Patent ID: 11971571
Assignee: SUMITOMO ELECTRIC INDUSTRIES, LTD.
Field: Materials, metallurgy (Chemistry)
Classification: CPC G  C | IPC G

Claim 0:
1. An optical fiber comprising:
a glass part extending in a direction of a central axis, wherein
the glass part is comprised of silica-based glass, includes a core and a cladding, and has residual stress approximately uniform throughout a cross section of the glass part orthogonal to the central axis, the core having the central axis and being doped with chlorine having a mass fraction of 1%, or more, the cladding surrounding the core and having a refractive index lower than a maximum refractive index of the core,
in the cross section of the glass part, an average value of residual stress in a region where a distance from a center of the cross section in a radial direction is 50 μm or more and 62.5 μm or less is lower than an average value of residual stress in a region where the distance from the center of the cross section in the radial direction is 45 μm or more and 55 μm or less, and
the average value of residual stress in the region where the distance from the center of the cross section in the radial direction is 45 μm or more and 55 μm or less is negative,
whereby the greater a value obtained by subtracting the average value of residual stress in the region where the distance from the center of the cross section in the radial direction is 55 μm or more and 62.5 μm or less from the average value of residual stress in the region where the distance from the center of the cross section in the radial direction is 45 μm or more and 55 μm or less, the lower a transmission loss.