Abstract:
An optical fiber alignment system for mounting optical fiber arrays on an optical fiber block having a plurality of grooves on its upper surface according to the present invention comprises jig assemblies including a first jig for propping up a part of the optical fiber arrays and a second jig for adsorbing and fixing the other part of the optical fiber arrays using a plurality of vacuum holes formed on the upper side; X-Y-Z-θ X -θ Y -θ Z  stages for translating and rotating the jig assemblies in 3D to align the optical fiber arrays on the block; a vision unit including an image detector to monitor the alignment process of the optical fiber arrays and a display for displaying the image signal on a screen; and, an vision unit translator for translating the vision unit in 3D.

Description:
CLAIM OF PRIORITY  
         [0001]    This application claims priority to an application entitled “OPTICAL FIBER ALIGNMENT SYSTEM,” filed in the Korean Industrial Property Office on Dec. 17, 2001 and assigned Serial No. 2001-79908, the contents of which are hereby incorporated by reference.  
         BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention generally relates to an optical fiber block and in particular, to an optical fiber alignment system for mounting optical fiber arrays on the optical fiber block.  
           [0004]    2. Description of the Related Art  
           [0005]    In general, an optical fiber block consists of a block with a plurality of V-grooves on its upper side on which optical fiber arrays are mounted and a glass lid covering the optical fiber arrays. The optical fiber block can be used to connect an optical fiber ribbon to the input end or the output end of a planar lightwave circuit. The optical fiber ribbon consists of an optical fiber array with each optical fiber made of a core and cladding, which is made of materials such as thermosetting resin, UV curing resin, etc.  
           [0006]    Briefly, a conventional method of manufacturing the optical fiber block comprises steps of: removing a part of the outer cover of the optical fiber ribbon; aligning the optical fiber array on the V-grooves; spreading adhesives on the optical fiber array; covering the optical fiber array with the glass lid; and, polishing a cross section of the optical fiber array in a desired angle.  
           [0007]    The conventional method of aligning the optical fiber array on the V-grooves with each tooth positioned in a 250 μm interval is performed manually by an operator using farsighted glasses. When aligning the optical fiber array on the V-grooves at a 127 μm interval, a optical fiber ribbon consisting of plural optical fibers with a 250 μm interval is used typically. The process of aligning first and second optical fiber ribbons, each one consisting of plural optical fibers with a 250 μm interval is performed by inserting a first optical fiber array of the first optical fiber ribbon between a second optical fiber array of the second optical fiber ribbon.  
           [0008]    Accordingly, the process involving a user&#39;s manual input tend to have undesirable human errors, thus degrading the quality and its productivity.  
         SUMMARY OF THE INVENTION  
         [0009]    The present invention relates to an optical fiber alignment system for aligning optical fibers easily and in a stable manner on an optical block during the manufacturing stage of an optical fiber block.  
           [0010]    According to one aspect of the invention, there is provided an optical fiber alignment system for mounting optical fiber arrays on a block having a plurality of grooves on its upper side, comprising: jig assemblies comprising a first jig for propping up a part of the optical fiber arrays, and a second jig for adsorbing and fixing the part of the optical fiber arrays using a plurality of vacuum holes formed on the upper side; X-Y-Z-θ X -θ Y -θ Z  stages for translating and rotating the jig assemblies in 3D in order to align the optical fiber arrays on the block; a vision unit comprising an image detector for outputting an image signal for an input image in order to monitor the alignment process of the optical fiber arrays and a display for displaying the image signal on a screen; and, a vision unit translator for translating the vision unit in 3D. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which:  
         [0012]    [0012]FIG. 1 is a schematic diagram illustrating a configuration of an optical fiber alignment system according to a preferred embodiment of the present invention;  
         [0013]    [0013]FIG. 2 is a diagram illustrating a configuration of a first jig assembly in FIG. 1 on which a first optical fiber array is not mounted;  
         [0014]    [0014]FIG. 3 is a diagram illustrating a configuration of a first jig assembly in FIG. 1 on which the first optical fiber array is mounted;  
         [0015]    [0015]FIG. 4 is a diagram illustrating a configuration of a second jig assembly in FIG. 1 on which a second optical fiber array is mounted;  
         [0016]    [0016]FIG. 5 is a flow chart illustrating an alignment method of the optical fiber alignment system in FIG. 1; and,  
         [0017]    FIGS.  6  to  8  are diagrams illustrating the alignment method disclosed in FIG. 5. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0018]    A preferred embodiment of the present invention will be described herein below with reference to the accompanying drawings. For the purposes of clarity and simplicity, well-known functions or constructions are not described in detail as they would obscure the invention in unnecessary detail.  
         [0019]    [0019]FIG. 1 is a schematic diagram illustrating the configuration of an optical fiber alignment system according to a preferred embodiment of the present invention. The optical fiber alignment system includes first and second jig assemblies  100 ,  200 , first and second vertical supporters  300  and  350 , first and second X-Y-Z-θ X -θ Y -θ Z  stages  400 ,  450 , a vision unit  500 , a display  660 , a vision unit translator  620 , and a translate controller  640 .  
         [0020]    [0020]FIG. 2 is a diagram illustrating the configuration of a first jig assembly of FIG. 1 without a first optical fiber array mounted thereon, and FIG. 3 is a diagram illustrating the configuration of a first jig assembly of FIG. 1 on which the first optical fiber array is mounted. As shown in FIGS. 2 and 3, the first jig assembly  100  includes first and second jigs  110 ,  120 , and a first horizontal supporter  130 . The first jig  110  comprises a metal substrate  112  onto which a plurality of square-type grooves  114  are formed on its upper surface and a cover  116  with a magnetic property hinged at one end of the substrate  112 . In the embodiment, the thickness and width of each groove  114  are set selectively according to the thickness and width of the first optical fiber ribbon  700  to be mounted on the grooves  114 .  
         [0021]    The second jig  120  includes a plurality of square-type grooves  122  on its upper surface. A first exhaust port  126  is formed at one end of the second jig  120  and connected to a vacuum pump (not shown) through a vacuum tube. A plurality of holes  124  are formed on the bottom surface of the grooves  122  and connected to the first exhaust port  126 . When the vacuum pump is operated, the first optical fiber ribbon  700  is attached fixably to the grooves  122  due to the force provided through the holes  124 . The first horizontal supporter  130  is attached fixably to each end of the first and second jigs  110  and  120  that are positioned apart in a predetermined distance.  
         [0022]    Referring back to FIG. 1, the upper side of the first vertical supporter  300  is fixably attached to the lower surface of the second jig  120 , and the lower surface of the first vertical supporter  300  is fixed to the first X-Y-Z-θ X -θ Y -θ Z  stage  400 .  
         [0023]    The first X-Y-Z-θ X -θ Y -θ Z  stage  400  is operative to translate or rotate the first vertical supporter  300  in three dimensions. Namely, the stage  400  translates the first vertical supporter  300  linearly in the direction of the X-axis, Y-axis or Z-axis, and rotates the first vertical supporter  300  around the X-axis, Y-axis or Z-axis in a predetermined angle (θ X ,θ Y , or θ Z ).  
         [0024]    [0024]FIG. 4 is a diagram illustrating the configuration of a second jig assembly of FIG. 1 on which a second optical fiber array is mounted. As shown in FIG. 4, the second jig assembly  200  comprises third and fourth jigs  210  and  220 , and a second horizontal supporter  230 . The third jig  210  comprises a metal substrate  212  to which a plurality of square-type grooves  214  are formed on its upper surface and a cover  216  with a magnetic property hinged with one end of the substrate  212 . The thickness and width of each groove  214  are set selectively according to the thickness and width of the second optical fiber ribbon  750  to be mounted on the grooves  214 .  
         [0025]    The fourth jig  220  includes a plurality of square-type grooves  722  on its upper side. A second exhaust port  226  is formed at one end of the fourth jig  220  and connected to a vacuum pump (not shown) through a vacuum tube. A plurality of holes  724  are formed on the bottom side of grooves  722  and connected to the second exhaust port  226 . When the vacuum pump is operated, the second optical fiber ribbon  750  is fixably attached to the grooves  722  due to the vacuum force provided through the holes  724 .  
         [0026]    The second horizontal supporter  230  is fixably attached to each end of the third and fourth jigs  210  and  220  and spaced a part by a predetermined distance. The upper side of the second vertical supporter  350  is attached to the lower side of the fourth jig  220 , and the lower side of the second vertical supporter  350  is fixed to the second X-Y-Z-θ X -θ Y -θ Z  stage  450 . The second X-Y-Z-θ X -θ Y -θ Z  stage  450  translates or rotates the second vertical supporter  350  in three dimensions. Namely, it translates the second vertical supporter  350  linearly in the direction of X-axis, Y-axis or Z-axis, and rotates the second vertical supporter  350  around the X-axis, Y-axis or Z-axis in a predetermined angle (θ X , θ Y , or θ Z ).  
         [0027]    Referring back to FIG. 1, a vision unit  500  provided with a Charge Coupled Device(CCD) camera  520  is employed according to the embodiment of the present invention. The CCD camera  520  comprises a lens portion  510  for magnifying and focusing an image input through the lens portion  510  and transforming the detected image as an image signal and an interface  530  for transforming the image signal into a signal proper to the display  660  and outputs the transformed signal. The display  660  outputs the output signal from the vision unit  500  on a screen.  
         [0028]    Meanwhile, the vision unit translator  620  translates the vision unit  500  linearly in the direction of the X-axis, Y-axis, or Z-axis according to a control signal from the translate controller  640 . The translate controller  640  outputs the control signal to the vision unit translator  620  in a such away that an operator can monitor the alignment status of the first and/or second optical fiber array  720  and/or  770  through the display  660 .  
         [0029]    [0029]FIG. 5 is a flow chart illustrating an alignment method of mounting first and second optical fiber arrays on an optical fiber block having a plurality of grooves mounted thereon using the inventive optical fiber alignment system shown in FIG. 1. and FIGS.  6  to  8  are illustrative diagrams showing the alignment steps provided in FIG. 5. As shown in FIG. 5, the alignment method includes the steps of: preparing the first optical fiber array (step  910 ), preparing the second optical fiber array (step  920 ), aligning the first and second optical fiber arrays (step  930 ), and aligning the first and second optical fiber arrays with the block (step  940 ).  
         [0030]    In the step of preparing the first optical fiber array (step  910 ), the first optical fiber ribbon  700  is mounted on the first jig assembly  100 . At the same time, an angle relative to X-axis and a position relative to Z-axis of the end of the first optical fiber array  720  are measured using the vision unit  500 .  
         [0031]    In the step of preparing the second optical fiber array (step  920 ), the second optical fiber ribbon  750  is mounted on the second jig assembly  200 . At the same time, an angle relative to X-axis and a position relative to Z-axis of the end of the second optical fiber array  770  are measured using the vision unit  500 .  
         [0032]    The step of aligning the first and second optical fiber array (step  930 ) further comprises first and second sub-aligning steps ( 932 ,  937 ). In the first sub-aligning step ( 932 ), the end of the second optical fiber array  770  is aligned with the end of the first optical fiber array  720  as shown in FIG. 6 by maneuvering the second X-Y-Z-θ X -θ Y -θ Z  stage  450  (or the first X-Y-Z-θ X -zθ Y -θ Z  stage  400 ). As such, after the first sub-aligning step ( 932 ), the end of the second optical fiber array  770  and the end of the first optical fiber array  720  are parallel to each other, and have the same position relative to Z-axis.  
         [0033]    Thereafter, the second sub-aligning step ( 937 ) rotates the second optical fiber ribbon  750  around the X-axis at a predetermined angle θ X  using the second X-Y-Z-θ X -θ Y -θ Z  stage  450  and translates the second optical fiber ribbon  750  linearly along the Y-axis in order to interpose each optical fiber forming the second optical fiber array  750  to align between the adjacent optical fibers of the first optical fiber array  720 , as shown in FIG. 6.  
         [0034]    [0034]FIG. 6 shows the first optical fiber ribbon  700  comprising the first optical fiber array  720  and the second optical fiber ribbon  750  comprising the second optical fiber array  770 . The second optical fiber array  770 , for example, consists of  4  string optical fibers similar to the first optical fiber array  720  is interposed between the optical fibers forming the first optical fiber array  720 . The second optical fiber  720  meets the first optical fiber array  720  in an oblique angle. Then, the second sub-aligning step ( 937 ) rotates the second optical fiber ribbon  750  backwardly around the X-axis in a reciprocal angle θ X  using the second X-Y-Z-θ X -θ Y -θ Z  stage  450 , so that the second optical fiber array  770  is aligned with the first optical fiber array  720  side by side.  
         [0035]    [0035]FIG. 7 shows an optical block  800  comprising equally spaced 8 V-grooves, for example. The block  800  consists of a body  820  equipped with the equally spaced 8 V-grooves on its upper surface and a supporting portion  810  extended from the body  820 . The supporting portion  810  is different from the body  820  in its thickness. This thickness difference is set selectively so that the first and second optical fiber array  720 ,  770  can be mounted in a stable manner on the V-grooves  830 .  
         [0036]    The step of aligning the first and second optical fiber arrays with the block ( 940 ) is to measure an angle relative to X-axis and a position relative to Z-axis of the end of the V-grooves  830  formed on the upper side of the block  800  using the vision unit  500 , align the end of the first and second optical fiber array  720  and  770  with the end of the V-grooves  830 , and mount the first and second optical fiber array  720 ,  770  on the V-grooves  830 . Here, the first and second optical fiber arrays  720 ,  770  are rotated around the X-axis at a predetermined angle θ X  and translated linearly along the Y-axis until they are mounted on the V-grooves  830  in a stable manner as shown in FIG. 8.  
         [0037]    [0037]FIG. 8 shows the first and second optical fiber arrays  720  and  770  mounted on the block  800  in a stable manner according to the step of aligning the first and second optical fiber arrays with the block ( 940 ). As shown, the first and second optical fiber ribbons  700  and  750  are piled up, and the first and second optical fiber arrays  720  and  770  are aligned side by side on the block  800 .  
         [0038]    As described above, the optical fiber alignment system according to the present invention has advantages in that the optical fibers can be aligned on the block in a stable manner and easily using the X-Y-Z-θ X -θ Y -θ Z  stage and vision unit.  
         [0039]    While the invention has been shown and described with reference to a certain preferred embodiment thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.