Abstract:
Networks may include optical cables to transmit data between various devices in the network. Indicators positioned on or within optical cables may be used to identify cables that have been compromised during installation, movement and/or use of the cables. Indicators may reduce a network downtime by decreasing the time needed to identify compromised cables. In some embodiments, indicators may change color and/or emit light to indicate that an optical cable has been compromised.

Description:
BACKGROUND  
         [0001]    1. Field of the Invention  
           [0002]    This invention relates to the field of optical cables, and more particularly to identifying failed, compromised or damaged optical cables.  
           [0003]    2. Description of Related Art  
           [0004]    Networks and/or computer systems rely on various types of cables to transmit data between components. Cables used in such systems may include, but are not limited to optical cables and/or copper cables. Optical cables may increase transmission rates between components. In some embodiments, a transmission rate of an optical cable may be greater than about a gigabit per second. Optical cables may also be used in other fields such as telecommunications (e.g., phone lines, cable lines), medical imaging (e.g., endoscopes, laparoscopes, and/or bronchoscopes), mechanical imaging (e.g., inspecting mechanical welds), and/or plumbing.  
           [0005]    Optical cables may include a core of optical fibers. Optical fibers may include long, thin strands of relatively pure glass. The thickness of the glass may be equal to about the thickness of human hair. Cladding and/or housings may be used to inhibit damage to the optical fibers from various external elements including, but not limited to, moisture, loads, and/or stress due to bending. For example, during installation, use, and/or movement, cables may be compromised due to stress induced by bending the cable. Transmission of data through a compromised cable may be inhibited or may fail. For example, a compromised cable may have been clamped, constrained or bent to the point where the surface or core of an optical fiber has split or cracked. Even a cut or nick on the surface of an optical fiber or a hairline crack may lead to transmission errors.  
           [0006]    Quick and accurate troubleshooting of compromised cables may minimize transmission delays or loss. Many challenges are presented during troubleshooting of compromised fiber optic cables. For example, cables may lack any visual identification of having been compromised. In many systems, multiple fiber optic cables may be routed together. Identifying the compromised cable may involve replacing cables one at a time. Testing may be performed after cable changes to ensure proper installation. In many instances, one or more cables may be replaced and tested before a compromised cable is identified. Thus, cables that are functioning properly may needlessly be replaced and tested. The cost of rework or replacement is often significant.  
         SUMMARY  
         [0007]    In an embodiment, optical cables may include an indicator that is activated when a portion of the optical fiber is compromised. For example, the optical cable may be compromised if a portion of the cable bends beyond a maximum bend radius of the cable. In some embodiments, the indicator may include two conduits, one positioned within the other. Each conduit may contain a fluid. Bending the cable beyond the maximum bend radius may allow the fluids to mix, thereby activating the indicator. The indicator may consist of a color change within the fluids and/or the emission of light from the fluids.  
           [0008]    An embodiment may include a plurality of cables having indicators coupled to two or more devices within a network. If a cable within the network is compromised then it can be identified by the activation of the indicator. For example, color change and/or emission of light within the cable may allow for identification of the compromised cable.  
           [0009]    In one embodiment, a cable system may include an optical fiber having a maximum bend radius and an indicator coupled to the optical fiber. The indicator may be activated after a portion of the optical fiber has exceeded the maximum bend radius of the optical fiber. In one embodiment, a cable system including an optical fiber may have a first conduit having a first fluid coupled to the optical fiber and a second conduit having a second fluid. The second conduit may be postionable within the first conduit and allow the first fluid and the second fluid to mix if a portion of the optical fiber has been compromised.  
           [0010]    In one embodiment, a network system may include one or more cables. One of the one or more cables may include a first conduit containing a first fluid, a second conduit containing a second fluid and an indicator configured to be activated if a portion of the cable is compromised. The network system may include at least two network devices. One of the network devices may be coupled to another using the cable.  
           [0011]    In one embodiment, a method may include monitoring a network system that connects components via a plurality of optical cables, each optical cable including a respective indicator. Each indicator may be configured to be activated if a portion of its respective cable is compromised. The method may include detecting a transmission error within the network system and locating one or more of the optical cables having an activated indicator. The one or more of the optical cables having an activated indicator may be replaced.  
           [0012]    The embodiments described above include optical cables. Some embodiments may include copper or other types of cables as a transmission media. A copper cable, multi-fiber copper cable, or other type of cable may include an indicator that activates if the cable is compromised. In some embodiments, the indicator may change color and/or emit light.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    [0013]FIG. 1 illustrates one embodiment of optical cables as physical transmission media for a storage network.  
         [0014]    [0014]FIG. 2 illustrates one embodiment of optical cables as physical transmission media for a telecommunications network.  
         [0015]    [0015]FIG. 3 illustrates an optical cable including an indicator that may activate if the optical cable is compromised, according to one embodiment.  
         [0016]    [0016]FIG. 4 illustrates an optical cable including an indicator that changes color and/or emits light if the optical cable is compromised, according to one embodiment.  
         [0017]    [0017]FIG. 5 illustrates an optical cable including an indicator positioned within cladding that changes color and/or emits light visible through a window if the optical cable is compromised, according to one embodiment.  
         [0018]    [0018]FIG. 6 illustrates an optical cable including a multi-conduit indicator that changes color and/or emits light if the optical cable is compromised, according to one embodiment.  
         [0019]    [0019]FIG. 7 illustrates an optical cable including an indicator that surrounds cladding and optical fiber and the indicator changes color and/or emits light if the optical cable is compromised, according to one embodiment.  
         [0020]    [0020]FIG. 8 illustrates an optical cable including an indicator with an opaque exterior cladding and the indicator changes color and/or emits light if the optical cable is compromised, according to one embodiment.  
         [0021]    [0021]FIG. 9 illustrates a multi-fiber optical cable that includes an indicator, according to one embodiment.  
         [0022]    [0022]FIG. 10 illustrates a method for using optical cables that include a respective indicator(s), according to one embodiment. 
     
    
       [0023]    While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and may herein be described in detail. The drawings may not be to scale. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present invention as defined by the appended claims.  
       DETAILED DESCRIPTION  
       [0024]    [0024]FIG. 1 illustrates an exemplary embodiment of storage network  100  interconnecting a direct attached private loop  606  and a fabric  510  via optical cables  101 . Storage network  100  may include one or more hosts  502  connected to one or more storage devices  508  and  608  via optical cables  101 . The storage network  100  may be configured in a variety of different ways and may include one or more direct attach devices, storage area networks (SANs), and/or network attach devices (NAS). Storage network  100  may include fibre channel technologies layered over optical cables  101  with optical cables  101  as physical transmission media. The storage network  100  may not be limited to fibre channel technologies and architectures but may include various types of technologies layered over optical cables  101 . For example, some of storage network  100  may be based on the InfiniBand™ architecture or Small Computer System Interface over IP (iSCSI). The storage network  100  may include various types of topologies (e.g., geometric arrangements of components in the network) and protocols (e.g., rules and encoding specifications for sending data).  
         [0025]    In some embodiments, a plurality of hosts may communicate with a plurality of storage devices via one or more host adapters  520  and  504 . Coupled to private loop  606  are one or more direct attach devices  608  (e.g., devices local to a host). Fabric  510  may include fibre channel switches  512  which are coupled to multiple fabric devices  508  via optical cables. Fabric devices  508  and  608  may be various storage devices such as storage systems, hard disk drives, optical drives, tape drives, etc. Each fibre channel switch  512  may connect to various fibre channel topologies via optical cables  101  such as point-to-point fibre channel connections or loops. Each switch  512  may also connect to one or more other fibre channel switches via optical cables  101 .  
         [0026]    [0026]FIG. 2 illustrates another embodiment of optical cables  101  connecting corporate telecommunications network  100  as an extension of PSTN (public switched telephone network)  230 . Network  100  may provide transmission of sound, data, facsimiles, pictures, voice, video, and other information between a plurality of corporate users  250  via optical cables  101 . A number of carriers and service providers  203  may provide various types of services to users. Carriers and service providers  203  may include ILECs (incumbent local exchange carriers), IXCs (interexchange carriers), CAPs (competitive access providers), CLECS (competitive LECs), ISPs (internet service providers), ICPs (integrated communications providers), or other entities that provide telecommunication services to users. Carriers and service providers  203  may provide such services over optical cables  101  as physical transmission media.  
         [0027]    A corporation may set up a public branch exchange (PBX)  210  as an extension of services provided by PSTN  230 . For example, a PBX  210   a  may be set up at a corporate facility  205  to accept calls for corporate users  250  routed from the PSTN. The PBX  201   a  may then distribute the calls to the corporate users  250 . Alternatively, a carrier  203  may maintain a PBX  210   c  (e.g., Centrex) at the carrier facility  203  to provide routing service to a corporation. Network  200  may include one or more PBX  210  providing services to the plurality of corporate users  250 . Optical cables may be used in any or all stages of telecommunications network  200 .  
         [0028]    Some embodiments of storage network  100  and corporate telecommunications network  200  may include other types of components than those shown in FIGS. 1 and 2. For example, some hosts within storage network  100  may include other components such as application software, other CPUs, video monitors, or other types of devices for use by hosts within storage system  100 . In addition, optical cables  101  may be used in a variety of networks. Optical cables  101  may also be used in a variety of fields. For example, optical cables  101  may be used for imaging. The number of components, types of components and systems of use are for illustration purposes of the types of systems in which one or more optical cables including an indicator(s) as described below may be employed.  
         [0029]    [0029]FIG. 3 illustrates one embodiment of an optical cable  101  including or coupled to an indicator  308 . Optical cable  101  may include optical fiber  306  protected by cladding  310 . Depending on the use of optical cable  101 , optical cable  101  may include various materials and types of optical fiber  306 . For example, optical fiber  306  may be further protected within a tight, soft plastic buffer. Optical fiber  306  may include one layer of glass or many layers of glass. Construction and types of optical cable  101  may vary.  
         [0030]    Optical cable  101  may be sensitive to physical constraint placed on the cable. For example, bending a portion of optical cable  101  beyond a certain radius may damage optical fiber  306 . In some instances, low environmental temperatures or other thermal stress may induce microbends which are small-scale distortions on the surface of optical fibers. For example, protective material may contract more than glass and the protective material may become rigid and bend. Consequently, enough load (e.g., physical pressure) may be exerted on optical fiber  306  to cause microbends. Manufacturers may specify bend diameters, critical angles, bend radius, or some other constraint parameter that indicates a bend allowance for optical fibers within a type of optical cable  101 .  
         [0031]    Indicator  308  may be part of or coupled to optical cable  101  to visibly identify a transmission error or problem with optical cable  101 . Indicator  308  may activate if optical cable  101  is compromised (e.g., bent beyond a specified bend radius or otherwise damaged). Indicator  308  may activate after a portion of the optical fiber  306  is compromised. Activation of indicator  308  may include a visible identifier that optical fiber  306  is compromised.  
         [0032]    [0032]FIG. 4 illustrates one embodiment of an optical cable  401  including an indicator  412  that activates when a portion of optical fiber  406  is compromised. Indicator  412  may include conduit  414  and conduit  416 . Conduits may extend the length of the optical cable  401 . In alternative embodiments, conduits may extend for one or more segments of the length of the optical cable  401 . Conduits  414  and  416  may have a circular, oval, rectilinear, and/or irregular cross-sectional areas. Conduit  416  may be positioned within conduit  414 . In some embodiments, conduits  414  and  416  may be concentric. In some embodiments, movement of conduit  416  relative to conduit  414  may be inhibited. For example, spacers and/or centralizers may be used to inhibit the movement of conduit  416 . In other embodiments, conduit  416  or a portion thereof may be free to move within conduit  414 .  
         [0033]    In one embodiment, a wall of conduit  414  may form a portion of the wall of cladding  408 . In some embodiments, the wall of conduit  414  may be translucent and/or transparent. In an embodiment, a portion of the wall of the first conduit acting as the wall of the cladding may be translucent and/or transparent.  
         [0034]    In one embodiment, conduit  414  may be relatively flexible. For example, conduit  414  may have flexibility similar to cladding  408 . In further embodiments, conduit  416  may be constructed to have mechanical strength properties (e.g., maximum bend radius, compression strength, etc.) similar to strength properties of optical fiber  406 . Load and/or stresses that may compromise optical fiber  406  may activate indicator  412 . For example, conduit  416  may have a maximum bend radius similar to about the maximum bend radius of the optical fiber  406 . In such embodiments, bending optical cable  401  beyond the maximum bend radius activates the indicator  412 . In some embodiments, conduit  416  may have a maximum bend radius that is less than about a maximum bend radius of the optical fiber  406 . In addition, conduit  416  may have a compressive strength equal to or less than about a compressive strength of optical fiber  406 .  
         [0035]    In some embodiments, conduit  414  may contain a fluid and conduit  416  may contain a fluid. If conduit  416  is compromised, fluid may flow out of conduit  416  into conduit  414  and mix with fluid in conduit  414 . Mixing of the fluids may cause a color change within the indicator  412 . In one embodiment, a component of at least one of the fluids may be a dye. Alternatively, a component may be a fluorescent dye. In certain embodiments, conduit  416  may be opaque. For example, dye may be present in opaque conduit  416 . As the optical cable  401  is stressed to a point at which the optical fiber  406  is compromised, a portion of the inner opaque conduit is also compromised allowing the dye to mix with fluid in conduit  414 . Thus, a color is altered in conduit  414 . In other embodiments, conduit  416  may be transparent or translucent.  
         [0036]    Mixing of the fluids may cause a chemical reaction that generates light and/or a color change in the indicator  412 . The mixing of the fluids may cause components in the mixture to emit light. In some embodiments, a component in one of the fluids may convert to a luminescent species after the fluids in conduit  414  and conduit  416  mix. For example, luminol may decompose in the presence of an activator (e.g., oxidants) to a compound (e.g., 3-aminophthalate) that may luminesce. In certain embodiments, a catalyst may also be present in the fluids. For example, a salicylate catalyst may be used.  
         [0037]    In one embodiment, a component of a fluid in conduit  414  may include an emitting species and/or a precursor of an emitting species. Precursors may include, but are not limited to, peroxyoxalates, phenyl oxalate ester, bis(2,4,6-trichlorophenyl)oxalate (TCPO), oxalyl chloride, oxalic phthalate ester, and/or luminol. In such embodiments, an activator (e.g., peroxides, hydrogen peroxide, perborate, permanganate, hypochlorite, iodine and/or mixtures thereof) may be present in conduit  416 . Mixing of an activator with fluid from conduit  414  may cause conversion of a precursor to an emitting species. In some embodiments, fluid in conduit  414  may also include a fluorophore. A fluorophore is generally defined as a dye capable of fluorescence. Examples of fluorophores may include, but may not be limited to, 5,6,11,12-tetraphenylnapthacene, 9,10-diphenylanthracene and/or 9,10-bis(phenylethynyl)anthracene.  
         [0038]    Optical cable  401  may bend such that conduit  416  ruptures within conduit  414 . Fluids present within conduit  416  may include a precursor such as oxalic phthalate. Oxalic phthalate may react with an activator (e.g., hydrogen peroxide) present in conduit  414  to form a dioxetanedione intermediate. This dioxetanedione intermediate may decompose to phenol and carbon while emitting energy. The energy may excite a fluorophore in the fluids that then releases light.  
         [0039]    In other embodiments, fluids present in conduit  414  may include an activator and fluids present in conduit  416  may include an emitting species and/or a precursor to an emitting species. In addition, fluorophores may be present in conduit  414  and/or conduit  416 .  
         [0040]    In some embodiments, components in the fluids may be sensitive to light. In such instances, UV absorbers may be present in the fluids in the conduits to reduce decomposition of components prior to activation. In some embodiments, fluids may contain radical inhibitors to inhibit decomposition of components in the fluids. For example, an activator such as hydrogen peroxide in conduit  416  may decompose when exposed to light. UV absorbers may be present in the fluid in conduit  414  to absorb light prior to reaching conduit  416 . Alternatively, conduits  414  and  416  may be constructed (e.g., conduit  416  may be opaque and/or contain UV absorbers) to inhibit light from reaching fluid in conduit  416 . In some instances, UV absorbers may be selected that absorb light outside of the range of the fluorophore and/or the luminescent species.  
         [0041]    In one embodiment, conduits  414  and  416  may include fluids that are alkaline, acidic and/or pH indicators. For example, conduit  416  may contain a pH indicator that will change color when the pH of the surrounding fluid is changed. If the maximum bend radius is exceeded, conduit  416  may be compromised allowing the pH indicator in conduit  416  to mix with fluid in conduit  414 . Fluids within conduits  414  and  416  may have significantly different pH values allowing the pH indicator to change color when the fluids mix. In alternative embodiments, fluids in conduit  414  may include a pH indicator.  
         [0042]    The above description of indicator activation, fluids, etc. may apply to any of the embodiments described herein.  
         [0043]    [0043]FIG. 5 illustrates another embodiment of an optical cable  501  having indicator  512  positioned within cladding  508 . Exterior cladding  518  surrounds cladding  508  and indicator  512 . Exterior cladding  518  may include a window  520  positioned proximate to indicator  512 . Window  520  may be translucent and/or transparent. In some embodiments, window  520  may be flexible. Window  520  may allow visualization of indicator  512  to identify which cable has been compromised.  
         [0044]    As illustrated in FIG. 6, another embodiment of an optical cable  601  may include indicator  612  surrounding cladding  608 . Conduits  616  may be positioned proximate cladding  608 . Conduit  614  may surround conduits  616  and cladding  608 . In addition, conduit  614  may serve as an exterior cladding for optical cable  601 . Alternatively, in some embodiments an additional exterior cladding may surround conduit  614 . Other embodiments may include three or more conduits  616 .  
         [0045]    [0045]FIG. 7 illustrates another embodiment of optical cable  701  with indicator  712  surrounding cladding  708  and optical fiber  706 . Conduit  716  may be positioned such that it surrounds cladding  708 . Fluid may be contained in conduit  716  between a wall of conduit  716  and cladding  708 . Conduit  714  may surround conduit  716  as shown.  
         [0046]    In some embodiments, a portion of a conduit may be opaque to inhibit absorption of light within fluids. Absorption of light within the fluids may inhibit decomposition of components in the fluids prior to activation of an indicator. FIG. 8 illustrates an alternative embodiment having exterior cladding  820  surrounding conduit  814  and positioned proximate conduit  816  to inhibit decomposition of any fluids  812  (e.g., an activator). Cladding  820  may be substantially opaque to inhibit decomposition of the fluids. Cladding  820  may include one or more gaps  823  to allow visual access to a portion of conduit  816  for observation. Alternatively, a window may be positioned over conduit  816 . Gaps and/or windows may be positioned to inhibit light from reaching fluids in conduits  814 .  
         [0047]    Optical cables as described in the above embodiments may be arranged in various configurations. Various cable configurations may exist, including those with multiple cables in a larger outer jacket or hybrid cables with optical fiber and copper cables in a same assembly. Most multi-fiber cables have optical fibers arranged in a circular cross-section. However, ribbon style cables may be used to maximize cable density for some applications. Other optical fiber cables may be arranged in different configurations.  
         [0048]    [0048]FIG. 9 illustrates a cross-section of one embodiment of a multi-fiber optical cable  901  that includes a plurality of optical cables  902 . An indicator  912  may be coupled to the multi-fiber optical cable  902 . The plurality of optical cables  902  may be arranged in a circular configuration enclosed by a bonding material  915 . Each optical cable  902  may include optical fiber  906 . The indicator  912  may be connected to the bonding material  915 . In one embodiment, bonding material  915  may be an outer jacket, a bonding matrix, or other material suitable for enclosing or bundling a plurality of optical cables  902 . The number and types of optical cable  902  are for illustration purposes. The actual number and types of optical cable  902  may vary.  
         [0049]    In one embodiment, indicator  912  may include an inner conduit within an outer conduit. In one embodiment, the inner conduit may be constructed to have mechanical strength properties (e.g., maximum bend radius, compression strength, etc.) similar to strength properties of optical fibers  906  within multi-fiber cable  902 . Note that for multi-fiber or bundled cables, the mechanical strength properties may be different than for individual cables and the indicator may be configured accordingly. Load and/or stresses that may compromise optical fibers  906  within multi-fiber cable  902  may activate indicator  912 . For example, the inner conduit may have a maximum bend radius similar to about the maximum bend radius of the bundled optical fibers  906  within multi-fiber cable  902 . In such embodiments, bending multi-fiber optical cable  902  beyond the maximum bend radius activates the indicator  912 . In some embodiments, the inner conduit may have a maximum bend radius that is less than about a maximum bend radius of the optical fibers  906  within multi-fiber cable  902 . In addition, the inner conduit may have a compressive strength equal to about a compressive strength of optical fibers  906  within multi-fiber cable  902 .  
         [0050]    The indicator  912  may activate indicating that one or more optical fibers  906  within multi-fiber cable  902  may have been compromised. In some embodiments, the indicator  912  may change color and/or emit light. The outer conduit may contain a dye and the inner conduit may contain a fluid. As the multi-fiber optical cable  902  is stressed to a point at which one or more optical fibers  906  are compromised, a portion of the inner conduit is also compromised allowing the dye to mix with the fluid in the inner conduit. Thus, a color is altered in the inner conduit indicating a transmission problem has been detected within one or more optical fibers  906  within multi-fiber cable  902 . The indicator  912  may be constructed similar to one of the embodiments described above.  
         [0051]    [0051]FIG. 10 illustrates one embodiment of a method for using optical cables that include an indicator(s) as described above. A system may be monitored to check for transmission errors within the system, as indicated in  1000 . For example, a storage network may be monitored to check for transmission errors within the storage network. The storage network may include one or more hosts connected to one or more storage devices via optical cables. The method may also be applied to other types of systems, such as telecommunication systems, that connect components via optical cables. The optical cables may include single optical cables and/or multi-fiber optical cables. Each optical cable or multi-fiber optical cable may include an indicator as described herein.  
         [0052]    A transmission error may be detected within the system, as indicated in  1010 . For example, an optical cable may have been compromised because the optical cable was bent beyond a specified bend radius and the excessive bending induces a transmission error. An indicator connected to the optical cable may activate when the optical cable is compromised. The indicator may activate when a portion of optical fiber within the optical cable is compromised. Activation of the indicator may show that an optical fiber within the optical cable is or may have been compromised. In one embodiment, the indicator may change color and/or emit light.  
         [0053]    A field technician, for example, may locate one or more optical cables having an indicator activated, as indicated in  1015 . The indicator may be part of or coupled to the optical cable to visibly identify a transmission error or problem with the optical cable. Thus, while searching for a source of a detected transmission error, the field technician may notice one or more optical cables having an indicator activated. The field technician may replace each compromised cable that has an indicator activated, as indicated in  1020 .  
         [0054]    The embodiments described above include optical fibers as a transmission media. Other embodiments may include other types of transmission media, such as copper wires in addition to or instead of optical fiber. For example, the transmission media may include copper wires surrounded by an insulator, twisted-pair cable consisting of copper-core wires surrounded by an insulator, and/or coaxial cable consisting of solid copper core surrounded by an insulator. An indicator as described above may be included with any type of transmission media. Copper or other types of cables may be arranged as bundled cables that include a plurality of cables as shown in FIG. 9. A copper wire cable, bundled wire cable, or other type of cable may include an indicator that activates if the cable is compromised, as described above. The indicator may be configured to activate under physical stress conditions approximating those that would damage the transmission media in the cable. The physical stress conditions may include one or more of stretching, bending, compression, twisting, etc. In some embodiments, the indicator may change color and/or emit light.  
         [0055]    Further modifications and alternative embodiments of various aspects of the invention may be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the general manner of carrying out the invention. It is to be understood that the forms of the invention shown and described herein are to be taken as the presently preferred embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features of the invention may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of this description of the invention. Changes may be made in the elements described herein without departing from the spirit and scope of the invention as described in the following claims.