Patent Publication Number: US-2023145265-A1

Title: Optical fiber connector

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Patent Application No. 63/276,549, which is hereby incorporated by reference in its entirety. 
    
    
     FIELD 
     This disclosure generally pertains to an optical fiber connector. 
     BACKGROUND 
     The prevalence of the Internet has led to unprecedented growth in communication networks. Consumer demand for service and increased competition has caused network providers to continuously find ways to improve quality of service while reducing cost. 
     Certain solutions have included deployment of high-density interconnect panels. High-density interconnect panels can consolidate the increasing volume of interconnections necessary to support fast-growing networks in a compacted form factor, thereby increasing quality of service and decreasing costs such as floor space and support overhead. However, room for improvement in the area of data centers, specifically as it relates to fiber optic connections, still exists. For example, manufacturers of connectors and adapters are always looking to reduce the size of the devices, while increasing ease of deployment, robustness, and modifiability after deployment. In particular, more optical connectors may need to be accommodated in the same footprint previously used for a smaller number of connectors in order to provide backward compatibility with existing data center equipment. 
     SUMMARY 
     In one aspect, an optical fiber connector can terminate a plurality of optical fiber cables. Each optical fiber cable comprises a jacket encasing at least one optical fiber and a strength element. The optical fiber connector comprises a connector housing having a back post configured so the optical fibers of the plurality of optical fiber cables extend into the connector housing through the back post. A single crimp ring is configured to crimp the strength members of the plurality of optical fiber cables onto the back post. 
     In another aspect, a method of terminating a plurality of optical fiber cables comprises inserting a plurality of optical fiber cables through a single crimp ring. Optical fibers of each of the plurality of optical fiber cables are terminated in a multifiber ferrule. The plurality optical fiber cables are loaded into a back body of a connector housing. Strength members of the plurality of optical fiber cables are crimped onto a back post of the back body using a single crimp ring. 
     Other aspects and features will be apparent hereinafter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective of a conventional very small form factor (VSFF) connector; 
         FIG.  2    is an exploded perspective of the VSFF connector of  FIG.  1   ; 
         FIG.  3    is a perspective of a breakout cable assembly; 
         FIG.  4    is a perspective of a breakout VSFF connector; 
         FIG.  4 A  is another perspective of the breakout VSFF connector; 
         FIG.  4 B  is another perspective of the breakout VSFF connector; 
         FIG.  5    is an exploded perspective of the breakout VSFF connector; 
         FIG.  6    is a perspective of a back body of the breakout VSFF connector; 
         FIG.  7    is another perspective of the back body; 
         FIG.  8    is a perspective of a crimp ring of the breakout VSFF connector; 
         FIG.  9    is a cross-sectional perspective of the crimp ring; 
         FIG.  10    is a perspective showing a step in a method of terminating a plurality of optical fiber cables with the breakout VSFF connector; 
         FIG.  11    is a perspective showing a subsequent step in the method; 
         FIG.  12    is a perspective showing a subsequent step in the method; 
         FIG.  13    is a perspective showing a subsequent step in the method; 
         FIG.  14    is a perspective showing a subsequent step in the method; 
         FIG.  15    is a perspective showing a subsequent step in the method; 
         FIG.  16    is a perspective showing a subsequent step in the method; 
         FIG.  17    is a perspective showing a subsequent step in the method; 
         FIG.  18    is a perspective showing a subsequent step in the method; 
         FIG.  19    is a perspective showing a subsequent step in the method; 
         FIG.  20    is a perspective showing a subsequent step in the method; 
         FIG.  21    is a perspective showing the breakout VSFF connector upon completion of the method. 
     
    
    
     Corresponding parts are given corresponding reference characters throughout the drawings. 
     DETAILED DESCRIPTION 
     Referring to  FIG.  1   , a conventional very small form factor (VSFF) connector is shown at reference number  10 . The illustrated VSFF connector  10  is an SN-type connector. SN connectors are sold by the assignee of the present disclosure. The VSFF connector  10  is configured to terminate an optical fiber cable  11 . In the illustrated embodiment, the optical fiber cable  11  comprises two optical fibers  31 , tensile strength members  33  (such as stranded Kevlar), and a cable jacket  35  encasing the optical fibers and the strength members. As shown in  FIG.  2   , the connector  10  may comprise a connector housing  12 , an inner front body  14 , a back body  16 . a back post  18 , and an outer housing  20 . The connector  10  may further comprise a pair of single-fiber ferrules  22  and corresponding ferrule springs  24 . The single cable  11  enters the connector housing  12  through the back post  18  and the ferrules  22  terminate the optical fibers  21 . A crimp ring  26  is used to secured strength members  33  of the cable  11  to the back post. A strain relief boot  28  is secured to the rear end of the housing  12  so that the strain relief boot covers part of the cable jacket  35  and provides strain relief. In  FIG.  1   , a dust cap  30  is releasably secured to the front end of the housing  12  to protect the ferrules  22 . 
     Referring to  FIG.  3   , an optical fiber breakout cable assembly in the scope of this disclosure is generally indicated at reference number  110 . This breakout cable assembly and a number of other breakout cable assemblies in the scope of this disclosure are presented in U.S. patent application Ser. No. 17/937,006, filed Sep. 30, 2022, which is hereby incorporated by reference in its entirety for all purposes. The break out cable assembly  110  comprises a plurality of VSFF connectors  10  and a single breakout connector  210 . As explained in further detail below, a prominent aspect of this disclosure pertains to exemplary configurations for the breakout connector  210 , particularly, breakout connector configurations that allow for multiple cables to extend out of a single back post, single crimp ring, and/or single strain relief boot. 
     In the illustrated embodiment, each VSFF connector  10  comprises a two-fiber connector configured to terminate a single two-fiber cable  11 . But it will be understood that other fiber breakout cable assemblies in the scope of this disclosure can use VSFF connectors opposite the breakout connector that are configured to terminate individual cables having other numbers of optical fibers. Opposite the individual connectors  10 , the breakout connector  210  terminates all of the cables  11 . In the illustrated embodiment, there are four cables  11 . Accordingly, the illustrated breakout connector  210  is configured to terminate four cables  11  having a total of eight optical fibers. It will be understood that other fiber breakout cable assemblies in the scope of this disclosure can use breakout connectors configured to terminate other numbers of cables and/or cables having other numbers of optical fibers. For example, U.S. patent application Ser. No. 17/937,006 discloses an alternative embodiment in which the breakout cable assembly comprises a breakout connector configured to terminate four eight-fiber cables. 
     Referring to  FIGS.  4 - 5   , the breakout connector  210  is generally configured for terminating a plurality of optical fiber cables  11  (e.g., 4 optical fiber cables). The breakout connector  210  provides a single plug that directly breaks out into four separate cables  11 . This enables the breakout cable assembly  110  discussed above to be devoid of mid-span fan outs, shuffle boxes, or cassettes between the breakout connector  210  and the individual connectors  10 . 
     The breakout connector  210  broadly comprises a connector housing  212  having a longitudinal axis LA. The connector  212  is configured to hold a single multifiber MT ferrule  222  so that the optical contact face of the ferrule faces forward along the longitudinal axis LA. The MT ferrule  222  is configured to terminate the optical fibers  31  of the four cables  11 . The MT ferrule  222  comprises a ferrule body  241 , a pin holder  243 , and a ferrule boot  245  configured to receive ribbonized optical fibers. The ferrule body  241  has at least one row of ferrule openings through the forward facing contact face. Each row of ferrule openings extends parallel to a fiber alignment axis FA of the connector  210 , which is perpendicular to the longitudinal axis LA. The ferrule body  241  also has a pair of guide pin openings  246  ( FIG.  4 A ) spaced apart along the fiber alignment axis LA. The pin holder  243  is configured to align with the guide pin openings  246  for selectively retaining guide pins (not shown) in the guide pin openings. 
     In the illustrated embodiment, the connector housing  212  is a VSFF connector housing, more particularly, an SN-MT connector housing. It will be understood, however, that the principles of this disclosure can be adapted for a breakout connector comprising another type of connector housing, e.g., another type of VSFF connector housing such as a CS connector housing, an MDC connector housing, or an MMC connector housing. In the SN-MT-style connector  210 , the connector housing  212  comprises an outer housing  220  and an inner housing assembly  213  ( FIG.  16   ) retaining the ferrule  222  and a ferrule spring  224  in the connector housing. As is known to those skilled in the art, in the SN-MT-style connector  210 , the outer housing  220  functions as a latch release actuator. To unlatch the connector  210  from a mating adapter, the outer housing  220  (broadly, the latch release actuator) is displaced rearward along the longitudinal axis LA of the connector in relation to a front body  214 , the ferrule  222 , and a back body  216 . Other types of pullback unlatch actuators can also be used on a connector housing (e.g., the pullback latch release arm of a CS, MDC, or MMT connector) without departing from the scope of the disclosure. 
     The inner housing assembly  213  comprises the front body  214 , the back body  216 , and a back post cover  217 . The back body  216  is configured to be secured to the front body  214  to capture the ferrule spring  224  and the ferrule  222  in the inner connector housing assembly  213  so that the spring yieldably biases the ferrule forward in the connector housing  212 . As explained more fully below, the back body  216  and the back post cover  217  are configured to form a back post  218  ( FIG.  16   ) of the connector  210 . Each of the cables  11  extends into the connector housing  212  through the back post  218 . The back post  218  is configured to retain the cables  11  in a single file cable row that extends parallel to the fiber alignment axis FA. The connector  210  further comprises a single crimp ring  226  configured to be crimped onto the back post  218  and a single cable strain relief boot  228  configured to be disposed over the crimp ring and the cables  11 . It can be seen that each of the cables  11  extends into the connector  210  through the back post  218 , each of the cables extends into the connector through the crimp ring  226 , and each of the cables extends into the connector through the strain relief boot  228 . 
     Referring to  FIGS.  6 - 7   , the back body  216  defines a passage  251  that extends along the longitudinal axis LA from a rear end portion through a front end portion of the back body  216 . The back body  216  comprises opposite first and second side walls  253 ,  255  spaced apart along the fiber alignment axis FA on opposite ends of the passage  251 . The back body  251  also comprises one end wall  257  extending along the fiber alignment axis FA from the first side wall  253  to the second side wall  255  on one side of the passage  251 . The passage  251  has an open side opposite the first end wall  257 . The open side of the passage  251  allows the optical fibers  31  to be loaded laterally into the back body  216  (those skilled in the art sometimes refer to this as “side-loading” fibers into the back body). 
     The back body  216  comprises a flange  261  that separates a font body attachment section  263  from a back post section  265 . Along the front body attachment section  263 , the side walls  253 ,  255  define opposing attachment wings  267  that are configured to latch with corresponding recesses of the front body  214  to secure the back body to the front body. The back post section  265  is configured to be secured to the back post cover  217  to form the back post  218 . When the back post section  265  is secured to the back post cover  217  to form the back post  218 , the back post has a perimeter that extends 360° circumferentially around the longitudinal axis LA. The cross-sectional shape of the outer perimeter of the back post  218  is elongated along the fiber alignment axis FA. The back post section  265  forms a first circumferential section of the 360° perimeter of the back post  218 , and the back post cover  217  defines an entire remainder of the 360° perimeter. 
     The back body  216  comprises at least one rib  269 ,  271  configured to partition the back post into a plurality of fiber channels  273 . In the illustrated embodiment, the back body comprises a central rib  271  and a pair of outer ribs  269  spaced apart from the central rib along the fiber alignment axis FA on opposite sides of the central rib. Each rib  269 ,  271  extends generally parallel to the longitudinal axis LA and has a respective length along the longitudinal axis. In one or more embodiments, the length of the central rib  271  is greater than the lengths of the outer ribs  269 . 
     The ribs  269 ,  271  are located along the back post section  265  to function as dividers that partition the interior of the back post  218  into a plurality of internal channels  273 . The back post  218  is configured to receive the fibers  31  of each optical fiber cable  11  in a respective one of the plurality of channels  273 . This separates and organizes the fibers  31  by cable as they enter the housing  212  through a single back post  218 . 
     In the illustrated embodiment, the back body  216  defines open-sided channels  273  to allow side loading of the fibers  231  into the channels. After the fibers  231  are loaded into the channels  273 , the back post cover  217  is configured to enclose each of the channels. 
     The ribs  269  are configured to maintain separation between the fibers  231  along the back post section  265  of the back body, whereas the back body passage  251  is undivided along the front body attachment section  263  so that the fibers  231  can come together as a ribbon in the front body attachment section. The difference between the lengths of the central rib  271  and the outer ribs  269  allows the fibers in the outer channels  273  to bend gradually inward along the fiber alignment axis FA (within the bending radius tolerance of the optical fibers) as they extend forward along the longitudinal axis LA to come together with the other fibers as a ribbon in the front body attachment section  263  of the back body. 
     Referring to  FIGS.  8 - 9   , the crimp ring  226  comprises a crimpable front section  281  and a back section  283  spaced apart along the longitudinal axis LA. The front section  281  has an inner perimeter that corresponds in shape to the perimeter of the back post  218  so that the front section can receive the back post therein and be crimped onto the back post. The back section  283  has smaller cross-sectional size that the front section  281  and defines a pair of glue ports  285  through which glue can be imparted into the interior of the crimp ring  226 . 
     Referring to  FIGS.  10 - 21   , an exemplary method of using the breakout connector  210  to terminate a plurality of optical fiber cables  11  will now be described. As shown in  FIG.  10   , at an initial stage, the ends of four optical fiber cables  11  are inserted into the single cable boot  228  and the single crimp ring  226 . The cable boot  228  and the crimp ring  226  receive the cables  11  in a single file cable row. At ends of each of the cables  11 , a portion of each jacket is removed to expose the strength members  33  which are folded backward onto the remaining jacket to further expose fibers  31 . As shown in  FIG.  11   , the bare fibers  31  are then brought together to form a fiber ribbon. As shown in  FIG.  12   , the ribbonized fibers are inserted into a ferrule spring  224 . Referring to  FIG.  13   , next the ribbonized fibers  31  are inserted through the ferrule boot  245  and terminates the fibers in the ferrule body  222 . 
     Referring to  FIG.  14   , the optical fiber cables  11  are subsequently loaded into the back body  216 . More particularly, the cables are loaded into the back body  216  by moving the exposed optical fibers  31  laterally into the passage  251 . A ribbonized section of the optical fibers  31  is loaded into the undivided section of the passage  251  along the front body attachment section  263 . From the ribbonized section, as the fibers  31  extend rearward, the fibers separate into groupings by cable. Each cable-specific grouping of fibers  31  is side-loaded into a respective channel  273  in the back post section  265  of the back body  216 . When the cables  11  have been side-loaded into the back body  216  in this fashion, the individual groupings of fibers  31  curve gently outward along the fiber axis FA as they extend away rearward along the longitudinal axis LA away from the ribbonized section toward the channels  273 . 
     As shown in  FIG.  15   , after the cables  11  have been side-loaded into the back body  216 , the front body  214  is installed on the back body  216  to secure the ferrule  222  and load the ferrule spring  224 . As shown in  FIG.  16   , to complete the inner housing assembly  213  and form the back post  218 , the back post cover  217  is placed onto the back post. This encloses the divided fiber channels  273  so that each grouping of fibers is retained in its respective channel. 
     As shown in  FIGS.  17  and  18   , the strength members  33  are folded forward onto the back post  218  ( FIG.  17   ), advances the crimp ring  226  forward so that the front section  281  receives the back post  218  ( FIG.  18   ), and crimps the front section of the crimp ring onto the back post ( FIG.  19   ). This simultaneously secures the strength members  33  of a plurality of fiber optic cables  11  to a single back post  218  using a single crimp ring  226 . Referring to  FIG.  20   , after the crimp ring  226  is crimped onto the back post  218 , curable adhesive is injected into the glue ports  85  to adhesively bond the crimp ring to the cable jackets  35 . As shown in  FIG.  21   , after the adhesive is applied, the breakout connector  210  is complete by advancing the strain relief boot  228  forward onto the back post and loading the inner housing assembly  213  into the outer housing  220 . 
     When introducing elements of the present disclosure or the preferred embodiment(s) thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. 
     In view of the above, it will be seen that the several objects of the disclosure are achieved and other advantageous results attained. 
     As various changes could be made in the above products and methods without departing from the scope of the disclosure, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.