US 6,236,789 B1Granted

Composite cable for access networks

AssigneePirelli Cables and Systems LLC

InventorJonathan G. Fitz

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Abstract

A composite cable for conveying electrical energy and optical signals from a source or sources thereof to electrically energized units which process the optical signals. The cable has one or more buffer tubes, each buffer tube encircling at least two optical fibers for supplying optical signals to at least two of the units, each unit having electrical current and voltage requirements. The cable has a layer of S-Z stranded electrically insulated conductors around the buffer tube or tubes, and pairs of conductors are selected in size to safely supply the current and voltages required by at least two units. The number of pairs of conductors is less than the number of active optical fibers which excludes conductor spares. Preferably, the buffer tubes are S-Z stranded. The cable also includes a strength member and an outer plastic jacket encircling the buffer tubes, the conductors and the strength member.

Claims26

Dependent claims

A composite cable for conveying electrical energy and optical signals to a plurality of electrically energized units which process the optical signals, each of said units having predetermined electrical current and predetermined voltage requirements, the cable having a longitudinal axis and comprising:

at least one longitudinally extending plastic buffer tube loosely containing at least one optical fiber for optical signal service to at least two of said electrically energized units, wherein the number of optical fibers is at least two;
at least one longitudinally extending layer of a plurality of insulated electrical conductors, wherein said conductors are S-Z stranded in side-by-side relation around said buffer tube to provide a layer of conductors having a radial thickness substantially equal to the thickness of a conductor, wherein a pair of said conductors has a resistance selected so that when the sum of the predetermined current for two of said electrically energized units flows therein, the voltage drop along said pair of conductors satisfies said predetermined voltage, wherein said pair of conductors has a safe current carrying capacity for the current required by said at least two of said electrically energized units and wherein the number of pairs of conductors is less than the number of optical fibers;
a plastic jacket encircling the layer of conductors;
and
at least one strength member extending longitudinally of said cable and disposed inwardly of the outer surface of said jacket.

2 more elements

An optical fiber communication system comprising:

a plurality of electrically energized units for processing optical signals, each of said units having predetermined electrical current and a predetermined electrical voltage requirements for operation in the processing of optical signals and having an electrical input and at least one optical signal conveying element;
a composite cable having a longitudinal axis and having electrical conductors for supplying electrical current at said predetermined voltage from an electrical source to a plurality of said units and having optical fibers for conveying optical signals between said units and other optical signal processing units, wherein said composite cable comprises:
a plurality of longitudinally extending optical fibers loosely received in at least one longitudinally extending buffer tube;
a plurality of longitudinally extending insulated electrical conductors disposed in side-by-side relation and S-Z stranded around the buffer tube or tubes;
a plastic jacket encircling the plurality of electrical conductors;
and
at least one longitudinally extending strength member within said jacket
wherein at least one pair of said electrical conductors is coupled to the electrical inputs of a plurality of said units and each conductor has a resistance and size to provide the predetermined electrical current and predetermined electrical voltage required by the last-mentioned said plurality of units without overheating;
and
wherein a plurality of said optical fibers is coupled to the optical signal conveying elements of the plurality of units to which said electrical conductors are coupled, the number of optical fibers coupled to the last-mentioned plurality of units being greater than the number of pairs of electrical conductors coupled to the electrical inputs of the last-mentioned said plurality of units.

7 more elements

Dependencies are inferred from the claim text.