Optical fiber cable

Patent metadata

Field	Value
Publication number	US-10514517-B2
Application number	US-201615748810-A
Country	US
Kind code	B2
Filing date	Jul 22, 2016
Priority date	Jul 31, 2015
Publication date	Dec 24, 2019
Grant date	Dec 24, 2019

Abstract

Provided is an optical fiber cable whereby macrobend loss can be suppressed even when ribbons are mounted at high density in grooves. An optical fiber cable provided with optical units in which ribbons each having a plurality of optical fiber cores arranged in parallel are collected, a slot rod having a plurality of grooves for accommodating optical units, a tension member on which tension is applied, and a cable jacket for covering the outside of the slot rod. Each of the optical units is accommodated in the corresponding groove in a stranded state, and the occupancy of the optical units calculated from the cross-sectional area of the optical units with respect to the cross-sectional area of the groove is 25% to 65%.

First claim

The invention claimed is:

1. An optical fiber cable comprising:
optical units in each of which ribbons each having a plurality of optical fibers arranged in parallel are collected;
a slot rod having a plurality of grooves each configured to accommodate therein the optical units;
a tension member to which tension is to be applied; and
a cable sheath configured to cover an outer side of the slot rod,
wherein in each of the grooves, the optical units are accommodated in a state where each of the optical units is stranded, and an occupancy of the optical units calculated from a cross-sectional area of the optical units relative to a cross-sectional area of the groove is 25% to 65%,
wherein each ribbon is intermittently provided with coupling portions, at which the adjacent optical fibers are coupled therebetween, and non-coupling portions, at which the adjacent optical fibers are not coupled therebetween, in a longitudinal direction between some or all of the optical fibers in a state where the plurality of optical fibers is arranged in parallel, and
wherein when an intermittent pitch of each ribbon in the longitudinal direction is denoted as P 1 , a stranding pitch of each optical unit is denoted as P 2 , and a stranding pitch of the slot rod is denoted as P 3 , a relation of 2.5≤P 2 /P 1 ≤7.5 is satisfied, and a composite stranding pitch Pmix expressed by 1/Pmix=1/P 2 +1/P 3 is 398 or smaller.

2. The optical fiber cable according to claim 1 , wherein when two adjacent optical fibers of each ribbon are configured as one sub-unit, at least one of a recess portion and a step portion positioned between adjacent sub-units is intermittently provided with a slit portion in a longitudinal direction.

3. The optical fiber cable according to claim 1 , wherein each ribbon is continuously provided with the coupling portions in the longitudinal direction between the adjacent optical fibers of both ends thereof.

4. The optical fiber cable according to claim 1 , wherein a coupling length of the coupling portion positioned at a more inner side in an aligning direction of each ribbon is longer than a coupling length of the coupling portion positioned at an outermore side.

5. The optical fiber cable according to claim 1 , wherein each ribbon is an optical fiber ribbon having 2N (N: an integer of 3 or greater) optical fibers, a sub-unit is integrated every M (M: an even number smaller than N) optical fibers, coupling portions and non-coupling portions are intermittently provided in a longitudinal direction between adjacent sub-units, the adjacent sub-units are coupled and a part at which the 2M optical fibers are coupled is one part or less.

6. The optical fiber cable according to claim 1 , wherein the ribbons to be accommodated in the same groove of the slot rod have at least two types of intermittent pitches.

7. The optical fiber cable according to claim 1 , wherein integrated ribbon parts in which the plurality of optical fibers is all coupled by the coupling portions and slitted ribbon parts in which the non-coupling portions adjacent to each other in an aligning direction of each ribbon are alternately arranged in a longitudinal direction of each ribbon are periodically provided in the longitudinal direction of each ribbon, and the slitted ribbon parts are configured to form single fiber ribbon parts, which are to be obtained by separating all the plurality of optical fibers with the non-coupling portions.

8. The optical fiber cable according to claim 1 , wherein a minimum thickness part of a rib configured to partition the respective grooves of the slot rod is positioned at an outermore side than a half circumferential portion of a diameter of a slot rod circumscribed circle of which a center is the tension member, and a rib thickness increases from the minimum thickness part toward a rib tip end.

9. The optical fiber cable according to claim 1 , wherein a stranding pitch of each optical unit is shorter than a stranding pitch of each respective groove.

10. The optical fiber cable according to claim 1 , wherein each groove is configured by a combination of an SZ locus of a short period and an SZ locus of a period longer than the short period.

Assignees

• Sumitomo Electric Industries

Inventors

• Sato Fumiaki
• Okada Keisuke
• Nagao Yoshiaki
• Tsuchiya Kenta
• Suzuki Nobuyuki

Classifications

• H01B7/08

  Flat or ribbon cables · CPC title

• G02B6/441

  built up from sub-bundles (G02B6/4429, G02B6/4439, G02B6/4479 take precedence) · CPC title

• G02B6/4432

  with fibre reinforcements · CPC title

• G02B6/448

  Ribbon cables · CPC title

• G02B6/4408

  Groove structures in support members to decrease or harmonise transmission losses in ribbon cables · CPC title