Optical fiber and optical fiber filter

Patent metadata

Field	Value
Publication number	US-2022196908-A1
Application number	US-202117557216-A
Country	US
Kind code	A1
Filing date	Dec 21, 2021
Priority date	Dec 23, 2020
Publication date	Jun 23, 2022
Grant date	—

Abstract

An optical fiber includes a silica-based glass. The optical fiber includes a core, an optical cladding surrounding the core, and a physical cladding surrounding the optical cladding. The optical cladding includes a first region in contact with the core and surrounding the core. A photosensitive material is added to the core and the first region. A concentration of the photosensitive material in the first region is 30% or more of a concentration of the photosensitive material in the core. A value obtained by integrating a light intensity of an LP01 mode at a wavelength of 1310 nm in a region added with the photosensitive material is 87% or more of a value obtained by integrating the light intensity in an entire region of the optical fiber.

First claim

What is claimed is:

1 . An optical fiber including a silica-based glass, comprising:
a core; an optical cladding surrounding the core; and a physical cladding surrounding the optical cladding, wherein the optical cladding includes a first region in contact with the core and surrounding the core, wherein a photosensitive material is added to the core and the first region, wherein a concentration of the photosensitive material in the first region is 30% or more of a concentration of the photosensitive material in the core, and wherein a value obtained by integrating a light intensity of an LP 01 mode at a wavelength of 1310 nm in a region added with the photosensitive material is 87% or more of a value obtained by integrating the light intensity in an entire region of the optical fiber.

2 . The optical fiber according to claim 1 ,
wherein the optical cladding further includes a second region surrounding the first region, and wherein a refractive index of the first region is equal to or higher than a refractive index of the second region.

3 . The optical fiber according to claim 2 , wherein a ratio d 1 /d CO of an outer diameter d 1 of the first region to an outer diameter d CO of the core is 1.5 or more and 3.0 or less.

4 . The optical fiber according to claim 1 , wherein a ratio d CL /d CO of an outer diameter d CL of the optical cladding to an outer diameter d CO of the core is 2.5 or more and 4.5 or less.

5 . The optical fiber according to claim 1 , wherein the photosensitive material is GeO 2 .

6 . The optical fiber according to claim 1 , wherein a relative refractive index difference between the core and the first region is 0.36% or more and less than 0.41%.

7 . The optical fiber according to claim 1 , wherein the core contains fluorine.

8 . The optical fiber according to claim 7 , wherein a fluorine concentration in the core is an amount reducing a relative refractive index by 0.01% or more.

9 . The optical fiber according to claim 1 , wherein the core has a step index type refractive index distribution shape.

10 . An optical fiber filter being provided with periodic refractive index modulation formed along a longitudinal direction in the core of the optical fiber according to claim 1 .

Assignees

• Sumitomo Electric Industries
• Sumitomo Electric Optifrontier Co Ltd

Inventors

• Nagano Shigehiro
• Hasegawa Takemi
• Shigehara Masakazu
• Yamazaki Masayuki

Classifications

• G02B6/02123

  characterised by the method of manufacture of the grating (photolithography G03F7/0005) · CPC title

• G02B6/02119

  Photosensitivity profiles determining the grating structure, e.g. radial or longitudinal · CPC title

• G02B6/021

  characterised by the core or cladding or coating, e.g. materials, radial refractive index profiles, cladding shape · CPC title

• G02B6/02052 Primary

  comprising optical elements other than gratings, e.g. filters (comprising gratings G02B6/02057) · CPC title

• G02B6/03627

  arranged - + · CPC title