsuyuki Tsuneishi, Osaka (JP)
Assigned to SUMITOMO ELECTRIC INDUSTRIES, LTD., Osaka (JP)
Filed by SUMITOMO ELECTRIC INDUSTRIES, LTD., Osaka (JP)
Filed on Jun. 21, 2023, as Appl. No. 18/212,282.
Claims priority of application No. 2022-100988 (JP), filed on Jun. 23, 2022.
Prior Publication US 2023/0416140 A1, Dec. 28, 2023
Int. Cl. C03B 37/025 (2006.01); C03C 25/104 (2018.01)

CPC C03B 37/0253 (2013.01) [C03B 37/0256 (2013.01); C03C 25/104 (2013.01); C03B 2203/16 (2013.01); C03B 2205/20 (2013.01)]

8 Claims

1. A method of manufacturing an optical fiber with a hole from a preform having a through hole, comprising:

placing the preform in a drawing furnace;

forming an optical fiber by melting and drawing the preform in the drawing furnace while a gas is introduced into the through hole;

capturing an image of the optical fiber drawn from the preform; and

measuring a hole diameter of the optical fiber based on an image captured in the image capturing and controlling a pressure of the gas introduced into the through hole based on a measurement result,

wherein, in the capturing of the image, when the optical fiber deviates, continuing to focus on the position of the optical fiber is taken as a predetermined countermeasure to make the image clear, and the image is maintained in a clear state.