Optical fiber

Patent metadata

Field	Value
Publication number	US-11740404-B2
Application number	US-202117339623-A
Country	US
Kind code	B2
Filing date	Jun 4, 2021
Priority date	Dec 13, 2018
Publication date	Aug 29, 2023
Grant date	Aug 29, 2023

Abstract

One embodiment of the present disclosure relates to an optical fiber having lower transmission loss. The optical fiber is an optical fiber comprised of silica-based glass and includes a core including a central axis and a cladding. The cladding surrounds the core and has a refractive index lower than a refractive index of the core. The core contains phosphorus, chlorine, and fluorine. The core further includes an alkali metal element or an alkaline earth metal element. In a cross section of the optical fiber orthogonal to the central axis, a ratio Rp/Ra of a radius Rp of a phosphorus-containing region with respect to a radius Ra of the core is 0.3 or more.

First claim

The invention claimed is:

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.

2. The optical fiber according to claim 1 , wherein
the ratio Rp/Ra is 0.6 or more.

3. The optical fiber according to claim 1 , wherein
the ratio Rp/Ra is 1.0 or more.

4. The optical fiber according to claim 1 , wherein
the ratio Rp/Ra is 1.4 or less.

5. The optical fiber according to claim 1 , wherein
an average mass fraction of the phosphorus contained in the core is 0.005 or more.

6. The optical fiber according to claim 1 , wherein
an average mass fraction of the phosphorus contained in the core is 0.06 or less.

7. The optical fiber according to claim 1 , wherein
an average mass fraction of the alkali metal element or the alkaline earth metal element contained in the core is 0.0002 or less.

8. The optical fiber according to claim 1 , wherein
the alkali metal element or the alkaline earth metal element contained in the core is any one selected from a group of sodium, potassium, rubidium, and cesium, or a combination of two or more selected from the group.

9. The optical fiber according to claim 1 , wherein
a ratio of an average mass fraction of the phosphorus in a range of 0.5 μm on both sides of a core/cladding interface separated from the central axis by the radius Ra with respect to a peak mass fraction of the phosphorus in the phosphorus-containing region is 0.9 or less in the cross section.

10. The optical fiber according to claim 1 , wherein
a ratio of an average mass fraction of the phosphorus in a range of 0.5 μm on both sides of a core/cladding interface separated from the central axis by the radius Ra with respect to a peak mass fraction of the phosphorus in the phosphorus-containing region is 0.8 or less in the cross section.

Assignees

• Sumitomo Electric Industries

Inventors

• Sakuma Hirotaka
• Tamura Yoshiaki
• Kawaguchi Yuki
• Suzuki Masato

Classifications

• G02B6/02395 Primary

  Glass optical fibre with a protective coating, e.g. two layer polymer coating deposited directly on a silica cladding surface during fibre manufacture (G02B6/02052, G02B6/02057, G02B6/024, G02B6/032, G02B6/105, G02B6/14 take precedence; coating on fibre gratings G02B6/02104; multilayer core or cladding G02B6/036; reinforcing splice joints G02B6/2558; optical cables, i.e. comprising protective structures external to the protective coating such as a jacket or plural coated optical fibres G02B6/44; coating of glass to obtain optical fibres C03C25/104) · CPC title

• G02B6/03694 Primary

  Multiple layers differing in properties other than the refractive index, e.g. attenuation, diffusion, stress properties · CPC title

• C03B2201/28

  doped with phosphorus · CPC title

• C03B2201/50

  doped with alkali metals · CPC title

• C03B2201/54

  doped with beryllium, magnesium or alkaline earth metals · CPC title