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US 12,663,578 B2Granted
Optical fiber cable
AssigneeFujikura Ltd.
InventorsMiku Miyata, Akira Murata
Life of this patent
Estimating the term…
Abstract
An optical fiber cable includes: optical fibers each including a glass portion including a core and a cladding surrounding the core, a primary covering layer covering the cladding, and a secondary covering layer covering the primary covering layer; and a sheath accommodating the optical fibers in an internal space. A value of a micro-bend loss characteristic factor FμBL_GΔβ is 1.2×10−9 or less when represented by FμBL_GΔβ=FμBL_G×FμBL_Δβ×Dc.
Claims14
An optical fiber cable comprising:
- ribbons in which optical fibers are intermittently bonded with resin along a longitudinal direction;
- and
- a sheath accommodating the ribbons in an internal space,
- wherein each of the optical fibers comprises:
- a glass portion including a core and a cladding surrounding the core;
- a primary covering layer that covers the cladding of the glass portion;
- and
- a secondary covering layer that covers the primary covering layer,
- wherein a value of a micro-bend loss characteristic factor FμBL_GΔβ is 1.2×10−9 or less when represented by
- FμBL_GΔβ=FμBL_G×FμBL_Δβ×DC
- where FμBL_G (Pa−1·m−10.5) is a geometry micro-bend loss characteristic of each optical fiber represented by
- F
-
- μ
-
- BL
-
- _
-
- G
- =
- Ks
- 2
- H
- f
- 2
- ×
- D
- o
- 0.375
- ×
- H
- o
- 0.625
- Ks
- =
- E
- p
-
- d
- f
- t
- p
- ,
- H
- f
- =
- π
- 4
-
- E
- g
- (
- d
- f
- 2
- )
- 4
- ,
- D
- o
- =
- E
- p
- +
- (
- t
- s
- R
- s
- ×
- 2
- )
- 3
-
- E
- s
- ,
- H
- o
- =
- π
- 4
-
- E
- s
- (
- R
- s
- 4
- -
- R
- p
- 4
- )
- ,
- where
- Hf (Pa·m4) is a flexural rigidity of the glass portion,
- D0 (Pa) a is a deformation resistance of the secondary covering layer,
- H0 (Pa·m4) a is a flexural rigidity of the secondary covering layer,
- Eg (GPa) a is a Young's modulus of the glass portion,
- Ep (MPa) is a Young's modulus of the primary covering layer,
- Es (MPa) is a Young's modulus of the secondary covering layer,
- df (μm) is an outer diameter of the glass portion,
- Rp (μm) is a radius of an outer circumferential surface of the primary covering layer,
- Rs (μm) is a radius of an outer circumferential surface of the secondary covering layer,
- tp (μm) is a thickness of the primary covering layer, and
- ts (μm) is a thickness of the secondary covering layer,
- FμBL_Δβ (1/(rad/m)8) is an optical micro-bend loss characteristic of each optical fiber represented by
- F
-
- μ
-
- BL
-
- _△
-
- β
- =
- 1
- (
- △β
- )
- 8
- ,
- where a propagation constant difference Δβ (rad/m) is a difference between a propagation constant in a guided mode of light propagating through each optical fiber and a propagation constant in a radiation mode, and
- Dc is a cable characteristic of the optical fiber cable represented by
- Dc=(0.5−a)2/b,
- where a is a porosity of the internal space and b is a number of cores of the optical fibers accommodated in the internal space,
- wherein
- the outer diameter df of the glass portion is 80 (μm) or more and 90 (μm) or less, and
- the porosity of the internal space is 0.31 or more and 0.42 or less.
129 more elements
Dependencies are inferred from the claim text.