EP4594802A1 - Identification and testing of laid optical fiber cables - Google Patents

Abstract

A hardened connector, including a fiber-optic connector, a protective cap body, and a locator fiber routed through the protective cap body, the locator fiber including a first end positioned within an interior cavity of the protective cap body, and a second end positioned exterior to the protective cap body, wherein a test signal transmitted through an optical fiber connected to the hardened connector enters the locator fiber at the first end within the protective cap body and illuminates the second end.

Description

Attorney Docket No.02316.8567WOU1/6652 IDENTIFICATION AND TESTING OF LAID OPTICAL FIBER CABLES CROSS-REFERENCE TO RELATED APPLICATIONS This application is being filed on September 14, 2023, as a PCT International application and claims the benefit of and priority to U.S. Provisional Application No. 63/411,831, filed September 30, 2022, the disclosure of which is hereby incorporated by reference in its entirety. BACKGROUND Fiber optic communication systems are becoming prevalent in part because service providers want to deliver high bandwidth communication capabilities (e.g., data and voice) to customers. Fiber optic communication systems employ a network of fiber optic cables to transmit large volumes of data and voice signals over relatively long distances. Optical fiber connectors are an important part of most fiber optic communication systems. Fiber optic connectors allow two optical fibers to be quickly and demateably optically connected without requiring a splice. Fiber optic connectors can be used to optically interconnect two lengths of optical fiber. Fiber optic connectors can also be used to interconnect lengths of optical fiber to passive and active equipment. Fiber optic cable connection systems are used to facilitate connecting and disconnecting fiber optic cables in the field without requiring a splice. A typical fiber optic cable connection system for interconnecting two fiber optic cables includes fiber optic connectors mounted at the ends of the fiber optic cables, and optionally a fiber optic adapter for mechanically and optically coupling the fiber optic connectors together. Fiber optic connectors sometimes include ferrules that support the ends of the optical fibers of the fiber optic cables, which are typically polished and are often angled. The fiber optic adapter includes co-axially aligned ports (i.e., receptacles) for receiving the fiber optic connectors desired to be interconnected. The fiber optic adapter includes an internal sleeve that receives and aligns the ferrules of the fiber optic connectors when the connectors are inserted within the ports of the fiber optic adapter. With the ferrules and their associated fibers aligned within the sleeve of the fiber optic adapter, a fiber optic signal can pass from one fiber to the next. The adapter also typically has a mechanical fastening arrangement (e.g., a snap-fit arrangement) for mechanically retaining the fiber optic connectors within the adapter. Examples of fiber optic connection systems are described in U.S. Pat. No. 9,482,829, the contents of which are incorporated herein to the extent that the disclosure does not conflict with the teachings herein. Further development in such systems is desired. SUMMARY Certain aspects of this disclosure generally relate to a hardened connector configured to aid technicians and other users in identification and testing of buried drop cables positioned near subscriber locations. In one embodiment, the hardened connector can include a fiber-optic connector, a protective cap body, and a locator fiber routed through the protective cap body, the locator fiber including a first end positioned within an interior cavity of the protective cap body, and a second end positioned exterior to the protective cap body, wherein a test signal transmitted through an optical fiber connected to the hardened connector enters the locator fiber at the first end within the protective cap body and illuminates the second end. Another aspect of the present disclosure relates to a method of testing an optical conductivity of an optical cable, including burying at least a portion of an optical cable terminating in a hardened connector, wherein the hardened connector includes a locator fiber having a first end optically coupled to the optical cable and a second end extending above a surface of the ground, sending a test signal through the optical cable, wherein receipt of the test signal at the second end of the locator fiber confirms proper conductivity, and optionally separating a portion of the locator fiber from the hardened connector. In one embodiment, the protective cap body is an elongate body having a first end and a second end, with a wall positioned therebetween defining an interior cavity into which a portion of the fiber-optic connector is selectively positioned, thereby shielding a terminal end of the optical fiber connected to the hardened connector. In one embodiment, the fiber-optic connector includes a ferrule supporting a terminal end of the optical fiber. In one embodiment, the protective cap body defines an alignment channel configured to at least partially surround the ferrule to aid in alignment of a first end of the locator fiber with the terminal end of the optical fiber. In one embodiment, the fiber- optic connector is a bare optical fiber connector. In one embodiment, the protective cap body is a dust cover. In one embodiment, the protective cap body selectively couples to the fiber-optic connector by at least one of a threaded coupling, keyed coupling arrangement, or partial turn connector. In one embodiment, the fiber-optic connector includes a seal configured to establish and maintain sealing contact with a portion of the interior cavity of the protective cap body. In one embodiment, the protective cap body is tethered to the fiber-optic connector by a lanyard. In one embodiment, the locator fiber has a predetermine length of at least one of about 0.5 meters, about 1 meter, about 2 meters, about 3 meters, or about 4 meters. In one embodiment, the locator fiber is a plastic optical fiber. In one embodiment, the locator fiber is positioned within an aperture defined by the protective cap body, with an adhesive sealing the aperture and fixedly securing the locator fiber to the protective cap body. In one embodiment, a portion the locator fiber is selectively separable from the hardened connector. In one embodiment, the locator fiber defines a materially weakened portion configured to encourage separation of the locator fiber from the hardened connector at the materially weakened portion when an external force is applied. A variety of additional aspects will be set forth in the description that follows. The aspects can relate to individual features and to combinations of features. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the broad inventive concepts upon which the examples disclosed herein are based. BRIEF DESCRIPTION OF THE DRAWINGS The disclosure can be more completely understood in consideration of the following detailed description of various embodiments of the disclosure, in connection with the accompanying drawings, in which: FIG.1 is a schematic diagram of an optical cable network, in accordance with an embodiment of the disclosure. FIG. 2 is a cross-sectional, perspective view of a hardened connector, in accordance with an embodiment of the disclosure. FIG.3 is a cross-sectional, perspective view of the hardened connector of FIG.2, in which a protective cap body is separated from a fiber-optic connector, in accordance with an embodiment of the disclosure. FIG.4 is a perspective view of a hardened connector including a locator fiber, in accordance with an embodiment of the disclosure. FIG.5 is a schematic diagram of an optical cable network, in which a portion of a drop cable including a hardened connector is positioned within a trench, in accordance with an embodiment of the disclosure. FIG. 6 is a schematic diagram of an optical cable network of FIG. 5, in which a portion of a locator fiber is separated from the hardened connector, and the hardened connector is buried within the trench positioned near a subscriber location, in accordance with an embodiment of the disclosure. While embodiments of the disclosure are amenable to various modifications and alternative forms, specifics thereof shown by way of example in the drawings will be described in detail. It should be understood, however, that the intention is not to limit the disclosure to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the subject matter as defined by the claims. DETAILED DESCRIPTION Various embodiments of the present disclosure will be described in detail with reference to the drawings, where like reference numerals represent like parts and assemblies throughout the several views. Reference to various embodiments does not limit the scope of the invention, which is limited only by the scope of the claims attached hereto. Additionally, any example set forth in the specification is not intended to be limiting and merely sets forth some of the many possible embodiments for the claimed invention. With reference to FIG.1, a schematic diagram of an optical cable network 100 is depicted in accordance with an embodiment of the disclosure. Within the network 100, one or more fiber-optic cables are typically routed from a service provider (e.g., in the form of one or more feeder cables 102), to an end user or network subscriber (e.g., in the form of one or more drop cables 104). Often the one or more feeder cables 102 are routed through a node 106, which can be in the form of a cabinet or other enclosure, typically serving a number of network subscribers. Within the node 106, various functions may be performed on the feeder cables 102, such as splicing sections of optical cable, splitting the optical cable, routing the optical cable through a wave division multiplexer, or connecting the optical cable through one or more fiber-optic adapters. Although the nodes 106 may be positioned above ground, typically the final leg of the drop cable 104 is buried in a trench routed near the subscriber location. In many cases, the trench can have a depth of 1 meter or more. Where the drop cable 104 is laid for future use (e.g., near the site of a future building location), the drop cable 104 may remain in an unconnected state, such that a pre-terminated, ruggedized end of the of the drop cable 104 (often including a standard connector) remains buried near the future subscriber location. Although the industry has developed various methods of testing and identifying unconnected, buried drop cables 104, less time consuming and more cost- effective solutions always desirable. With additional reference to FIGS. 2-4, a hardened connector 108 having structure configured to aid in proper identification of buried drop cables is depicted in accordance with an embodiment of the disclosure. In one embodiment, the hardened connector 108 includes a protective cap body 110 (occasionally referred to as a "dust cover") operably coupled to a locator fiber 112, which in some embodiments can be routed out of the trench to extend above the ground near the future subscriber location to aid in proper identification and testing of a buried drop cable 104. In embodiments, the protective cap body 110 can generally be configured to couple to a standardized fiber-optic connector 114 located on an end of the drop cable 104, in a manner that generally seals and protects the fiber-optic connector 114 for future use. For example, in some embodiments, the protective cap body 110 can generally be configured as an elongate body having a first end 116 and a second end 118, with the wall 120 positioned therebetween defining an interior cavity 122 into which a terminal end 124 of the fiber-optic connector 114 can be selectively positioned, thereby shielding a terminal end 124 of one or more optical fibers carried by the drop cable 104. Although FIGS. 2-4 depict the terminal end 124 as being encapsulated in a ferrule 126, use of a hardened fiber-optic connector 114 with a non-ferruled or bare optical fiber is also contemplated, provided that the protective cap body 110 can be coupled to the fiber-optic connector 114 in a manner that generally seals and protects the terminal end 124 of one or more optical fibers carried by the drop cable 104. In some embodiments, the protective cap body 110 can be operably coupled to the fiber-optic connector 114 by way of a coupling 115, such as a threaded coupling like that depicted in FIGS. 2 and 3. In other embodiments, the protective cap body 110 can be coupled to the fiber-optic connector 114 through a keyed coupling arrangement (e.g., bayonet coupling, etc.) or a partial turn connector such as that described in US Patent Publ. No. 2022/0299713, the contents of which are incorporated by reference to the extent that the disclosure does not conflict with the teachings herein. Further, in some embodiments, the fiber-optic connector 114 can carry a seal 127 configured to establish and maintain sealing contact with a portion of the interior cavity 122, thereby further inhibiting the intrusion of moisture and other contaminants. For convenience, in some embodiments, the protective cap body 110 can be tethered to the fiber-optic connector 114, for example via lanyard 128. The locator fiber 112 can be configured to traverse through an aperture 130 defined in proximity to the second end 118 of the protective cap body 110 , such that the locator fiber 112 traverses from an exterior of the protective cap body 110 to the interior cavity 122 for optical coupling to the terminal end 124 of one or more optical fibers carried by the drop cable 104. In some embodiments, the protective cap body 110 can define an alignment channel 129 (e.g., to at least partially surround the ferrule 126) to aid in alignment of a first end 131 of the locator fiber with the terminal end 124 of one or more optical fibers carried by the drop cable 104. The aperture 130 through which the locator fiber 112 traverses can be environmentally sealed to inhibit the intrusion of moisture and other contaminants. For example, in one embodiment, once the locator fiber 112 has been positioned within the aperture 130 and adhesive 132 can be applied to the connection, thereby both sealing the aperture 130 and fixedly securing the locator fiber 112 to the protective cap body 110 . In other embodiments, at least a portion of the protective cap body 110 can be injection molded around a portion of locator fiber 112, such that the protective cap body 110 itself maintains sealing contact with the locator fiber 112. The locator fiber 112 can be of a predetermined length. For example, in some embodiments, a locator fiber 112 can be at least about 0.5 m, 1 m, 2 m, 3 m, or 4 m in length. In some embodiments, the locator fiber 112 can be constructed of a plastic optical fiber, a portion of which can be selectively removed from the hardened connector 108 and discarded after use; although the use of other materials in the construction of the locator fiber 112 are also contemplated. For example, in some embodiments, the locator fiber 112 can include at least one of a groove 134, notch, tear, perforation, or other materially weakened portion configured to encourage separation of the locator fiber 112 at the groove 134 when an external force (e.g., tensile force, shear force, etc.) is applied to the locator fiber 112, such that only a small portion of the locator fiber 112 remains attached to the hardened connector 108. With additional reference to FIGS.5 and 6, in operation, one or more drop cables 104 can be routed from a node 106 connection to one or more feeder cables 102. Along the routing to the subscriber location, a final leg of the drop cable 104 can be positioned in a trench 136, with the hardened connector 108 including the standardized fiber-optic connector 114, protective cap body 110 and locator fiber 112 positioned within the trench 136 near the subscriber location. To identify and test an optical conductivity of the drop cable 104, in some embodiments, at least a portion of the locator fiber 112 can be configured to extend from the hardened connector 108 located in the trench 136 to a position above ground, such that a second end 138 of the locator fiber 112 is located above the ground surface 140 when the trench 136 is backfilled. In embodiments, a test signal (e.g., electromagnetic radiation from a 650 nm laser 142, or the like) can be introduced to one of the feeder cables 102 or a portion of the node 106 (sometimes referred to as a "point-of-presence") to verify routing and test optical conductivity of the drop cable 104. Following observation of the test signal, at least a portion of the locator fiber 112 can be removed from the hardened connector 108. For example, in one embodiment, a user can pull on the portion of the locator fiber 112 positioned above the ground surface 140, thereby causing the locator fiber 112 to break at the groove 134, such a portion of the locator fiber 112 can be removed and discarded, leaving the standardized fiber-optic connector 114 and protective cap body 110 buried within the trench 136. Accordingly, in embodiments, no portion of the hardened connector 108 extends above the ground surface 140 upon completion of testing and identification of the unconnected, buried drop cables 104. From the foregoing detailed description, it will be evident that modifications and variations can be made in the devices and methods of the disclosure without departing from the spirit or scope of the invention.

Claims

What is claimed is: 1. A hardened connector, comprising: a fiber-optic connector; a protective cap body; and a locator fiber routed through the protective cap body, the locator fiber including a first end positioned within an interior cavity of the protective cap body, and a second end positioned exterior to the protective cap body, wherein a test signal transmitted through an optical fiber connected to the hardened connector enters the locator fiber at the first end within the protective cap body and illuminates the second end.

2. The hardened connector of claim 1, wherein the protective cap body is an elongate body having a first end and a second end, with a wall positioned therebetween defining an interior cavity into which a portion of the fiber-optic connector is selectively positioned, thereby shielding a terminal end of the optical fiber connected to the hardened connector.

3. The hardened connector of claim 1, wherein the fiber-optic connector includes a ferrule supporting a terminal end of the optical fiber.

4. The hardened connector of claim 3, wherein the protective cap body defines an alignment channel configured to at least partially surround the ferrule to aid in alignment of a first end of the locator fiber with the terminal end of the optical fiber.

5. The hardened connector of claim 1, wherein the fiber-optic connector is a bare optical fiber connector

6. The hardened connector of claim 1, wherein the protective cap body is a dust cover.

7. The hardened connector of claim 1, wherein the protective cap body selectively couples to the fiber-optic connector by at least one of a threaded coupling, keyed coupling arrangement, or partial turn connector.

8. The hardened connector of claim 1, wherein the fiber-optic connector includes a seal configured to establish and maintain sealing contact with a portion of the interior cavity of the protective cap body.

9. The hardened connector of claim 1, wherein the protective cap body is tethered to the fiber-optic connector by a lanyard.

10. The hardened connector of claim 1, wherein the locator fiber has a predetermine length of at least one of about 0.5 meters, about 1 meter, about 2 meters, about 3 meters, or about 4 meters.

11. The hardened connector of claim 1, wherein the locator fiber is a plastic optical fiber.

12. The hardened connector of claim 1, wherein the locator fiber is positioned within an aperture defined by the protective cap body, with an adhesive sealing the aperture and fixedly securing the locator fiber to the protective cap body.

13. The hardened connector of claim 1, wherein a portion the locator fiber is selectively separable from the hardened connector.

14. The hardened connector of claim 1, wherein the locator fiber defines a materially weakened portion configured to encourage separation of the locator fiber from the hardened connector at the materially weakened portion when an external force is applied.

15. A method of testing an optical conductivity of an optical cable, comprising: burying at least a portion of an optical cable terminating in a hardened connector, wherein the hardened connector includes a locator fiber having a first end optically coupled to the optical cable and a second end extending above a surface of the ground; sending a test signal through the optical cable, wherein receipt of the test signal at the second end of the locator fiber confirms proper conductivity.

16. The method claim 15, further comprising separating a portion of the locator fiber from the hardened connector.