Optical fiber

Patent metadata

Field	Value
Publication number	US-9588286-B2
Application number	US-201414897192-A
Country	US
Kind code	B2
Filing date	Jun 6, 2014
Priority date	Jun 10, 2013
Publication date	Mar 7, 2017
Grant date	Mar 7, 2017

Abstract

The optical fiber includes a core, the first cladding, and second cladding. The core is made of silica based glass containing Cl. The first cladding and the second cladding are made of silica based glass containing fluorine. The refractive index of the first cladding is lower than that of the core. The refractive index of the second cladding is lower than that of the core and higher than that of the first cladding. The second cladding is divided into an outer region having a uniform refractive index and an inner region having a refractive index higher than that of the outer region. The difference ΔP between the maximum refractive index of the inner region and the refractive index of the outer region is 0.02% to 0.10% in terms of relative refractive index with respect to pure silica based glass. The radial thickness R of the inner region is 10 μm to 25 μm.

First claim

The invention claimed is:

1. An optical fiber comprising:
a core made of silica based glass containing Cl;
a first cladding that surrounds the core, that has a refractive index lower than a refractive index of the core, and that is made of silica based glass containing fluorine; and
a second cladding that surrounds the first cladding, that has a refractive index lower than the refractive index of the core and higher than the refractive index of the first cladding, and that is made of silica based glass containing fluorine,
wherein the second cladding is divided into an outer region that has a substantially uniform refractive index and an inner region that is located inside of the outer region and that has a refractive index higher than the refractive index of the outer region,
wherein a difference between a maximum refractive index of the inner region and the refractive index of the outer region is 0.02% or greater and 0.10% or smaller in terms of relative refractive index with respect to pure silica glass, and
wherein a radial thickness of the inner region is 10 μm or greater and 25 μm or smaller.

2. The optical fiber according to claim 1 , wherein the difference between the maximum refractive index of the inner region and the refractive index of the first cladding is 0.05% or greater and 0.15% or smaller in terms of relative refractive index with respect to pure silica glass.

Assignees

• Sumitomo Electric Industries

Inventors

• Haruna Tetsuya
• Hirano Masaaki
• Tamura Yoshiaki
• Hikichi Nobuhiro

Classifications

• G02B6/0283

  Graded index region external to the central core segment, e.g. sloping layer or triangular or trapezoidal layer (G02B6/0288, G02B6/0286 take precedence) · CPC title

• G02B6/03644 Primary

  arranged - + - · CPC title

• G02B6/0286

  Combination of graded index in the central core segment and a graded index layer external to the central core segment (G02B6/0288 takes precedence) · CPC title