AND METHODS

PRIORITY APPLICATION

[0001] This application claims the benefit of priority under 35 U.S.C. § 119 ofU.S. Provisional Application Serial No. 62/052,752, which was filed on September 19, 2014, the content of which is relied upon and incorporated herein by reference in its entirety.

FIELD

[0002] The present disclosure relates to optical fiber connection assemblies, and more particularly, to optical fiber connection assembly cable, hardware, and/or modules that support both single-mode and multi-mode optical connectivity.

BACKGROUND

[0003] The disclosure relates generally to fiber optic cables and more particularly to hybrid fiber optic cables having multi-mode and single-mode optical fibers, which may be used for simultaneous multi-mode and single-mode connectivity at a common connection point. Related components, systems, and methods are also disclosed.

[0004] Benefits of utilizing optical fiber include extremely wide bandwidth and low noise operation. Because of these advantages, optical fiber is increasingly being used for a variety of applications, including but not limited to broadband voice, video, and data

transmission. Fiber optic networks employing optical fiber are being developed for use in delivering voice, video, and data transmissions to subscribers over both private and public networks. These fiber optic networks often include separated connection points linking optical fibers to provide "live fiber" from one connection point to another. In this regard, fiber optic equipment is located in data distribution centers or central offices to support live fiber interconnections. For example, the fiber optic equipment can support interconnections between servers, storage area networks (SANs), and/or other equipment at data

centers. Interconnections may be further supported by fiber optic patch panels or modules.

[0005] Different types of optical fiber may be used for different applications within a network. Multi-mode fiber, for example, refers to optical fiber that supports multiple "modes" or cross-sectional areas for a laser light source. Multi-mode fiber has the advantage of being able to use larger, relatively inexpensive laser light sources because of its relatively large cross-sectional area. Single -mode fiber, on the other hand, refers to optical fiber that supports a single "mode" or cross-sectional area for a laser light source, and has a significantly smaller cross sectional area. Single-mode fiber has the advantage of having a high bandwith - distance product enabling higher amounts of data to be transmitted over a given distance but requires more expensive light sources because of it's relatively small cross sectional area. Thus, most applications favor less expensive multi-mode fiber solutions for spanning shorter distances, and favor single-mode fiber only when necessary for transmitting high bandwith over longer distances than would be supported by multi-mode fiber.

SUMMARY

[0006] Embodiments of the disclosure include a hybrid fiber optic cable comprising a plurality of optical fibers including a plurality of single -mode optical fibers and a plurality of multi-mode optical fibers, with a cable jacket surrounding the plurality of optical fibers. One advantage of this arrangement is that transition back and forth between single-mode and multi-mode connectivity, or simultaneous use of both types of connectivity, is enabled through installation of a single cable. In one exemplary embodiment, without limitation, eight (8) multi-mode fibers are included, corresponding to fiber positions 1-4 and 9-12 of a conventional BASE-8 parallel optical connection scheme. Rather than leave fiber positions 5-8 unused, however, four (4) single-mode optical fibers may be disposed in the otherwise unused fiber positions 5-8, thereby enabling simultaneous connectivity with a pair of single- mode duplex connections, or other single-mode connectivity. In this manner, a single multi- fiber connection can support both parallel optical multi-mode connectivity and serial single- mode connectivity simultaneously, thereby allowing easy transition between the two connectivity solutions as requirements change over time.

[0007] One embodiment of the disclosure relates to a hybrid fiber optic cable comprising a plurality of optical fibers. The plurality of optical fibers comprises a plurality of single- mode optical fibers, and a plurality of multi-mode optical fibers. The fiber optic cable further comprises at least one cable jacket surrounding the plurality of optical fibers.

[0008] An additional embodiment of the disclosure relates to a fiber optic trunk cable. The fiber optic trunk cable comprises at least one hybrid fiber optic cable subunit. Each hybrid fiber optic cable subunit comprises a plurality of optical fibers, comprising a plurality of single-mode optical fibers, and a plurality of multi-mode optical fibers. Each hybrid fiber optic cable subunit further comprises at least one surrounding cabling element at least partially surrounding the plurality of optical fibers. The surrounding cabling element may be an elongate binder such as a thread binder or filament binder. The surrounding cabling element may alternatively be a tape, armor, jacket or sheath or others suitable covering. The fibers comprising the subunit may be loose within the subunit, tight buffered or may be in the form of a ribbon. The subunits may also comprise strength elements, water blocking elements or other commonly used cabling elements. The fiber optic trunk cable further comprises a cable jacket or other coverings or binders at least partially surrounding the at least one hybrid fiber-optic cable subunits or the subunits may be stranded together to form a jacketless trunk with or without a binder.

[0009] An additional embodiment of the disclosure relates to a breakout assembly for a hybrid fiber optic cable in the form of at least one harness or in the form of a breakout module containing at least one harness. The at least one harness of the breakout assembly comprises a first multi-fiber connector. The at least one harness of the breakout assembly further comprises at least one multi-mode connector, and a plurality of multi-mode optical fibers connected between the first multi-fiber connector and the at least one multi-mode connector. The at least one harness of the breakout assembly further comprises at least one single-mode connector, and a plurality of single-mode optical fibers connected between the first multi-fiber connector and the at least one single-mode connector.

[0010] Additional features and advantages will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from the description or recognized by practicing the embodiments as described in the written description and claims hereof, as well as the appended drawings.

[0011] It is to be understood that both the foregoing general description and the following detailed description are merely exemplary, and are intended to provide an overview or framework to understand the nature and character of the claims.

[0012] The accompanying drawings are included to provide a further understanding, and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiments), and together with the description serve to explain principles and operation of the various embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG. 1 illustrates a cross-sectional view of exemplary multi-mode and single- mode fibers;

[0014] FIG. 2 illustrates a multi-fiber connector having a multi-fiber ferrule that has a horizontal linear array of fiber positions for receiving a plurality of multi-mode and single- mode optical fibers;

[0015] FIGS. 3A-3C illustrate a plurality of fiber optic cables each having a plurality of single-mode and multi-mode optical fibers;

[0016] FIG. 4 illustrates a breakout module configured to convert between a hybrid multi-mode/single-mode configurations and separated multi-mode configurations and single- mode configurations;

[0017] FIG. 5 illustrates an alternative breakout module having a pair of single-mode LC duplex connectors and four (4) multi-mode LC duplex connectors;

[0018] FIG. 6 illustrates a portion of a fiber optic network including a hybrid multi- mode/single-mode fiber optic cable connected between a pair of fiber optic breakout modules;

[0019] FIG. 7 illustrates a portion of an alternative fiber optic network including a hybrid multi-mode/single-mode fiber optic cable connected between a different pair of fiber optic breakout modules;

[0020] FIG. 8 illustrates an alternative fiber optic network including a hybrid fiber optic cable connected between a pair of multi-fiber jumper cables each connected to a Quad Small Form-factor Pluggable (QSFP) transceiver; and

[0021] FIG. 9 illustrates an alternative fiber optic network including a fiber optic cable connected between a pair of multi-fiber to multi-fiber jumper cables, each connected to a BASE-8 multi-fiber to LC duplex breakout module. DETAILED DESCRIPTION

[0022] Embodiments of the disclosure include a hybrid fiber optic cable comprising a plurality of optical fibers including a plurality of single -mode optical fibers and a plurality of multi-mode optical fibers Embodiments of the disclosure also relate to a terminated fiber optic trunk cable comprising at least one hybrid fiber optic cable subunit terminated with at least one multi-fiber connector. Each hybrid fiber optic cable subunit comprises a plurality of optical fibers, each subunit comprising a plurality of single-mode optical fibers, and a plurality of multi-mode optical fibers. Each hybrid fiber optic cable subunit further comprises at least one surrounding cabling element at least partially surrounding the plurality of optical fibers. The surrounding cabling element may be an elongate binder such as a thread binder or filament binder. The surrounding cabling element may alternatively be a tape, armor, jacket or sheath or others suitable covering. The fibers comprising the subunit may be loose within the subunit, tight buffered or may be in the form of a ribbon. The subunits may also comprise strength elements, water blocking elements or other commonly used cabling elements. The fiber optic trunk cable may further comprise a cable jacket or other coverings or binders at least partially surrounding the at least one hybrid fiber-optic cable subunits or the subunits may be stranded together to form a jacketless trunk with or without a binder. One advantage of this arrangement of fibers is that transition back and forth between single- mode and multi-mode connectivity, or simultaneous use of both types of connectivity is enabled through installation of a single cable. In one exemplary embodiment, without limitation, eight (8) multi-mode fibers are included, corresponding to fiber positions 1-4 and 9-12 of a conventional BASE-8 parallel optical connection scheme. Rather than leave fiber positions 5-8 unused, however, four (4) single-mode optical fibers may be disposed in the otherwise unused fiber positions 5-8, thereby enabling simultaneous connectivity with a pair of single-mode duplex connections, or other single-mode connectivity. In this manner, a single multi-fiber connection can support both parallel optical multi-mode connectivity and serial single-mode connectivity simultaneously, thereby allowing easy transition between the two connectivity solutions as requirements change over time. . In another exemplary embodiment, without limitation, eight (8) multi-mode fibers are included, corresponding to fiber positions 3-10 of a conventional BASE-8 parallel optical connection scheme. Rather than leave fiber positions 1 -2 and 1 1-12 unused, however, four (4) single-mode optical fibers may be disposed in the otherwise unused fiber positions 1 -2 and 11-12, thereby enabling simultaneous connectivity with a pair of single -mode duplex connections, or other single- mode connectivity. In this manner, a single multi- fiber connection can support both parallel optical multi-mode connectivity and serial single-mode connectivity simultaneously, thereby allowing easy transition between the two connectivity solutions as requirements change over time.

[0023] Various embodiments will be further clarified by the following examples. In this regard, FIG. 1 illustrates cross-sectional views of exemplary multi-mode and single -mode fibers according to the prior art. Multi-mode fiber 10 includes a multi-mode core 14 surrounded by protective cladding 16. In this embodiment, the multi-mode core 14 has a diameter DM of 50 μιη, and the entire optical fiber has a diameter DF of 125 μιη. Single- mode fiber 12, on the other hand, includes a core 18 having a diameter DS of 9μιη surrounded by a substantially thicker cladding 20 to achieve the same 125 μιη diameter DF. In this manner, although the cores 14, 18 of the optical fibers 10, 12 have substantially different diameters, the overall diameter DF of both optical fibers 10, 12 are 125 μιη, to ensure compatibility with standardized ferrule sizes. Both optical fibers 10, 12 are also typically enclosed within a protective coating to increase the diameter of the optical fiber 10, 12 to 250 μιη

[0024] Conventional fiber optic trunks and other cables generally use only multi-mode or only single-mode fibers. Because of the distance limitations with multi-mode fiber and the added expense of single-mode solutions, a large proportion of network design is devoted to selecting whether to use single-mode or multi-mode solutions for each leg of the network. In addition, as transceiver technology rapidly evolves, users are transitioning between parallel optical multi-mode solutions and duplex single -mode solutions as the network architecture changes over time.

[0025] In this regard, referring now to FIG. 2, a multi-fiber connector is illustrated having a form factor similar to and/or compatible with the standard multi-fiber connector such as a MTP and/or MPO connector. In this embodiment, the connector 22 includes a multi-fiber ferrule 24 that has a horizontal linear array of fiber positions 26 for receiving a plurality of optical fibers 10, 12. The multi-fiber ferrule 24 may also include one or more alignment features, such as alignment bores 28. As can be seen from FIG. 2, the linear array 26 of fiber positions includes 8 multi-mode optical fibers 10 at positions 1 through 4 and 9 through 12, and four single-mode optical fibers 12 at positions 5 through 8. In this manner, backwards compatibility is maintained with conventional BASE-8 multi-fiber connection schemes, while including additional single-mode functionality at otherwise unused fiber positions 5 through 8.

[0026] Referring now to FIGS. 3 A through 3C, a plurality of fiber optic cables are illustrated. In FIG. 3A, a fiber optic cable subunit 30 is illustrated having a bundle of 8 multi-mode optical fibers 10(1) through 10(4) and 10(9) through 10(12), and 4 single-mode optical fibers 12(5) through 12(8). It should be understood that in FIG. 3A, as well as FIG. 2, fiber positions 1 through 12 correspond to the standard fiber positions 1 through 12 of a multi-fiber adapter array, with each corresponding single -mode or multi-mode optical fiber 10, 12 having a corresponding color. The bundle of optical fibers 10, 12 is surrounded by cable subunit covering 32. The cable subunit 30 may also include strength members 34 such as aramid yarn within the cable subunit covering 32.

[0027] In this embodiment, each of the optical fibers 10, 12 may include one or more indicia, such as color coding, to indicate to which fiber position the optical fiber 10, 12 corresponds. In this regard, the optical fibers 10, 12 may be color coded according to a standard 12-fiber multi- fiber array, according to the fiber positions of the optical fibers 10, 12 discussed above. In this embodiment for example, multi-mode optical fiber 10(1 ) may be blue, multi-mode optical fiber 10(2) maybe orange, multi-mode optical fiber 10(3) may be green, and multi-mode optical fiber 10(4) may be brown. Meanwhile, single-mode optical fiber 12(5) may be slate, single-mode optical fiber 12(6) may be white, single-mode optical fiber 12(7) maybe red, and single-mode optical fiber 12(8) may be black. Finally, multi- mode optical fiber 10(9) may be yellow, multi-mode optical fiber 10(10) may be violet, multi-mode optical fiber 10(11) may be rose, and multi-mode optical fiber 10(12) may be aqua.

[0028] In this manner, multi-mode optical fibers 10 are color coded such that they are assigned to the outside fiber positions 1-4 and 9-12 of a standard multi- fiber connector for a BASE-8 configuration, for example using a universal wiring polarity scheme. At the same time, the otherwise unused fiber positions 5-8 may be occupied by appropriately color coded single-mode optical fibers 12. Either set of optical fibers 10, 12 may be kept "dark" when not in use, or both sets of optical fibers 10, 12 can be used simultaneously.

[0029] Multiple cable subunits 30 can also be bundled together into a larger trunk cable. In this regard, FIG. 3B illustrates a 24-fiber trunk cable 36 having a pair of 12-fiber cable subunits 30 surrounded by a cable jacket 38. An additional layer of strength members 40, such as aramid yarn, may also be included. Likewise, FIG. 3C illustrates a 144-fiber trunk cable 42 having 12, 12-fiber cable subunits 30 disposed therein. The cable subunits 30 are surrounded by a single cable jacket 44, and may include additional layers of strength members 46, such as aramid yarn. In alternate embodiments the trunk cable may not have a jacket and the subunits may be bound together with a binder or other appropriate covering.

[0030] An advantage of this hybrid MTP cable 30, 36, 42 is that the complexity in planning and cabling migration is reduced. Rather than plan out separate single-mode and multi-mode connections at the design phase, the hybrid MTP cables 30, 36, 42 can be used throughout an installation, and their use within the installation can be determined at any time, and can also be changed over time. For example, a user could plan to use only multi-mode fiber for an installation. If transmission distance issues arise at any stage, however, the installation will already have pre-terminated single -mode fiber installed and ready to use, which can be activated without running any new cable. This will allow users to save time and money on planning, and save labor cost on future planning, implementation, and upgrades.

[0031] Referring now to FIG. 4, a breakout module 48 configured to convert between hybrid multi-mode/single-mode configurations and separated multi-mode configurations and single-mode configurations is illustrated. In this embodiment, the breakout module 48 includes a module housing 50. A multi-fiber connector 52 is configured to optically connect to a hybrid multi-mode/single-mode multi-fiber configuration. Meanwhile, the other end of the breakout module 48 includes a pair of single-mode LC duplex connectors 54, for connecting to single-mode LC solutions, such as 40GB or 100GB connectivity, and also includes a BASE-8 multi-fiber connector 56, for connecting to conventional BASE-8 multi- mode solutions, such as 40GB or 100GB parallel optics solutions. In this embodiment, the single-mode LC duplex connectors 54 are optically connected to the single-mode fiber positions, i.e., fiber positions 5 through 8, of multi-fiber connector 52. Likewise, multi-mode multi-fiber connector 56 is optically connected to the multi-mode fiber positions, i.e., fiber positions 1 through 4 and 9 through 12, of multi-fiber connector 52. In this manner, a single connection to multi-fiber connector 52 can support a BASE-8 multi-mode multi-fiber connection, a pair of LC duplex single-mode connections, or both simultaneously. In addition, in this embodiment, it should be noted that the breakout module 48 is sized to be disposed in and backwards compatible with existing 4-slot Pretium EDGE Solutions, as provided by Corning Optical Communications LLC, and may also be sized to be larger or more compact to accommodate alternative solutions, such as 6-slot BASE-8 solutions, for example.

[0032] Referring now to FIG. 5, an alternative breakout module 58 is illustrated. Similar to breakout module 48, breakout module 58 includes a module housing 60. Breakout module 58 includes a similar multi-fiber connector 52 at the rear of breakout module 58, for receiving a hybrid multi-mode/single-mode multi-fiber connection. At the front of breakout module 58, however, in addition to a pair of single -mode LC duplex connectors 54, additional 4 multi-mode LC duplex connectors 62 are disposed on the front of the breakout module 58 as well. In this manner, each of the single -mode and multi-mode fibers connected to multi- fiber connector 52 may be broken out into respective multi-duplex pairs. In addition, it should be understood that it may be desirable to visibly distinguish the multi-mode LC duplex connectors 62 from the single-mode LC duplex connectors 54. In this regard, it may be desirable to include indicia or a distinct coloring on one or both sets of single-mode LC duplex connectors 54, 62. Similar to breakout module 48 of FIG. 4 above, breakout module 58 is sized to be disposed in and backwards compatible with existing 4-slot Pretium EDGE- Solutions, and may also be resized as desired.

[0033] The above embodiments enable a wide variety of connection arrangements to be assembled, with a minimum of disassembly required, and while maximizing the available fiber density. In this regard, FIG. 6 illustrates a portion of a fiber optic network 64 including a hybrid multi-mode/single-mode fiber optic cable 66 connected between a pair of fiber optic breakout modules 48. The respective ends of fiber optic cable 66 are connected to breakout modules 48 by a respective multi-fiber to multi-fiber jumper cable 68. In this regard, two- way communication is enabled for both a pair of single -mode LC duplex connectors as well as a multi-mode BASE-8 multi-fiber connector. [0034] Referring now to FIG. 7, an alternative fiber optic network 70 is illustrated, in which a pair of breakout modules 58 are connected via the hybrid fiber optic cable 66 and multi-fiber to multi-fiber jumper cable 68. In this manner, 2 single-mode LC duplex connection pairs are enabled, as well as 4 multi-mode LC duplex connections.

[0035] Referring now to FIG. 8, another connection scheme is illustrated in which a fiber optic network 72 includes a hybrid fiber optic cable 66 terminated with multi-fiber MTP connector on each leg 74 containing one or more subunits 30 each MTP terminated leg 74connected to an MTP adaptor panel 76. A multi-fiber MTP jumper 78 is connected between each MTP panel 76 and a Quad Small Form-factor Pluggable (QSFP) transceiver 80.

[0036] Referring now to FIG. 9, an alternative fiber optic network 82 includes fiber optic cable 66 connected between a pair of multi-fiber to multi-fiber jumper cables 68, each connected to a BASE-8 multi-fiber to LC duplex breakout module 84. In this embodiment, LC duplex breakout module 84 includes four (4) multi-mode LC duplex connectors 62 only. This permits the LC duplex breakout module 84 to have a smaller form factor than other modules sized to accommodate six (6) LC duplex connections for example. Thus, in this embodiment, only the multimode connections are employed, with the single -mode connections remaining unused. In this manner, the hybrid fiber optic cable 66 is backward compatible with BASE-8 LC duplex solutions.

[0037] Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order.

Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is no way intended that any particular order be inferred.

[0038] It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit or scope of the disclosure. Since modifications combinations, sub-combinations and variations of the disclosed embodiments incorporating the spirit and substance of the disclosure may occur to persons skilled in the art, the disclosure should be construed to include everything within the scope of the appended claims and their equivalents.