Abstract:
An end cap holder includes a main body and a pump which generates a vacuum pressure. The main body includes a bore hole extending therethrough along a central axis, and a contact surface which surrounds an end of the bore hole. Activation of the pump may generate a vacuum pressure within the bore hole.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is based upon and claims the benefit of priority from U.S. Provisional Patent Application No. 62/351,709, filed Jun. 17, 2016, the disclosure of which is incorporated by reference herein in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present disclosure relates generally to end cap holders for optical fiber end caps, and more particularly to end cap holders which utilize vacuum pressure to hold the end caps in place. 
       BACKGROUND OF THE INVENTION 
       [0003]    End caps are widely utilized in various optical fiber applications. The end cap typically has a different diameter than the optical fiber to which it is attached. These different diameters allow the power density at the end of the optical fiber to be adjusted. For example, a larger diameter end cap may decrease the power density at the end of the optical fiber. 
         [0004]    One method for attaching an end cap to an optical fiber is to splice the end cap to the optical fiber. The end cap may, for example, be clamped in place and aligned with the optical fiber for such splicing. However, in order for the end cap to be clamped and have a portion exposed for splicing, the end cap must be relatively long. It is thus difficult to splice relatively shorter end caps to optical fibers. 
         [0005]    Accordingly, improved end cap holders would be desired in the art. In particular, end cap holders which facilitate splicing of relatively shorter end caps to optical fibers would be advantageous. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0006]    Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention. 
         [0007]    In accordance with one embodiment of the present disclosure, an end cap holder is provided. The end cap holder includes a main body and a pump which generates a vacuum pressure. The main body includes a bore hole extending therethrough along a central axis, and a contact surface which surrounds an end of the bore hole. Activation of the pump may generate a vacuum pressure within the bore hole. 
         [0008]    In exemplary embodiments, a rigid sleeve may be provided to connect a hose of the pump and the main body. 
         [0009]    In exemplary embodiments, the contact surface may be disposed within a recess defined in the main body. 
         [0010]    In exemplary embodiments, the contact surface is oriented perpendicular to the bore hole and central axis. The contact surface may, for example, be a flat, planer surface. 
         [0011]    In exemplary embodiments, the contact surface may be a polished surface. 
         [0012]    These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which: 
           [0014]      FIG. 1  is a side perspective view of an end cap holder in accordance with embodiments of the present disclosure; and 
           [0015]      FIG. 2  is a side cross-sectional view of an end cap holder in accordance with embodiments of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0016]    Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents. 
         [0017]    The present disclosure generally provides end cap holders which advantageously utilize vacuum pressure, rather than physical clamping mechanisms or other mechanical affixing apparatus, to hold end caps for splicing. The use of such vacuum pressure advantageously allows the end cap to be properly positioned for splicing together with an optical fiber. Further, because only vacuum pressure is utilized to hold the end cap in place with the end cap holder, end caps having relatively smaller lengths can advantageously be utilized. 
         [0018]    Referring now to  FIGS. 1 and 2 , an end cap holder  10  for releasably holding an end cap  12  is provided. Any suitable end caps  12  may be utilized. For example, an end cap  12  may be formed from silica, and may be a pure silica end cap, a doped end cap (such as a Graded Index Lens (“GRIN”) end cap, an end cap having an antireflection coating, an end cap having a curved lens, or any other suitable end cap suitable for use with an optical fiber. 
         [0019]    The end cap  12  may have any suitable maximum diameter (which may be greater than or less than the maximum diameter of the optical fiber to which the end cap  12  is being attached) and any suitable maximum length  14 . End cap holders  10  in accordance with the present disclosure are particularly useful with end caps  12  that have maximum lengths of less than or equal to 5 millimeters, such as less than or equal to 4 millimeters, such as less than or equal to 3 millimeters, such as between 1 millimeter and 3 millimeters. 
         [0020]    An end cap  12  may be attached to the end  18  of an optical fiber  16 . Any suitable optical fiber  16  may be utilized, whether single mode or multi-mode, and having any suitable maximum diameter. The end cap  12  and the optical fiber  16  may be spliced together, i.e. via fusion splicing, laser splicing, or another suitable splicing technology. 
         [0021]    As illustrated, end cap holder  10  may include a main body  20  which may extend along a central axis  21  between a first end  22  and a second end  24 . A bore hole  26  may be defined through the main body  20  along the central axis  21 . In some embodiments, a male connector tube  28  (which may have a smaller maximum diameter than the main body  20 ) may extend along the central axis  21  from the first end  22 , and the bore hole  26  may additionally be defined through the connector tube  28 . 
         [0022]    As discussed herein, an end cap  12  may be releasably held in contact with the main body  20  adjacent the second end  24  via a vacuum pressure that is generated through the main body  20 , and specifically through the bore hole  26 . A pump  30 , such as a vacuum pump, may be in fluid communication with the main body  20  to generate a vacuum pressure (i.e. a suction or negative pressure) within the bore hole  26 . Notably, the required vacuum pressure for use in holding an end cap  12  in accordance with the present disclosure may advantageously be relatively minimal, thus facilitating both secure holding during splicing and easy removal from the holder  10  after removal. For example, the required vacuum pressure may be less than 10 pounds per square inch (“psi”), such as less than 6 psi, such as less than 5 psi, such as between 3 psi and 5 psi. 
         [0023]    A hose  32  may extend from the pump  30  and connect the pump  30  to the main body  20 . In some embodiments, for example, the hose  32  may be in contact with the main body  20 . For example, a portion of the hose  32  may fit over or within the connector tube  28 . In these embodiments, the vacuum pressure generated by the pump  20  is provided through hose  32  to bore hole  26 . Alternatively, a rigid sleeve  34  may be provided between the hose  32  and the main body  20 . The rigid sleeve  34  may, for example, be formed from a suitable metal. The rigid sleeve  34  may extend along the central axis  21  between a first end  36  and a second end  38 . A bore hole  35  may be defined in the rigid sleeve  34 , and may extend between the first end  36  and the second end  38  along the central axis  21 . The second end  38  of the sleeve  34  may fit over (as shown) or within the connector tube  28 , and the first end  28  of the sleeve  34  may fit over (as shown) or within the hose  32 . The rigid sleeve  34  may connect the pump  30  and main body  20 , such that the vacuum pressure generated by the pump  20  is provided to bore hole  26  through hose  32  and bore hole  35 . 
         [0024]    Notably, when a rigid sleeve  34  is utilized, the sleeve  24  may be clamped in the splicer to position the end cap holder  10 , and thus the end cap  12 , for splicing together with an optical fiber  16 . 
         [0025]    In exemplary embodiments, the main body  20  is generally cylindrical. An end cap  12  may be releasably held in contact with the main body  20  adjacent the second end  24  via the vacuum pressure. For example, the main body  20  may include a contact surface  40  which an end cap  12  may directly contact when the end cap  12  is releasably held in contact with the main body  20 . The contact surface  40  may be concentric with the bore hole  26  and central axis  21 , and may thus surround an end of the bore hole  26 . In some embodiments, the contact surface  40  may be a portion of the second end  24 , such as a portion of the second end  24  surrounding the bore hole  26  at the second end  24 . Alternatively, as illustrated, the contact surface  40  may be defined between the first end  22  and the second end  24  along the central axis  21 . For example, a recess  42  may be defined in the main body  20 . In exemplary embodiments, recess  42  is generally cylindrical. Recess  42  may be defined in the second end  24 , and may extend from the second end  24  towards the first end  22  along the central axis  21 . A maximum diameter  43  of the recess  42  may be greater than a maximum diameter  27  of the bore hole  26 , and may further be greater than a maximum diameter of an end cap  12  to be releasably held by the main body  20 . The recess  42  may be concentric with the bore hole  26  and central axis  21 . The contact surface  40  may be defined within the recess  42 , and may be the surface of the main body  20  that is a base defining the recess  42 . Accordingly, in these embodiments, when an end cap  12  is removably held by end cap holder  10 , a portion of the end cap  12  may be disposed within the recess  42 . 
         [0026]    The main body  20  may be formed as a single, unitary component, or may be formed from multiple components. Additionally, the connector tube  28  may be integral with the main body  20  (or a component thereof) to form a single unitary component, or may be a separate component connected thereto. For example, in exemplary embodiments, the main body  20  may include a plug  50  and a socket  52 . The plug  50  may include the first end  22 , and the connector tube  28  may be integral with or connected to the plug  50 . Additionally, and notably, a distal end (from the first end  22  of the plug  50  may be or include the contact surface  40 . The socket  52  may include the second end  24 . The plug  50  may be disposed at least partially within the socket  52 , such as via a press-fit or other suitable connection, to form the main body  20 . 
         [0027]    In exemplary embodiments, the main body  20  is formed from a metal. In embodiments, wherein multiple components (such as a plug and socket) are utilized, these components may be formed from the same or different materials. Additionally, the connector tube  28  may in exemplary embodiments be formed from a metal, which may be the same as or different from the material(s) of the main body  20 . 
         [0028]    The contact surface  40  may advantageously be oriented perpendicular to the central axis  21 . Further, the contact surface  40  may be a flat, planer surface. Still further, the contact surface  40  may advantageously be a polished surface. For example, the contact surface  40  in exemplary embodiments may be polished with at least a  320  grit material and/or may have a #8 Mirror Finish level polish. Such configuration of the contact surface  40  advantageously allows the end cap  12  to accurately be positioned concentrically with the central axis  21  and with the optical fiber  16  to which the end cap  12  is to be spliced. This facilitates accurate attachment of the end cap  12  to the optical fiber  16 . 
         [0029]    To utilize end cap holders  10  in accordance with the present disclosure, the pump  30  may be activated to generate a vacuum pressure within the bore hole  26 . An end cap  12  may then be placed against the contact surface  40  and an end of the bore hole  26  surrounded by the contact surface  40 . The vacuum pressure may force the end cap  12  against the contact surface  40 , and thus removably hold the end cap  12  on the end cap holder  10 . 
         [0030]    The vacuum pressure generated by pump  30  may be maintained during splicing. Accordingly, the end cap holder  10  may be place and secured in a suitable splicer. An end cap  12  may be placed on the contact surface  40  and removably held by the end cap holder  10  before or after securing of the end cap holder  10  in the splicer. An optical fiber  16  may be secured in the splicer and placed into contact with the end cap  12 , and the end cap  12  and optical fiber  16  may be spliced together. The end cap  12  may then be easily removed from the end cap holder  10 , such as by pulling the end cap  12  from the contact surface  40 . Accordingly, easy, efficient and accurate end cap  12  attachment to optical fibers  16  is facilitated by end cap holders  10  in accordance with the present disclosure. 
         [0031]    This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.