Abstract:
A connector is provided for use in fiber to the desk applications. The connector according to the present invention includes a main housing with a passageway therethrough, a ferrule assembly mountable to the main housing, and a splice member. The connector also includes a latch on at least one exterior surface of the main housing to engage a corresponding structure in an adapter sleeve.

Description:
BACKGROUND 
     The present invention is directed to a fiber optic connector and an associated adapter. More specifically, the fiber optic connector and adapter are designed primarily for use in fiber-to-the-desk (FTTD) applications, where an inexpensive, quickly installable connector is needed. Typically, this connector is used in “behind the wall” applications. That is, the connector according to the present invention will be installed by the installers behind the connection point for the users of the FTTD applications (i.e., behind the wall, in gang boxes, panels, etc.) Since they are “behind the wall” and will not be subject to the typical stresses imparted on normal fiber optic connectors, they do not need the mechanical strength that is designed into normal fiber optic connectors. As a result, the connection point of the optical fibers with these connectors can be less substantial, and therefore easier to access and connect. 
     While there are other available connectors designed for in-wall applications (NTT&#39;s SC plug/jack connector and Siecor&#39;s Plug &amp; Jack Connectors, for example), they typically terminate only one fiber, require an epoxy or other adhesive to mount, as well as require polishing of the ferrule end face. The installation cost and difficulty of such connectors is high, and the connection is permanent and does not easily allow changes once the connection is finished. Also, when multiple optical fibers are required in the FTTD application, the installer must not only install multiple connectors, but also a corresponding number of adapters, which further increases costs. 
     Thus, a need exists for an inexpensive connector that can be quickly and removably mounted on at least one optical fiber for use behind the wall. 
     SUMMARY OF THE INVENTION 
     Among the objects of the present invention is to provide a fiber optic connector that is installed on the ends of a fiber optic cable easily, is removable, and is mountable in conventional panels or cutouts. It is also an object of the present invention to provide a fiber optic connector and an associated sleeve to receive the fiber optic connector according to the present invention. 
     Other objects and advantages of the present invention will become apparent from the following detailed description when viewed in conjunction with the accompanying drawings, which set forth certain embodiments of the invention. The objects and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. 
     To achieve the objects and in accordance with the purposes of the invention as embodied and broadly described herein, the invention comprises a fiber optic connector for mounting on respective end portions of a plurality of optical fibers, the connector comprising a main housing having a passageway therethrough to receive the plurality of optical fibers, a ferrule assembly mountable in the main housing and in communication with the passageway, the ferrule assembly having a plurality of fiber bores for securing optical fiber stubs therein, and a splice member insertable into the main housing, the splice member configured to hold the optical fiber stubs and the end portions of the optical fibers in mechanical and optical alignment. 
     To achieve the objects and in accordance with the purposes of the invention as embodied and broadly described herein, the invention also comprises a fiber optic connector for mounting on an end portion of at least one optical fiber, the connector comprising, a main housing having a passageway therethrough to receive the at least one optical fiber, a ferrule assembly mountable in the main housing and in communication with the passageway, the ferrule assembly having at least one fiber bore for securing at least one optical fiber stub therein, and a splice member insertable into the main housing, the splice member configured to hold the at least one optical fiber stub and the end portion of the at least one optical fiber in mechanical and optical alignment. 
     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 invention as claimed. 
     The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective of the connector according the present invention; 
     FIG. 2 is a exploded view of the connector of FIG. 1; 
     FIG. 3 is a front end view of the connector of FIG. 1; 
     FIG. 4 is a top view of the connector of FIG. 1; 
     FIG. 5 is a cross-sectional view of the connector of FIG. 1 along the line  5 — 5  in FIG. 4; 
     FIG. 6 is a cross-sectional view of the connector of FIG. 1 along the line  6 — 6  in FIG. 5; 
     FIG. 7 is a cross-sectional view of the connector of FIG. 1 along the line  7 — 7  in FIG. 4; 
     FIG. 8 is a perspective view of the connector of FIG. 1 with an adapter to be used with an MT-RJ connector; 
     FIG. 9 is a perspective view of the connector and adapter of FIG. 8 from the other side; 
     FIG. 10 is a perspective view of the connector of FIG. 1 with an adapter to be used with an SC-DC connector; and 
     FIG. 11 is a perspective view of the connector and adapter of FIG. 10 from the other side; 
     FIG. 12 is a perspective view of a different embodiment of the fiber optic connector according to the present invention to be used with an adapter for two LC connectors. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A fiber optic connector  10  is shown in FIG.  1  and in an exploded perspective view in FIG.  2 . Referring to FIG. 2, fiber optic connector  10  includes main housing  12  and a back plate or back member  14  to retain splice member  16  and the spring  18  in the main housing  12 . A crimp tube  19  is insertable in the backside of back member  14  to hold the optical fiber cable relative to the connector  10 . A button  21  inserted in opening  23  on the top of the housing  12  is used to depress splice member  16  down and away from a flat surface  20  inside passageway  22 . Passageway  22  extends through main housing  12 . See FIG.  5 . Splice member  16  is resiliently pressed upward against the flat surface  20  in housing  12  by a spring  18 . Spring  18  is shown as a cylindrical spring, but could be any type of a resilient element including a leaf spring. 
     A ferrule assembly  24  (which may be of any configuration, although a DC ferrule made by Siecor Corp. of Hickory, N.C. is shown) is inserted into the front part  38  of the housing  12 . Preferably, fiber optic stubs  26 , which will mechanically and optically connect with the optical fibers from the cable, are secured within bores of the ferrule assembly  24 , and then the front face  28  of ferrule assembly  24  is polished. The fiber optic connector  10  also includes, in this preferred embodiment, two guide pins  30  and a ferrule/guide pin jacket  32  to hold the guide pins in the side grooves  34  of the ferrule assembly  24 . It should be understood however, that the jacket  32  is not necessary and can be replaced by any structure (e.g., an o-ring, a tie, etc.) that would keep the pins  30  aligned in the grooves  34  on either side of the ferrule assembly  24 . Preferably, the ferrule assembly  24  is fixed in the front portion  38  of the main housing  12  by an adhesive, such as epoxy or an equivalent. See, e.g., FIGS. 5 and 6. However, it may also be possible that the housing  12  and ferrule assembly  24  be of a unitary construction. 
     Now referring to the cross sections of the fiber optic connector  10  as shown in FIGS. 5-7, the ferrule assembly  24 , typically with fiber optic stubs  26  already in place, is mounted in the front portion  38  of the main housing  12 . A rearward portion of the ferrule assembly  24  is in communication with passageway  22 . Splice member  16  is supported by the spring  18  in the passageway  22 , which extends from the front portion  38  behind ferrule assembly  24  through to the rearward portion  40  of main housing  12 . As shown in FIGS. 5 and 7, spring  18  biases the splice member  16  against the top surface  20  of main housing  12  to hold the fiber optic stubs  26  and the optical fibers in mechanical and optical alignment. In FIGS. 4-6, back member  14  is shown attached to the rear portion  40  of main housing  12 . As can be seen in these figures, the spring element  18  is in an opening  42  adjacent to and in communication with the passageway  22 . Button  21  is shown in opening  23  in main housing  12 , and in conjunction with FIG. 7, it can be seen that two clip members  44  engage an inner portion of main housing  12  to prevent the button  21  from being lifted or falling out of main housing  12 . Additionally, as can be seen in FIG. 7, button  21  has two downward projecting legs  46  to engage and depress the splice member  16 , thereby allowing optical fibers to be inserted between the upper surface  20  and the grooves  48  (see FIG. 6) in the splice member  16 . The button  21  when depressed moves the splice member  16  only 100 μm, a sufficient distance to allow the optical fibers to be inserted into the grooves  48 , but not so as to allow them to be inserted anywhere else in connector  10 . This arrangement ensures that the optical fibers will be in mechanical and optical contact with the fiber optic stubs  26 . 
     In the embodiment shown in the figures, the grooves are shown in splice member  16 . However, it is possible for the grooves  48  to also be formed in either the flat upper surface  20  in the main housing  12  or in both the upper surface  22  of the main housing  12  and in the splice member  16  in order to provide a channel for the optical fibers. Although not shown in FIG. 6, the optical fiber stubs  26  would extend rearwardly from the ferrule assembly  24  about half the distance to the back member  14  along the grooves  48  in splice member  16 . 
     As shown in detail in FIG. 6, the back member  14  has an opening  50  that is bifurcated into two openings  52  to receive the optical fibers from the optical cable (not shown). In the preferred embodiment in which the ferrule assembly  24  is a DC ferrule, the back member  14  has two fiber bores  52 , which correspond to the two grooves  48  in the splice member  16  and bores in ferrule assembly  24 . Other ferrule assemblies having a differing number of fiber bores would have a corresponding number of grooves  48  in the splice member  16 , or upper surface  20  of the housing  12 , and back member  14 . Alternatively, the fiber bores  52  could be located in elements other than the back member  14 . For example, the bores  52  could be at the front end of crimp tube  19  or on the back end of splice member  16  and/or upper surface  20  of the main housing  12 . The strain relief boot  54  of FIGS. 1,  4 , and  8 - 12  are not shown in FIGS. 5 and 6 so that the crimp tube can be clearly seen. 
     As seen in FIGS. 1,  3 , and  4 , the fiber optic connector  10  presents a configuration that mimics the MT-RJ configuration. However, as can be seen from these figures, the fiber optic connector  10  includes two latches  35  on the outside surface  36  of the fiber optic connector  10  to allow it to engage an associated adapter, shown in FIGS. 8-12, rather than the standard MT-RJ latch. As discussed more fully below, this allows the user to change the polarity. 
     FIGS. 8-12 show fiber optic connector  10  of the present invention with an associated adapter  60 . Adapter  60  is configured on a first side  62  to engage and hold fiber optic connector  10  in association with latches  35 . In FIGS. 8 and 9 second side  64  of adapter  60  is configured to receive a MT-RJ type connector. (The internal configuration of the second side  64  is described in detail in copending application Ser. No. 09/118,440, assigned to same assignee as the present invention, the contents of which are incorporated herein by reference.) As the ferrule assembly  24  and fiber optic connector  10  in FIG. 8 has guide pins, the MT-RJ connector (not shown) that would be mated in FIG. 8 would not need the guide pins. Conversely, if the MT-RJ connector had alignment pins, then connector  10  would not need to have the pins. Typically, the connector mounted behind the wall, connector  10  in this application would already have alignment pins installed and the user&#39;s connector would not, and could not, have alignment pins. 
     The preferred outer configuration adapter  60  is configured such that it will fit a standard RJ-45 keystone footprint faceplate. Therefore, adapter  60  could be inserted into the faceplate by the installer, with second side  64  extending outward towards the desk or end user. The installer would then insert fiber optic connector  10  into first side  62  to provide a fiber connection at the desk or at the wall. Additionally, although not shown in the figures, the second side  64  of the adapter could come in to the wall surface at angles other than 90°, e.g., 45°, 30°, etc. The adapter  60  could also be configured to fit other standard openings, provided the openings allowed the adapter to have sufficient internal space to receive the desired connectors. 
     FIGS. 10 and 11 illustrate the fiber optic connector  10  with an adapter  60  that is configured to have a DC ferrule from Siecor Corp. inserted on the second side of the adapter. As can be seen in FIG. 11, the adapter  60  has a round opening  66  in the center to allow the DC ferrule (see FIG. 2) with two semi-circular slots  68 . The guide pins  30  on each side of the connector  10  align in slots  68 , and in conjunction with the opening  66 , align the ferrule assembly  24  in the adapter  60  to mate with a connector inserted from the other side of the adapter. It should be noted that fiber optic connector  10  can be inserted in one of two directions. As can be seen from FIG. 4, fiber optic connector  10  is symmetrical about the line for the cross section of FIG.  5 . Therefore, the installer could, in effect, reverse the polarity of the connection by simply turning fiber optic connector over 180° (with the button  21  facing downward rather that upward) and plugging it back in to the first side  62 . However, the normal installation is with the button  21  being upward, or at least using the button  21  as the reference point. Although not shown, a mark or indicator could be included on one surface of the adapter  60  to indicate the correct orientation for the user. The person installing the connector  10  would then know how to orient connector  10  to assist the user in achieving the correct polarity. 
     FIG. 12 shows yet another embodiment of adapter  60  as well as a new configuration for the front of fiber optic connector  10 . In this embodiment, two is individual ferrules are secured into the front surface of the main housing  12  rather than a single dual fiber ferrule as shown in the preferred embodiment. The remainder of the fiber optic connector  10  will be the same except the grooves in the splice member  16  and/or the upper surface  20  of passageway  22  would be further apart to coincide with the wider-spaced ferrules of this embodiment. The front side  64  of adapter  60  in FIG. 10 corresponds to the LC connector, sold by Lucent Technologies, Inc.