US 12,404,201 B2
Preform for optical fiber and manufacturing method of optical fiber
Katsuhiro Iwasaki, Nagahama (JP); Qiuyue Piao, Nagahama (JP); and Yusuke Kinoshita, Nagahama (JP)
Assigned to KOHOKU KOGYO CO., LTD., Nagahama (JP)
Appl. No. 18/040,880
Filed by KOHOKU KOGYO Co., Ltd., Nagahama (JP)
PCT Filed Aug. 5, 2021, PCT No. PCT/JP2021/029123
§ 371(c)(1), (2) Date Feb. 7, 2023,
PCT Pub. No. WO2022/030583, PCT Pub. Date Feb. 10, 2022.
Claims priority of application No. 2020-135396 (JP), filed on Aug. 7, 2020.
Prior Publication US 2023/0303421 A1, Sep. 28, 2023
Int. Cl. C03B 19/06 (2006.01); G02B 6/02 (2006.01)
CPC C03B 19/066 (2013.01) [G02B 6/02042 (2013.01); C03B 2201/02 (2013.01); C03B 2203/14 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A method of manufacturing a preform for optical fiber made of a quartz glass sintered body, the method comprising:
a step of mixing a glass raw material solution containing a quartz glass powder, a solvent, a dispersant, and a hardening resin to blend a slurry;
a step of hardening a mixture of the slurry and a hardener in a molding die to form a molded body;
a step of removing the molding die from the molded body;
a step of drying the molded body;
a step of degreasing the molded body after the step of drying;
a step of sintering the molded body after the step of degreasing to obtain the quartz glass sintered body, wherein:
(a) at least a portion of the quartz glass sintered body is an opaque body, the opaque body has a visible light transmittance of 90% or less at a length of 5 mm or less in one direction, and the opaque body has a bulk density of 2.1 g/cm3 or more;
(b) at least a portion of the quartz glass sintered body is an opaque body, the opaque body has a visible light transmittance of 90% or less at a length of 5 mm or less in one direction, and the opaque body has an open porosity of 3.5% or less; or
(c) at least a portion of the quartz glass sintered body is an opaque body, the opaque body has a visible light transmittance of 2.5% or more and 90% or less at a length of 5 mm or less in one direction.