Fiber optic connector with protective cap

[0001] This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/906,786 filed Mar. 13, 2007, which application is hereby incorporated by reference in its entirety.

[0002] The present disclosure relates to fiber optic data transmission, and more particularly to fiber optic cable connection systems.

[0003] Fiber optic cables are widely used to transmit light signals for high speed data transmission. A fiber optic cable typically includes: (1) an optical fiber or optical fibers; (2) a buffer or buffers that surrounds the fiber or fibers; (3) a strength layer that surrounds the buffer or buffers; and (4) an outer jacket. Optical fibers function to carry optical signals. A typical optical fiber includes an inner core surrounded by a cladding that is covered by a coating. Buffers (e.g., loose or tight buffer tubes) typically function to surround and protect coated optical fibers. Strength layers add mechanical strength to fiber optic cables to protect the internal optical fibers against stresses applied to the cables during installation and thereafter. Example strength layers include aramid yarn, steel and epoxy reinforced glass roving. Outer jackets provide protection against damage caused by crushing, abrasions, and other physical damage. Outer jackets also provide protection against chemical damage (e.g., ozone, alkali, acids).

[0004] 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 an adapter for mechanically and optically coupling the fiber optic connectors together. Fiber optic connectors generally include ferrules that support the ends of the optical fibers of the fiber optic cables. The end faces of the ferrules are typically polished and are often angled. The adapter includes co-axially aligned ports (i.e., receptacles) for receiving the fiber optic connectors desired to be interconnected. The 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 adapter. With the ferrules and their associated fibers aligned within the sleeve of the 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. One example of an existing fiber optic connection system is described in U.S. Pat. Nos. 6,579,014, 6,648,520, and 6,899,467.

[0005] One aspect of the present disclosure relates to an assembly including a fiber optic connector having an interface end that can be covered by a protective cap. The interface end of the fiber optic connector includes a ferrule. Structure is provided within the protective cap for preventing misalignment of a ferrule.

[0006] A variety of additional inventive aspects will be set forth in the description that follows. The inventive aspects can relate to individual features and to combinations of features. It is to be understood that both the forgoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the broad inventive concepts upon which the embodiments disclosed herein are based.

[0014] FIG. 1 illustrates a fiber optic connector assembly 20 having features that are examples of inventive aspects in accordance with the principles of the present disclosure. The fiber optic connector assembly 20 includes a fiber optic connector 22 and a cap 24 for protecting a connector interface end 26 of the fiber optic connector 22. The fiber optic connector 22 includes an outer housing 28 and a connector interface housing 30. The connector interface housing 30 supports a ferrule 32 located at the connector interface end 26 of the fiber optic connector 22. Referring to FIG. 2, a base end 31 of the connector interface housing 30 is supported at a retention block 34 mounted within the outer housing 28. A stabilizing structure 36 (see FIG. 7) is provided within the cap 24 for maintaining alignment of the connector interface housing 30 and ferrule 32 relative to the outer housing 28. When the cap 24 is mounted over the connector interface end 26 of the fiber optic connector 22, the stabilizing structure 36 compresses against the retention block 34 to prevent movement of the retention block 34 thereby ensuring that the connector interface housing 30 and its corresponding ferrule 32 are properly oriented relative to the outer housing 28.

[0015] The outer housing 28 of the fiber optic connector 22 is elongated along a central axis 40 and includes a first end 42 positioned opposite from a second end 44. The first end 42 of the outer housing 28 is positioned at the connector interface end 26 of the fiber optic connector 22 and includes a pair of opposing extensions or paddles 46 positioned on opposite sides of the connector interface housing 30. The paddles 46 are generally parallel to the central axis 40 and are separated from one another by a gap 48 in which the connector interface housing 30 is located. The second end 44 of the outer housing 28 is adapted to receive a fiber optic cable 50. A resilient boot 52 can be positioned over the second end 44 of the outer housing 28 to provide bend radius protection at the interface between the outer housing 28 and the fiber optic cable 50.

[0016] Referring still to FIG. 1, the outer housing 28 of the fiber optic connector 22 defines an outer circumferential groove 54 positioned near the first end 42 of the outer housing 28. A sealing member 56 such as a resilient O-ring is mounted in the circumferential groove 54. The fiber optic connector 22 also includes a retention nut 58 rotatably mounted about the exterior of the outer housing 28. The retention nut 58 is mounted between the resilient boot 52 and an outer shoulder 60 of the outer housing 28 and is free to be manually turned relative to the outer housing 28 about the central axis 40. The retention nut 58 includes an externally threaded portion 62 and a gripping portion 64. The gripping portion 64 includes a plurality of flats that allow the gripping portion 64 to be easily grasped to facilitate manually turning the retention nut 58 about the central axis 40.

[0017] The fiber optic cable 50 can include at least one optical fiber capable of carrying optical signals. The optical fiber can include a core surrounded by cladding. The core is the light-conducting central portion of the optical fiber. The cladding surrounds the core and is composed of a material having a lower index of refraction than the material of the core. Light is internally reflected within the core to transmit the optical signal along the core. The optical fiber can be protected within a buffer tube. The fiber optic cable can also include strength members within the fiber optic cable to increase the tensile strength of the fiber optic cable. The optical fiber, strength members, buffer tube and other cable components can be surrounded by an outer jacket or sheath that provides a protective covering for the cable components. As shown at FIGS. 2 and 3, the fiber optic cable 50 includes a central buffer tube 70 containing at least one optical fiber 72. Strength members 74 are positioned on opposite sides of the central buffer tube 70. The strength members 74 and the buffer tube 70 are positioned within an outer jacket 76 of the fiber optic cable 50.

[0018] The fiber optic cable 50 enters the fiber optic connector 22 through the second end 44 of the outer housing 28. The optical fiber 72 of the fiber optic cable 50 has an end portion that is mounted within the ferrule 32. As shown at FIG. 3, the buffer tube 70 and the strength members 74 of the fiber optic cable 50 are anchored within corresponding slots provided within the retention block 34. In certain embodiments, a bonding material such as an adhesive (e.g., epoxy) can be used to anchor the strength members 74 and the buffer tube 70 within the retention block 34. A crimp sleeve 78 is mounted about the exterior of the retention block 34 to further mechanically secure the strength members 74 and the buffer tube 70 within the retention block 34. The base end 31 of the connector interface housing 30 is anchored within a recess 106 provided within an end face 102 of the retention block 34. The fiber optic connector 22 also includes a ferrule holder 104 positioned within the connector interface housing 30 for supporting the ferrule 32. A base end 107 of the ferrule holder 104 is also anchored within the retention block 34. When the fiber optic connector 22 is assembled, the retention block 34 is anchored (e.g., bonded by an adhesive material) within the outer housing 28 with the connector interface housing 30 positioned between the paddles 46 at the connector interface end 26 of the fiber optic connector 22.

[0019] Referring now to FIGS. 4-6, the cap 24 of the fiber optic connector assembly 20 includes a cap housing 80 defining an interior 82 adapted to receive the connector interface end 26 of the fiber optic connector 22. The cap housing 80 includes an open end 86 positioned opposite from a closed end 88. A generally cylindrical outer wall 87 of the cap housing 80 extends from the open end 86 to the closed end 88. Internal threads 90 are defined at the inside surface of the outer wall 87 adjacent the open end 86 of the cap housing 80. The inside surface of the outer wall 87 also includes a sealing surface 89 provided adjacent the internal threads 90. The stabilizing structure 36 is provided within the interior 82 adjacent the closed end 88 of the cap housing 80. In the depicted embodiment, the stabilizing structure 36 is shown as a cylindrical member 92 having a base end 94 integrally formed with the closed end 88 of the cap housing 80. In alternative embodiments, the cylindrical member 92 can be a separate element from the cap housing 80. The cylindrical member 92 has an inner diameter sized larger than a perimeter of the connector interface housing 30 such that the connector interface housing 30 can fit within the interior of the stabilizing structure 36. The stabilizing structure 36 also includes an end 98 adapted to engage the end face 102 of the retention block 34 when the cap 24 is mounted over the connector interface end 26 of the fiber optic connector 22. In certain embodiments, the cap 24 and the stabilizing structure 36 have a molded plastic construction and can be molded as a unitary one-piece part.

[0020] In use, the cap 24 is inserted over connector interface end 26 of the fiber optic connector 22 to protect the connector interface housing 30 and its corresponding ferrule 32. Once the cap 24 is inserted over the connector interface end 26, the externally threaded portion 62 of the retention nut 58 is threaded into the internal threads 90 of the cap 24. As the retention nut 58 is tightened, the cap 24 is drawn toward the fiber optic connector 22 until the end 98 of the stabilizing structure 36 seats firmly against the end face 102 of the retention block 34. As so positioned, the connector interface housing 30 is positioned within the cylindrical member 92 with the cylindrical member 92 and the ferrule 32 being concentric with the central axis 40 (see FIG. 7). Further more, the paddles 46 of the fiber optic connector 22 are located between the cylindrical member 92 and the outer wall 87 of the cap housing 80. With the cap 24 positioned as described above, the cylindrical member 92 presses against the end face 102 of the retention block 34 to prevent forward movement or lateral tilting of the retention block 34 within the outer housing 28 of the fiber optic connector 22. In this way, misalignment of the connector interface housing 30 and its corresponding ferrule 32 with respect to the central axis 40 is prevented. Additionally, the sealing member 56 of the fiber optic connector 22 contacts the sealing surface 89 within the cap housing 80 to form an annular seal that prevents moisture or other contaminants from reaching the connector interface end 26 of the fiber optic connector 22.

[0021] From the forgoing detailed description, it will be evident that modifications and variations can be made in the devices of the disclosure without departing from the spirit or scope of the invention.