Abstract:
The present disclosure relates to fiber optic connection systems including fiber optic connector having retractable noses for protecting bare fiber ends of ferrule-less connectors. In certain examples, the retractable noses are used in combination with protective shutters. In other examples, the retractable noses can accommodate multiple optical fibers.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of provisional application Ser. No. 62/092,315, filed Dec. 16, 2014, which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     Optical adapters are used to optically couple together optical fiber tips of optical connectors. The optical adapters include alignment structure that aligns the fiber tips to enable the transfer of optical signals therebetween. Optical connectors can be secured to the optical adapters when received at the ports of the optical adapters. 
     In certain examples, the optical connectors include ferrule-less optical connectors. For example, an example ferrule-less optical connector  300  known in the art is shown at  FIG. 1 . The optical connector  300  includes a connector body  322  having a front mating end  324  and a rear cable terminating end  326 . An optical fiber extends forwardly through the connector body  322  and has a ferrule-less end portion that is accessible at the front mating end  324  of the connector body  322 . The optical fiber is anchored adjacent the rear cable terminating end  326  against axial movement relative to the connector body  322 . When two connectors  300  are coupled together, the end faces of the ferrule-less end portions abut one another, thereby causing the optical fibers to be forced rearwardly into the connector bodies  322  and to buckle/bend within fiber buckling regions of the connector bodies  322 . A shutter  328  moves between closed and open positions. The shutter  328  protects the ferrule-less end portion of the optical fiber from contamination when shut and allows access to the ferrule-less end portion when open. 
     The connector  300  also includes a latch  330  that engages a catch  355  of a fiber optic adapter  350  (see  FIG. 2 ). The latch  330  includes a resilient cantilever style latch. When the connectors  300  are inserted within the coaxially aligned ports of the adapter  350 , the shutters  328  of the connectors  300  are retracted, thereby exposing the ferrule-less ends of the optical fibers. Continued insertion causes the ferrule-less ends to enter an optical fiber alignment device. In an example, the fiber alignment device includes funnels leading to a fiber alignment groove, and spring-biased balls pressing the fibers into the groove. Other examples of ferrule-less optical connectors and corresponding optical adapters can be found in U.S. patent application Ser. No. 14/377,189, filed Aug. 7, 2014, and titled “Optical Fiber Connection System Including Optical Fiber Alignment Device,” the disclosure of which is incorporated herein by reference. 
     Other ferrule-less fiber optic connection systems are disclosed by United States Patent Application Publication Nos. US 2013/0216186 and US 2014/0072265. The &#39;186 publication discloses a ferrule-less connector with a retractable nose piece. The &#39;265 publication discloses an alignment system for multi-fiber connectors. Improvements are needed in the areas of enhanced fiber end protection and fiber alignment in the areas of single fiber and multi-fiber fiber optic connectors. 
     SUMMARY 
     Aspects of the present disclosure relate to features for enhancing fiber protection in ferrule-less connectors. In certain examples, a fiber optic connector in accordance with the principles of the present disclosure can include a shutter for providing initial protection of a fiber end, and a retractable nose piece for providing secondary protection of the fiber end. In certain examples, the nose piece can also be configured to assist in directing the fiber end into a corresponding alignment feature of a fiber optic adapter. In certain examples, the shutter and the nose piece are both automatically opened as the fiber optic connector is inserted within a corresponding fiber optic adapter. In certain examples, the shutter can include a latch that retains the shutter in a closed position until the fiber optic connector is inserted within the corresponding fiber optic adapter. 
     Another aspect of the present disclosure relates to a multi-fiber, ferrule-less connector having a retractable nose piece for protecting end portions of optical fibers of the fiber optic connector. In certain examples, the nose piece can assist in registering the end portions of the optical fibers with alignment features of a corresponding fiber optic adapter. In certain examples, the fiber optic adapter can include an array of V-grooves that receive the end portions of the optical fibers. 
     A further aspect of the present disclosure relates to a fiber optic connector including a connector body having a front end and an opposite rear end. The connector body defines a longitudinal axis that extends through the connector body in an orientation that extends from the front end to the rear end of the connector body. An optical fiber extends through the connector body from the rear end to the front end. The optical fiber has a fiber end that is accessible at the front end of the connector body. The fiber optic connector also includes a nose piece mounted at the front end of the connector body. The nose piece defines a fiber passage through which the optical fiber extends. The nose piece is movable along the longitudinal axis between an extended position where a front end portion of the optical fiber is protected within the fiber passage and a retracted position where the front end portion of the optical fiber projects forwardly beyond the nose piece. The fiber optic connector further includes a shutter mounted at the front end of the connector body. The shutter is movable between a first position where the shutter covers the nose piece and a second position where the nose piece is exposed. The nose piece provides protection to the front end portion of the optical fiber in the event the shutter is opened prior to insertion within a fiber optic adapter. Additionally, the nose piece can assist in registering the front end portion of the optical fiber with a corresponding alignment feature of the fiber optic adapter. 
     Another aspect of the present disclosure relates to a fiber optic connector including a connector body having a front end and an opposite rear end. The connector body defines a longitudinal axis that extends through the connector body in an orientation that extends from the front end to the rear end of the connector body. A plurality of optical fibers extend through the connector body from the rear end to the front end. The optical fibers have fiber ends accessible at the front end of the connector body. The fiber optic connector also includes a nose piece mounted at the front end of the connector body. The nose piece defines a plurality of fiber passages through which the optical fibers extend. The nose piece is movable along the longitudinal axis between an extended position where front end portions of the optical fibers are protected within the fiber passages and a retracted position where the front end portions of the optical fibers project forwardly beyond the nose piece. 
     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. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of the description, illustrate several aspects of the present disclosure. A brief description of the drawings is as follows: 
         FIG. 1  illustrates a prior art ferrule-less fiber optic connector; 
         FIG. 2  illustrates a prior art fiber optic adapter compatible with the ferrule-less fiber optic connector of  FIG. 1 ; 
         FIG. 3  is a cross-sectional view showing a ferrule-less fiber optic connector in accordance with the principles of the present disclosure, the fiber optic connector is shown with a shutter in a closed position and a nose piece in an extended position; 
         FIG. 4  illustrates the ferrule-less fiber optic connector of  FIG. 3  with the shutter in an open position and the nose piece in a retracted position; 
         FIG. 5  illustrates the ferrule-less fiber optic connector of  FIGS. 3 and 4  in the process of being inserted into a mating fiber optic adapter; 
         FIG. 6  illustrates the ferrule-less fiber optic connector of  FIGS. 3 and 4  fully inserted within the mating fiber optic adapter; 
         FIG. 7  is a perspective view illustrating a multi-fiber, ferrule-less connector in accordance with the principles of the present disclosure, a nose-piece of the fiber optic connector is shown in an extended orientation; 
         FIG. 8  is a cross-sectional view of the multi-fiber, ferrule-less connector of  FIG. 7 ; 
         FIG. 9  illustrates the multi-fiber, ferrule-less connector of  FIG. 7  with the nose piece in a retracted orientation; 
         FIG. 10  is a cross-sectional view of the multi-fiber, ferrule-less connector of  FIG. 9 ; 
         FIG. 11  illustrates a multi-fiber, ferrule-less fiber optic connection system in accordance with the principles of the present disclosure; 
         FIG. 12  is another view of the fiber optic connection system of  FIG. 11 ; 
         FIG. 13  is an exploded view of the fiber optic connection system of  FIGS. 11 and 12 ; 
         FIG. 14  is a rear, perspective view of a multi-fiber connector of the fiber optic connection system of  FIGS. 11 and 12 ; 
         FIG. 15  is an end view of a port of a fiber optic adapter of the fiber optic connection system of  FIGS. 11 and 12 ; 
         FIG. 16  is a cross-sectional view of the fiber optic connection system of  FIGS. 11 and 12  in a partially connected state (i.e., the fiber optic connector is partially inserted within the port of the corresponding fiber optic adapter); 
         FIG. 17  is a cross-sectional view of the fiber optic connection system of  FIGS. 11 and 12  in a fully connected state (i.e., the fiber optic connector is partially inserted within the port of the corresponding fiber optic adapter); 
         FIG. 18  is a cross-sectional view taken along section line  18 - 18  of  FIG. 17  showing a fiber alignment tray stack that forms a fiber alignment feature of the fiber optic adapter; 
         FIG. 19  is a cross-sectional view taken along section line  19 - 19  of  FIG. 18  showing cantilever springs that oppose and extend along V-grooves of the fiber alignment feature an that function to bias/hold optical fibers in contact with angled alignment surfaces of the v-grooves; 
         FIG. 20  is an isolated, exploded view of one of the fiber alignment trays and a biasing layer of the fiber alignment tray stack; 
         FIG. 21  shows the biasing layer of  FIG. 20  mounted on its corresponding fiber alignment tray; 
         FIG. 22  is an enlarged view of a fiber management and anchoring tray stack of the multi-fiber connector depicted at  FIGS. 16 and 17 ; and 
         FIGS. 23-26  are further views showing fiber management trays of the tray stack of  FIG. 22 . 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to exemplary aspects of the present disclosure that are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
     Aspects of the present disclosure relate to ferrule-less fiber optic connectors. As used herein, a ferrule-less fiber optic connector is a fiber optic connector that does not have a ferrule bonded or otherwise affixed to an end portion of an optical fiber of the fiber optic connector. Structures are disclosed herein to provide enhanced fiber protection to end portions of optical fibers. Example structures can include shutters and/or retractable nose pieces. 
       FIGS. 3 and 4  illustrate an example fiber optic connector  20  in accordance with the principles of the present disclosure. The fiber optic connector  20  is depicted as a ferrule-less fiber optic connector. The fiber optic connector  20  includes a connector body  22  having a front end  24  and an opposite rear end  26 . The connector body  22  defines a longitudinal axis  28  that extends through the connector body  22  in an orientation that extends from the front end  24  to the rear end  26  of the connector body  22 . An optical fiber  30  extends through the connector body  22  from the rear end  26  to the front end  24 . The optical fiber  30  has a fiber end  32  accessible at the front end  24  of the connector body  22 . The fiber optic connector  20  also includes a nose piece  34  mounted at the front end  24  of the connector body  22 . The nose piece  34  defines a fiber passage  36  through which the optical fiber  30  extends. The nose piece is movable along the longitudinal axis  28  between an extended position (see  FIG. 3 ) where a front end portion  38  of the optical fiber  30  is protected within the fiber passage  36  and a retracted position (see  FIG. 4 ) where the front end portion  38  of the optical fiber  30  projects forwardly beyond the nose piece  34 . The fiber optic connector  20  further includes a shutter  40  mounted at the front end  24  of the connector body  22 . The shutter is movable between a first position (e.g., a closed position as shown at  FIG. 3 ) where the shutter  40  covers the nose piece  34  and a second position (e.g., open position as shown at  FIG. 4 ) where the nose piece  34  is exposed. 
     In certain examples, the fiber optic connector  20  can include a spring  42  for biasing the nose piece  34  toward the extended position. In certain examples, the nose piece  34  retracts back into the connector body  22  as the nose piece  34  moves from the extended position toward the retracted position. In certain examples, the shutter  40  is configured to pivot relative to the connector body  22  as the shutter moves between the open and closed positions. In certain examples, the fiber optic connector  20  can include a latch for retaining the shutter  40  in the closed position. In certain examples, the latch can be released when the fiber optic connector  20  is inserted within a mating fiber optic adapter thereby allowing the shutter  40  to be moved between the closed and open positions. In certain examples, relative movement is permitted between the nose piece  34  and the optical fiber  30  so that the nose piece  34  can slide relative to the optical fiber  30 . In certain example, the fiber optic connector  20  includes a fiber anchoring region  41  near the rear end of the connector body  22  where the optical fiber  30  is fixed in position relative to the connector body  22  thereby preventing relative axial movement between the fiber  30  and the connector body  22  at the anchoring location  41 . In certain examples, a fiber buckling region  43  is provided in the connector body  22  between the anchoring region  41  and the end portion  38  of the optical fiber  30 . The buckling region allows the fiber to buckle (i.e., bend, flex) within the connector body  22  when an optical connection is being made. 
       FIGS. 5 and 6  show an example fiber optic adapter  50  compatible with the fiber optic connector  20 . It will be appreciated that the fiber optic connector  50  is configured for coupling two of the fiber optic connectors  20  together such that optical signals can be conveyed between the optical fibers of the coupled fiber optic connectors  20 . The fiber optic adapter  50  can have an alignment feature  52  for receiving and coaxially aligning the front end portions  38  of the optical fibers of the coupled fiber optic connectors  20 . In certain examples, the alignment feature  52  can include an alignment passage such as a V-groove  53 . In certain examples, the alignment feature  52  can include a biasing structure such as a spring-loaded component that presses the front end portions  38  of the optical fibers  30  into the alignment passage. As depicted, the spring-loaded components can include members  55  (e.g., balls, rods, or other structures) spring-biased toward fiber alignment surfaces (e.g., surfaces defining a v-groove) of the alignment passage. 
     In certain examples, fiber optic adapter  50  can include opposite first and second adapter ports  54 ,  56  with the alignment feature  52  disposed therein between. The first and second adapter ports  54 ,  56  can be configured for respectively receiving fiber optic connectors  20  desired to be coupled together. It will be appreciated that the shutters  40  of the fiber optic connectors  20  move from the closed position to the open position as the fiber optic connectors  20  are inserted into their respective ports  54 ,  56 . Similarly, the nose pieces  34  of the fiber optic connectors  20  move from the extended positions to the retracted positions as the fiber optic connectors  20  are inserted into their respective ports  54 ,  56 . When the nose pieces  34  retract, the front end portions  38  of the optical fibers  30  protrude forwardly beyond the nose pieces  34  and thereby can be inserted into the alignment passage (e.g., groove) of the alignment feature  52 . In certain examples, the shutters  40  move at least partially toward the open positions prior to the nose pieces  34  beginning to move from the extended positions toward the retracted positions. In certain examples, the fiber passages  36  of the nose pieces  34  align with the alignment passages of the alignment feature  52  to assist in guiding the front end portions  38  into the alignment groove of the alignment feature  52  as the nose pieces  34  retract. 
     As described above, in certain examples, the alignment passage is defined by an open-sided groove such as a V-groove. Additionally, in certain examples, resilient structures are provided for biasing the front end portions  38  of the optical fibers  30  into the open sided grooves. In certain examples, the resilient structures can include structures such as spring-biased balls, flexible cantilevers and other structures. 
     In certain examples, the alignment passage is defined by the fiber alignment feature  52  of the fiber optic adapter  50 . In certain examples, the fiber alignment feature  52  can include first and second opposite ends  58 ,  59 . In certain examples, the nose pieces  34  of the fiber optic connectors  20  inserted within the adapter ports  54 ,  56  respectively abut against the first and second ends  58 ,  59  of the fiber alignment feature  52  when the fiber optic connectors  20  are inserted into the first and second adapter ports  54 ,  56  thereby causing the nose pieces  34  to retract. 
       FIGS. 7-10  illustrate another fiber optic connector  120  in accordance with the principles of the present disclosure. In the depicted example, fiber optic connector  120  is a ferrule-less, multi-fiber fiber optic connector. 
     Referring still to  FIGS. 7-10 , the fiber optic connector  120  includes a connector body  122  having a front end  124  and an opposite rear end  126 . In certain examples, a fiber optic cable can be coupled to the fiber optic connector  120  adjacent the rear end  126 . The connector body  122  defines a longitudinal axis  128  that extends through the connector body  122  in an orientation that extends from the front end  124  to the rear end  126  of the connector body  122 . A plurality of optical fibers  130  extend through the connector body  122  from the rear end  126  to the front end  124 . The optical fibers  130  have fiber ends  132  accessible at the front end  124  of the connector body  122 . The fiber optic connector  120  also includes a nose piece  134  mounted at the front end  124  of the connector body  122 . The nose piece  134  defines a plurality of fiber passages  136  through which the optical fibers  130  extend. It will be appreciated that the optical fibers  130  are slidable within the fiber passages  136  such that relative movement is permitted in an orientation that extends along the longitudinal axis  128 . The nose piece  134  is movable along the longitudinal axis  128  relative to the connector body  122  between an extended position (see  FIGS. 7 and 8 ) where front end portions  138  of the optical fibers  130  are protected within the fiber passages  136  and a retracted position (see  FIGS. 9 and 10 ) where the front end portions  138  of the optical fibers  130  project forwardly beyond the nose piece  134 . It will be appreciated that when the nose piece  134  is in the retracted position, the front end portions  138  of the optical fibers  130  project forwardly beyond the nose piece  134  a distance sufficiently long to allow the front end portions  138  to be inserted within a suitable alignment structure. In certain examples, an alignment structure can be provided within a fiber optic adapter configured for coupling two of the fiber optic connectors  120  together. In another example, a direct connection may be made between mating fiber optic connectors without the use of an intermediate adapter. In such an example, the front end portions  138  of the fibers of one fiber optic connector may fit within alignment grooves defined by a mating fiber optic connector. 
     Referring to  FIGS. 8 and 10 , the fiber optic connector  120  can include a spring  142  for biasing the nose piece  134  toward the extended orientation. Additionally, as shown at  FIGS. 7 and 9 , registration elements can be provided on the nose piece  134  to assist in providing registration between two fiber optic connectors desired to be coupled together. In certain examples, the registration structures can include alignment pins  143  and/or alignment openings  144 . In certain examples, the alignment pins  143  can fit within alignment openings of a corresponding fiber optic connector or a corresponding fiber optic adapter, and the alignment openings  144  can receive alignment pins of a mating fiber optic connector or a mating fiber optic adapter. 
     In certain examples, fiber optic connector  120  is a robust, hardened fiber optic connector suitable for outdoor use. In certain examples, fiber optic connector  120  can include structure for providing environmental sealing when inserted within the port of a corresponding fiber optic adapter or when coupled to a mating fiber optic connector. For example, as shown at  FIGS. 8 and 10 , the fiber optic connector  20  can include a sealing element such as an annular sealing ring  145  (e.g., an O-ring) that mounts within an annular groove that extends about the perimeter of the connector body  122 . In certain examples, a robust coupling element can be provided for securing the connector body  22  within the corresponding port of a fiber optic adapter or to a mating fiber optic connector. For example, the robust coupling element can include a twist-to-lock coupling element such as a threaded coupling element  147  (e.g., an exteriorly threaded nut or an interiorly threaded sleeve) or a bayonet-style coupling element. 
     It will be appreciated that the connector body  122  can also include one or more keying features for ensuring that the fiber optic connector is inserted into a corresponding port of a fiber optic adapter or mating fiber optic connector at a predetermined rotational orientation. Example keying structures can include rails, projections, grooves or other structures. As depicted, the fiber optic connector  120  is provided with a key in the form of a rail  146  configured to fit within a corresponding groove defined by a mating adapter or connector port. 
       FIGS. 11-13  illustrate another multi-fiber fiber optic connector  220  in accordance with the principles of the present disclosure. The fiber optic connector  220  includes a connector body  222  having a front end  224  and an opposite rear end  226 . The connector body  222  defines a longitudinal axis  228  that extends along a length of the connector body  222 . The rear end  226  of the connector body  224  can be configured to couple to a fiber optic cable  227 . The fiber optic cable  227  can include a jacket  229  containing a plurality of optical fiber ribbons  231 . The fiber optic cable  227  can include reinforcing members  233  (e.g., reinforcing rods such as epoxy reinforced fiber glass rods or other types of reinforcing elements such as Aramid yarn). In certain examples, the reinforcing members  233  can be secured (e.g., bonded, clamped, or otherwise attached) to the connector body  222 . In certain examples, the reinforcing members  233  can be secured within openings  235  (see  FIG. 14 ) defined adjacent the rear end  226  of the connector body  222 . As depicted, the fibers are not shown routed through the fiber optic connector  220 . 
     Referring to  FIG. 13 , the connector body  122  has a two-part construction including a main body  237  and a cover  239 . The main body  237  and the cover  239  mate together to form the connector body  222 . A reinforcing sleeve  241  can be mounted over the connector body  222  after the cover  239  and the main body  237  have been mated together. The fiber optic connector  120  can also include an outer housing  243  that mounts over the connector body  222 . Additionally, the fiber optic connector  220  can include a fastening element such as a robust fastening element for securing the fiber optic connector  220  to a corresponding fiber optic adapter  245 . In certain examples, the fastening element can include a twist-to-lock fastening element such as a bayonet-style fastening element or a threaded fastening element. As depicted, the fastening element includes an internally threaded sleeve  247  that mates with corresponding exterior threads  249  provided at one end of a fiber optic adapter  245 . 
     The fiber optic adapter  245  includes a first port  251  that receives the fiber optic connector  222  and an opposite second port  253  adapted to receive a fiber optic connector desired to be optically coupled to the fiber optic connector  222 . In certain examples, the fiber optic adapter  245  can be mounted within a hole in an enclosure or panel and can have suitable sealing structure for providing an environmental seal with the panel or enclosure. 
     Referring to  FIG. 13 , fiber optic connector  220  can include a nose piece  234  that is movable along the longitudinal axis  228  relative to the connector body  222  between an extended position and a retracted position. The nose piece  234  can define a plurality of fiber passages  236  that receive front end portions of optical fibers corresponding to the optical fiber ribbons  231 . In certain examples, the front end portions can be bare glass portions of the optical fibers including only the fiber cores and cladding layers. It will be appreciated that the front end portions (not shown) of the optical fibers can slide within the nose piece  234  as the nose piece  234  is moved between the extended and retracted positions. When the nose piece  234  is extended, the front end portions of the optical fibers are protected and enclosed within the nose piece  234 . When the nose piece  234  is retracted, the front end portions of the optical fibers are exposed thereby allowing the front end portions to be inserted within a corresponding alignment feature provided in the fiber optic adapter  245 . 
     In certain examples, the nose piece  234  can be spring-biased toward the extended position by one or more springs  255  positioned within the connector body  222 . In certain examples, the nose piece  134  can include a main body  257  and a front extension  259 . The main body  257  can be captured within an interior of the connector body  222 , and the front extension  259  can extend into a front opening  260  defined at the front end  224  of the connector body  222 . The main body  257  can define flanges that project outwardly from the front extension  259 . In certain examples, the springs  255  can be positioned on opposite sides of the optical fibers (e.g., above and below) and can engage a backside of the main body  257  at the flanges. In certain examples, the two-piece construction of the connector body  222  facilitates laterally loading the nose piece  234 , the springs  255  and other components into the interior of the connector body  222 . 
     It will be appreciated that the fiber optic connector  220  can also include structure within the interior of the connector body  220  for managing and anchoring the optical fibers. In certain examples, the fiber management and anchoring structure can be defined by a stack of miniature fiber management trays  261  positioned within the connector body  222 . The fiber management trays  261  can define a separate fiber buckling passages  262  corresponding to each of the optical fibers. The stack of fiber management trays  261  can also include a fiber anchoring region  265  for anchoring the optical fibers relative to the connector body  222 . It will be appreciated that the fiber buckling passages  264  are positioned between the fiber anchoring region  265  and the passages  236  in the nose piece  234  for receiving the front end portions of the optical fibers. 
     As shown at  FIGS. 22-26 , the fiber management trays  261  can each include a first side (e.g., a top side as depicted) defining a plurality of parallel shallow grooves  290  and an opposite second side (e.g., a bottom side as depicted) defining a plurality of deeper grooves  291 . When the trays  261  are stacked, the top and bottom sides of adjacent trays  261  oppose one another and interlock or mate with one another to provide mechanical registration between the trays  261 . The shallow and deeper grooves  291  register within one another and cooperate to define the separate fiber buckling passages  262 . The opposing sides of adjacent trays  261  also form clamping regions  293  where the spacing between the opposing sides is small enough that the optical fibers are compressed between the trays and held in place. The clamping regions  293  can form the fiber anchoring region  265 . 
     In certain examples, fiber management trays  261  are mounted in fixed relation relative to the connector body  222 , and the nose piece  234  is free to move forwardly and rearwardly relative to the fiber management trays  261 . In certain examples, the fiber buckling slots  263  generally align with the fiber passages  236  of the nose piece  234 . 
     It will be appreciated that the fiber optic adapter  245  can include an interior fiber alignment feature  271  for coaxially aligning the optical fibers of the fiber optic connector  220  with the optical fibers of a corresponding fiber optic connector desired to be coupled to the fiber optic connector  220  via the fiber optic adapter. In certain examples, the fiber alignment feature  271  includes a stack of fiber alignment trays  272  that define an array of alignment grooves (e.g., V-grooves  295 ) for receiving the front end portions of the optical fibers when the fiber optic connector  220  is inserted within the first port  251  and the nose piece  234  is retracted. It will be appreciated that the fiber passages  236  assist in registering the optical fibers  130  with the alignment grooves  295  defined by the fiber alignment trays  272  (see  FIG. 19 ). In certain examples, an end of the fiber alignment feature  271  can fit or mate at least partially within the front end  224  of the connector body  222  (e.g., the alignment feature can fit within the front opening  260 ). In this way, the distance the fibers project beyond the front end of the connector body  222  is minimized while still allowing substantial lengths of the optical fibers to be inserted within the fiber alignment feature  271  of the fiber optic adapter  245 . 
     The fiber optic adapter  245  can also include alignment projections  275  that fit within corresponding alignment openings  277  defined by a front face of the connector body  222  when the fiber optic connector  220  is inserted within the first port  251  of the fiber optic adapter  245 . The mating alignment projections  275  and alignment openings  277  can provide an alignment and keying function. Additionally, when the alignment projections  275  slide into the alignment openings  277 , the alignment projections  275  can engage a front side of the main body  257  of the nose piece  234  thereby causing the nose piece to move from the extended position toward the retracted position as the fiber optic connector  220  is inserted into the first port  251 . 
     When the fiber optic connector  220  is optically coupled to another fiber optic connector by the fiber optic adapter  245 , the fiber ends of the coupled fiber optic connectors preferably engage one another. The fiber buckling slots  263  provide space for allowing the optical fibers  230  to slightly buckle within the connector body  222  as the fiber ends  232  contact one another. Thus, the fiber buckling slots  263  provide take-up regions for receiving buckled portions of the fibers when an optical connection is made. The buckling of the fibers provides axial loading on the optical fibers that ensures the end faces of the optical fibers remain in contact with one another. Additionally, the ability to allow the optic fibers to buckle provides extra tolerance and range of motion that ensures all of the optical fibers of the interconnected fiber optic connectors in engagement with one another. 
     In certain examples, the fiber alignment feature  271  can include rows of cantilevers  280  for biasing the fiber end portions into the v-grooves  295  (see  FIGS. 20 and 21 ). In certain examples, one cantilever  280  is provided for every two of the v-grooves  295 . The cantilevers  280  can be part of a biasing layer  296  that includes two sets of cantilevers  280  with one set of cantilevers  280   a  corresponding to the fibers of one of the fiber optic connectors received within the fiber optic adapter and the other set of cantilevers  280   b  corresponding to the other fiber optic connector received within the fiber optic adapter. The biasing layers  296  can be formed by stamping the cantilevers  280  from plates. The biasing layers  296  can be provided between the fiber alignment trays  272  of the alignment tray stack. 
     Various modifications and alterations of this disclosure will become apparent to those skilled in the art without departing from the scope and spirit of this disclosure, and it should be understood that the scope of this disclosure is not to be unduly limited to the illustrative examples set forth herein.