Optical fiber cable including a plurality of multifiber units within a single tube and methods of making
First Claim
1. An optical fiber cable, which comprises:
- a core which comprises a plurality of units, each of the units comprising a plurality of optical fibers which are assembled together without intended stranding to form said each unit which extends along the cable and a binder wrapped about the unit;
a single tube which is made of a plastic material and which encloses the plurality of units with the ratio of the cross-sectional area of the plurality of optical fibers to the cross-sectional area within the tube not exceeding a predetermined value, said tube being substantially parallel to the longitudinal axis of the cable;
a waterblocking material which is disposed within the tube and which fills substantially the interstices between the optical fibers and between the units and the tube, the waterblocking material having a critical yield stress and a shear modulus which allows movement of the units within the core when the waterblocking material is subjected to a predetermined stress;
a strength member; and
a jacket which encloses said tube and which is made of a plastic material.
5 Assignments
0 Petitions
Accused Products
Abstract
An optical fiber cable (20) includes a core (21) comprising a plurality of units (22--22). Each unit is formed by a plurality of optical fibers (24--24) which are assembled together without intended stranding. The plurality of units are enclosed in a common tube (34) which provides a predetermined packing density and which is substantially parallel to the longitudinal axis of the cable. In one embodiment, a waterblocking material (36) is disposed within the tube to fill the interstices between the optical fibers and between the units. The waterblocking material is such that its critical yield stress does not exceed about 70 Pa at 20° C. and such that it has a shear modulus of less than about 13 KPa at 20° C. The common tube is enclosed with non-metallic or metallic strength members and a plastic inner jacket and by another layer of strength members and by a plastic outer jacket. This arrangement is such that the cable may be manufactured and installed with the optical fibers capable of moving within the cable structure to prevent undue stresses being imparted thereto which would cause unwanted microbending losses.
83 Citations
22 Claims
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1. An optical fiber cable, which comprises:
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a core which comprises a plurality of units, each of the units comprising a plurality of optical fibers which are assembled together without intended stranding to form said each unit which extends along the cable and a binder wrapped about the unit; a single tube which is made of a plastic material and which encloses the plurality of units with the ratio of the cross-sectional area of the plurality of optical fibers to the cross-sectional area within the tube not exceeding a predetermined value, said tube being substantially parallel to the longitudinal axis of the cable; a waterblocking material which is disposed within the tube and which fills substantially the interstices between the optical fibers and between the units and the tube, the waterblocking material having a critical yield stress and a shear modulus which allows movement of the units within the core when the waterblocking material is subjected to a predetermined stress; a strength member; and a jacket which encloses said tube and which is made of a plastic material. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An optical fiber cable, which comprises:
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a core comprising a plurality of units with each of said units comprising a plurality of optical fibers which are assembled together without intended stranding and wrapped with a binder to form a unit that extends in a direction substantially along a longitudinal axis of the cable; a tube which is made of a plastic material and which is disposed commonly about the plurality of units without each of said units being enclosed individually with a tube and with the ratio of the cross-sectional area of the pluralities of optical fibers of said plurality of units to the cross-sectional area within the tube not exceeding a predetermined value, said tube being substantially parallel to the longitudinal axis of the cable; a strength member; and a jacket which is made of a plastic material and which encloses said tube. - View Dependent Claims (11)
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12. An optical fiber cable, which comprises:
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a unit which comprises a plurality of optical fibers which are assembled together without intended stranding and held together to form said unit which extends in a direction substantially along a longitudinal axis of the cable, said unit also including a binder for holding together said fibers of said unit; a tube which is made of a plastic material and which encloses said unit with the ratio of the cross-sectional area of the plurality of optical fibers to the cross-sectional area within the tube not exceeding a predetermined value, said tube being substantially parallel to the longitudinal axis of the cable; a waterblocking material which is disposed within the tube and which fills substantially the interstices between the optical fibers and between the unit and the tube, the waterblocking material having a critical yield stress and a shear modulus which allow movement of the unit within the core when the waterblocking material is subjected to a predetermined stress; a strength member; and a jacket which is made of a plastic material and which encloses said tube.
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13. A method of making an optical fiber cable, said method including the steps of:
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assembling a plurality of optical fibers without intended stranding to form a core comprising a unit; causing a plurality of the units to be advanced along a path of travel; providing a sheath system which is accomplished to enclose the plurality of units, said step of providing including the steps of; enclosing the plurality of units in a common tube of a plastic material which is disposed about the units and which is substantially parallel to a longitudinal axis of the cable, the step of enclosing being such that the ratio of the cross-sectional area of the optical fibers to the cross-sectional area within the tube does not exceed a predetermined value and such that each of said units is enclosed only by material which encloses the plurality of the units; causing a strength system comprising a plurality of strength members to be disposed about the tube; and extruding a plastic covering about the strength members. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification