Optical fiber

Patent metadata

Field	Value
Publication number	US-11048039-B2
Application number	US-201916956131-A
Country	US
Kind code	B2
Filing date	Feb 1, 2019
Priority date	Feb 13, 2018
Publication date	Jun 29, 2021
Grant date	Jun 29, 2021

Abstract

An optical fiber includes: a core; a depressed layer surrounding the core; and a cladding surrounding the depressed layer. A refractive index profile of the core is an α-th power distribution having an index α of 1.0 or more and 2.9 or less. A relative refractive index difference Δ− of the depressed layer with respect to the cladding has an absolute value |Δ−| that is 0.05% or more and 0.15% or less. A ratio r1/r2 of a radius r1 of the core to an outer radius r2 of the depressed layer is 0.35 or more and 0.60 or less. A cable cutoff wavelength λcc of 22 m is less than 1.26 μm. A mode field diameter at a wavelength of 1.31 inn is larger than 8.6 inn and smaller than 9.5 μm.

First claim

What is claimed is:

1. An optical fiber comprising:
a core;
a depressed layer surrounding the core; and
a cladding surrounding the depressed layer,
wherein a refractive index profile of the core is an α-th power distribution having an index α of 1.0 or more and 2.9 or less,
wherein a relative refractive index difference Δ − of the depressed layer with respect to the cladding has an absolute value |Δ − | that is 0.05% or more and 0.15% or less,
wherein a ratio r1/r2 of a radius r1 of the core to an outer radius r2 of the depressed layer is 0.35 or more and 0.60 or less,
wherein a cable cutoff wavelength λcc of 22 m is less than 1.26 μm,
wherein a mode field diameter at a wavelength of 1.31 μm is larger than 8.6 μm and smaller than 9.5 μm and
wherein the index α is obtained by calculating the α-th power distribution that minimizes a square error of an actual refractive index profile n′(r) of the optical fiber in a range of 0 ≤r≤r0,
where r is a distance from a central axis of the optical fiber, and r0 is a radius of the optical fiber for obtaining a minimum value of a first order differential dn′(r)/dr of n′(r).

2. The optical fiber according to claim 1 ,
wherein the ratio r1/r2 is 0.40 or more and 0.60 or less.

3. The optical fiber according to claim 1 ,
wherein a loss increase at a wavelength of 1.55 μm is less than 0.03 dB when the optical fiber is wound 10 times around a cylindrical mandrel with a radius of 15 mm,
wherein a loss increase at a wavelength of 1.625 μm is less than 0.1 dB when the optical fiber is wound 10 times around a cylindrical mandrel with a radius of 15 mm,
wherein a loss increase at a wavelength of 1.55 μm is less than 0.1 dB when the optical fiber is wound once around a cylindrical mandrel with a radius of 10 mm, and
wherein a loss increase at a wavelength of 1.625 μm is less than 0.2 dB when the optical fiber is wound once around a cylindrical mandrel with a radius of 10 mm.

4. The optical fiber according to claim 1 ,
wherein any one condition is satisfied from the group consisting of:
a value of a zero dispersion wavelength ZDW is 1.305 μm or more and 1.319 μm or less;
a value of a zero dispersion slope is 0.092 ps/km/nm 2 or less; and
a value of chromatic dispersion at a wavelength of 1.55 μm is 18.00 ps/km/nm or less.

5. The optical fiber according to claim 1 ,
wherein the index α is 1.0 or more and 2.2 or less, and the absolute value |Δ − | is 0.08% or more and 0.15% or less.

6. The optical fiber according to claim 5 ,
wherein a loss increase at a wavelength of 1.55 μm is less than 0.03 dB when the optical fiber is wound 10 times around a cylindrical mandrel with a radius of 15 mm,
wherein a loss increase at a wavelength of 1.625 μm is less than 0.1 dB when the optical fiber is wound 10 times around a cylindrical mandrel with a radius of 15 mm,
wherein a loss increase at a wavelength of 1.55 μm is less than 0.1 dB when the optical fiber is wound once around a cylindrical mandrel with a radius of 10 mm,
wherein the loss increase at a wavelength of 1.625 μm is less than 0.2 dB when the optical fiber is wound once around a cylindrical mandrel with a radius of 10 mm,
wherein the loss increase at a wavelength of 1.55 μm is less than 0.5 dB when the optical fiber is wound once around a cylindrical mandrel with a radius of 7.5 mm, and
wherein the loss increase at a wavelength of 1.625 μm is less than 1.0 dB when the optical fiber is wound once around a cylindrical mandrel with a radius of 7.5 mm.

7. The optical fiber according to claim 1 ,
wherein the ratio r1/r2 is 0.40 or more and 0.55 or less.

8. The optical fiber according to claim 1 ,
wherein the mode field diameter at a wavelength of 1.31 μm is 8.8 μm or more and 9.2 μm or less.

Assignees

• Fujikura Ltd

Inventors

• Maruyama Ryo

Classifications

• G02B6/03627

  arranged - + · CPC title

• G02B6/02004

  characterised by the core effective area or mode field radius · CPC title

• G02B6/0228

  Characterised by the wavelength dispersion slope properties around 1550 nm (G02B6/02228 takes precedence) · CPC title

• G02B6/02266

  Positive dispersion fibres at 1550 nm · CPC title

• G02B6/0281 Primary

  Graded index region forming part of the central core segment, e.g. alpha profile, triangular, trapezoidal core (G02B6/0288, G02B6/0286 take precedence) · CPC title