Optical fiber
AssigneeFurukawa Electric Co., Ltd.
InventorsKazunori Mukasa, Keiichi Aiso
Life of this patent
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Abstract
An optical fiber includes a core portion made of silica-based glass; and a cladding portion made of silica-based glass having lower maximum refractive index than the core portion, the cladding portion surrounding an outer periphery of the core portion. The core portion is doped with an alkali metal element and chlorine. An average concentration of chlorine is higher than 800 atomic ppm on a cross-section perpendicular to a longitudinal direction of the core portion. A region doped with the alkali metal element is larger than a region doped with chlorine at 800 atomic ppm or higher.
Claims17
An optical fiber comprising:
- a core portion made of silica-based glass;
- and
- a cladding portion made of silica-based glass having a maximum refractive index lower than the core portion, the cladding portion surrounding an outer periphery of the core portion, wherein the core portion is doped with an alkali metal element and chlorine,
- an average concentration of the chlorine is higher than 900 atomic ppm and lower than 3000 atomic ppm on a cross-section of the core portion perpendicular to a longitudinal direction, and a region of the core portion doped with the alkali metal element is larger than a region of the core portion having a chlorine concentration of 800 atomic ppm or higher,
- a ratio of a diameter of a substantially circular region doped with the alkali metal element to a diameter of a substantially circular region of the core portion having a chlorine concentration of 800 atomic ppm or higher is greater than 1.0,
- the substantially circular region doped with the alkali metal element and the substantially circular region of the core portion having a chlorine concentration of 800 atomic ppm or higher are centered at a center of the core portion, and
- an average concentration of the alkali metal element is equal to or higher than 10 atomic ppm and equal to or lower than 100 atomic ppm.
Dependencies are inferred from the claim text.