Patent Publication Number: US-11650378-B2

Title: Fiber optic adapter and cassette

Description:
This application is a Continuation of U.S. patent application Ser. No. 16/620,103, filed on Dec. 6, 2019, now U.S. Pat. No. 11,215,767; which is a National Stage Application of PCT/US2018/036466, filed on Jun. 7, 2018; which claims the benefit of U.S. Patent Application Ser. No. 62/516,201, filed on Jun. 7, 2017, the disclosures of which are incorporated herein by reference in their entireties. To the extent appropriate, a claim of priority is made to each of the above disclosed applications. 
    
    
     BACKGROUND 
     Modern optical devices and optical communications systems widely use fiber optic cables. A typical fiber optic cable includes one or more optical fibers contained within a protective jacket. Reinforcing structures such as aramid yarns and/or fiber reinforced epoxy rods can be used to provide reinforcement to the optical cables. It is well understood that a typical optical fiber includes a glass fiber processed so that light beams transmitted through the glass fiber are subject to total internal reflection wherein a large fraction of the incident intensity of light directed into the fiber is received at the other end of the fiber. A typical optical fiber includes a glass core surrounded by a cladding layer having a lower refractive index as compared to the refractive index of the core. The cladding causes light to be confined to the core by total internal reflection at the boundary between the two. The cladding layer of an optical fiber is often covered by one or more polymeric coatings (e.g., acrylate) to protect the glass and to facilitate handling of the optical fiber. 
     Fiber optic communication systems employ a network of fiber optic cables to transmit large volumes of data and voice signals over relatively long distances. Optical fiber connectors are an important part of most fiber optic communication systems. Fiber optic connectors allow two optical fibers to be quickly optically connected without requiring a fusion splice. Fiber optic connectors can be used to optically interconnect two lengths of optical fiber. Fiber optic connectors can also be used to interconnect lengths of optical fiber to passive and active equipment. 
     A typical fiber optic connector includes a ferrule assembly supported at a distal end of a connector housing. A spring is used to bias the ferrule assembly in a distal direction relative to the connector housing. The ferrule assembly includes a ferrule that functions to support an end portion of at least one optical fiber (in the case of a multi-fiber ferrule, the ends of multiple fibers are supported). The ferrule has a distal end face at which a polished end of the optical fiber is located. When two optical fibers are interconnected, the distal end faces of the ferrules abut one another and the ferrules are forced proximally relative to their respective connector housings against the bias of their respective springs. With the fiber optic connectors connected, their respective optical fibers are coaxially aligned such that the end faces of the optical fibers directly oppose one another. In this way, an optical signal can be transmitted from optical fiber to optical fiber through the aligned end faces of the optical fibers. For many fiber optic connector styles, alignment between two fiber optic connectors is provided through the use of an intermediate fiber optic adapter including an alignment sleeve that receives and coaxially aligns the ferrules of the fiber optic connectors desired to be interconnected. For certain styles of fiber optic connectors, the optical fibers are secured within their respective ferrules by a potting material such as epoxy. 
     SUMMARY 
     One aspect of the invention concerns a connector including two connector portions each including a ferrule and a latch, each latch including a distal end, and a proximal end, wherein the latch is pivotable about an intermediate connection portion; and a boot mounted to the connector portions, the boot movable longitudinally relative to the connector portions, wherein the boot causes the distal ends of the latch to pivot toward the ferrule of each connector portion as the boot is moved away from the connector portions. 
     In another aspect of the invention, front housings of the connector portions can each be rotated about the longitudinal axis of the ferrule without rotating the ferrule or the boot, to change the polarity of the two connector portions. 
     In a further aspect of the invention, the spacing between the two ferrules is adjustable. 
     In one example, a holder holds the connector portions, the holder including side slots, the connector portions inserted laterally into the side slots. The holder defines an area for receipt of a fiber optic cable when the ferrule is pushed in a direction toward the boot. 
     In one example, a ferrule assembly includes a ferrule, a hub, and a spring. The ferrule assembly includes a front sleeve and a rear sleeve which together hold the ferrule, hub, and spring. 
     In a further example, a connector includes (a) two connector portions each including a ferrule assembly including a ferrule and a hub mounted together, and a spring, the ferrule assembly including a front sleeve and a rear sleeve, the front and rear sleeves mounted together with the ferrule end protruding and the spring located in an interior area biasing the ferrule toward an extended position; a front housing mounted to the ferrule assembly and including a latch, each latch including a distal end and a proximal end, wherein the latch is pivotable about an intermediate connection portion, wherein the distal end includes a shoulder for mating with a latching shoulder of an adapter; (b) a holder for holding the connector portions, the holder including side slots, the connector portions mounted to the holder by moving laterally to the side slots, the holder including a rearwardly projecting crimp support; and (c) a boot mounted to the connector portions, the boot movable longitudinally relative to the connector portions, wherein the boot causes the distal ends of the latch to pivot toward the ferrule of each connector portion as the boot is moved away from the connector portions. 
     In one example, a clip holds the two connector portions at the desired spacing. The clip can be used to position the connector portions at one of at least two different spacings. 
     According to another example of the disclosure, a dual-layered fiber optic adapter block configured for mating the above-discussed connectors may be provided. The fiber optic adapter block may include at least one upper receptacle, at least one lower receptacle vertically aligned with the upper receptacle to form a column of receptacles, and a center divider that divides the at least one upper receptacle from the at least one lower receptacle, the center divider defining latching shoulders for mating with latches of both a connector to be mounted at the upper receptacle of the column and the lower receptacle of the column, wherein the adapter block is configured to orient the fiber optic connectors latched to the upper and lower receptacles of the column such that latches of the fiber optic connectors face each other, and wherein the column defines a total height of less than about 0.875 inches. 
     According to another inventive aspect, the disclosure is directed to a fiber optic cassette comprising a cassette body defining a front end, a rear end, an interior for routing fibers therein, a connection panel at the front end, wherein the connection panel defines a plurality of upper receptacles, a plurality of lower receptacles vertically aligned with the upper receptacles to form columns of receptacles, and a center divider that divides the upper receptacles from the lower receptacles, the center divider defining latching shoulders for mating with latches of both a connector to be mounted at an upper receptacle of a given column and the lower receptacle of the given column, wherein the connection panel is configured to orient the fiber optic connectors latched to the upper and lower receptacles of each column such that latches of the fiber optic connectors face each other, and wherein the connection panel of the fiber optic cassette defines a total height of less than about 0.875 inches, the rear end of the cassette body including connector ports for receiving multi-fiber connectors carrying fibers to be relayed to the front panel with terminated connectors. 
     According to further inventive aspects, the disclosure is directed to a fiber optic connector port arrangement, the connector port arrangement comprising at least one upper receptacle and at least one lower receptacle vertically aligned with the upper receptacle to form a column of receptacles, the column including a center divider that divides the at least one upper receptacle from the at least one lower receptacle, the center divider defining latching shoulders for mating with latches of both a connector to be mounted at the upper receptacle of the column and the lower receptacle of the column. 
     According to further inventive aspects, the disclosure is directed to a fiber optic connector port arrangement, the connector port arrangement comprising at least one upper receptacle and at least one lower receptacle vertically aligned with the upper receptacle to form a column of receptacles, wherein the connector port arrangement is configured to orient the fiber optic connectors latched to the upper and lower receptacles of the column such that latches of the fiber optic connectors face each other. 
     According to yet further inventive aspects, the disclosure is directed to a dual-layered fiber optic connector port arrangement comprising at least one upper receptacle and at least one lower receptacle vertically aligned with the upper receptacle to form a column of receptacles, wherein the column defines a total height of less than about 0.875 inches. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of one example fiber optic connector in accordance with aspects of the present invention; 
         FIG.  2    is a side view of the connector of  FIG.  1    shown in the latched position; 
         FIG.  3    is a side view of the connector of  FIG.  1    shown in the unlatched position; 
         FIG.  4    is an exploded perspective view of the connector of  FIG.  1   ; 
         FIG.  5    is a perspective view of the connector, showing the front housings of the connector portions being rotated to change the polarity of the connector; 
         FIG.  6    is a top view of the connector of  FIG.  1   ; 
         FIG.  7    is a side view of the connector of  FIG.  1   ; 
         FIG.  8    is a cross-sectional view of the connector of  FIG.  7    taken along line  8 - 8 ; 
         FIG.  9    is an enlarged view of a front portion of the connector of  FIG.  8   ; 
         FIG.  10    is an enlarged view of an intermediate portion of the connector of  FIG.  8   ; 
         FIG.  11    is an end view of the connector of  FIG.  1   ; 
         FIG.  12    is a cross-sectional view of the connector of  FIG.  11   , taken along line  12 - 12 ; 
         FIG.  13    is an enlarged view of a front portion of the connector of  FIG.  12   ; 
         FIG.  14    is a rear perspective view in cross-section of the front housing of one of the connector portions; 
         FIG.  15    is a rear perspective view of the front sleeve of one of the ferrule assemblies; 
         FIG.  16    is a rear perspective view in cross-section of the front sleeve of  FIG.  15   ; 
         FIG.  17    is a perspective view of the rear sleeve of one of the ferrule assemblies; 
         FIG.  18    is a front perspective view of the holder of the connector; 
         FIG.  19    is a rear perspective view of the holder of the connector; 
         FIG.  20    is a front view of the holder of the connector; 
         FIG.  21    is front perspective view in cross-section showing one of the rear sleeves mounted to the holder; 
         FIG.  22    is a cross-sectional side view of the connector along the centerline; 
         FIGS.  23  and  24    are two perspective views of a duplex adapter for mating with the connector of  FIG.  1   ; 
         FIG.  25    is a cross-sectional view of the duplex adapter of  FIGS.  23  and  24   ; 
         FIG.  26    is a front, right, top perspective view of an example adapter block including a connector port arrangement having features that are examples of inventive aspects in accordance with the present disclosure; 
         FIG.  27    illustrates the adapter block of  FIG.  26    with a number of connectors similar to those shown in  FIGS.  1 - 22    of the application in an exploded configuration; 
         FIG.  28    illustrates the adapter block of  FIG.  27    with the connectors coupled thereto; 
         FIG.  29    is a front, bottom, left side perspective view of the adapter block of  FIG.  28   ; 
         FIG.  30    is a rear, top, right side perspective view of the adapter block of  FIG.  28   ; 
         FIG.  31    is a rear, bottom, right side perspective view of the adapter block of  FIG.  28   ; 
         FIG.  32    is a rear, top, left side perspective view of the adapter block of  FIG.  28   ; 
         FIG.  33    is a front, bottom, right side perspective view of the adapter block of  FIG.  28   ; 
         FIG.  34    is a rear, bottom, left side perspective view of the adapter block of  FIG.  28   ; 
         FIG.  35    is a top view of the adapter block of  FIG.  28   ; 
         FIG.  36    is a bottom view of the adapter block of  FIG.  28   ; 
         FIG.  37    is a front view of the adapter block of  FIG.  28   ; 
         FIG.  38    is a rear view of the adapter block of  FIG.  28   ; 
         FIG.  39    is a right side view of the adapter block of  FIG.  28   ; 
         FIG.  40    is a left side view of the adapter block of  FIG.  28   ; 
         FIG.  41    is a cross-sectional view taken along line  41 - 41  of  FIG.  39   ; 
         FIG.  42    illustrates an example of an adapter block similar to that shown in  FIGS.  26 - 41    but formed from removable features that are coupled together, the adapter block shown in an exploded configuration and including a connector port arrangement having features that are examples of inventive aspects in accordance with the present disclosure similar to that shown in  FIGS.  26 - 41   ; 
         FIG.  43    is a front, bottom, right side perspective view of the adapter block of  FIG.  42    shown in an exploded configuration; 
         FIG.  44    is a front, right, top perspective view of an example fiber optic cassette including a connector port arrangement similar to that shown for the adapter blocks of  FIGS.  26 - 43   , the connector port arrangement having features that are examples of inventive aspects in accordance with the present disclosure; 
         FIG.  45    illustrates the cassette of  FIG.  44    with a number of connectors similar to those shown in  FIGS.  1 - 22    of the application exploded off the front connector port arrangement and a number of multi-fiber connectors exploded off the rear of the cassette; 
         FIG.  46    illustrates the cassette of  FIGS.  44 - 45    in a fully exploded configuration; 
         FIG.  47    is a front, bottom, right side perspective view of the cassette of  FIG.  46    shown in a fully exploded configuration; 
         FIG.  48    is a rear, top, left side perspective view of the cassette of  FIGS.  44 - 47    shown in an assembled configuration with the connectors coupled thereto; 
         FIG.  49    is a rear, bottom, right side perspective view of the cassette of  FIG.  48   ; 
         FIG.  50    is a front, top, right side perspective view of the cassette of  FIG.  48   ; 
         FIG.  51    is a front, top, left side perspective view of the cassette of  FIG.  48   ; 
         FIG.  52    is a rear, top, right side perspective view of the cassette of  FIG.  48   ; 
         FIG.  53    is a top view of the cassette of  FIG.  48   ; 
         FIG.  54    is a bottom view of the cassette of  FIG.  48   ; 
         FIG.  55    is a front view of the cassette of  FIG.  48   ; 
         FIG.  56    is a rear view of the cassette of  FIG.  48   ; 
         FIG.  57    is a right side view of the cassette of  FIG.  48   ; 
         FIG.  58    is a left side view of the cassette of  FIG.  48   ; 
         FIG.  59    is a cross-sectional view taken along line  59 - 59  of  FIG.  57   ; and 
         FIG.  60    is a cross-sectional view taken along line  60 - 60  of  FIG.  57   . 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to  FIGS.  1 - 22   , an example connector  10  includes two fiber optic connector portions  12  and a boot  14 . Connector portions  12  each include a ferrule  78  for holding a fiber optic cable. Connector  10  may also be referred to as duplex connector assembly or duplex connector. Connector  10  is matable to an adapter  200  shown in  FIGS.  23 - 25   . Adapter  200  mates two connectors  10  together or mates another connector to connector  10  for fiber optic signal transmission. 
     The two connector portions  12  of connector  10  are arranged in a parallel position. Each connector portion  12  has a latch  18  including a latch body  20  with a proximal end  22  and a distal end  24 . Latch  18  pivots around a connection point  26  during latching and unlatching of latch  18 . Latch  18  secures connector  10  to adapter  200 . Boot  14  is movable away from connector portions  12  in a longitudinal direction (Direction A in  FIG.  2   ) causing pivoting movement of latch  18  about connection point  26  (Direction B in  FIG.  2   ). Such pivoting movement allows for unlatching of connector portions  12  from adapter  200 . Boot  14  simultaneously moves both latches  18  to allow for connector  10  to be unlatched from a duplex adapter or adapters with side-by-side ports  210 . Latch body  20  includes a shoulder  28  which mates with latching shoulder  208  of adapter  200  to secure the connector  10  to the adapter  200 . 
     In the illustrated embodiment, each connector portion  12  defines an LC profile, meaning that the connector portion  12  can mate with an LC adapter. 
     Boot  14  includes slots  50  which receive distal ends  24  of latch  18 . Slots  50  and proximal ends  22  are angled so as to cause a lifting motion for proximal ends  22  which results in a downward movement of distal ends  24  of latch  18  when boot  14  is pulled longitudinally away from a remainder of connector  10 . Compare  FIGS.  2  and  3   . A user can pull on boot  14  in a longitudinal direction away from the ferrules, and remove the connector  10  from the adapter  200 , without directly engaging latches  18 . 
     Connector portion  12  includes a front housing  32  and a ferrule assembly  76 . Ferrule assembly  76  includes a ferrule  78 , a hub  80  which holds the ferrule  78 , and a spring  82  which biases hub  80  and ferrule  78  toward front housing  32 . A front sleeve  88  and a rear sleeve  90  are mounted together with the ferrule  78 , the hub  80 , and the spring  82  housed inside to form the ferrule assembly  76 . An internal tube  84  is provided extending from the hub  80 . Tube  84  prevents epoxy from interfering with the movement of the ferrule  78 , the hub  80  and the spring  82 . The rear sleeve  90  is received in holder  96  through a side slot  98 . A rear crimp ring  104  and a crimp sleeve  106  allow crimping of a cable  150  to holder  96 . 
     A clip  180  may be used to hold connector portions  12  in the desired position as shown in  FIG.  1   . If an alternative position of connectors  12  is desired, such as to reverse the polarity of the connector portions  12 , clip  180  is removed, thereby allowing rotation of the front housings  32  with the latches to an opposite side of connector  10 . Such operation is desirable to change the polarity of connector portions  12  with respect to boot  14 . Once the front housings  32  are rotated, clip  180  is repositioned to maintain the front housings  32  in the new desired position. Boot  14  includes similar slots  52  on an opposite side of boot  14  so that boot  14  does not need to be rotated. Clip  180  can also be provided with different dimensions so as to change the spacing between connector portions  12 , if desired. Clip  180  includes outer arms  182 , and an inner arm  184 , and shoulders  186  on each of arms  182 ,  184  for securing to front housings  32  of the connector portions  12 . 
     In the illustrated example, front housing  32  mounts to ferrule assembly  76 . Ferrule assembly  76  mounts to holder  96 . Holder  96 , which mounts to two ferrule assemblies  76 , mounts to boot  14 . Boot  14  is engageable with latches  18  of the front housings  32 . Cable  150  is crimped to holder  96 . The individual fibers of cable  150  are fixed to the ferrules  78 , such as with epoxy. 
     Cable  150  includes an outer jacket  152 , strength members  154 , typically in the form of an aramid yarn, and two fibers  156 ,  158 . Each fiber  156 ,  158  includes an outer coating  160  and a bare fiber  162 . Typically, the coating  160  is removed and the bare fiber  162  is inserted into the ferrule  78 , and affixed, such as with epoxy. 
     Front housing  32  includes a key  34  for mating with an inner passage  202  of adapter  200 . Alignment sleeve  204  aligns the ferrules  78  to mate two connectors  10 . Adapter  200  includes two ferrule alignment sleeves  204 , and side-by-side passages  202  for each receiving a connector portion  12 . 
     Front housing  32  includes latch  18  on an exterior, and an inner passage  36  in the interior for receiving ferrule assembly  76 . Inner passage  36  includes a front shoulder  38 , an inner slot  40  and a side slot  42 . 
     Boot  14  includes an opening  54  for mating with structure on holder  96 . Boot  14  includes an interior area  56 , and a flexible rear portion  58 . 
     Holder  96  includes a tab  100  for mating with structure on rear sleeve  90  of ferrule assembly  76 . Holder  96  includes a rear projection  102  for receiving the crimp ring  104  and the crimp sleeve  106 . Holder  96  includes cross slots  108  for receiving proximal ends  22  of latch  18 . A shoulder  110  mates with opening  54  of boot  14  to allow longitudinal movement of boot  14  relative to holder  96 . Side slots  98  lead to oval openings  112 . Oval openings  112  allow for lateral movement of connector portions  12  to vary the lateral spacing. Oval openings  112  clip over ferrule assemblies  76  to retain the assemblies with holder  96 . 
     Holder  96  is provided with a lateral slot  114 , and a rear stop  115  for mating with rear sleeve  90  of each ferrule assembly  76 . 
     Front sleeve  88  of ferrule assembly  76  includes a keyed surface  118  for mating with a keyed surface  116  of hub  80 . 
     Inner surface  122  of front sleeve  88  is press fit onto outer surface  136  of rear sleeve  90 . Rear sleeve  138  defines an inner passage  138 . 
     Rear sleeve  90  includes a front collar  124  received in inner slot  40  of front housing  32 . Rear collar  126  of rear sleeve  90  is received in slot  114  of holder  96 . Outer surface  128  of rear sleeve  90  includes a reduced diameter portion  130 , and a shoulder  132 . Reduced diameter portion  130  is received in oval opening  112 . Oval opening  112  retains rear sleeve as the side slot  98  is slightly smaller than reduced diameter portion  130 . Notch  134  of rear sleeve  90  receives tab  100  of holder  96 . Rear sleeve  90  and the rest of ferrule assembly  76  is prevented from rotating relative to holder  96 . 
     To assemble connector  10 , cable  150  is inserted through boot  14 , crimp ring  104  and crimp sleeve  106 . The fibers  156 ,  158  are affixed to the ferrules  78  of the ferrule assemblies  76 . The ferrule assemblies  76  with the front housings  32  attached are mounted to the holder  96 . The cable jacket  152  and strength members  154  are crimped to rear projection  106  between crimp ring  104  and crimp sleeve  106 . Although crimp sleeve  106  is optional is some implementations. Boot  14  is pulled over holder  96  until shoulder  110  of holder  96  is retained in opening  54  of boot  14 , and proximal ends  22  of the latches  18  are in one of slots  50 ,  52  of boot  14 . 
     To switch polarity of connector portions  12 , the front housings  32  are rotated in opposite directions so that the proximal ends  22  of the latches  18  are moved between slots  50 ,  52 . During polarity switching, boot  14  remains mounted to housing  96 . Clip  180  is removed during the polarity switching operation. 
     Front housings  32  with latches  18  can each be made as a one-piece element. Front housing  32  defines an LC profile for mating with ports  210  of adapter  200 . As noted, front housings  32  are rotatable about the longitudinal axis of each connector portion  12  to change the polarity of the connector  10 , without rotating the ferrule  78  or the ferrule assembly  76 . 
     While the example connector  10  includes two fiber optic connector portions  12  and a boot  14 , it is to be appreciated that connector  10  can include a single connector portion  12 . 
     In some examples, clip  180  is not used. Clip  180  can be used to provide a certain spacing of connector portions  12 . One spacing is sized at 6.25 millimeters. See Dimension D of  FIG.  9   . Another spacing that may be used is 5.25 millimeters. See Dimension C of  FIG.  9   . A different clip  180  with a different spacing may be used, or the clip may be not used for the closer spacing. 
     Boot  14  is shown as including a spring return feature. Pocket  140  of holder  96  receives a spring holder  142  including a peg  144 . Spring holder  142  with peg  144  holds a return spring  146 . Spring  146  biases boot  14  toward the forward position of  FIG.  2    when released by the user. When the user pulls boot  14  longitudinally away from the connector portions  12 , the spring  146  is compressed. Spring  146  moves the boot  14  back to the rest position of  FIG.  2    upon release by the user. Pocket  140  of holder  96  is accessible through opening  148 . 
     Referring now to  FIGS.  26 - 41   , an example of another fiber optic adapter  300  that is configured for mating connectors similar to the connectors  10  of  FIGS.  1 - 22    described above is illustrated. 
     According to one example embodiment, the depicted fiber optic adapter  300 , unlike the adapter  200  shown in  FIGS.  23 - 25   , is a dual layer adapter and provides a connector port arrangement  302  including at least one upper port or receptacle  304  and at least one lower port or receptacle  306  vertically aligned with the upper receptacle  304  to form a column  308  of receptacles. The column  308  includes a center divider  310  that divides the at least one upper receptacle  304  from the at least one lower receptacle  306 . 
     In the depicted example, the dual layer adapter  300  is provided in the form of an adapter block comprising a plurality of the columns  308  of vertically aligned upper and lower receptacles  304 ,  306 . According to one example as shown in  FIGS.  26 - 41   , the adapter block  300  is provided as a unitarily molded structure wherein all of the receptacles  304 ,  306  and the center divider  310  are formed as an integral unit, wherein ferrule alignment sleeves  312  may be inserted therein. 
     As noted, each adapter of the block  300  may define a ferrule alignment structure  314  located within an axial cavity extending through each adapter. The ferrule alignment structure  314  includes a sleeve mount  316  defining an axial bore  318  for receiving a ferrule alignment sleeve  312 . In certain examples, where the adapter block  300  is a unitarily molded structure, the sleeve  312  may be inserted axially into the sleeve mount  316  after the block  300  has been molded. In other examples, wherein the adapter block  300  is not necessarily a unitarily molded structure, for example, as in an adapter block  300  formed from front and rear halves that are ultrasonically welded, the sleeve  312  may be inserted into the bore  318  from either end before welding the two adapter block halves together. It should be noted that in such examples, the front and rear halves may also be coupled together via other methods such as with snap-fit interlocking instead of ultrasonic welding. 
     In the example shown, the adapter block  300  defines twenty-four individual ports or receptacles, wherein twelve receptacles  306  are provided on a lower level  322  and twelve receptacles  304  are provided at an upper level  320 . It should be noted that the twelve receptacles provided on each level  320 ,  322  may be grouped in duplex pairs and the adapter block  300  may be deemed to contain six duplex adapters on each level  320 ,  322 . Other numbers of receptacles are possible depending upon the connectivity need. 
     The depicted adapter block  300  is configured such that the latches  18  of the connectors  10  coupled at the lower level  322  face toward the latches  18  of the connectors  10  coupled at the upper level  320  when the connectors  10  are mounted to the lower and upper receptacles  306 ,  304 . For each given column  308  of the upper and lower receptacles, the center divider  310  that is shared by both the lower receptacle  306  and the upper receptacle  304  defines at least a portion of the latching structures  324  of the adapter  300 , as will be described in further detail below. 
     As shown, the center divider  310  is integrally molded into the adapter block  300 . By defining a single center divider  310  that is used by both the upper and lower receptacles  304 ,  306  in providing latching structures  324  for the connectors  10 , the adapter block  300  is able to increase connection density. For example, in the depicted example, for an adapter block  300  that is configured to be used with the connectors  10  described above in  FIGS.  1 - 22   , the adapter block  300  may define a height H of about 0.75 inches. It should be noted that the height H of 0.75 inches is configured to accommodate connectors  10  such as those described above with respect to  FIGS.  1 - 22    that have latches  18  which can be unlocked by longitudinally-movable boots  14 . In other examples, wherein the adapter block  300  may be configured to couple standard LC connectors with standard latches, the divider  310  may be provided with a slightly wider profile, with the height H of the adapter block  300  being less than about 0.875 inches. It should be understood that the adapter block  300  may be modified for different types of fiber optic connector formats. The shared center divider  310  between the upper level  320  and the lower level  322  of receptacles provides the ability to increase the density of the adapter block  300  to levels not found in prior fiber optic adapters. 
     As noted above, the center divider  310  includes or defines at least a portion of the latching structures  324 , specifically latching shoulders  326 , for both an upper receptacle  304  and a lower receptacle  306  for each given column  308  of the receptacles. As described above, the shoulders  28  defined on the latches  18  of connectors  10  similar to those described above with respect to  FIGS.  1 - 22    mate with the latching shoulders  326  of the upper and lower adapter receptacles  304 ,  306  to secure the connectors  10  to the adapters  300 . The adapter block  300  is configured such that when the connectors  10  are mated to the adapter ports within a given column  308 , the latch body  20  of a connector  10  coupled at the lower level  322  faces toward the latch body  20  of a connector  10  coupled at the upper level  320 . 
     In connectors  10  similar to those shown in  FIGS.  1 - 22   , the front housings  32  thereof may include a key  34  for mating with an inner passage of adapters  300 . Alignment sleeve  312  within each adapter  300  aligns the ferrules  78  to mate two such connectors  10 . As noted above, each adapter of the adapter block  300  includes a ferrule alignment sleeve  312  for receiving and mating two connectors  10 . 
     As described above with respect to  FIGS.  1 - 22   , in removing connectors similar to connectors  10 , the boot  14  of each connector  10  may include slots  50 ,  52  which receive distal ends  24  of latch  18 . Slots  50 ,  52  and proximal ends  22  are angled so as to cause a lifting motion for proximal ends  22  which results in a downward movement of distal ends  24  of latch  18  when boot  14  is pulled longitudinally away from a remainder of connector  10 . A user can pull on boot  14  in a longitudinal direction away from the ferrules  78 , and remove a connector  10  from the adapter ports  304 ,  306 , without directly engaging latches  18 . 
     In the depicted embodiment, the connector port arrangement  302  shown in  FIGS.  26 - 41    is part of a fiber optic adapter  300  defining ports at both a front end  328  and a rear end  330  for optically mating fiber optic connectors  10 . Each fiber optic adapter of the block  300  of  FIGS.  26 - 41    defines symmetric ports at both the front and rear ends  328 ,  330  of the adapter  300  for mating similar fiber optic connectors  10 . In other examples, as will be described below, the fiber optic adapters  300  may define dissimilar ports at the front and rear ends  328 ,  330  for mating two different types of connectors. 
     Even though the adapter  300  discussed above has been described as being a unitarily molded adapter or an adapter wherein a front half and a rear half may be ultrasonically welded or snap-fit together to capture the ferrule alignment sleeves,  FIGS.  42 - 43    illustrate another possible embodiment for forming an adapter  400 . In the embodiment shown in  FIGS.  42 - 43   , the adapter  400  is depicted as being formed from a center structure  402  that is captured between top and bottom covers  404 ,  406 . As shown, the center structure  402  and the top and bottom covers  404 ,  406  may include intermating keys  408  and slots  410  for orientation/alignment purposes. As described above with respect to an adapter block that may formed from front and rear halves, the adapter embodiment  400  shown in  FIGS.  42 - 43    may also be ultrasonically welded or coupled with snap interlocks once the parts  402 ,  404 ,  406  have been fit together. 
     Referring now to  FIGS.  44 - 60   , instead of being provided as an adapter block  300 ,  400 , the connector port arrangement  302  discussed above may be provided as part of a fiber optic cassette  500 . The connector port arrangement  302  may be part of a front panel  502  of the cassette  500 , as shown in  FIGS.  44 - 60   , wherein the front panel  502  defines upper and lower receptacles  504 ,  506  and a shared center divider  508 , similar to the adapter blocks  300 ,  400  of  FIGS.  26 - 43   . 
     In the depicted example, similar to the adapter block  400  specifically discussed with respect to  FIGS.  42 - 43   , the cassette  500 , including the front panel  502  thereof, may be formed from multiple parts that are snapped together to form the cassette  500 . 
     As shown in  FIGS.  44 - 60   , the cassette defines a cassette body  510  having a base  512  and a cover  514  that is configured to be snap-fit to the base to capture a center structure  516 . The center structure  516  defines the front panel  502 . As shown, the center structure  516  may be oriented/aligned with respect to the base  512  (and the cover  514 ) with intermating keys  518  and slots  520  and also fixed with respect to the base  512  (and the cover  514 ) with flexible fingers  522 . The center structure  516 , once in place, is captured between the base  512  and the cover  514 . 
     Once the base  512  and the cover  514  capture the center structure  516  therebetween and the cassette body  510  has been assembled, the cassette body  510  forms a closed interior  524  for routing fibers therein between a front end  526  defined by the cassette body  510  and a rear end  528  defined by the cassette body  510 . The front connection panel  502  defined by the center structure  516  is provided at the front end  526 . The rear end  528  of the cassette body  510  includes connector ports  530  for receiving connectors  532  (e.g., multi-fiber connectors) carrying fibers to be relayed to the front panel  502  with terminated connectors as will be described in further detail. 
     It should be noted that in other example embodiments, instead of being part of a removable structure, the front panel  502  may be integrally molded to parts of the cassette body  510  such as the base  512  or the cover  514 . 
     The depicted fiber optic cassette  500  is configured to provide a connection point at the front end  526  utilizing the connectors  10  described above with respect to  FIGS.  1 - 22   . At the rear end  528 , as shown, the cassette  500  may include the multi-fiber type connectors  532 , wherein fibers entering the cassette  500  via the multi-fiber connectors  532  are separated out and relayed to the front panel  502  within the body  510  of the cassette  500 . It should be noted that the fibers may simply be separated out and relayed to the front panel  502  in a signal flow-through design that provides for a format-switching cassette  500 , wherein the format may be changed from a multi-fiber connector  532  to individual simplex or duplex connectors  10  such as those shown in  FIGS.  1 - 22    or standard LC connectors. In certain examples, the fibers may be provided as loose fibers within the body  510  of the cassette  500  or may be provided as part of a flexible circuit utilizing a flexible substrate that fixes the fibers as they are relayed from the rear connectors  532  to the front panel  502 . In further examples, the fibers within the cassette  500  may be processed via optical devices such as fan-outs, splitters, multiplexers, filters, couplers, etc. before being relayed to the front panel  502  for connection. 
     In the depicted example, as shown in  FIGS.  46 ,  47 ,  59 , and  60   , the center structure  516  and the front panel  502  defined thereby may be configured such that, while the external receptacles  504 ,  506  are configured for receiving standard fiber optic connectors  10 , an internal side  534  of the panel  502  is configured with non-standard adapter receptacles  536  such as those shown and described in U.S. Pat. Nos. 9,535,229; 9,488,788; and 9,223,094, the disclosures of which are incorporated herein in their entireties. In such examples, the fibers within the interior  524  of the cassette  500  extending from the rear connectors  532  to the front panel  502  may be terminated with non-conventional connectors that are coupled to the internal side  534  of the front panel  502 . Such non-conventional connectors may mate with standard format fiber optic connectors  10  coupled to the upper and lower receptacles  504 ,  506  of the front connection panel  502 , coming from an exterior of the cassette  500 . When mating standard and non-standard type connectors, each adapter may still include a standard alignment sleeve therewithin for aligning the ferrules of the mated connectors. 
     In other examples, the front panel  502  of the cassette  500  may be provided with a full adapter block configuration that mates standard fiber optic connectors  10  from both the external side and the internal side. In such an example, the separated out fibers coming from the multi-fiber connectors  532  would be terminated with standard type fiber optic connectors  10  that are coupled to the internal side  534  of the front panel  502 . 
     It should also be noted that although only a fiber optic cassette  500  has been shown to include a connection panel  502  that is configured to mate external standard connectors and internal non-conventional connectors, such an arrangement may be provided in the adapter blocks  300 ,  400  discussed above with respect to  FIGS.  26 - 43   . Such an adapter block  300 ,  400  may be provided as a stand-alone structure or be mounted in a removable manner to different optical devices such as fiber optic cassettes for defining the front panels of such cassettes, as discussed above. 
     The above specification, examples and data provide a complete description of the manufacture and use of the inventive concepts. Since many embodiments of the disclosure can be made without departing from the spirit and scope thereof, the inventive concepts reside in the claims hereinafter appended.