Abstract:
An optical fiber for information transmission contains a glass tube core wrapped in a sheath of conductive material attachable to a power source such as a battery or generator to transmit power via the conductive sheath of the fiber. Methods to transmit power via an optical fiber, together with fiber optic networks are described.

Description:
FIELD OF THE DISCLOSURE 
   The present disclosure relates to fiber optic cables, and in particular to fiber optic cable having one or more conductive sheaths around a fiber optic core such that the conductive sheaths are adapted to transmit power along the fiber optic cable. 
   BACKGROUND 
   A fiber optic cable may typically contain a plurality of bundles of optical fibers, each bundle having from dozens to hundreds of optical fibers. Each optical fiber typically has a fiber optic core consisting of a glass tube with refractive properties selected to contain electromagnetic transmissions. Radiating concentrically from the core may be a plurality of layers, often of alternating dielectric and conductive materials, housed in a protective jacket, which forms the exterior concentric layer of the fiber. For example, one layer might consist of a hygroscopic material to exclude water from the cable to keep the cable dry, while another layer might consist of an insulator to protect the cable from electrical surges or lightning hits. 
   Additionally, one or more protective sheaths are often among the layers interior to the jacket. Typically, the purpose of the sheaths is to stiffen the cable so that the cable cannot bend so far as to damage the glass fiber optical core. The sheaths are frequently composed of copper fiber that is suitably disposed around an interior layer. It is not uncommon that one or more sheaths are composed of braided copper wire formed into a tube, when viewed in isolation from the cable. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The detailed description that follows, by way of non-limiting examples of embodiments, makes reference to the noted drawings in which reference numerals represent the same parts throughout the several views of the drawings, and in which: 
       FIG. 1  is a diagrammatic illustration of a fiber optic cable of a specific exemplary embodiment of the present disclosure. 
       FIG. 2  A is an isometric diagrammatic illustration of a fiber optic cable of an alternative specific exemplary embodiment of the present disclosure. 
       FIG. 2  B is a cross-sectional view of the fiber optic cable of  FIG. 2A . 
       FIG. 3A  is a diagrammatic illustration of a fiber optic cable of another alternative specific exemplary embodiment of the present disclosure. 
       FIG. 3B  is an alternative view of the fiber optic cable of  FIG. 3A . 
       FIG. 4  is a diagrammatic illustration of a fiber optic cable of yet another alternative specific exemplary embodiment of the present disclosure. 
       FIG. 5  is a diagrammatic illustration of a fiber optic cable of still another alternative specific exemplary embodiment of the present disclosure. 
       FIG. 6  is a diagrammatic illustration of a fiber optic cable of a further alternative specific exemplary embodiment of the present disclosure. 
       FIG. 7  is a diagrammatic illustration of a specific exemplary embodiment of a network of the present disclosure. 
   

   DETAILED DESCRIPTION 
   In view of the foregoing, through one or more various aspects, embodiments and/or specific features or sub-components, the present disclosure is thus intended to bring out one or more of the advantages that will be evident from the description. The present disclosure makes reference to one or more specific embodiments by way of illustration and example. It is understood, therefore, that the terminology, examples, drawings and embodiments are illustrative and are not intended to limit the scope of the disclosure. 
   Optical fiber cable from a Central Office (CO) to a Service Area Interface (SAI) Optical Line Terminal (OLT) box may have a metallic sheath that can carry current, which may be advantageous when commercial alternating current (AC) is unavailable, for example. As the fiber cable count gets larger, the OFNR (Optical Fiber, Non-conductive, Riser) metallic sheath gets thicker. 
   The metallic sheath may vary in size based, for example, on the amount of fibers in the cable. The presence of thick sheaths of conductive metal in fiber optic cables suggests that a great amount of current may be carried along the fiber optical cable by connecting one or more sheaths to a source of current. Such current may provide continuous Central Office power to areas. For example, power may be provided to an area where FTTP is being deployed but that lacks Commercial AC. Power may also be deployed to SAI mounted boxes. 
     FIG. 1  is a diagrammatic illustration of a fiber optic cable of a specific exemplary embodiment of the present disclosure. The embodiment of  FIG. 1A  represents a fiber optic cable  110  housing a plurality of fiber optic fibers  120 ,  130 . Each fiber  120 ,  130 , has an optical core  122 ,  132 ; jacket  124 ,  134 ; and insulated conductive sheath  126 ,  136 ; respectively. Sheath  126  may carry a current in a first direction  128 . Similarly, sheath  136  may a current in a second direction  138 . For example, direction  128  may represent the “from battery” or anode direction of a voltage or current source whereas direction  138  may represent the “to battery” or cathode direction of the voltage source. Accordingly, by providing a plurality of fibers in a cable, one may readily ascertain that power may be transmitted through the plurality of insulated conductive sheaths  126 ,  136  within the cable  110 . 
     FIG. 2A  is an isometric diagrammatic illustration of a fiber optic cable  240  of an alternative specific exemplary embodiment of the present disclosure and  FIG. 2B  is a cross-sectional view of the fiber optic cable  240  of  FIG. 2A . Optical core  242  and jacket  244  are present as described above in  FIG. 1 . The insulated conductive sheath, however, is subdivided into two or more portions  246   a  and  246   b  by dielectric strips  248   a  and  248   b . Accordingly, current from a voltage source may be carried by a single fiber having one or more split sheaths, rather than by two or more fibers as depicted in  FIG. 1 . It may be readily apparent that the sheath of  FIGS. 2A , B may be effectively subdivided a plurality of times to provide a plurality of currents. 
     FIG. 3A  is a diagrammatic illustration of a fiber optic cable of another alternative specific exemplary embodiment of the present disclosure and  FIG. 3B  is an alternative view of the fiber optic cable of  FIG. 3A . In  FIG. 3A , Jacket  310  is depicted in lateral cross-section to show optical core  320  disposed within jacket  310 . A plurality of sheath fibers  330  is disposed around core  320  to form a sheath. Sheath fibers  330  may be braided or otherwise woven together to form the sheath. One or more sheath fibers  330  may include an insulated conductor to carry current  340 ,  350 .  FIG. 3B  depicts the cable of  FIG. 3A  in a front end vertical cross-section to reveal the arrangement of sheath fibers  330  around core  320 . 
     FIG. 4  is a diagrammatic illustration of a fiber optic cable of yet another alternative specific exemplary embodiment of the present disclosure. Radiating concentrically outward from optical core  410  are layer  420 , sheath  430 , layer  425 , sheath  440  and jacket  450 . Layer  425  may be, for example, a dielectric material or an insulator to electrically isolate sheath  430  from sheath  440 . 
   Current from a voltage source may be carried in direction  460  by insulated conductive sheath  440  and in direction  465  by insulated conductive sheath  430 . Again, a single fiber may carry current in two or more directions. However, rather than providing a plurality of fibers, as shown in  FIG. 1 , or subdividing a single sheath as shown in  FIGS. 1A , B; here a plurality of sheaths in a single fiber may be electrically isolated from each other by arranging them in concentric rings to obtain a comparable result. 
   Also shown in  FIG. 4  is connection portion  455 , which may include an opening in Jacket  450  through which connection may be made between a power source such as battery or a generator and one or more conductive sheaths. 
   A fiber optic cable construction, which may also be capable of power transmission, may contain a plurality of optical fibers that employ any one or more of the described embodiments in any permutation suitable to obtain a desired result. Thus may a fiber optic system intended primarily for information transmission be adapted to be a power transmission line construction as well. 
     FIG. 5  is a diagrammatic illustration of a fiber optic cable of still another alternative specific exemplary embodiment of the present disclosure. A cable of  FIG. 5  may provide portion  510  to carry so-called “stranded wire(s)”  520  and portion  540  to carry one or more fibers. Portion  510  and portion  540  may be connected by messenger portion  530 . Portion  540  may include, for example, tube filling compound  542 , loose tube  544 , cable filling compound  545 , steel tape coated with polyethylene (PE)  546 , and PE jacket  548 . 
     FIG. 6  is a diagrammatic illustration of a fiber optic cable of a further alternative specific exemplary embodiment of the present disclosure. Similar to the embodiment of  FIG. 5 , a cable of  FIG. 6  may provide portion  610  to carry cable(s)  620  and portion  640  to carry fiber(s)  641 . Portion  610  and portion  640  may be connected by messenger portion  630 . Fibers  641  may be disposed around strength member  642  and be covered by tape or sheath  644 . Cable filling compound may fill space  645  and be contained by tube  646 , which in turn is protected by PE jacket  648 . 
     FIG. 7  is a diagrammatic illustration of a specific exemplary embodiment of a network of the present disclosure. The network may include fiber optic cabling  710  containing one or more sheaths adapted to carry power as described above. Cabling  710  may connect two or more components of the network, such as for example CO  720 , OLT  730 , power source  740  connected to one or more insulated sheaths of cable  710 , as described above, SAI  750 , and ONTs  760 ,  762 ,  764  such as residences or office buildings. Power source  740  is depicted generically here, but will be understood to contemplate alternating electric current (AC) source  742  and direct electric current (DC) source  744 . Central Office  720  may include fiber optic tower  722 , disclosed here to provide an example of a source of a fiber optic transmission carried by cable  710 . 
   Although shown in  FIG. 7  as being located exterior to CO  720 , it will be understood that one or more power source  740  may be connected to an insulated conductive sheath of cable  710  at any point, including within CO  720 . Power source  740  may connected to an insulated conductive sheath of the present disclosure by any one of a number of suitable means. By accessing an exposed, uninsulated, portion of the sheath, power source  740  may be connected by clamps, alligator clips, screws, and so forth. 
   OLT  750  may include the optical interfaces to the outside plant, as well as interfaces to the core networks, such as PSTN  724 , ATM, Internet  726  or local media servers. The feeder section of the network, also described as the service area, may include up to 400 homes or buildings. The feeder cable, which may contain dozens to hundreds of fibers, may be aerial or buried along the feeder route. 
   The portion of the network between the feeder and the drop section may be thought of as beginning with the SAI and ending at the end distribution point (EDP). This distribution portion may include the splitters, splitter housings, fiber, conduit, splices and man- or hand-holes. The EDP may include a physical pedestal close to servicing subscriber premises. The drop section may start at the EDP and end at the subscriber. It may include the optical network terminal (ONT) an optical-to-electric (O-E) converter at the subscriber premises. The ONT terminates the fiber, decodes and interprets the signal, and passes the results to different outputs such as voice, data or video. 
   The present disclosure contemplates embodiments in which the conductive material of the insulated conductive sheath (or portion thereof) includes a special conductive material. For example, metal conductors such as copper may include copper that has been doped in the manufacturing process to provide a conductor having specified characteristic. Similarly, certain advantageous metal alloys may be selected for inclusion in the conductive material. 
   The illustrations of embodiments described herein are intended to provide a general understanding of the structure of various embodiments, and they are not intended to serve as a complete description of all the elements and features of apparatus and systems that might make use of the structures described herein. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. Other embodiments may be utilized and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. Figures are merely representational and may not be drawn to scale. Certain proportions thereof may be exaggerated, while others may be minimized. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. 
   Such embodiments of the inventive subject matter may be referred to herein, individually and/or collectively, by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any single invention or inventive concept if more than one is in fact disclosed. Thus, although specific embodiments have been illustrated and described herein, it should be appreciated that any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description. 
   The Abstract of the Disclosure is provided to comply with 37 C.F.R. §1.72(b), requiring an abstract that will allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it can be seen that various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment. 
   The description has made reference to several exemplary embodiments. It is understood, however, that the words that have been used are words of description and illustration, rather than words of limitation. Changes may be made within the purview of the appended claims, as presently stated and as amended, without departing from the scope and spirit of the disclosure in all its aspects. Although description makes reference to particular means, materials and embodiments, the disclosure is not intended to be limited to the particulars disclosed; rather, the disclosure extends to all functionally equivalent technologies, structures, methods and uses such as are within the scope of the appended claims.