Abstract:
An optical fiber splice holder device for connecting jacketed optical fiber cables includes a cover and a main body that houses a splice device therein. The splice device is configured to splice a first fiber end to a second fiber end. The main body also includes first and second fiber jacket clamping portions disposed at first and second ends of the main body to clamp a respective fiber&#39;s jacket portion that surrounds a portion of the respective fiber upon actuation. The optical fiber splice device also includes first and second fiber jacket boots that are attachable to the main body at the first and second ends of the main body. The boots each actuate the respective fiber jacket clamping regions of the optical fiber cables upon attachment to the main body.

Description:
BACKGROUND 
     1. Field of the Invention 
     The present invention is directed to a compact optical fiber splice holder device. 
     2. Related Art 
     Mechanical devices for connecting and/or splicing optical fibers for the telecommunications industry are known. These devices can be part of an optical fiber network such as a FTTH (Fiber to the Home) network. For example, conventional devices are described in U.S. Pat. Nos. 4,824,197; 5,102,212; 5,138,681; 5,159,653; 5,337,390; and 5,155,787. 
     Another preferred conventional splicing method is fusion splicing. In large deployments, many splices are required to be made in many different areas of the city at the same time. However, as fiber optics are being deployed deeper into the metro and access areas of the network, splicing in these areas of the network are often performed in the air, in cramped closets, and in difficult-to-maneuver locations. Fusion splicing in these types of locations is difficult, and often there is no power available for fusion splicing machine, thus requiring battery power. Also, if many locations are scheduled in a given day, many different installation crews will require fusion splicing machines, resulting in a capital investment for the installation company. 
     In recent years, a mechanical field-mountable optical fiber connecting structure has become more desirable. The connecting structure can have a mechanical splice structure therein. This structure can be used to permanently connect ends of naked optical fibers to each other such that the ends of the fibers abut each other, without fusion welding or adhering. For example, PCT Publ. No. WO2009/111176 provides an example mechanical splice (this device may also be referred to as a mechanical splice-type connector). 
     SUMMARY 
     According to a first aspect of the present invention, an optical fiber splice holder device for connecting jacketed optical fiber cables is provided. The optical fiber splice holder device includes a cover and a main body that houses a splice device therein, where the splice device is configured to splice a first fiber end to a second fiber end. The main body also includes first and second fiber jacket clamping portions disposed at first and second ends of the main body to clamp a respective fiber&#39;s jacket portion that surrounds a portion of the respective fiber upon actuation. The optical fiber splice device also includes first and second fiber jacket boots that are attachable to the main body at the first and second ends of the main body. The boots each actuate the respective fiber jacket clamping regions of the optical fiber cables upon attachment to the main body. 
     In a preferred aspect, the splice device comprises a mechanical splice device. 
     The above summary of the present invention is not intended to describe each illustrated embodiment or every implementation of the present invention. The figures and the detailed description that follows more particularly exemplify these embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will be further described with reference to the accompanying drawings, wherein: 
         FIG. 1A  is an isometric view of an exemplary optical fiber splice holder device according to an aspect of the invention. 
         FIG. 1B  is a partial exploded view of an exemplary optical fiber splice holder device according to an aspect of the invention. 
         FIGS. 2A-2J  illustrate an exemplary splicing sequence for the optical fiber splice holder device according to another aspect of the invention. 
         FIGS. 3A and 3B  are isometric and close up views of an exemplary optical fiber splice holder device for splicing alternative optical fiber cables according to another aspect of the invention. 
         FIG. 4A  is an exploded view of the cover, mechanical splice device and the main body of the splice holder device according to an aspect of the invention. 
         FIG. 4B  is an isometric view of an alternative main body of the splice holder device according to another aspect of the invention. 
         FIG. 5  is an isometric view of a cover piece according to another aspect of the invention. 
         FIG. 6  is an isometric view of a boot according to another aspect of the invention. 
         FIG. 7A  is an isometric view of an alternative optical fiber splice holder device with a flexible secondary boot extension according to an aspect of the invention. 
         FIG. 7B  is a close up view of the cable jacket boot and flexible secondary boot extension of the alternative optical fiber splice holder device of  FIG. 7A . 
         FIG. 7C  is an isometric view of another alternative optical fiber splice holder device with an alternative flexible secondary boot extension according to an aspect of the invention. 
     
    
    
     While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the appended claims. 
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     In the following Detailed Description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. In this regard, directional terminology, such as “top,” “bottom,” “front,” “back,” “leading,” “forward,” “trailing,” etc., is used with reference to the orientation of the Figure(s) being described. Because components of embodiments of the present invention can be positioned in a number of different orientations, the directional terminology is used for purposes of illustration and is in no way limiting. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. 
     The present invention is directed to an optical fiber splice holder device. In particular, the optical fiber splice holder device of the exemplary embodiments is of rugged construction, compact length and is capable of being utilized in straightforward field splicing. Further, the straightforward field splicing can be accomplished without the use of a separate field termination platform or separate crimping tool. The exemplary splice holder device(s) described herein can be readily installed and utilized for Fiber To The Home (FTTH) and/or Fiber To The X (FTTX) network installations. The exemplary splice device(s) can be utilized in installation environments that require ease of use, especially where labor costs are more expensive. In addition, the splice holder device can be utilized with different types of jacketed drop cables, such as conventional 3 mm drop cable and rectangular (in cross section) 2 mm×3 mm FRP cable. Further, the splice holder device can be utilized for repairs of broken drop cables in the field. 
     According to an exemplary embodiment of the present invention, an optical fiber splice holder device  100  is shown in isometric view in  FIG. 1A  and in exploded view in  FIG. 1B . Individual components of the optical fiber splice holder device  100  are shown in more detail in  FIGS. 4A ,  4 B,  5 , and  6 . A sequence for performing a splicing operation with the exemplary optical fiber splice holder device  100  are shown in  FIGS. 2A-2F . 
     Optical fiber splice holder device  100  completes and houses a splice made between two optical fiber cables, here cables  134  and  135 . The fibers within each cable are spliced by a splice device  110 , described in further detail below, which is nested inside a splice holder main body (or backbone)  116 . In a preferred aspect, the splice device  110  comprises a mechanical splice device and the splice holder embodiments herein will be described with respect to a mechanical splice device. However, in an alternative aspect, splice holder device  100  can house a fusion splice, as would be apparent to one of ordinary skill in the art given the present description. 
     A cover  150  can be utilized to actuate and enclose the mechanical splice device  110  within the main body  116 . The splice holder main body  116  includes two cable jacket clamping regions  117   a  and  117   b  disposed on either side of the mechanical splice  110 . Each cable jacket clamping region engages with a respective cable jacket boot  180 ,  181  that clamps the respective fiber cables in place with respect to the splice. 
     In this exemplary embodiment, splice holder device  100  can be utilized to splice two field optical fiber cables  134 ,  135 . Optical fiber cables  134 ,  135  are jacketed cables that each include an outer jacket  136 , a buffer portion  137  (e.g., with a buffer coating or the like), a bare fiber portion (e.g., the bare clad/core, not shown), and strength members (not shown). Fiber cables  134 ,  135  can each comprise a standard single mode or multimode optical fiber, such as SMF 28 (available from Corning Inc.). In a preferred aspect, the strength members comprise aramid, Kevlar, or polyester yarn or strands disposed between an inner surface of the fiber jacket  136  and an outer surface of coated portion  137 . 
     The main body  116  provides structural support for the splice holder device  100 . As shown in  FIG. 4A , the main body  116  is an elongated structure (preferably having a length of from about 76 mm to about 95 mm, and more preferably about 92 mm) and a generally cylindrical shape with a continuous axial bore to permit passage of the optical fibers being spliced. Main body  116  includes a central opening  115  that receives and houses or supports a mechanical splice device  110 . The main body structure also clamps the optical fiber cables being spliced in the field. The clamping regions  117   a  and  117   b  formed on the ends of the main body  116  can provide further axial strain relief by providing a clamping surface for the strength members of the optical fibers being spliced. 
     Each clamping region  117   a ,  117   b  can further include a mounting structure  118  that provides for coupling to the cable jacket boot  180 ,  181 . In an exemplary aspect, the mounting structure comprises a threaded surface formed on an outer portion of main body  116  that is configured to engage a corresponding threaded surface  184  of the respective boot  180 ,  181  (see e.g.,  FIG. 6 ). Also, the mounting structure  118  can provide a retention area for securing the strength members of the optical fiber cable being spliced. 
     In addition, each clamping region  117   a ,  117   b  can include a fiber guide  113  formed in an interior portion therein to provide axial alignment support for the optical fiber cable being terminated. In an exemplary aspect, the fiber guide portion  113  is a funnel-shaped channel or groove that aligns a buffered portion of the optical fiber and guides the fiber toward the mechanical splice device  110  housed in the main body  116 . 
     Main body  116  can further include one or more stops  114  formed on an interior portion of the clamping regions  117   a ,  117   b  to provide a boundary for the insertion of the jacketed portion  136  of the optical fiber cable  134 ,  135  being spliced. In addition, clamping regions  117   a ,  117   b  each include a clamping portion  119  formed at the axial end of the main body. The clamping portions  119  are configured to clamp onto the jacket portion  136  of the optical fiber cables  134 ,  135  being spliced in device  100 . In a preferred aspect, clamping portion  119  comprises a collet-type, split body shape that is actuated when the cable jacket boot  180 ,  181  is secured to mounting structure  118 . The clamping portion  119  can include raised inner surfaces to permit ready clamping of the cable jacket portion  136 . In addition, the clamping portion  119  also can provide a guide structure when inserting fiber cable  135  during the splicing process. Thus, cable jacket boots  180 ,  181  can be utilized to clamp the fiber strength members and the jacket  136  of the respective optical fiber cables. The interaction of the cable jacket boots  180 ,  181  and the clamping regions  117   a ,  117   b  will be described in greater detail below. 
     According to an exemplary embodiment of the present invention, main body  116  and cover  150  are formed or molded from a polymer material, although metal and other suitably rigid materials can also be utilized. For example, main body  116  can comprise an injection-molded material. 
       FIG. 5  shows a close up view of cover  150 . Cover  150  is preferably secured to main body  116  via snap fit, although an interference fit construction can also be utilized. 
     Cover  150  also includes side walls  154  that extend to enclose the opening  115  of the main body  116 . Thus, as shown in  FIG. 1A , in a preferred aspect, when cover  150  is secured to main body  116 , the splice holder device  100  has a compact, smooth, cylindrical shape. 
     Referring back to  FIG. 1B , main body  116  further includes an opening  115  in which a mechanical splice device can be inserted and secured in the central cavity of main body  116 . In an exemplary embodiment, the mechanical splice device  110  includes a mechanical splice element, an actuating cap, and a splice support housing to receive the element and actuating cap. In this aspect, as shown in  FIG. 5 , exemplary cover  150  includes an inner surface  152  having a structure configured to conform with and engage the actuating cap of the mechanical splice device when enclosing the splice holder device. 
     In general, the mechanical splice device can include a splice element that comprises a sheet of ductile material having a focus hinge that couples two legs, where each of the legs includes a fiber gripping channel (e.g., a V-type (or similar) groove) to optimize clamping forces for conventional glass optical fibers received therein. The ductile material, for example, can be aluminum or anodized aluminum. In addition, a conventional index matching fluid can be preloaded into the V-groove region of the splice element for improved optical connectivity within the splice element. In another aspect, no index matching fluid is utilized. 
     The mechanical splice device allows a field technician to splice the two bare fiber ends of optical fiber cables at a field installation location. In an exemplary embodiment, the actuating cap is moved to a closed position (e.g. downward in the embodiment depicted in FIG.  2 F—in the direction of arrow  107 ) as the cover  150  is secured onto the main body  116  via a pressing force. This movement causes one or more cam bars located on an interior portion of the actuating cap to slide over the legs of the splice element, urging them toward one another. The two fiber ends are held in place in grooves formed in the splice element and butted against each other and are spliced together in a channel, such as a V-groove channel to provide sufficient optical connection, as the element legs are moved toward one another. 
     Example mechanical splice devices (also referred to herein as splice devices or splices) include a 3M™ FIBRLOK™ 4×4 mechanical fiber optic splice device, such as is described in U.S. Pat. No. 7,140,787, incorporated by reference herein in its entirety. The 3M™ FIBRLOK™ 4×4 mechanical fiber optic splice device is commercially available from 3M Company, of Saint Paul, Minn.  FIG. 1B  and  FIGS. 2A-2E  show an exemplary splice device  110  configured as a 3M™ FIBRLOK™ 4×4 mechanical fiber optic splice device. As shown in  FIG. 4A , main body  116  can include a seat or nest  112  that is configured to snugly receive and support a portion of the outer shape of the mechanical splice  110 . 
     In an alternative aspect, the main body can be configured to receive a different mechanical splice. For example, as shown in  FIG. 4B , alternative main body  116 ′ can have an alternative opening  115 ′ that is shaped to receive and support another mechanical splice device, such as a commercially available 3M™ FIBRLOK™ II mechanical fiber optic splice device, available from 3M Company, of Saint Paul, Minn. The operation of a similar mechanical splice device is also described in U.S. Pat. No. 5,159,653, incorporated herein by reference in its entirety. 
     In further alternative aspects, other conventional mechanical splice devices can be utilized with splice holder device  100 , for example those described in U.S. Pat. Nos. 4,824,197; 5,102,212; 5,138,681; and 5,155,787, each of which is incorporated by reference herein, in their entirety. 
     The cable jacket boots  180 ,  181  can each be utilized for several purposes with optical splice holder device  100 . Boots  180 ,  181  can each have the same construction. As shown in  FIG. 6  (only boot  180  is shown for simplicity) cable jacket boots  180 ,  181  can each include a tapered body having an axial bore throughout. Each cable jacket boot  180 ,  181  includes threaded grooves  184  formed on an inner surface of the body  182  at the opening  185 , where the grooves are configured to engage with the correspondingly threaded mounting structure  118  of the main body  116 . In addition, the axial length of cable jacket boot  180  can be configured such that a rear section  187  of the boot, which has a smaller opening than at front opening  185 , engages the jacket clamp portion  119  of the main body  116 . For example, as the cable jacket boot  180 ,  181  is secured onto the mounting structure  118  of the main body  116 , the axial movement of the boot relative to the main body (see arrow  105  in  FIG. 2E ) forces the legs of clamp portion  119  to move radially inwards (see arrows  106  shown in  FIG. 2F ) so that the fiber jacket  136  is tightly gripped. Also, the strength members of the optical fiber cable can be disposed between the boot and the threaded mounting structure  118  to secure the strength members as the boot is installed. This construction can also provide a splice capable of surviving rougher handling and greater pull forces. 
     In an exemplary aspect, cable jacket boots  180 ,  181  are formed from a rigid material, such as a fiberglass reinforced polymer material. For example, one exemplary material can comprise a fiberglass reinforced polyphenylene sulfide compound material or an ULTEM 2100 (or 1010 or CRS 5001) material. In another aspect, the material used to form the cable jacket boots  180 ,  181  and the main body  116  is the same material. In an alternative aspect, cable jacket boots  180 ,  181  may have attached thereto a more flexible secondary boot extending from a back end  187  of the cable jacket boot, thus enabling better response to side pull forces. 
     For example, an alternative aspect of the invention is shown with respect to  FIGS. 7A-7C . In  FIGS. 7A and 7B , optical fiber splice holder device  100 ″ completes and houses a splice made between two optical fiber cables, here cables  134  and  135 . The fibers within each cable are spliced by a mechanical splice device (not shown), similar to those described above. A cover  150 , similar to that described above, can be utilized to actuate and enclose the mechanical splice device  110  within the main body. The splice holder main body includes two cable jacket clamping regions, similar to those described above, disposed on either side of the mechanical splice. Each cable jacket clamping region engages with a respective jacket boot  180 ″,  181 ″ that clamps the respective fiber cables in place with respect to the splice. Cable jacket boot  180 ″,  181 ″ are configured to engage a more flexible secondary boot  190 ,  191  extending from a back end  187  of the boot. 
     In particular, as is shown in a more close-up view in  FIG. 7B  (where only cable jacket boot  181 ″ is shown for simplicity, as cable jacket boot  180 ″ may also have the same construction), cable jacket boot  181 ″ includes an engagement portion  189  having a boss structure that engages a corresponding mating structure (not shown) formed on an inner surface of secondary boot  191  near the opening  193 . In this configuration, secondary boot  191  can be fitted over fiber  134  and snapped onto the engagement portion  189  during the field splicing process. Secondary boots  190  and  191  can have a slotted outer shape to permit side-to-side bending and can be formed from a flexible material such as a thermoplastic urethane or similar material. 
     In a further alternative aspect, as is shown in  FIG. 7C , an optical fiber splice holder device  100 ′″ can have a configuration similar to that described above with respect to  FIGS. 7A and 7B , except that secondary boots  190 ′ and  191 ′ each have a narrow, mating portion  195  that engages engagement portions formed inside the back end of jacket boots  180 ′″ and  181 ′″. 
     An exemplary fiber cable utilized in this embodiment comprises a 3.0 mm jacketed drop cable, commercially available from Samsung Cable (of Korea), Thai-han Cable (of Korea), and others. As would be understood by one of ordinary skill in the art given the present description, the optical fiber splice holder device of the exemplary embodiments can be configured to terminate the fibers of other types of jacketed drop cable, including 3.5 mm drop cable, and others. 
     In an alternative aspect, as is shown in  FIGS. 3A and 3B , an alternative cable having a rectangular cross section, referred to as an FRP cable, can be utilized. In  FIG. 3A , splice holder device  100 ′ completes and houses a splice made between two optical fiber cables, here FRP cables  134 ′ and  135 ′. A cover  150  can be utilized to actuate and enclose the mechanical splice device within the main body  116 . The splice holder main body  116  includes two cable jacket clamping regions (only clamping region  117   a  is shown in  FIG. 3B  for simplicity) disposed on either side of the mechanical splice  110 . Each cable jacket clamping region engages with a respective cable jacket boot  180 ,  181  that clamps the respective fiber cables in place with respect to the splice. As shown in  FIG. 3B , the outer cable jacket  136 ′ is gripped by a clamping portion  119  formed at the axial end of the main body  116 . The fiber guides  113 , stops  114  and mounting structure  118  can be constructed in the same manner as is described above for device  100 . 
     As mentioned above, the optical fiber splice holder device of the exemplary embodiments is of compact length and is capable of straightforward field splicing without the use of a connector termination platform or separate crimping tool. An exemplary splicing process is now described with reference to  FIGS. 2A-2J . Please note that reference numbers used in these figures correspond with like features from  FIGS. 1A ,  1 B and  4 - 6 . 
     As shown in  FIG. 2A , an optical fiber cable  134  is prepared by removing a portion of the fiber cable jacket  136  to expose a buffer portion  137  and stripping off a portion of the buffer coating near the fiber end to leave a bare fiber portion  139 . Also, strength members, such as aramid strands (not shown), that were disposed between the cable jacket  136  and the buffer portion  137  can be exposed. The end of the bare fiber (not shown) is cleaved either as a flat cleave or an angled cleave using a conventional cleaver. Optionally, the fiber end may also be polished using a conventional field polisher tool and/or process. The bare fiber end of cable  134  is then inserted into the splice element of the mechanical splice device  110 . In an exemplary aspect, about 50 mm of the jacket  136  can be removed. The stripped fiber can have a length of about 30 mm to about 40 mm, with about 10 mm of bare glass exposed at its end. For example, a commercial fiber cleaver such as an Ilsintech MAX CI-01 or the Ilsintech MAX CI-08, available from Ilsintech (Korea) (not shown) can be utilized to provide a flat or an angled cleave. The cable jacket boot  181  can be slid over the fiber cable  134  for later use. In one aspect, the cable jacket boot  181  can be slid over the fiber cable  134  prior to cleaving/polishing. 
     As shown in  FIG. 2B , optical fiber cable  134  can be inserted in the direction of arrow  103  through the clamping region  117   b  of the main body  116  so that the bare fiber is inserted into the splicing element of the mechanical splice device  110 . The jacket stops  114  in the clamping region  117   b  can provide a stop for the insertion of the fiber as the end  138  of the jacket of cable  134  contacts the stops  114 . At this position, the bare end of optical fiber cable  134  is positioned well within the splice element of the mechanical splice device  110 , ready for splicing with the bare end of the second optical cable  135 . 
     As shown in  FIG. 2C , cable jacket boot  181  is slid into position and fastened onto clamping region  117   b , for example, by screwing cable jacket boot  181  onto mounting structure  118 . This fastening secures the strength members of optical fiber cable  134  onto the clamping region  117   b  of the main body  116  and axially secures the jacket portion  136  of the optical fiber cable  134  with respect to the main body  116 . Any remaining unsecured strength members may be cut off. 
     The second optical fiber cable  135  can be prepared by removing a portion of the fiber cable jacket  136  to expose a buffer portion  137  and stripping off a coated portion of the fiber near the fiber end to leave a bare fiber portion (not shown). Also, strength members, such as aramid strands (not shown), that were disposed between the cable jacket  136  and the buffer  137  can be exposed. The end of the bare fiber (not shown) is cleaved either as a flat cleave or an angled cleave using a conventional cleaver. Optionally, the fiber end may also be polished using a conventional field polisher tool and/or process. These processes can be performed in the same manner as is described above. The cable jacket boot  180  can be slid over the fiber cable  135  for later use. 
     As shown in  FIG. 2D , optical fiber cable  135  can be inserted in the direction of arrow  105  through the clamping region  117   a  of the main body  116  so that the bare fiber is inserted into the splicing element of the mechanical splice device  110 . The insertion process continues as the bare end of optical fiber cable  135  contacts the bare end of optical fiber cable  134  already inserted into the splice element of the mechanical splice device  110 . 
     As shown in  FIG. 2E , upon contact between the bare end of optical fiber cable  135  and the bare end of optical fiber cable  134 , a fiber bend  137 ′ occurs as axial force in the direction of arrow  105  is maintained. 
     As shown in  FIG. 2F , the splice device can be actuated in the following manner. A retaining force can be applied to optical fiber cable  135  via a pressing of the clamping portion  119  formed at the axial end of the main body  116  in the direction of arrows  106 . This retaining force can be applied with a simple finger pinching motion. While the retaining force is maintained, the cover  150  can be moved into place on main body  116 . As shown in  FIG. 2G , a further pressing force, in the direction of arrow  107  shown in  FIG. 2G , fully actuates the actuating cap of the mechanical splice device  110  such that the splice element therein is fully closed, keeping the bare fiber ends in contact. In  FIG. 2H , the retaining force can be removed at the clamping portion  119 , allowing the optical fiber cable to move back axially, thereby substantially releasing the previously formed bend  137 ′. 
     As shown in  FIG. 2I , cable jacket boot  180  is slid into position and fastened onto clamping region  117   a , for example, by screwing cable jacket boot  180  onto mounting structure  118 . This fastening secures the strength members of optical fiber cable  135  onto the clamping region  117   a  of the main body  116  and axially secures the jacket portion  136  of the optical fiber cable  135  with respect to the main body  116 . Any remaining unsecured strength members may be cut off.  FIG. 2J  shows device  100  in its fully installed state. 
     As would be apparent to one of ordinary skill in the art given the present description, the above method may be modified so that the installation steps may be modified and/or performed in a different sequence. 
     Thus, the above procedure can be accomplished without the use of any additional installation platform or specialized tool. In addition, the optical splice holder device is re-usable. The device offers a low-cost approach to repair a broken optical fiber cable, such as a broken drop cable. In addition, the construction of the splice holder device allows for the device to be pre-installed on a cable used for later splicing. 
     The optical splice holder device described above can be used in many conventional splicing applications. The optical fiber splice holder devices described above can also be utilized for FTTH drop splicing or jacketed cable splicing. 
     Various modifications, equivalent processes, as well as numerous structures to which the present invention may be applicable will be readily apparent to those of skill in the art to which the present invention is directed upon review of the present specification.