US 12,216,309 B2
Optical fiber
Hirotaka Sakuma, Osaka (JP); Yoshiaki Tamura, Osaka (JP); Yuki Kawaguchi, Osaka (JP); and Masato Suzuki, Osaka (JP)
Assigned to SUMITOMO ELECTRIC INDUSTRIES, LTD., Osaka (JP)
Appl. No. 17/754,581
Filed by SUMITOMO ELECTRIC INDUSTRIES, LTD., Osaka (JP)
PCT Filed Oct. 20, 2020, PCT No. PCT/JP2020/039370
§ 371(c)(1), (2) Date Apr. 6, 2022,
PCT Pub. No. WO2021/085236, PCT Pub. Date May 6, 2021.
Claims priority of application No. 2019-198768 (JP), filed on Oct. 31, 2019.
Prior Publication US 2023/0266523 A1, Aug. 24, 2023
Int. Cl. G02B 6/02 (2006.01); C03B 37/012 (2006.01); C03B 37/014 (2006.01)
CPC G02B 6/02395 (2013.01) [G02B 6/02009 (2013.01); C03B 37/01228 (2013.01); C03B 37/01248 (2013.01); C03B 37/014 (2013.01); C03B 2201/12 (2013.01); C03B 2201/20 (2013.01); C03B 2201/50 (2013.01); C03B 2201/54 (2013.01); C03B 2203/02 (2013.01)] 10 Claims
OG exemplary drawing
 
1. An optical fiber formed from silica-based glass, the optical fiber comprising:
a core including a central axis; and
a cladding surrounding the core,
wherein a refractive index of the core is greater than a refractive index of the cladding,
the core contains chlorine, and one or more kinds of elements selected from an element group consisting of alkali metal elements and alkaline earth metal elements,
a relative refractive index difference of the core based on a refractive index of pure silica is 0.00% or greater and 0.15% or less, and
wherein in the cladding, the average concentration of fluorine in a region where a distance from the central axis is one to two times a radius of the core is 1.2% or less in a mass fraction.