Abstract:
An optical circuit device providing a system for redistributing a series of optical ribbons through the device to a predefined output configuration. The optical circuitry device utilizes a plurality of stacked substrates to reconfigure the input optical ribbons to a specific output pattern. The optical member includes an input section and an output section including a plurality of vertically stacked substrates that mix or redistribute the optical fibers from the input section to the output section.

Description:
FIELD 
       [0001]    This invention generally relates to three dimensional optical circuits, and more particularly, to a three dimensional optical circuit assembly comprising a layered optical redistribution member and method of making the same. 
       BACKGROUND 
       [0002]    Optical fiber networks are becoming increasingly common in modern telecommunications systems, high speed routers, computer systems and other systems for managing large volumes of data. Optical fiber networks typically include a large number of optical fibers that are routed over relatively long distances. In order to increase transmission speeds and efficiencies relative to the propagation of conventional electrical signals there is the need to route individual optical fibers between various connection points throughout the system creating an optical circuit.  FIGS. 1 to 3  show typical systems that accomplishing this type of routing. 
         [0003]    One of the more common ways of producing this optical circuit in use today is referred to as an optical shuffle, as illustrated in  FIG. 2 . The optical shuffle generally includes a series of input optical ribbons that include multiple individual optical fibers, a shuffle zone and a series of similar output optical ribbons. This process involves weaving the individual optical fibers by hand through the shuffle zone and create the desired output optical fiber configuration. This process is time consuming and costly and due to its complexity, can be prone to errors. 
         [0004]    An alternative to the optical shuffle is an optical manifold. The optical manifold comprises a cast or layer generated structure providing a predetermined optical fiber redistribution configuration. The structure is typically generated by an “SLA” process in which a liquid polymer is laser sintered, layer on top of layer, until the structure is complete as best shown in  FIG. 3 . This three dimension array is then used a guide for the optical fibers. A fiber is inserted into an input channel an is the routed to a predetermined output location. The output fibers are then grouped into a desired output ribbon. 
         [0005]    Along similar lines to the manifold, a layered technique is sometimes preferred. In this instance, a substrate is provided, and layered upon the substrate is a series of inserts that generate a series of grooves upon the substrate. This technique is repeated until a desired number of layers are produced. Similar to the cast or laser sintered manifold, the optical fibers are passed through the grooves between adjacent layers, from the input section to output section generated the desired optical fiber bundles. 
         [0006]    Finally, flexible circuitry as depicted in  FIG. 1  can also be used to redistribute the optic fibers. This method is automated but requires the optic fibers to be coupled to each end of the flexible circuit. These flexible circuits can be large and difficult to use in confined areas. 
         [0007]    With respect to the listed techniques for producing the three dimensional optical circuit, all of the processes require a great deal of time and effort and can be quite costly. 
       SUMMARY 
       [0008]    In order to overcome the disadvantages inherent in previously known optical circuitry, there is provided a low cost and easily manufactured method of producing these types of three dimensional optical circuitry. Additionally, along with effectively producing this circuitry, there is also provided a method and system for making these optical components small in size so they may be used in environments with certain size restraints, in particular along the z-axes or stacking depth. 
         [0009]    The present new and improved optical circuitry device provides a system for redistributing a series of optical ribbons through the device to a predefined output configuration. The optical circuitry device utilizes a plurality of stacked substrates to reconfigure the input optical ribbons to a specific output pattern. Connectors or other connection devices may be coupled to the input and output ends of the device to incorporate the device into existing systems and other fiber optic environments. 
         [0010]    In an exemplary embodiment of the invention, a first set of optical ribbons is provided in which each optical ribbon contains multiple optical fibers therein. An optical member having an input section and an output section including a plurality of vertically stacked substrates is provided to mix or redistribute the optical fibers from the input section to the output section. The optical fibers are adhered to the substrates in a predetermined pattern so that the input optical fibers are regrouped to an appropriate output configuration according to prescribed requirements. The optical fibers extending from the output section are grouped according to any predetermined arrangement and are connected to an optical fiber device. The output sections can have any type of interface and may include, but is not limited to, optical fiber connectors, edge type connections or optical transceivers. 
         [0011]    Other objects, features and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0012]    In the course of this detailed description, the reference will be frequently made to the attached drawings in which: 
           [0013]      FIG. 1  is a top elevational view of a conventional optical mixing circuit utilizing a flexible circuit; 
           [0014]      FIG. 2  is a top elevational view of a conventional optical shuffle; 
           [0015]      FIG. 3  is a perspective view of a conventional optical manifold; 
           [0016]      FIG. 4  is a perspective view of a first embodiment of the three dimensional optical mixing device according to the present invention; 
           [0017]      FIG. 5  is an exploded view of the three dimensional optical mixing device of  FIG.4 ; 
           [0018]      FIG. 6  is a top elevational view of the first embodiment of the present invention illustrating a typical optical fiber arrangement on a substrate; 
           [0019]      FIG. 7  is an end elevation view of the output section of the present invention of  FIG. 6 ; 
           [0020]      FIG. 8  is a detail view of one optical ribbon of the output section of  FIG. 7 ; 
           [0021]      FIG. 9  is a side elevational view of the output section of the present invention of  FIG. 6 ; 
           [0022]      FIG. 10  is a top elevational view of a second embodiment according to the present invention; 
           [0023]      FIG. 11  is an end elevation of the second embodiment according to the present invention of  FIG. 10 ; 
           [0024]      FIG. 12  is a detail view of one optical ribbon of the output section of  FIG. 11 ; 
           [0025]      FIG. 13  is a side elevational view of the output section of the second embodiment according to the present invention of  FIG. 10 ; 
           [0026]      FIG. 14  is a top elevational view of a third embodiment according to the present invention; 
           [0027]      FIG. 15  is an end elevation of the third embodiment according to the present invention of  FIG. 14 ; 
           [0028]      FIG. 16  is a side elevational view of the output section of the third embodiment according to the present invention of  FIG. 14 ; 
           [0029]      FIG. 17  is a top elevational view of a fourth embodiment according to the present invention; 
           [0030]      FIG. 18  is an end elevation of the fourth embodiment according to the present invention of  FIG. 17 ; 
           [0031]      FIG. 19  is a side elevational view of the output section of the fourth embodiment according to the present invention of  FIG. 17 ; 
       
    
    
     DETAILED DESCRIPTION  
       [0032]    Referring to the drawings in greater detail, and first to  FIGS. 4 to 8 , the present optical circuitry device is embodied in an optical circuit assembly  10 . The optical circuit assembly  10  includes an optical circuit  20  that takes an input optical ribbon  30  having multiple optical fibers  32 . The device reorganizes the fibers  32  in a specific pattern and outputs an optical ribbon  40  having a different optical fiber arrangement within the output optical ribbon  40  than the input optical fibers  32  of the input optical ribbon  30 . 
         [0033]      FIG. 4  best shows the optical circuit assembly  10  in accordance with a first embodiment. The optical circuit assembly includes a plurality of input optical ribbons  30 , an optical circuit  20  and a plurality of output optical ribbons  40 . For illustrative purposes, the figures show an optical circuit assembly having eight input optical ribbons, an eight layer optical circuit and eight output optical ribbons. Each optical ribbon  30 , 40  includes eight individual optical fibers  32 ,  42 . A conformal coating surrounds the optical fibers  32 ,  42  holding them together to create the optical ribbons  30 ,  40 . These types of optical ribbons are generally flat and consist of the optical fibers lying in a side-by-side relationship. This type of arrangement is typically known as an 8×8 system or array. The exemplary embodiment is depicted as an 8×8 system but any number configuration can be used. 
         [0034]    The optical circuit assembly  10  includes an optical circuit  20  positioned between the input optical ribbons  30  and the output optical ribbons  40 . The optical circuit  20  includes a plurality of substrates  22  that are arranged in a stacked relationship. As best shown in  FIGS. 5 and 6 , in can be seen that in the exemplary embodiment there are a total of eight substrates  22 . It is to be noted that fewer or greater substrates may be used as needed. Each substrate  22  includes an input section  26  and an output section  28  and a substrate surface  24  therebetween. Each substrate  22  includes an input ribbon  30  extending from the input section  26  of each substrate  22  and an output ribbon  40  extending from the output section  28  of each substrate  22 . 
         [0035]    As shown more particularly in  FIG. 6 , an individual substrate  22  includes input optical ribbons  30  extending from the input section  26  of the substrate  22 . The input optical ribbon  30  extends from the substrate  22  in a generally parallel orientation to the substrate  22 . The individual input optical fibers  32  are separated from the input optical ribbon  30  and are position on the substrate surface  24 . The optical fibers  32  are adhered to the substrate surface  24  and are separated from the input optical ribbon  30  and spread out along the substrate surface  24  from the input section  26  of the substrate  22  to the output section  28  of the substrate  22 . 
         [0036]    It should be understood that the spacing between individual optical fibers  30  is dictated by either of the input optical ribbons  32  or the output optical ribbons  40 . For example, in the exemplary embodiment shown in  FIGS. 5 and 6 , each of the input optical ribbons  30  is first separated and then position on a particular substrate  22  in a predetermined orientation. The spacing A between individual optical fibers  32  can only be equal to or greater than the width B of an optical ribbon  30 . If the separation between the optical fibers  32  positioned on the substrate  22  tends to be less than the width of an optical ribbon  30  then the situation of fiber crossover will exist, that is, the optical ribbons  30  or a portion of the optical ribbons  30  will overlap each other. This will create undesired stress on the optical fibers  32  and increase the overall thickness of the optical circuit  20 . 
         [0037]    All of the output optical fibers  42  for each of the substrates  22  maintain the specific predetermined separation. The eight substrates  22  are stacked one on top of the other until they are all layered creating the optical circuit  20  of  FIG. 4 .  FIG. 7  also shows an end view of the completed optical circuit  20 . The optical circuit  20  consists of the eight substrates  22  stacked in a vertical relationship with the individual optical fibers  32  lying therebetween. In can be seen that the only space between the substrates is due to the thickness of the optical fibers. 
         [0038]    In the present exemplary embodiment, as shown in  FIGS. 8 and 9 , the output optical fibers  42  extend from the output section  28  of the optical circuit  20  in a predetermined separation or arrangement. The output optical fibers  42  are now grouped in a vertical arrangement. All of the output optical fibers  42  lying vertically in the first column are combined to form an output optical ribbon  40 . These optical fibers  42  also have a conformal coating applied to them to secure those optical fibers  42  together. Although, there are no literal gaps between optical fibers  42  in the optical ribbon  40 , there is a transition section C from an optical fiber  42  exiting the substrate  22  to the start of the output optical ribbon  40 , where the optical fiber  42  is bent to a distance of substrate thickness to be next to the other optical fiber  42 . Additionally, all groups of vertically positioned output optical  42  fibers are combined successively to form the remaining output optical ribbons  40 . 
         [0039]    In addition to vertically orientated output optical ribbons  40 , horizontal output optical ribbons  40  are also required. As each group of vertically aligned optical fibers  42  exits the substrate  22 , the output optical fibers  42  twist along the transition section C where they are first vertically orientated as they exit the substrate  22  and transition to horizontally orientated as they are grouped together to form the output optical ribbon  40 . 
         [0040]    In the present exemplary embodiment, the output section  28  of the optical circuit  20  has a plurality of output optical ribbons  40  extending therefrom. It should be understood that any form of termination can used in place of the output optical ribbons. This includes and is not limited to: optical fiber connectors, edge terminations, flexible circuitry and opto-electrical transceiver modules. 
         [0041]      FIG. 10  shows an alternative embodiment to the optical circuit  20  described above, where similar structure is given the same reference number. The optical circuit  20 , includes an 8×8 optical circuit system  10  identical to that described above but having output optical ribbons  40  extending from the output section  28  of the optical circuit  20  in a generally parallel orientation to the substrates  22 . This is accomplished by having the output optical fibers  42  extending from the output section  28  of each of successively layered substrates  22 , horizontally offset from one another. This process effectively groups the output optical fibers  42  in a generally flat relationship to the substrates  22 . 
         [0042]    Due to the fact that individual output optical fibers  42  extend from individual substrates  22 , the output optical ribbons  40 , although shown flat, extend from the output section  28  of the optical circuit  20  at an angle to the surface of the substrates  22 . 
         [0043]      FIGS. 11 and 12 , show the output optical ribbons  40  at an angle to the substrate surface  24 . As best shown in  FIG. 13 , as the output optical ribbons  40  extend further from the optical circuit  20 , the optical ribbons  40  are transitioned flat. By utilizing this offset, there is no twisting of the output optical fibers  42  and the transition area C for the optical ribbons to get to the flat state is minimized. 
         [0044]    In an additional embodiment shown in  FIG. 14 , the substrates  22  used to make the optical circuit  20  have variable lengths. The substrates  22  are arranged from shortest to longest with appropriate optic fibers  32  positioned therebetween as previously described in the prior two embodiments. By having substrates  22  with increasing lengths, the optic fibers  32  disposed on the shorter substrate surfaces can be successively supported along their length by the remaining substrates until all of the optical fibers  32  exit the output section  28  of the substrate  22 . 
         [0045]    By producing the optical circuit in this manner, the transition section at the output portion of the optical circuit, as previously described is virtually eliminated and thereby minimizing the twisting of the output optical fibers. This allows the output optical fibers to be easily aligned and the conformal coating used to create the ribbon can be applied and cured without any unnecessary stress to the fibers. For illustrative purposes the distance each substrate  22  extends past the previous substrate is exaggerated, but in actuality are minimized to keep the overall length of the optical circuit  20  to a minimum. However, a variety of lengths may be used as designed or needed. 
         [0046]    The output optical fibers  42  in this embodiment extend from the optical circuit  20  in a parallel orientation to the substrates  22 , in other words the output optical ribbon  40  remains flat to the last or longest substrate as can be seen best in  FIGS. 15 and 16 . 
         [0047]    In a fourth embodiment, as best shown in  FIG. 17 , adjacent substrates  22  are incorporated into a single combined substrate and adjacent input optical fibers  32  are paired and disposed onto the combined single substrate. This allows the total number of substrates  22  to be reduced and to effect an overall reduction in the thickness of the optical circuit  20 . As previously described the optic fibers  32  disposed on the shorter substrate surfaces can be successively supported along their length by the remaining substrates until all of the optical fibers  32  exit the output section  28  of the substrates  22 . Additionally, the output optical fibers  42  in this embodiment extend from the optical circuit in a parallel orientation to the substrates  22  and remain flat to the last or longest substrate  22  as can be seen in  FIGS. 18 and 19 . 
         [0048]    This embodiment depicts adjacent substrates and adjacent optical fibers as being combined in pairs, although other combinations may be used as well. For example, three adjacent fibers may be combined onto a single substrate, leaving a single optical fiber to be placed onto another substrate. This embodiment depicts only one possibility and is not limited to the configuration shown. 
         [0049]    In practice, automating processes are used to construct these optical circuits. This process involves first adhering all of the optical fibers from one of the input optical ribbons to a first substrate in the predetermined orientation. The optical circuit is completed by successively stacking addition substrates on top of the previously completed layer, adhering the optical fibers from the next optical ribbon to that substrate and repeating this process until the optical circuit is complete. Although in this exemplary embodiment each layer is fashioned in serial order until the optical circuit is completed, it should be understood that alternative layering schemes may be employed. For example, the top and bottom layers have the optical fibers attached first, and then the intermediate layers are subsequently added. By use of this automated process for regrouping optical fibers within an optical circuit the overall size of the optical circuit is significantly reduced and all hand operations are eliminated thereby, minimizing the cost produce this optical circuit. 
         [0050]    It will be understood that the invention may be embodied in other specific forms without departing from the spirit or central characteristics thereof. The present examples and embodiments, therefore, are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein.