Abstract:
A spacer is provided to assist in orienting and aligning optical fibers in a connector. The spacer may also provide strain relief for the optical fibers. The spacer is especially useful with smaller optical fibers that are to be used in connectors that are designed for larger optical fibers or cables. Openings extending through the spacer, which may have a channel that allows for communication between the openings. The spacer can have as many openings as there are fibers for the connector. The spacer also assists in holding the fibers during the cleaving process so that the fibers are cleaved simultaneously and consistently.

Description:
BACKGROUND 
     The present invention is directed to a spacer and strain relief for a fiber optic connector. More specifically, the spacer and strain relief are designed primarily for use with multi fiber connectors in which inserting the fibers into the individual fiber bores is difficult. In particular, the present invention assists the user to terminate loose-tube type cables or two (or more) individual fibers. 
     Many of the existing fiber optic connectors have been designed to accommodate 900 micron tight buffered optical cables, which have been prevalent in the industry. However, newer smaller cables are being designed and used. One such cable is the MIC 2  cable available from Corning Cable Systems of Hickory, N.C., the assignee of this application. Rather than redesigning the connectors (and any associated items) for the smaller cables, it is preferable to be able to retrofit the connector or otherwise accommodate the smaller cables. At the same time, it is necessary to be able to strain relieve these smaller fibers. Since these smaller fibers do not have the additional buffer material around them that the 900 micron tight buffered optical cables do, it is necessary to provide strain relief without simply crimping a crimp band or a lead-in tube around the fibers. Doing so would cause damage to the optical fibers, degrading or even eliminating the signal passing that point. 
     Thus, a need exists for a spacer and strain relief that can be used with multifiber connectors that assists in spacing the optical fibers and strain relieving the fibers at the same time. 
     SUMMARY OF THE INVENTION 
     Among the objects of the present invention is to provide a spacer for a fiber optic connector that spaces the ends of an optical fiber easily and may also be used for strain relief that the same time. 
     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 spacer for use with a multifiber connector, the spacer includes an elongated central element having a first and second end and at least two openings extending between the first and second ends of the elongated central element. 
     To achieve the objects and in accordance with the purposes of the invention as embodied and broadly described herein, the invention also comprises a resilient elongated central element having a first and second end, and at least two openings extending between the first and second ends of the elongated central element, the openings have centers that are about 750 microns apart. 
     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 a spacer according the present invention; 
     FIG. 2 is an end view of the spacer of FIG. 1; 
     FIG. 3 is a side elevational view of the spacer of FIG. 1; 
     FIG. 4 is a perspective view of the spacer of FIG. 1 with optical fibers partially inserted therethrough; 
     FIG. 5 is an enlarged view of a portion of the spacer and optical fibers of FIG. 4; 
     FIG. 6 is a perspective view of the spacer of FIG. 1 with the optical fibers fully inserted therethrough; 
     FIG. 7 is a perspective view of a spacer according to the present invention being inserted into a representative connector; 
     FIG. 8 is a cross sectional view of the connector and spacer of FIG. 7 with the spacer installed therein; 
     FIG. 9 is a cross sectional view of another embodiment of a spacer according to the present invention; 
     FIGS. 10 and 11 are opposing end views of the spacer of FIG. 9; 
     FIG. 12 is a perspective view of another embodiment of a spacer according to the present invention; 
     FIG. 13 is an end view of the spacer of FIG. 12; 
     FIG. 14 is a cross sectional view of another embodiment of a spacer according to the present invention; 
     FIGS. 15 and 16 are opposing end views of the spacer of FIG. 14; 
     FIG. 17 is a perspective view of another embodiment of a spacer according to the present invention; 
     FIG. 18 is perspective view of the spacer of FIG. 17 in an open configuration; and 
     FIG. 19 is a top view of the spacer of FIG.  18 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     One embodiment of the spacer  10  is shown in FIGS. 1-3. Spacer  10  is preferably an elongated member  12  with two annular openings  14 , 16  extending between a first end  18  and a second end  20 . The spacer  10  preferably has an outer configuration that corresponds to a fiber optic connector designed to receive a 900 micron tightly buffered fibers. While the illustrated spacer  10  is generally oval, it can be of any configuration that centers the optical fibers in the connector. The openings  14 , 16  are sized to allow a 250 micron (coated) optical fiber to pass through the spacer  10 . The two annular openings  14 , 16  are in communication with one another along the length of member  12  through a channel  20 . Channel  20 , as shown in the figures, is a generally rectangularly shaped slot that allows only a stripped optical fiber (typically 125 microns in diameter) to pass between the two openings  14 , 16 . As described in more detail below, the size of channel prevents a coated 250 micron fiber from moving between the openings  14 , 16  and keeps the optical fibers correctly spaced. In the preferred embodiment, the annular openings  14 , 16  are spaced apart by 750 microns (center-to-center). The spacer  10  is preferably manufactured from Teflon® PTFE fluorocarbon resin, a resilient material. However, any suitable resilient material can be used. 
     The openings  14 , 16  are shown to be generally round and extend through the spacer  10 . However, the openings could be of any shape, including oval, hexagonal, square, etc., as long as they allow a 250 micron coated optical fiber to pass through the openings. While the openings  14 , 16  may be of any shape, they must be disposed in the spacer  10  such that the optical fibers have a spacing of 750 microns to match the spacing in the connector. Naturally, if the connector to be used has a fiber bore spacing that is different from 750 microns, then openings would be disposed to match the spacing. Similarly, while the channel  20  is generally shown as a rectangular channel, it also may be of any shape as long as a 125 micron optical fiber can pass between the openings  14 , 16  but the 250 micron coated optical fibers cannot. 
     As shown in FIG. 3, the ends  18 , 20  are preferably slanted at approximately 450 relative to a longitudinal axis  22 , which passes through the spacer  10  and is parallel to the openings  14 , 16 . While the ends can be slanted at any angle between 0° and 90°, angles between 30 and 90 are more preferable, and an angle of about 45° is most preferable. Slanted ends  18 , 20  cause the openings  14 , 16  to be oval shaped at the end and provide for easier insertion of the fibers into the spacer  10 . Also, while both ends are shown to be slanted in the figure, either one of the ends or none of the ends may be slanted. 
     Only two openings are illustrated in the figures, but the spacer  10  can have any number of openings, depending on the number of optical fibers needed for the connector that will be used. If more than two openings are used in the spacer, alignment of the openings in any certain arrangement is not required. Therefore, the openings can be arranged in a straight line or any other geometric shape (circular, rectangular, triangular, etc.). 
     The use of the spacer  10  will be described with reference to FIGS. 4-8. Optical fibers  24 , 26  have two portions as shown in FIGS. 4-6. The portions  24   a , 26   a  are the coated optical fibers that are about 250 microns in diameter, while the portions  24   b , 26   b  are the stripped portions of the optical fibers  24 , 26  that are about 125 microns in diameter. As is known in the art, the optical fibers are typically provided with a coating and the user must strip it off before the optical fibers can be terminated with a connector. In the figures, the portion  24   b , 26   b  already has the coating stripped off. The optical fibers that are to be connectorized are preferably inserted into one of the openings  14 , 16 . While the fibers could each be inserted into their own opening, the loose fibers tend to align themselves next to one another. Since the openings  14 , 16  are about 250 microns and the stripped portions are inserted into the spacer  10 , the stripped portion of the optical fibers  24 , 26  will pass through the spacer  10 . Once the fibers are inserted such that the coated portions  24   a , 26   a  are next to the spacer  10 , one of the fibers can then be moved through channel  20  to the other opening as shown in FIGS. 4 and 5. Once the fibers are in their respective openings, the fibers are then inserted such that the coated portions  24   a , 26   a  are moved through and partially beyond the opposite end  20  of the spacer  10  as shown in FIG.  6 . In this position, the fibers will not be able to move relative to one another and they will keep the spacing of the openings (preferably 750 microns). It should be noted that the fibers may be able to move along the length of the spacer  10  since the openings are preferably slightly larger than 250 microns. The spacer  10  may be made such that the openings are closer to the size of the coated fibers if the users desire to have a tighter fit between the fibers and the spacer  10 . 
     The fibers  24 , 26  are preferably each advanced the same amount through the spacer  10 . The spacer  10  provides an advantageous holder to allow the user to simultaneously cleave both fibers to an appropriate length for the connector to be used. By cleaving both fibers at the same time, the user will save time and effort and be more assured of having both fibers cleaved at the same length. 
     FIG. 7 illustrates how the spacer  10  and the fibers  24 , 26  are inserted into a connector after having been cleaved. An MT RJ UniCam® connector, available from Coming Cable Systems, is illustrated, although any connector can be used. Since the spacer has positioned the fibers at 750 micron spacing and the outer surface of the spacer  10  is configured to fit within the lead-in tube of the connector, the fibers will correctly align inside the connector. As illustrated in FIG. 8, the fibers  24 , 26  and spacer  10  are inserted into the lead-in tube  28  of the connector  30 . The fibers  24 , 26  then align with optical fiber stubs  32 , 34  that are secured within the ferrule  36 . The lead-in tube  28  is then crimped around the spacer  10  at  33  to strain relieve the optical fibers  24 , 26 . The spacer  10  sufficiently protects the optical fibers so that they are not bent, crushed, or otherwise affected so as to reduce their optical transmission. 
     Another embodiment of a spacer is shown in FIGS. 9-11. Spacer  40  is similar to spacer  10 , except that the central element  42  has a flared portion  44  at one end  46  rather than an angled end, and it has a flat portion  48  at the other end  50 . In this embodiment, only end  50  can be inserted into the connector or lead-in tube. As with the previous embodiment, the openings  14 , 16  and channel  20  are the same. The openings  14 , 16  and channel  20  can similarly be modified as described above in reference to spacer  10 . 
     FIGS. 13 and 14 illustrate another embodiment of a spacer according to the present invention. Spacer  60  has a central elongated element  62  that comprises two cylindrical elements  62   a  and  62   b . As with the previous embodiments, each of the elements  62   a  and  62   b  have openings  14 , 16 , but, unlike those embodiments, there is no channel connecting the openings  14 , 16 . The openings are similarly space at 750 microns center-to-center. Spacer  60  has two ribs  68  along each side of elements  62   a  and  62   b  that assists in centering the spacer  60  within the connector. One or both ends  64 , 66  of the spacer  60  may also be angled as with the first embodiment to aid in inserting the optical fibers into openings  14 , 16 . 
     FIGS. 14-16 illustrate another embodiment of a spacer according to the present invention. The spacer  70  has openings  14 , 16  that extend through the elongated central element  72 . Openings  14 , 16  have a flared portion  74 , 76  at one end of the spacer  70  to assist the user in inserting optical fibers. As with the previous embodiment, the spacer  70  does not have a channel that allows communication between the openings  14 , 16 . While the spacer  70  generally has a figure eight shape, it could have any shape that would allow it to be inserted into the back of a connector, such as oval, rectangular, etc. 
     Another embodiment of a spacer  80  is illustrated in FIGS. 17-19 that has a central element  82 . Element  82  has a top  84  and a bottom  86  attached along an edge  88 . Openings  14 , 16  extend through the spacer  80  as in the previous embodiments. The top  84  and the bottom  86  each have concave portions  14   a , 16   a  and  14   b , 16   b , respectively, that form openings  14 , 16  when the top and bottom are mated as shown in FIG.  17 . As with several of the previous embodiments, the spacer  80  has a flared entry portion  88 , 90  at one end of the spacer to assist the user in aligning the fibers with openings  14 , 16 . Also, there is no channel in the spacer  80 , so the optical fibers must be inserted into the appropriate opening  14 , 16  from the start. The spacer  80  may also have a divider or tang  90  that extends outward from the spacer  80  and is disposed between the two openings  14 , 16  to assist the user in guiding the optical fibers into the correct opening. 
     Although the present invention has been described with respect to certain preferred and alternative embodiments, it should be understood that various changes, substitutions and modifications may be suggested to one skilled in the art, and it is intended that the present invention encompass such changes, substitutions, and modifications as fall within the scope of the appended claims and their equivalents.