Abstract:
An optical connector includes a housing configured to accommodate an optical fiber; two or more pins configured to correspondingly project distal ends of the two or more pins from a surface of the housing on a side of an end surface of the optical fiber and to correspondingly have male threads; and a pin adjuster configured to adjust an amount of projection of the two or more pins by rotating the male threads.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2015-176059, filed on Sep. 7, 2015, the entire contents of which are incorporated herein by reference. 
       FIELD 
       [0002]    The embodiments discussed herein are related to an optical connector and a method of coupling the optical connector. 
       BACKGROUND 
       [0003]    Servers, supercomputers, and so forth with a demanded system performance of 100 petabytes per second or more, for example, perform optical communication. An optical connector such as a mechanically transferable (MT) ferrule to which an optical fiber cable is connected is coupled to a lens block that includes an optical element on a substrate, on which a plurality of central processing units (CPUs) are mounted, to achieve large-capacity high-speed transfer. 
         [0004]    In the related art, however, displacement such as inclination tends to be caused when coupling the optical connector and the lens block to each other, and desired optical power may not be obtained. In this case, the optical connector is not usable, and a sufficient yield may not be obtained. 
         [0005]    Related technologies are disclosed in Japanese Laid-open Patent Publication No. 2012-027327 and Japanese Laid-open Patent Publication No. 2005-345560. 
         [0006]    It is desirable to provide an optical connector and a method of coupling the optical connector that improve the yield. 
       SUMMARY 
       [0007]    According to an aspect of the embodiments, an optical connector includes a housing configured to accommodate an optical fiber; two or more pins configured to correspondingly project distal ends of the two or more pins from a surface of the housing on a side of an end surface of the optical fiber and to correspondingly have male threads; and a pin adjuster configured to adjust an amount of projection of the two or more pins by rotating the male threads. 
         [0008]    The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims. 
         [0009]    It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, as claimed. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0010]      FIG. 1A  is a side view illustrating the structure of an optical connector according to a first embodiment; 
           [0011]      FIG. 1B  is a front view illustrating the structure of the optical connector according to the first embodiment; 
           [0012]      FIG. 1C  is a sectional view illustrating the structure of the optical connector according to the first embodiment; 
           [0013]      FIG. 2A  is a front view illustrating the structure of a lens block; 
           [0014]      FIG. 2B  is a side view illustrating the structure of the lens block; 
           [0015]      FIG. 2C  is a sectional view illustrating the structure of the lens block; 
           [0016]      FIG. 3  is a flowchart illustrating a method of coupling the optical connector to the lens block; 
           [0017]      FIG. 4  is a sectional view illustrating the optical connector and the lens block after being coupled to each other; 
           [0018]      FIG. 5A  is a sectional view illustrating a state in which the optical connector is fixed to the lens block; 
           [0019]      FIG. 5B  is a sectional view illustrating a state in which the amount of projection of two pins has been adjusted; 
           [0020]      FIG. 5C  is a sectional view illustrating a state in which the amount of projection of one pin has been adjusted; 
           [0021]      FIG. 6A  is a side view illustrating the structure of an optical connector according to a second embodiment; 
           [0022]      FIG. 6B  is a front view illustrating the structure of the optical connector according to the second embodiment; 
           [0023]      FIG. 7A  is a side view illustrating the structure of an optical connector according to a third embodiment; 
           [0024]      FIG. 7B  is a front view illustrating the structure of the optical connector according to the third embodiment; 
           [0025]      FIG. 8A  illustrates an example of variations in optical power caused along with adjustment of the amount of projection of the pins; and 
           [0026]      FIG. 8B  illustrates an example of variations in optical power caused along with adjustment of the amount of projection of the pins. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0027]    Hereinafter, embodiments will be specifically described with reference to the accompanying drawings. 
         [0028]    First, a first embodiment will be described.  FIGS. 1A, 1B, and 1C  are a side view, a front view, and a sectional view, respectively, illustrating the structure of an optical connector according to a first embodiment. 
         [0029]    As illustrated in  FIGS. 1A through 1C , an optical connector  100  according to the first embodiment includes a housing  51  that accommodates 16 optical fibers  53 . Of the 16 optical fibers  53 , eight optical fibers  53  are used for transmission (TX) for eight channels, and the remaining eight optical fibers  53  are used for reception (RX) for eight channels. The respective end surfaces of the optical fibers  53  form lines on one surface  54  of the housing  51 . The 16 optical fibers  53  are bundled and included in an optical fiber cable  52 . 
         [0030]    The housing  51  is formed with threaded holes  41  and  42  in which female threads are formed. The threaded hole  41  is formed on the outer side of one end portion of two lines of the optical fibers  53  for transmission and the optical fibers  53  for reception. The threaded hole  42  is formed on the outer side of the other end portion of the two lines of optical fibers  53 . A pin  111  on which male threads are formed is inserted into the threaded hole  41 . A pin  112  on which male threads are formed is inserted into the threaded hole  42 . End portions of the pins  111  and  112  on the surface  54  side are formed in the shape of a cone with a rounded distal end. A lever  121  is fixed to the pin  111 . When the lever  121  is tilted, the pin  111  is rotated to move the distal end of the pin  111  by a distance that matches the amount of inclination of the lever  121  and the pitch of the threads, which varies the amount of projection of the distal end of the pin  111  from the surface  54 . Similarly, a lever  122  is fixed to the pin  112 . When the lever  122  is tilted, the pin  112  is rotated to move the distal end of the pin  112  by a distance that matches the amount of inclination of the lever  122  and the pitch of the threads, which varies the amount of projection of the distal end of the pin  112  from the surface  54 . 
         [0031]    Next, a lens block to which the optical connector  100  is to be coupled will be described.  FIGS. 2A, 2B, and 2C  are a front view, a side view, and a sectional view, respectively, illustrating the structure of a lens block. 
         [0032]    As illustrated in  FIG. 2A through 2C , a lens block  60  to which the optical connector  100  is to be coupled includes a housing  61  that accommodates 16 lenses  63 . Of the 16 lenses  63 , eight lenses  63  are used for transmission (TX) for eight channels, and the remaining eight lenses  63  are used for reception (RX) for eight channels. The lenses  63  form lines on one surface  64  of the housing  61 . The housing  61  accommodates an optical element  65  such as a photoelectric conversion element. Light radiated to the lenses  63  is collected at the optical element  65 , and light emitted by the optical element  65  is output from the lenses  63 . The lens block  60  includes a guide wall  62  that projects from the surface  64  of the housing  61  to guide the optical connector  100 . 
         [0033]    A guide hole  71  that guides the pin  111  and a guide hole  72  that guides the pin  112  are formed in the surface  64  of the housing  61 . The guide hole  71  is formed on the outer side of one end portion of two lines of the lenses  63  for transmission and the lenses  63  for reception. The guide hole  72  is formed on the outer side of the other end portion of the two lines of lenses  63 . 
         [0034]    Next, a method of coupling the optical connector  100  to the lens block  60  will be described.  FIG. 3  is a flowchart illustrating a method of coupling the optical connector to the lens block.  FIG. 4  is a sectional view illustrating the optical connector and the lens block after being coupled to each other. 
         [0035]    First, the optical connector  100  is fixed to the lens block  60  using a clip (not illustrated) by inserting the optical connector  100  inside the guide wall  62  and causing the respective distal ends of the pins  111  and  112  to abut against the inside of the guide holes  71  and  72 , respectively (step S 101 ). Then, it is verified whether or not desired optical power is obtained (step S 102 ). If desired optical power is obtained (step S 103 ), a coupling operation is finished. In the case where desired optical power is not obtained (step S 103 ), on the other hand, the amount of projection of one or both of the pins  111  and  112  from the surface  54  is adjusted by operating one or both of the levers  121  and  122  (step S 104 ). Verification (step S 102 ) and adjustment (step S 104 ) are repeated until desired optical power is obtained. 
         [0036]    By coupling the optical connector  100  to the lens block  60  in this way, desired optical power may be obtained through appropriate adjustment even if desired optical power is not obtained because of displacement such as inclination in the early stage of fixation. Thus, the yield may be improved. 
         [0037]    An example of the method of adjusting the amount of projection of one or both of the pins  111  and  112  from the surface  54  will be described. It is assumed, for example, that the state illustrated in  FIG. 5A  has been established when the optical connector  100  is fixed to the lens block  60  using a clip. In the case where the result of the verification performed in this state indicates that the optical fibers  53  are too close to the lenses  63 , the amount of projection of the pins  111  and  112  is increased. As a result, as illustrated in  FIG. 5B , the distance of the optical fibers  53  from the lenses  63  is increased. Meanwhile, in the case where the result of the verification performed in the state illustrated in  FIG. 5A  indicates that desired optical power is obtained in channels close to the pin  111  but that the optical fibers  53  are too close to the lenses  63  in channels close to the pin  112 , only the amount of projection of the pin  112  is increased. As a result, as illustrated in  FIG. 5C , the distance of the optical fibers  53  from the lenses  63  is increased more significantly for channels closer to the pin  112 . It may be considered that the focal length is adjusted in the example illustrated in  FIG. 5B . It may be considered that the focal length and the angle are adjusted in the example illustrated in  FIG. 5C . 
         [0038]    Next, a second embodiment will be described.  FIGS. 6A and 6B  are a side view and a front view, respectively, illustrating the structure of an optical connector according to a second embodiment. 
         [0039]    As illustrated in  FIG. 6A , an optical connector  200  according to a second embodiment includes a housing  51  that accommodates 16 optical fibers  53 , as in the first embodiment. The housing  51  is formed with threaded holes  43  and  44  in which female threads are formed, in place of the threaded holes  41  and  42 . The threaded hole  43  is formed at a side of a line of optical fibers  53  for transmission. The threaded hole  44  is formed at a side of a line of optical fibers  53  for reception. A pin  113  on which male threads are formed is inserted into the threaded hole  43 . A pin  114  on which male threads are formed is inserted into the threaded hole  44 . End portions of the pins  113  and  114  on the surface  54  side are formed in the shape of a cone with a rounded distal end. A lever  123  is fixed to the pin  113 . When the lever  123  is tilted, the pin  113  is rotated to move the distal end of the pin  113  by a distance that matches the amount of inclination of the lever  123  and the pitch of the threads, which varies the amount of projection of the distal end of the pin  113  from the surface  54 . Similarly, a lever  124  is fixed to the pin  114 . When the lever  124  is tilted, the pin  114  is rotated to move the distal end of the pin  114  by a distance that matches the amount of inclination of the lever  124  and the pitch of the threads, which varies the amount of projection of the distal end of the pin  114  from the surface  54 . The optical connector  200  is otherwise the same as the optical connector  100 . 
         [0040]    As with the lens block  60 , a lens block to which the optical connector  200  is to be coupled includes a housing that accommodates 16 lenses. A guide hole that guides the pin  113  and a guide hole that guides the pin  114  are formed in the housing, in place of the guide holes  71  and  72 . The guide hole which guides the pin  113  is formed at a side of the lenses  63  for transmission. The guide hole which guides the pin  114  is formed at a side of the lenses  63  for reception. The lens block is otherwise the same as the lens block  60 . 
         [0041]    Also in the second embodiment, as in the first embodiment, desired optical power may be obtained through appropriate adjustment even if desired optical power is not obtained because of displacement such as inclination in the early stage of fixation. Thus, the yield may be improved. In the first embodiment, the focal length or the like may be adjusted among the plurality of channels. In the second embodiment, the focal length or the like may be adjusted between the line of lenses  63  for transmission and the line of lenses  63  for reception. 
         [0042]    Next, a third embodiment will be described.  FIGS. 7A and 7B  are a side view and a front view, respectively, illustrating the structure of an optical connector according to a third embodiment. 
         [0043]    As illustrated in  FIG. 7A , an optical connector  300  according to a third embodiment includes a housing  51  that accommodates 16 optical fibers  53 , as in the first embodiment. The housing  51  is formed with threaded holes  43  and  44 , as in the second embodiment, in addition to the threaded holes  41  and  42 . The pin  111  is inserted into the threaded hole  41 . The pin  112  is inserted into the threaded hole  42 . The pin  113  is inserted into the threaded hole  43 . The pin  114  is inserted into the threaded hole  44 . The optical connector  300  is otherwise the same as the optical connector  100 . 
         [0044]    As with the lens block  60 , a lens block to which the optical connector  300  is to be coupled includes a housing that accommodates 16 lenses. A guide hole that guides the pin  113  and a guide hole that guides the pin  114  are formed in the housing, as in the second embodiment, in addition to the guide holes  71  and  72 . The lens block is otherwise the same as the lens block  60 . 
         [0045]    Also in the third embodiment, as in the first and second embodiments, desired optical power may be obtained through appropriate adjustment even if desired optical power is not obtained because of displacement such as inclination in the early stage of fixation. Thus, the yield may be improved. In the third embodiment, the focal length or the like may be adjusted among the plurality of channels, and the focal length or the like may be adjusted between the line of lenses  63  for transmission and the line of lenses  63  for reception as well. 
         [0046]    Next, an example of variations in optical power caused along with adjustment of the amount of projection of the pins will be described.  FIGS. 8A and 8B  illustrate an example of variations in optical power caused along with adjustment of the amount of projection of the pins. In the example, it is assumed that transfer is performed in 12 channels. 
         [0047]    It is assumed that the distribution of optical power as indicated by diamond marks in  FIG. 8A  has been obtained at first. In this state, optical power in channels Ch00 to Ch03 is too high, and optical power in channels Ch07 to Ch11 is too low. In this state, the amount of projection of two pins provided on the outer side of end portions of lines of optical fibers, such as the pins  111  and  112 , is increased such that optical power in the channel Ch00 is about the median value (2.0 dBm) of the target range. As a result, optical power is reduced as a whole, and the distribution of optical power generally as indicated by square marks in  FIG. 8A  is obtained. In this state, the amount of projection of one pin provided on the channel Ch11 side is reduced such that optical power in the channel Ch11 is about the median value (2.0 dBm) of the target range. As a result, optical power is increased more significantly on the channel Ch11 side, and the distribution of optical power generally as indicated by triangular marks in  FIG. 8A  is obtained. 
         [0048]    Such optical connectors may be used in servers, high-end computers for use for high-performance computing (HPC) or the like, devices that use a printed board on which an optical component with a vertical cavity surface emitting laser (VCSEL)/photo diode (PD) optical element is mounted, and so forth. The optical connectors may be mechanically transferable (MT) ferrules. 
         [0049]    All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although the embodiments of the present invention have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.