US 11,740,404 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)
Filed by SUMITOMO ELECTRIC INDUSTRIES, LTD., Osaka (JP)
Filed on Jun. 4, 2021, as Appl. No. 17/339,623.
Application 17/339,623 is a continuation of application No. PCT/JP2019/045675, filed on Nov. 21, 2019.
Claims priority of application No. 2018-233536 (JP), filed on Dec. 13, 2018.
Prior Publication US 2021/0294028 A1, Sep. 23, 2021
Int. Cl. G02B 6/02 (2006.01)
CPC G02B 6/02395 (2013.01) 10 Claims
OG exemplary drawing
 
1. An optical fiber comprised of silica-based glass, the optical fiber comprising:
a core including a central axis; and a cladding surrounding the core and having a refractive index lower than a refractive index of the core, wherein
the core contains phosphorus, chlorine, and fluorine, the core containing an alkali metal element or an alkaline earth metal element, and
a phosphorus-containing region containing the phosphorus is set in such a manner that a ratio Rp/Ra of a radius Rp of the phosphorus-containing region with respect to a radius Ra of the core is 0.3 or more, in a cross section of the optical fiber orthogonal to the central axis.