CPC G02B 6/02395 (2013.01) | 10 Claims |
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.
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