Optical fiber cable
An optical fiber cable includes: a sheath; and a core that is housed in the sheath and includes optical fibers. Recesses and protrusions are disposed alternately in a circumferential direction on an outer circumferential surface of the sheath. The optical fiber cable has a compressive strength of 12.8 N/mm 2 or greater and 32.4 N/mm 2 or less.
1 . An optical fiber cable comprising:
a sheath; and
a core that is housed in the sheath and comprises optical fibers,
wherein recesses and protrusions are disposed alternately in a circumferential direction on an outer circumferential surface of the sheath, and the optical fiber cable has a compressive strength of 12.8 N/mm 2 or greater and 32.4 N/mm 2 or less.
2 . The optical fiber cable according to claim 1 , wherein the recesses each comprise:
two connecting portions respectively connected to radial inner ends of two adjacent protrusions; and
a bottom surface positioned between the two connecting portions.
3 . The optical fiber cable according to claim 2 , wherein the two connecting portions have a convex surface shape that is radially inward.
4 . The optical fiber cable according to claim 1 , wherein the core further comprises a wrapping tube that wraps the optical fibers.
5 . The optical fiber cable according to claim 4 , wherein the wrapping tube comprises:
a wrap portion where a first end portion of the wrapping tube overlaps with a second end portion of the wrapping tube; and
a non-wrap portion positioned between the first end portion and the second end portion.
6 . The optical fiber cable according to claim 5 , wherein
a wrap rate R of the optical fiber cable is calculated as R=W 1 ÷(W 1 +W 2 )×100, where W 1 is a circumferential length of the wrap portion and W 2 is a circumferential length of the non-wrap portion, and
the wrap rate R is 5% or greater and 20% or less.
7 . The optical fiber cable according to claim 1 , wherein in a transverse cross-sectional view, a cross-sectional area of the recesses that is enclosed by closed curves tangent to radial outer ends of the protrusions and all the recesses is 1.3 mm 2 or greater and 4.8 mm 2 or less.
8 . The optical fiber cable according to claim 1 , wherein a twist angle of the sheath per 1 m along a longitudinal direction of the optical fiber cable is 10 degrees/m or greater and 180 degrees/m or less.
9 . The optical fiber cable according to claim 1 , wherein a radius of curvature of each outer circumferential surface of the protrusions is smaller than a radius of the sheath.
10 . The optical fiber cable according to claim 1 , further comprising: tensile strength members embedded inside the protrusions on the sheath, wherein
the protrusions and the tensile strength members have a spirally twisted shape centered on a central axis of the optical fiber cable.
11 . The optical fiber cable according to claim 1 , further comprising: tensile strength members embedded inside the protrusions on the sheath, wherein the tensile strength members are made of poly-paraphenylene benzobisoxazole fiber reinforced plastics (PBO-FRP).
12 . The optical fiber cable according to claim 1 , further comprising: tensile strength members embedded in the sheath, wherein in a transverse cross-sectional view, the tensile strength members are disposed inside each of the protrusions on the sheath.
13 . The optical fiber cable according to claim 1 , wherein an SZ-shaped twist is applied to the sheath by twisting the optical fibers in an SZ shape.
14 . The optical fiber cable according to claim 1 , wherein the sheath comprises:
a base material; and
a low friction material having a friction coefficient smaller than a friction coefficient of the base material, and
the low friction material is disposed at least on tops of the protrusions.
15 . The optical fiber cable according to claim 1 , further comprising:
tensile strength members and ripcords embedded in the sheath, wherein
in a transverse cross-sectional view,
the ripcords are disposed inside some of the protrusions, and
the tensile strength members are disposed inside the remaining protrusions.
16 . The optical fiber cable according to claim 1 , wherein the optical fibers are included in an intermittently-adhered optical fiber ribbon such that adhesive portions of the intermittently-adhered optical fiber ribbon intermittently adhere the optical fibers together in a longitudinal direction.
17 . The optical fiber cable according to claim 1 , further comprising: members embedded in the sheath, wherein a number of the members is 8 or more and 12 or less.
18 . The optical fiber cable according to claim 17 , wherein the members include tensile strength members.
19 . The optical fiber cable according to claim 17 , wherein a number of the protrusions is equal to a number of the members.
20 . The optical fiber cable of claim 17 , wherein the number of protrusions does not match the number of members.
21 . The optical fiber cable of claim 17 , wherein the number of protrusions is greater than the number of members.
22 . The optical fiber cable of claim 1 , wherein in a transverse cross-sectional view, a cross-sectional area of the recesses that is enclosed by closed curves tangent to radial outer ends of the protrusions and all the recesses is 2.8 mm 2 or greater and 4.8 mm 2 or less.
23 . The optical fiber cable of claim 1 , wherein in a transverse cross-sectional view, a cross-sectional area of the recesses that is enclosed by closed curves tangent to radial outer ends of the protrusions and all the recesses is 3.4 mm 2 or greater and 4.8 mm 2 or less.
24 . An optical fiber cable comprising:
a sheath;
at least one tensile member embedded in the sheath; and
a core that is housed in the sheath and comprises optical fibers,
wherein:
recesses and protrusions are disposed alternately in a circumferential direction on an outer circumferential surface of the sheath, and
the optical fiber cable has a compressive strength of 12.8 N/mm 2 or greater and 32.4 N/mm 2 or less.