Patent Publication Number: US-2023161115-A1

Title: Fiber optic ferrule and fiber optic ferrule receiver

Description:
REFERENCE TO RELATED CASE 
     This application claims priority under 35 U.S.C. § 119 (e) to U.S. provisional application no. 63/014,491 filed on Apr. 23, 2020, and to U.S. provisional application no. 63/047,657 filed on Jul. 2, 2020, the contents of which are hereby incorporated by reference in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     Transceivers interface with various duplex LC connectors with one optical link for the transmitter and another for the receiver. Duplex LC connectors are also used in non-transceiver interfaces, which have tight space requirements. Many such LC duplex connectors interface with transceivers having a footprint according to various industry multisource agreements (MSAs). Two of these include the Quad Small Form-factor Pluggable (QSFP) or the Small Form-factor Pluggable (SFP) MSAs and are defined by specifications associated with these MSAs. These connectors are used in communications applications with speeds up to 400 GBps, with higher speeds currently in research and development. One such duplex connector with a housing and a push-pull boot is illustrated in Applicant&#39;s WIPO patent application publication WO 2019/195652, filed Apr. 5, 2019. 
     By definition, duplex connectors can only accommodate two optical fiber ferrules (and hence, two optical fibers). This also provides a limitation on how many channels may be interfaced with the transceiver. Conventional non-duplex multi-fiber ferrules, such as the ubiquitous MT-ferrule, has a footprint that allows only one MT-ferrule to interface with the transceiver. For example, the MT-ferrule has shoulder(s) at the back that help the MT ferrule seat inside a typical MPO connector housing, in which the ferrule is used. The shoulder contributes to a larger footprint of the MT-ferrule that has a typical height of 3 mm, a length of 8 mm, and a width of 7 mm. Further, molding such ferrules to simply reduce the footprint is challenging with current multi-fiber ferrule designs. 
     Accordingly, at this time, only one MT ferrule in an MPO connector housing footprint meets the space requirements of an SFP/QSFP footprint transceiver interface. Accordingly, Applicant provides a multi-fiber ferrule that allows for a plurality of duplex connector housings to fit in a footprint matching that of a QSFP/SFP footprint transceiver interface, and supporting more than two optical fibers (e.g., 16 optical fibers). As a result, two or more of such MT-like ferrules within respective housings can be interfaced with an SFP/QSFP transceiver interface. 
     In order to use the new higher density fiber optic ferrule, there needs to be a new housing that can receive the new fiber optic ferrule and mate to the transceiver or other assembly. 
     SUMMARY OF THE INVENTION 
     According to one aspect, the present invention is directed to a fiber optic ferrule receiver to receive a fiber optic ferrule therein that includes a main body extending between a front end and a rear end and having four sides, the main body having an opening extending between the front end and the rear end and being defined at least by a portion of internal surfaces of the four sides, a first side in the opening having a first tapered surface and a second tapered surface, the first tapered surface reducing the opening between the rear end and a first position and the second tapered surface increasing the opening between the first position and the front end, a second side in the opening and across the opening from the first side, the second side having a third tapered surface and a fourth tapered surface, the third tapered surface reducing the opening between the rear end and a second position and the second tapered surface increasing the opening between the second position and the front end, a first projection extending into the opening from the first side to engage a first portion of the fiber optic ferrule at the first position, and a second projection extending into the opening from second side to engage a second portion of the fiber optic ferrule at the second position. 
     In some embodiments, there is at least one tab extending from the rear end, the tab having opposing cut-outs to form legs. 
     In some embodiments, the rear end has a rear surface, the rear surface being non-perpendicular to a longitudinal axis extending through the opening from the front end to the rear end. 
     In some embodiments, a configuration of the rear end of the main body corresponds to the location of the first projection and the second projection in the opening of the fiber optic ferrule receiver. 
     In some other embodiments, the tab has a rearmost portion, the rear most portion having a surface that is orthogonal to a longitudinal axis extending through the opening from the front end to the rear end. 
     In some embodiments, the main body has a plurality of shoulders extending from the front end to the rear end to align the fiber optic ferrule receiver with an adapter. 
     In some embodiments, each of the first projection and the second projection have a length, the length of the first projection is less than the second projection. 
     In some embodiments, the first projection and the second projection provide a keying function for the fiber optic ferrule. 
     In some embodiments, the first and second tapered surfaces on both the first side and the second side are connected to one another across at least a portion of the opening. 
     In some embodiments, the second tapered surface of the first side comprises two second tapered surfaces and the first projection is disposed between the two second tapered surfaces. 
     In other embodiments, the fourth tapered surface of the second side comprises two fourth tapered surfaces and the second projection is disposed between the two fourth tapered surfaces. 
     It is to be understood that both the foregoing general description and the following detailed description of the present embodiments of the invention are intended to provide an overview or framework for understanding the nature and character of the invention as it is claimed. The accompanying drawings are included to provide a further understanding of the invention, and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments of the invention and, together with the description, serve to explain the principles and operations of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a top perspective view of one embodiment of a multi-fiber ferrule according to the present invention; 
         FIG.  2    is a bottom perspective view of the multi-fiber ferrule in  FIG.  1   ; 
         FIG.  3    is a rear elevational view of the multi-fiber ferrule in  FIG.  1   ; 
         FIG.  4    is front elevational view of the multi-fiber ferrule in  FIG.  1   ; 
         FIG.  5    is a cross sectional view from the rear of the multi-fiber ferrule in  FIG.  1   ; 
         FIG.  6    is a cross sectional view of the multi-fiber ferrule in  FIG.  1   ; 
         FIG.  7    is a front elevational view of the multi-fiber ferrule in  FIG.  1   ; 
         FIG.  8    is a perspective view of one embodiment of a fiber optic connector according to the present invention from the top left and using the multi-fiber ferrule in  FIG.  1   ; 
         FIG.  9    is a perspective view of the fiber optic connector in  FIG.  8    from the bottom right and using the multi-fiber ferrule in  FIG.  1   ; 
         FIG.  10    is an exploded view of the fiber optic connector in  FIG.  8   ; 
         FIG.  11    is a left side perspective view of one embodiment of a fiber optic ferrule receiver/cap with the multi-fiber ferrule of  FIG.  1    disposed therein; 
         FIG.  12    is a cross-sectional view of the fiber optic ferrule receiver/cap of  FIG.  1   ; 
         FIG.  12 A  is an elevational view of a cross section of the fiber optic ferrule receiver/cap of  FIG.  1     
         FIG.  13    is a front elevational view of the fiber optic ferrule receiver/cap of  FIG.  11   ; 
         FIG.  14    is a rear perspective view of the fiber optic ferrule receiver/cap of  FIG.  11   ; 
         FIG.  15    is a perspective view from the bottom left of a cross-section of the fiber optic connector of  FIG.  8   ; 
         FIG.  16    is a left side elevational view of the fiber optic connector in  FIG.  8   ; 
         FIG.  17    is a left side elevational view of the fiber optic connector in  FIG.  8    with fiber optic ferrule receiver/cap of  FIG.  11    removed; 
         FIG.  18    is a perspective view of the housing of the fiber optic connector in  FIG.  8    from the top rear; 
         FIG.  19    is a perspective view of the housing of the fiber optic connector in  FIG.  8    from the bottom left side; 
         FIG.  20    is a perspective view of a cross section of the housing in  FIG.  18    with the second portion of the rear section removed; 
         FIG.  21    is a front elevational view of the housing of the fiber optic connector in  FIG.  8   ; 
         FIG.  22    is a perspective view of the housing of the fiber optic connector in  FIG.  8    from the rear; 
         FIG.  23    is a rear elevational view of the housing of the fiber optic connector in  FIG.  8   ; 
         FIG.  24    is an exploded view of a cross section of the housing of the fiber optic connector in  FIG.  8    with the second portion on the left side; 
         FIG.  25    is an elevational view of a cross section of the fiber optic connector in  FIG.  8    with a push-pull boot and connector latch installed thereon; 
         FIG.  26    an elevational view of a cross section of the fiber optic connector in  FIG.  8    with a push-pull boot and connector latch installed thereon and at a different position within the connector; 
         FIG.  27    is a perspective view of the fiber optic connector in  FIG.  25    from the top left; 
         FIG.  28    is an elevational view of a cross section of a portion of the fiber optic connector in  FIG.  25   ; 
         FIG.  29    is a perspective view of another embodiment of a fiber optic connector according to the present invention; 
         FIG.  30    is a front elevational view of the housing in the fiber optic connector in  FIG.  29   ; 
         FIG.  31    is a perspective view of a cross section of the housing in  FIG.  30   ; 
         FIG.  32    is an elevational view of a cross section view of the fiber optic connector in  FIG.  29   ; 
         FIG.  33    is a perspective view of the fiber optic ferrule receiver/cap used with the fiber optic connector in  FIG.  29   ; 
         FIG.  33 A  is a left side elevational view of the fiber optic ferrule receiver/cap in  FIG.  29   ; 
         FIG.  34    is a cross section of the fiber optic ferrule receiver/cap of  FIG.  33    with a multi-fiber ferrule installed therein; 
         FIG.  35    is a perspective view of another embodiment of a combination of a fiber optic ferrule receiver/cap and housing according to the present invention; 
         FIG.  36    illustrates the multi-fiber ferrule and the spring disposed within the opening of the housing in  FIG.  35   ; 
         FIG.  37    is a perspective view of a cross section of the housing in  FIG.  35    showing the front end thereof; 
         FIG.  38    is a perspective view of the housing in  FIG.  35    without the multi-fiber ferrule installed; 
         FIG.  39    is an exploded perspective view of another embodiment of a housing according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made in detail to the present preferred embodiment(s) of the invention, examples of which are illustrated in the accompanying drawings. 
     Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts. 
     Illustrated in  FIGS.  1 - 6    is one embodiment of a multi-fiber ferrule  100  according to the present invention. The multi-fiber ferrule  100  has a main body  102  having a top portion  104  and a bottom portion  106 . There is a first side portion  108  that extends between the top portion  104  and the bottom portion  106 . There is also a second side portion  110  extending between the top portion  104  and the bottom portion  106  on opposites sides of the main body  102 . The main body  102  also has an end face  112  at a front end  114  of the main body  102  and a rear face  116  at a rear end  118  of the main body  102 . The multi-fiber ferrule  100  is significantly smaller than the conventional MT—ferrule and has typical dimensions of 1.25 mm height, 4 mm length (between the front end  114  and the rear end  118 ), and a width of 6.4 mm between the first side portion  108  and the second side portion  110 . 
     Applicant notes that the term “front” or “forward” means that direction where the fiber optic ferrule would meet with another fiber optic ferrule or device, while the term “rear” or “rearward” is used to mean the direction from which the optical fibers enter into the fiber-optic ferrule or fiber optic connector. In the present application, the multi-fiber ferrule and the fiber optic connector will therefore have a front and a rear, the front will be inserted into an adapter, sleeve or other receptacle. Thus, in  FIG.  1   , the “front” of the multi-fiber ferrule is on the left side of the figure and pointing out of the figure. The “rear” or “back” is that part of multi-fiber ferrule is on the right side of  FIG.  1    and “rearward” and “backward” is toward the right and into the page. The same is true with the fiber optic connector as illustrated in  FIG.  8   —the front is to the left and out, while rear is to the right and back. 
     As seen in  FIG.  3   , the multi-fiber ferrule  100  has a rear central opening  120  extending into the main body  102  from the rear face  116  and configured to receive at least three optical fibers (not shown). The multi-fiber ferrule  100  also has a plurality of fiber support structures  122  to support the optical fibers. See also  FIG.  5   . The fiber support structures  122  are in communication with the rear central opening  120  and extending through the main body  102  to the end face  112 . Along the length of the fiber support structures  122  there may be chamfered portions  124  that assist in insertion of the optical fibers into the multi-fiber ferrule  100  without the skiving of the front ends of the optical fibers. The fiber support structures  122  may be fiber openings or fiber bores, but may alternatively be groove structures, or the combination or both. The main body  102  may also include two guide pin holes  126 , which extend between the end face  112  and the rear face  116 . The guide pin holes  126  provide a reference point with respect to the main body  102  and other structures to which the multi-fiber ferrule  100  is mated. As noted below, the guide pin holes  126  are outside the area of cutouts to allow for enough material in the main body  102  to allow for the guide pin holes  126 . The end face  112  may have a rectangular profile, although a trapezoidal profile (as shown) may also be provided as an alternative. 
     The top portion  104  has a top cut-out  130  that forms a first forward facing surface  132 . The first forward facing surface  132  is used as a stop surface in conjunction with a housing for a connector, e.g., an SFP/QSFP connector. There may also be a number of other surfaces formed by the top cut-out  130 . For example there is a second, slanted surface  134  on both sides of the top cut-out  130  that assist in the location of the multi-fiber ferrule  100  in the housing for a connector. The second, slanted surfaces  134  assist in moving the multi-fiber ferrule  100  in a side-to-side manner relative to the housing. There are also laterally facing surfaces  136  on each side that form the last part of the cut-out  130  and extend to the end face  112  from the second, slanted surfaces  134 . As illustrated in the figures, the top cut-out  130  does not extend all of the way to the rear end  118 , but stops short at the first forward facing surface  132 . However, a portion of the top cut-out  130  could extend all the way to the back of the multi-fiber ferrule  100 . For example, a cutout in the shape of a “T” with a thin narrow section going all the way to the back would work as well, as long as there is at least one forward facing surface adjacent to such a variation of the top cut-out  130 . This applies to a bottom cut-out  150  as well, described below. 
     The top portion  104  has a first surface  140  that lies in a first plane A and the cut-out  130  forms a second surface  142  that lies in a second plane B. See  FIG.  4   . Planes A and B are preferably parallel to one another but off set, with plane B being closer to a longitudinal axis E passing through the center of the main body  102  and through the rear central opening  120  between the front end  114  and the rear end  118 . See also  FIG.  5   . It should also be noted that the cut-out portion  130  does not extend into the rear central opening  120  or the fiber support structures  122 . 
     Similarly, the bottom portion  104  has the bottom cut-out  150  that forms a second forward facing surface  152 . The second forward facing surface  152  is also used as a stop surface in conjunction with a housing for a connector. The bottom cut-out  150  also has two laterally facing surfaces  154  that form a portion thereof. The bottom cut-out  150  extends from the end face  112  towards the rear end  118 , but does not reach the rear end  118 . It may reach the same distance toward the rear end  118  from the end face  112  as does the top cut-out  130 , but it may stop short of or beyond where the top cut-out  130  stops at forward facing surface  132 . 
     The bottom portion  104  has a first surface  160  that lies in a third plane C and the bottom cut-out  150  forms a fourth surface  162  that lies in a fourth plane D. See  FIGS.  4  and  5   . The Planes C and D are preferably parallel to one another but off set, with plane D being closer to the longitudinal axis E passing through the center of the main body  102  and through the rear central opening  120  between the front end  114  and the rear end  118 . It should also be noted that the bottom cut-out  150  does not extend into the rear central opening  120  or the fiber support structures  122 . 
     It should be noted that the thickness of the main body  102  varies across a width and a depth. As seen in  FIGS.  4  and  6   , the thickness of the main body  102  is least where the two cut-outs  130 ,  150  are located. This is seen in  FIG.  4    and represented by the distance between planes B and D. The thickness of the main body  102  is greatest where there are no cut-outs, which corresponds to the distance between the planes A and C. 
     Returning to the main body  102 , there is first side portion  108  that extends between the top portion  104  and the bottom portion  106 . There is also a second side portion  110  extending between the top portion  104  and the bottom portion  106  on opposites sides of the main body  102 . The first side portion  108  and the second side portion  110  are smooth between the front end  114  and the rear end  118 . Additionally, there is no shoulder with multi-fiber ferrule  100  making the profile from the back to the front the same as the front to the back—and also the same at the end face  112  and the rear face  116 . That is, the multi-fiber ferrule  100  is shoulder-less. The term shoulder-less referring to a lack of any protrusions or other features on the first side portion  108  and the second side portion  110  that may be used to engage the multi-fiber ferrule  100  with a receptacle or an adapter. There are also no sharp edges along the length of the multi-fiber ferrule  100  at the junction of the side portions  108 ,  110  to the top and bottom portions  104 ,  106 . See, e.g.,  FIGS.  1  and  2   . It should also be noted that the top portion  104  may be wider than the bottom portion. That is, the distance across the top portion  104  may be greater than the distance across the bottom portion  106  between the side portions. That is, W 1  may be greater that W 2  as illustrated in  FIG.  3   . Alternatively, W 1  equals W 2 . 
     It should also be noted that the rear surface  116  at the rear end  118  may also be used as a reference surface for any work that may be done to the multi-fiber ferrule  100 . For example, the rear surface  116  may be used as a reference surface for polishing the end face  112  of the main body  102 . The use of the rear surface  116  is in addition to the first forward facing surface  132  and/or the second forward facing surface  152 . Preferably, the wider of the first forward facing surface  132  and the second forward facing surface  152  would be used as a reference datum surface for polishing and interferometry. The end face  112  may be angle-polished (i.e., at an angle relative to the rear face  116 ). Alternatively, the end-face  112  may be flat polished. The top cut-out  130  may have a different width than the bottom cut-out  150 . This may act as a polarity indication and/or may cause the ferrule to be oriented in a specific direction when received inside a receptacle or an adapter for mating with another ferrule. Alternatively, the top cut-out  130  may have a same width as the bottom cut-out  150 . 
     An alternative embodiment of a multi-fiber ferrule  100 ′ is illustrated in  FIG.  7   . In this embodiment, the top portion  104 ′ has two top cut-outs  130 ′ that form two first forward facing surfaces  132 ′. The two top cut-outs  130 ′ are separated by a continuation  104   a ′ of the top portion  104 ′. The continuation  104   a ′ of the top portion  104 ′ acts as a key for the a multi-fiber ferrule  100 ′. This is in addition to the top cut-out  130 ′ having a different width that the bottom cut-out  150 ′. Thus the continuation  104   a ′ may act as a polarity key or wedge. In an alternative aspect, the continuation  104   a ′ may be presented only partially separate the two top cutouts  130 ′. Otherwise, the multi-fiber ferrule  100 ′ is the same as noted above with regard to multi-fiber ferrule  100 . 
     Moving to  FIGS.  8 - 16   , there is one embodiment of a fiber optic ferrule receiver  200  to receive a fiber optic ferrule  100  according to the present invention. The fiber optic ferrule receiver  200  can be used in a number of different connectors and assemblies. As illustrated in  FIGS.  8  and  9   , the fiber optic ferrule receiver  200  is a part of a fiber optic connector  400 . Additionally and as discussed in more detail below, the elements of the fiber optic ferrule receiver  200  may be found in other receivers as well. For example, the features of the fiber optic ferrule receiver  200  may be included in an adapter, into which the fiber optic ferrule  100  would be directly inserted. 
     Now turning to  FIG.  10   , the components of the fiber optic connector  400  will be described, moving in a front to rear direction (or left to right in the figure). The fiber optic ferrule receiver  200  is on the far left, with the multi-fiber ferrule  100  that will be inserted into the fiber optic ferrule receiver  200  next in line. While the multi-fiber ferrule  100  is illustrated, the invention may apply to other fiber optic ferrules as well. Behind the multi-fiber ferrule  100  is a guide pin keeper or spacer  402 . A spring  404  (or other elastic element) is disposed in front end of a housing  406  (and is described in more detail below) to bias the multi-fiber ferrule  100  in a forward direction with the fiber optic ferrule receiver  200 . A crimp ring  408  is used to secure the strength members associated with the optical fibers (not shown) to the housing  406 . Finally, a push-pull boot  410  is attached to the housing  406 . 
     The fiber optic ferrule receiver  200  includes a main body  202  extending between a front end  204  and a rear end  206 . See  FIGS.  11  and  12   . The main body  202  has four sides  208 ,  210 ,  212 ,  214 , and an opening  216  extending between the front end  204  and the rear end  206  and being defined at least by a portion of internal surfaces of the four sides  208 ,  210 ,  212 ,  214 . As illustrated, the first side  208  and the second side  210  are on opposite sides of the opening  216 , while the third side  212  and the fourth side  214  are each connected to the first side  208  and the second side  210  and are opposite each other about the opening  216 . The third side  212  and the fourth side  214  have internal surfaces that are preferably flat and linear, but they may have tapering features like the internal surfaces of first side  208  and second side  210 , discussed in detail below. In one aspect of this disclosure, the third side  212  may include a polarity step or a polarity mark to indicate orientation of the fiber optic ferrule receiver  200  and hence, the fiber optic ferrule  100 . See also  FIG.  13   . 
     The first side  208  has a first tapered surface  208   a  in the opening  216  as well as a second tapered surface  208   b , the first tapered surface  208   a  reducing the opening  216  between the rear end  206  and a first position  220 , and the second tapered surface  208   b  increasing the opening  216  between the first position  220  and the front end  204 . As illustrated in  FIG.  12   , the first tapered surface  208   a  may have a number of ramped and flat portions. The first tapered surface  208   a  is to prevent the front end  114  of the main body  102  of the multi-fiber ferrule  100  from encountering any surface that causes damage to the front end  114  or causes the multi-fiber ferrule  100  from catching as it is inserted into the opening  216 . 
     The second side  210  also has a third tapered surface  210   a  in the opening  216  as well as a fourth tapered surface  210   b , the third tapered surface  210   a  reducing the opening  216  between the rear end  206  and a second position  222 , and the fourth tapered surface  210   b  increasing the opening  216  between the second position  222  and the front end  204 . As can be seen in  FIG.  12   , the first position  220  and the second position  222  are directly across the opening  216  from each other. However, depending on the configuration of the cut-outs in the multi-fiber ferrule, the first position  220  and the second position  222  may be off set from one another along a longitudinal axis F through the fiber optic ferrule receiver  200 . The first portion  220  and the second portion  222  can be thought of as a line that extends across the opening  416  between the third side  212  and the fourth side  214  and on the first side  208  and the second side  210 , respectively. 
     Alternatively, the first position  220  and/or the second position  222  may be a flat surface, e.g., parallel to the first side  208  and the second side  210 . That is, there may be a flat surface formed at a junction of the first tapered surface  208   a  and the second tapered surface  208   b . Likewise, there may be another flat surface formed at a junction of the third tapered surface  210   a  and the fourth tapered surface  210   b.    
     The fiber optic ferrule receiver  200  has a first projection  230  extending into the opening  216  from the first side  208  to engage the multi-fiber ferrule  100  at the first position  220 . Preferably the first projection  230  engages the first forward facing surface  132  of the multi-fiber ferrule  100 . However, as noted above, the first projection  230  could engage any appropriate structure on the multi-fiber ferrule  100 . The projection  230  preferably has a rearward facing surface  232  to engage the first forward facing surface  132  of the multi-fiber ferrule  100 . Additionally, the first projection  230  extends across the opening  216  in the appropriate location and width for that engagement. The first projection  230  preferably has a ramp surface  234  that extends from the first position  220  towards the front end  204 . While the ramp surface  234  extends all of the way to the front end  204 , it could stop short thereof. Alternatively, the first projection  230  may have other configurations, such as a flat plateau like profile, instead of a ramp to engage the multi-fiber ferrule  100 . 
     Similarly, the ferrule receiver  200  has a second projection  240  extending into the opening  216  from the second side  210  to engage the multi-fiber ferrule  100  at the second position  222 . Preferably the second projection  240  engages the second forward facing surface  152  of the multi-fiber ferrule  100 . However, as noted above, the second projection  240  could engage any appropriate structure on the multi-fiber ferrule  100 . The second projection  240  preferably has a rearward facing surface  242  to engage the second forward facing surface  152  of the multi-fiber ferrule  100 . Additionally, the second projection  240  extends across the opening  216  in the appropriate location and width for that engagement with the fiber optic ferrule receiver  200 . As is clear in  FIG.  13    (showing the view from the front of the ferrule receiver  200 ), the first projection  230  is not as wide as the second projection  240  so that the multi-fiber ferrule  100  can only be inserted into the fiber optic ferrule receiver  200  in one way. The second projection  240  also preferably has a ramp surface  244  that extends from the second position  222  towards the front end  204 . While the ramp surface  244  extends all of the way to the front end  204 , it could stop short thereof. Alternatively, similar to the first projection  230 , the second projection  240  may have other configurations, such as a flat plateau like profile, instead of a ramp to engage the multi-fiber ferrule  100 . 
     The configuration of the first projection  230  and the second projection  240 , particularly with the ramp surfaces  234 ,  244  cause the second and fourth tapered surfaces  208   b ,  210   b  to be split into two sections—one on each side of the projections  230 ,  240 . See  FIG.  13   . At those locations, the first tapered surface  208   a  and the second tapered surface  208   b , as well as the third tapered surface  210   a  and the fourth tapered surface  210   b , are connected to one another about the first position  220  and second position  222 , respectively. Such a connection, as noted above, may be along a line or along a flat plane. 
     The rear end  206  of the main body  202  is not orthogonal to the longitudinal axis F extending through the main body  202 . See, e.g.,  FIG.  11   . Rather, it has an angle that matches the angle at the front of the housing  406 . One will be able to discern from this angled surface, where the first projection  230  and the second projection  240  are within the main body  202 . This will allow for the multi-fiber ferrule  100  to be inserted so that the first projection  230  and the second projection  240  engage correct ones of the forward facing surfaces  132 ,  152  in the multi-fiber ferrule  100 . See, e.g.,  FIGS.  12  and  15   . 
     Extending from the rear end  206 , and away from the main body  202 , are two tabs  250 , one is mounted on side  208  and the other on side  210 . The two tabs  250  each have a shape of the letter “T”. The tabs  250  have cut-outs  252  which form legs  254 . The tabs  250  and the legs  254  are able to flex outward from the opening  216  and engage the housing  406  as described below. See also  FIGS.  15  and  16   . The tabs  250  have a rear surface  256  that is perpendicular to the longitudinal axis F. The cut-outs  252  between the tab  205  and the legs  254  are not rectangular, but are trapezoidal, allowing the rear end  206  to be angled, while still having the rear surface  256  and the front end  204  perpendicular to the longitudinal axis F. 
     The main body  202  of the fiber optic ferrule receiver  200  has a plurality of shoulders  260  that extending from the front end  204  to the rear end  206 . The shoulders are generally at the corners of the main body  202 , where the sides  208 ,  210 ,  212 ,  214  meet. These shoulders  260  act as a guide to align the fiber optic connector  400  with another receptacle, such as an adapter. 
     The housing  406  will now be described with reference to  FIGS.  18 - 28   . The housing  406  has a main body  420  that extends between a front end  422  and a rear end  424  and generally has three sections. The housing  406  also has an opening  426  that extends between the front end  422  and the rear end  424 . The first section  428  is a front section that receives an elastic member such as spring  404 . As noted above, the elastic member or spring  404  is to engage, directly or indirectly, the rear end of the multi-fiber ferrule  100  and bias it in a forward direction. The spring  404  engages forward facing surfaces  430  that extend into the opening  426  from the interior surface  432  and function as an integral spring stop. Referring to  FIG.  20   , in the cross-section, two of the forward facing surfaces  430  are illustrated, each continuing around one side of the housing  406  internally (see also  FIG.  21   ) on the other half of the main body  420  that is not visible. 
     Alternatively, there could preferably be four of the forward facing surfaces  430 , two for the half shown in  FIG.  20   , and two more for the half of the housing  406  that has been cut in the cross-section of  FIG.  20   . See also  FIGS.  25  and  26   . The front end  422  has a chamfered surface  434  that assists in inserting the spring  404  during the initial insertion as well as movement of the spring  404  during use of the housing  406  in the fiber optic connector  400 . The opening  426  is illustrated as being oval in cross section, but it could have other configurations as needed (e.g., an elliptical configuration). The spring  404  is accordingly shaped to be received inside the opening  426 , and engage and seat at the forward facing surfaces  430 . 
     Also at the front end  422  and on first side  440  and on opposing second side  442  are depressions  444  to receive the tab  250  and legs  254  from the fiber optic ferrule receiver  200  to removably secure the fiber optic ferrule receiver  200  to the main body  420 . See,  FIG.  19    and  FIG.  21    showing a front view of the housing  406 . 
     The main body  420  of the housing  406  has a plurality of shoulders  460  that extending from the front end  422  to the rear end  424 . The shoulders are generally at the corners of the main body  420 , where first side  440  meets with top side  462  and bottom side  464  and second side  442  meets with top side  462  and bottom side  464 . These shoulders  460  act as a guide to align the fiber optic connector  400  with another receptacle, such as an adapter. The shoulders  460  also match with the shoulders  260  on the fiber optic ferrule receiver  200  to form a continuous shoulder at each corner. 
     The second or middle section  470  provides an area for the optical fibers  300  to transition from a flat ribbon to a grouping that can be protected by a round fiber optic cable covering. Referring to  FIG.  26   , the optical fibers  300  extend from the multi-fiber ferrule  100  in a flat configuration, the middle section  470  allows for them to be grouped together to pass out the rear end  424  in circular configuration and in a cable sheath  302 . As is known in the art, the optical fibers  300  cannot be bent beyond their bend radius without damaging the optical fibers  300 . This transition area  470  assists in preventing such damage. The transition area  470  is dimensioned to maintain a safe bend radius for the individual optical fibers  300  as these optical fibers  300  transition from a ribbon form to a fiber optic cable form with loose fibers therein. 
     The third or rear section  480  is used to finalize the configuration of the optical fibers  300  from the transition area in the middle section  470  to the cable format. The rear section  480  has an outer surface  482  to engage the crimp ring  408 . The outer surface  482  is on a circular extension or crimp body  486  that extends from the rear end  424 . 
     Additionally, the crimp body  486  is preferably made from two portions, a first portion  490  that is integral with the main body  420  and a second portion  492  that is removable from the main body  420  and the first portion  490 . See  FIGS.  19 - 20  and  23 - 24   . The second portion  492  has a rear section  494  that is a half cylinder and a forward section  496  that mates with the main body  420  to close the middle section  470 . The rear portion  494  mates with the first portion  490  to form the cylindrical shape that can accept the crimp ring  408 . The rear section  494  mates with the first portion  490  with a series of projections  500  and recesses  502 . As illustrated in the figures, the projections  500  are on the first portion  490  and the recesses  502  are on the second portion  492 . However, the projections and recesses could be reversed or mixed with regard to their positions on the first portion  490  and the second portion  492 . The projections  500  preferably frictionally engage the recesses  502  and then once the crimp ring  408  is secured around the crimp body  486 , the two portions  490 ,  492  will not move relative to one another. 
     The forward section  496  of the second portion  492  mates with the main body  420  of the housing  406 . The main body  420  has an extra portion  504  that has been cut out to allow for more optical fibers and larger groups of optical fibers to pass through the opening  426 . This makes the opening  426  at the forward section  496  larger than on the opposing side. The larger opening  426  allows the housing  406  to be installed onto the cable and slid down the cable and out of the way during termination and polishing of the ferrule  100 . That is when viewed straight into the opening  426  from the rear section  494 , or even from the front end  422 , the opening  426  is asymmetrical due to the presence of the first portion  490  and the extra portion  504 . See  FIGS.  22 ,  23   . The forward section  496  of the crimp body  486  has a tab  506  that extends into the extra portion  504  to close it off when the two portions  490 ,  492  are mated. 
     The housing  406  also has a number of latches  520  that extend from the main body  420  to engage a push-pull boot  410  and more specifically two latches  522  on the push-pull boot. See  FIGS.  9 ,  10 ,  24 , and  27   . As illustrated, the latches  522  on the push-pull boot can slide in the area  524  between two latches  520  on each side of the housing  406 . See  FIG.  27   . When the push-pull boot  410  is pulled, the latches  522  slide within the area  524  until they reach the end of the latches  520  and at this point, the force is transferred to the latches  520  and the housing  406  to remove the fiber optic connector from its receiver. To insert the fiber optic connector  400 , the push-pull boot  410  is pushed until the latches  522  engage the front end of the area  524 , which then transfers to the housing  406  and moves the fiber optic connector in a forward direction to secure it within a receptacle. 
     It is also possible, as an alternative to this configuration, whereby at least one of the latches is molded on the second portion. Referring to  FIG.  39   , there is a housing  406   a  that has a second portion  492   a  of a crimp body  486   a  and a latch  520   a  molded thereon. The housing  406   a  has the same components as the housing discussed above, as well as the extra portion  504 ′ that has been cut out to allow for more optical fibers and larger groups of optical fibers to be used with this housing  406   a.    
     Another embodiment of a housing  406 ′ and a fiber optic ferrule receiver  200 ′ according to the present invention are illustrated in  FIGS.  29 - 34   . First, it should be noted that the fiber optic ferrule that is used in these figures corresponds to multi-fiber ferrule  100  discussed above, but another fiber optic ferrule could also be used. 
     This embodiment of a fiber optic ferrule receiver  200 ′ includes a main body  202 ′ extending between a front end  204 ′ and a rear end  206 ′. As in the prior embodiment, the main body  202 ′ also has four sides  208 ′,  210 ′,  212 ′, 214 ′, and an opening  216 ′ extending between the front end  204 ′ and the rear end  206 ′ and being defined at least by a portion of internal surfaces of the four sides  208 ′,  210 ′,  212 ′,  214 ′. The fiber optic ferrule receiver  200 ′ also includes two tabs  250 ′ that extend rearwardly from the rear end  206 ′. The two tabs  250 ′ each have a projection  252 ′ that extend outwardly and away from each other. The projections  252 ′ are designed to engage an opening  444 ′ on each side of the housing  406 ′, as described in more detail below. The two tabs  250 ′ are somewhat flexible in that they can flex inward to be inserted into the housing  406 ′ and subsequently return, at least partially, to their pre-flexed configuration. This allows the fiber optic ferrule receiver  200 ′ to be retained in the housing  406 ′. 
     Turning to  FIG.  33 A , the length of fiber optic ferrule receiver  200 ′ (the distance between the front end  204 ′ and the rear end  206 ′) is shorter than that of fiber optic ferrule receiver  200 . The housing  406 ′ is therefore longer so that the combination of the housing  406 ′ and the fiber optic ferrule receiver  200 ′ are preferably the same overall length. It is also clear from  FIG.  33 A  that the rear end  206 ′ of the a fiber optic ferrule receiver  200 ′ and the front end of the housing  406 ′ are slanted as in the previous embodiment for the purposes of polarity. 
     The opening  216 ′ of the fiber optic ferrule receiver  200 ′ has the same general configuration of a fiber optic ferrule receiver  200 . That is, first side  208 ′ and second side  210 ′ are on opposite sides of the opening  216 ′, while third side  212 ′ and fourth side  214 ′ are each connected to the first side  208 ′ and the second side  210 ′ and are opposite each other about the opening  216 ′. Third side  212 ′ and fourth side  214 ′ have internal surfaces that are preferably flat and linear, but they may have tapering features discussed above. 
     First side  208 ′ has a first tapered surface  208   a ′ in the opening  216 ′ as well as a second tapered surface  208   b ′, the first tapered surface  208   a ′ reducing the opening  216 ′ between the rear end  206 ′ and a first position  220 ′, and the second tapered surface  208   b ′ increasing the opening  216 ′ between the first position  220 ′ and the front end  204 ′. See  FIG.  34   . The first tapered surface  208   a ′ may have a number of ramped and flat portions. The first tapered surface  208   a ′ is to prevent the front end  114  of the main body  102  of the multi-fiber ferrule  100  from encountering any surface that causes damage to the front end  114  or causes the multi-fiber ferrule  100  from catching as it is inserted into the opening  216 ′. 
     Second side  210 ′ also has a third tapered surface  210   a ′ in the opening  216 ′ as well as a fourth tapered surface  210   b ′, the third tapered surface  210   a ′ reducing the opening  216 ′ between the rear end  206 ′ and a second position  222 ′, and the fourth tapered surface  210   b ′ increasing the opening  216 ′ between the second position  222 ′ and the front end  204 ′. As can be seen in  FIG.  34   , the first position  220 ′ and the second position  222 ′ are directly across the opening  216 ′ from each other. However, depending on the configuration of the cut-outs in the multi-fiber ferrule  100 , the first position  220 ′ and the second position  222 ′ may be off set from one another. The first portion  220 ′ and the second portion  222 ′ can be thought of as a line (that may have a number of thicknesses) that extends across the opening  416 ′ between the third side  212 ′ and the fourth side  214 ′ and on the first side  208 ′ and the second side  210 ′, respectively. 
     However, as described with respect to the embodiments above, the first portion  220 ′ and the second portion  222 ′ can also be a plane rather than a line. 
     As with the prior embodiment, the fiber optic ferrule receiver  200 ′ has a first projection  230 ′ extending into the opening  216 ′ from the first side  208 ′ to engage the multi-fiber ferrule  100  at the first position  220 ′. Preferably the first projection  230 ′ engages the first forward facing surface  132  of the multi-fiber ferrule  100 . The ferrule receiver  200 ′ has a second projection  240 ′ extending into the opening  216 ′ from the second side  210 ′ to engage the multi-fiber ferrule  100 ′ at the second position  222 ′. Preferably the second projection  240 ′ engages the second forward facing surface  152  of the multi-fiber ferrule  100 . 
     Turning to  FIGS.  28 - 31   , the other embodiment of the housing  406 ′ will be explained. The housing  406 ′ has a main body  420 ′ that extends between a front end  422 ′ and a rear end  426 ′ and generally has three sections. The first section  428 ′ is a front section that receives an elastic member such as spring  404 . The second or middle section  470 ′ provides an area for the optical fibers  300  to transition from a flat ribbon to a grouping that can be protected by a round fiber optic cable covering. The third or rear section  480 ′ is used to finalize the configuration of the optical fibers from the transition area in the middle section  470 ′ to the cable format. Except for the first section  428 ′, the other sections are the same as discussed above and will not be repeated here. 
     The housing  406 ′ also has an opening  426 ′ that extends between the front end  422 ′ and the rear end  424 ′. The first section  428 ′ receives an elastic member such as spring  404 . As noted above, the elastic member or spring  404  is to engage, directly or indirectly, the rear end of the multi-fiber ferrule  100  and bias it in a forward direction. The spring  404  engages forward facing surfaces  430 ′ that extend into the opening  426 ′ from the interior surface  432 ′ and function as an integral spring stop. Referring to  FIG.  31   , two of the forward facing surfaces  430 ′ are illustrated. The front end  422 ′ has a chamfered surface  434 ′ that assists in inserting the spring  404  during the initial insertion as well as movement of the spring  404  during use of the housing  406 ′ in a fiber optic connector  400 . The opening  426 ′ is illustrated as being oval in cross section, but it could have other configurations as needed. 
     The main body  420 ′ of the housing  406 ′ has a plurality of shoulders  460 ′ that extending from the front end  422 ′ to the rear end  424 ′. The shoulders are generally at the corners of the main body  420 ′, where first side  440 ′ meets with top side  462 ′ and bottom side  464 ′ and second side  442 ′ meets with top side  462 ′ and bottom side  464 ′. These shoulders  460 ′ act as a guide to align the fiber optic connector  400  with another receptacle, such as an adapter. The shoulders  460 ′ also match with the shoulders on the both of the embodiments of fiber optic ferrule receiver to form a continuous shoulder at each corner. 
     At the front end  422 ′ of the main body  420 ′ and on both first side  440 ′ and second side  442 ′ is a depression  448 ′ that also has the opening  444 ′ to receive the projections  252 ′ from the tabs  250 ′ when the fiber optic ferrule receiver  200 ′ is inserted into the opening  426 ′. There are also two pockets  436 ′ that are closest to the top side  462 ′ and bottom side  464 ′ to receive a part of the ferrule and/or the guide pin keeper or spacer  402 . See  FIGS.  30  and  32   . 
     Illustrated in  FIGS.  35 - 38    is an embodiment of a combination of a housing and a fiber optic ferrule receiver according to the present invention. The housing  600  has a front section  602  that incorporates the features of the fiber optic ferrule receiver  200 ,  200 ′ above. The housing  600  has a front end  604  and a rear end  606  with an opening  608  extending therebetween. The housing  600  has a rear section  610  that receives the spring  404  from the rear end  606 . As with other housings, the spring  404  engages the back of the multi-fiber ferrule  100 , either directly or indirectly to bias it to the front of the housing  600 . 
     The front section  602  has a first side  612  that has a first tapered surface  612   a  in the opening  608  as well as a second tapered surface  612   b . See  FIG.  37   . As with the prior embodiments, the first tapered surface  612   a  reduces the opening  608  between the rear end  606  and a first position  614 , and the second tapered surface  612   b  increasing the opening  608  between the first position  614  and the front end  604 . 
     The front section  602  has a second side  616  that has a third tapered surface  616   a  in the opening  608  as well as a fourth tapered surface  616   b . As with the prior embodiments, the third tapered surface  616   a  reduces the opening  608  between the rear end  606  and a second position  618 , and the fourth tapered surface  616   b  increasing the opening  608  between the second position  618  and the front end  604 . 
     The front section  602  also includes a first projection  620  that extends into the opening  608  from the first side  612  to engage the multi-fiber ferrule  100  at the first position  614 . It also includes a second projection  622  that extends into the opening  608  from the second side  616  to engage the multi-fiber ferrule  100  at the second position  618 . Thus, the elements of the fiber optic ferrule receiver have been incorporated into the housing and could, by extension, be added to other structures as well. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention. Thus it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.