Abstract:
A method and apparatus involve: yieldably urging movement of a first section relative to a second section in two directions transverse to each other and to a reference axis of the first section, where an optical fiber end portion can be supported on the first section; selectively operating positioning structures that respectively move the first section relative to the second section in the two directions against the yieldable urging. A different method and apparatus involve: selectively operating positioning structure that can move a first section with a reference axis relative to a second section in directions within a plane perpendicular to the axis, that can maintain the first section in a selected position, and that includes plural angularly-offset radial threaded openings in the second section that each have a screw therein with an end engaging the first section, an optical fiber end portion being supported on the first section.

Description:
FIELD OF THE INVENTION 
     This invention relates in general to techniques for aligning an optical fiber with other optics and, more particularly, to techniques for accurately positioning an end of an optical fiber. 
     BACKGROUND 
     In fiber optic systems, it is frequently necessary to effect alignment, in relation to other optics, of an optical fiber end that emits or receives radiation. One existing approach is to use three separate, commercially-available devices that are known as “stages” and that can each effect relative movement of two parts parallel to a single direction. The three stages are assembled so that each effects movement of the optical fiber end in a respective one of three orthogonal directions. Although the resulting mechanism with three separate stages has been generally adequate for its intended purpose, it has not been entirely satisfactory in all respects. For example, the size, weight and cost of this type of mechanism are each larger than desirable. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A better understanding of the present invention will be realized from the detailed description that follows, taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a diagrammatic, partially-exploded perspective view of an apparatus that includes aspects of the present invention. 
         FIG. 2  is a diagrammatic central sectional side view of the apparatus of  FIG. 1 , taken along the section line  2 - 2  in  FIG. 1 . 
         FIG. 3  is a diagrammatic perspective exploded view showing selected portions of the apparatus of  FIGS. 1 and 2 , including an optical fiber with a connector, and an adjuster assembly. 
         FIG. 4  is diagrammatic perspective exploded view similar to  FIG. 3 , but showing the optical fiber and connector with an alternative embodiment of the adjuster assembly. 
         FIG. 5  is a diagrammatic, partially-exploded perspective view similar to  FIG. 1 , but showing an apparatus that is an alternative embodiment of the apparatus of  FIG. 1 . 
         FIG. 6  is a diagrammatic central sectional side view taken along the section line  6 - 6  in  FIG. 5 . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a diagrammatic, partially-exploded perspective view of an apparatus  10  that includes aspects of the present invention. The apparatus  10  includes an optical fiber  11  with an optical connector  12  at one end, and a micro-adjuster  13 . The optical fiber  11  and connector  12  are conventional, and are therefore not described here in detail. In  FIG. 1 , the connector  12  is a type of connector known in the art as an FC/APC (angled polished connector). Alternatively, the connector  12  could be a PC (straight polished connector), or any other suitable fiber connector. 
       FIG. 2  is a diagrammatic central sectional side view of the apparatus  10  of  FIG. 1 , taken along the section line  2 - 2  in  FIG. 1 . With reference to  FIGS. 1 and 2 , the micro-adjuster  13  includes an optional bracket  16  that is made of aluminum, but that could alternatively be made of any other suitable material. The bracket  16  has a horizontal base plate  17  with cylindrical holes  18  and  19  extending vertically therethrough near opposite ends thereof. The bracket  16  also has a vertical plate  22  that extends upwardly from the base plate  17  between the holes  18  and  19 . The vertical plate  22  has a threaded cylindrical opening  23  extending horizontally through a central region thereof. 
     The micro-adjuster  13  includes an optional lens support  26  that is made of aluminum, but that could alternatively be made of any other suitable material. The lens support  26  has a cylindrical end with external threads  27  that engage the threads in the opening  23  through plate  22 . Alternatively, the cooperating threads could be omitted from the lens support  26  and the plate  22 , and the lens support could be affixed to the plate in any other suitable manner, for example by a friction fit and/or a suitable assembly adhesive. The lens support  26  has an approximately cylindrical opening  28  extending horizontally and axially therethrough. The opening has portions of different diameter, thereby defining an axially-facing annular shoulder  29 . An optical lens  31  of a known type is disposed within the opening  28 , with one end of the lens disposed against the shoulder  29 . A retainer ring  32  is held by a snap fit within the opening  28  near one end thereof, the lens  31  being held against axial movement by the shoulder  29  and the ring  32 . 
     The micro-adjuster  13  includes an adjuster assembly  36  that is fixedly secured to the rear side of the vertical plate  22  by four screws  37 . The plate  22  has four threaded openings that are not visible in the drawings, and that each receive the threaded shank of a respective one of the screws  37 . 
       FIG. 3  is a diagrammatic perspective exploded view showing selected portions of the apparatus  10  of  FIGS. 1 and 2 , including the fiber  11 , connector  12  and adjuster assembly  36 . As best seen in  FIGS. 2 and 3 , the adjuster assembly  36  includes a body  51  that is an approximately square plate with beveled corners. The body  51  is made of stainless steel, but could alternatively be made of aluminum or any other suitable material. Each beveled corner has a semi-cylindrical groove  52  therein, and each of the screws  37  ( FIG. 1 ) has a threaded shank that extends though a respective one of the grooves  52 . 
     The body  51  has a planar front surface  53  on one side thereof. An approximately square recess  54  extends into the body  51  from the front surface  53 . The recess  54  extends most but not all of the way through the body  51 , thereby leaving a back wall  56  at the rear of the recess, the back wall being an integral part of the body. The back wall  56  has a circular opening  57  extending horizontally therethrough, the diameter of the opening  57  being slightly less than the width and the height of the recess  54 . 
     The body  51  has a cylindrical opening  61  that extends vertically upwardly from the recess  54 , and opens through a top surface of the body  51 . The body has a further cylindrical opening  62  that extends horizontally outwardly from the recess  54 , and opens through a side surface of the body. On a side of the recess  54  opposite from the opening  61 , a smaller recess  63  extends into the body  51  from the recess  54 . Similarly, on a side of the recess  54  opposite from the opening  62 , a smaller recess  64  extends into the body  51  from the recess  54 . 
     Two threaded openings  71  and  72  each extend horizontally into the body  51  from the front surface  53 , on opposite sides of the recess  54 . In addition, two cylindrical openings  73  and  74  each extend horizontally into the body  51  from the front surface  53 , on opposite sides of the recess  54 . 
     A cylindrical insert  76  is disposed in and has a diameter only slightly less than the diameter of the opening  61 . The insert  76  has at its lower end an annular, radially-outwardly projecting flange  78  that engages the body  51  and prevents the insert from moving upwardly within the opening  61 . A further insert  77  is identical to the insert  76 , and has a flange  79 . The insert  77  is disposed in the opening  62 , and the flange  79  engages the body  51  and prevents the insert  77  from moving outwardly within the opening  62 . The inserts  76  and  77  are each held against rotation in the associated opening  61  or  62  by a force-fit. Further, the inserts  76  and  77  can optionally be secured in place by a conventional and commercially-available adhesive, for example a suitable epoxy adhesive. The inserts  76  and  77  have respective threaded cylindrical openings  81  and  82  extending coaxially therethrough. Two setscrews  83  and  84  respectively engage the threaded openings  81  and  82  in the inserts  76  and  77 . In the disclosed embodiment, the threads on the setscrews and in the openings  81  and  82  have an extra fine pitch, in order to permit very fine adjustment. However, it would alternatively be possible to use threads with some other pitch. In the disclosed embodiment, the inserts  76  and  77  are each made of stainless steel, but they could alternatively be made of aluminum, or any other suitable material. 
     Two coil springs  86  and  87  are respectively disposed in the recesses  63  and  64  in the body  51 . With reference to  FIG. 1 , a threaded cylindrical opening  88  extends outwardly through the body  51  from one corner of the square recess  54  to the groove  52  in one corner of the body. With reference to  FIG. 3 , a setscrew  89  threadedly engages the opening  88 . 
     The adjuster assembly  36  includes a mount  101  that is made of stainless steel, but that could alternatively be made of aluminum, or any other suitable material. The mount  101  has a base  102  with the shape of an approximately square plate. The base  102  is disposed within the recess  54  in the body  51 , and has vertical and horizontal dimensions that are less than the vertical and horizontal dimensions of the recess  54 , so that the base  102  can move vertically and horizontally within the recess  54 . The base  102  has a thickness that is only slightly less than the depth of the recess  54 . The inner end of spring  86  engages the bottom of the base  102 , and urges the base upwardly against the inner end of setscrew  83 . Similarly, the inner end of spring  87  urges the base  102  horizontally against the inner end of setscrew  84 . 
     The mount  101  has a cylindrical projection  104  that extends horizontally forwardly from the base  102 . The projection  104  has an outside diameter that is substantially equal to the vertical and horizontal dimensions of the base  102 . A cylindrical opening  106  extends completely through the mount  101 , coaxial with the cylindrical projection  104 . The mount  101  has a reference axis  107  that is coaxial with the cylindrical projection  104  and the cylindrical opening  106 . When the optical fiber  11  is releasably coupled to the adjuster assembly  36  by the connector  12 , the optical axis of the end of the fiber is coincident with the reference axis  107 . The setscrews  83  and  84  and their threaded openings  81  and  82  each extend approximately radially with respect to the reference axis  107 , and the springs  86  and  87  act approximately radially with respect to the reference axis. 
     The mount  101  has a threaded opening that is not visible in the drawings, but that extends radially outwardly from the cylindrical opening  106  to one corner of the base  102 . This threaded opening has a setscrew  108  therein. The body  51  has, between the cylindrical openings  61  and  62 , a cylindrical opening that extends outwardly from one corner of the recess  54  to an outer corner of the body  51 , and a tool of the type known as an Allen wrench or hex key can be inserted through this opening to engage and rotate the setscrew  108  relative to the mount  101 . 
     The adjuster assembly  36  also includes a square plate  116  that has beveled corners, with a semi-circular recess  117  in each corner. The plate  116  is made of stainless steel, but it could alternatively be made of aluminum of any other suitable material. The plate  116  has a planar rear surface that is disposed against the front surface  53  of the body  51 , in a manner so that the semi-circular recesses  117  are each aligned with a respective one of the semi-cylindrical grooves  52 . The plate  116  has a circular opening  121  that extends therethrough in a central region thereof. The diameter of the opening  121  is approximately the same as the diameter of the opening  57  in the body  51 , and the openings  121  and  57  are substantially coaxially aligned with each other. The cylindrical projection  104  on the mount  101  extends outwardly through the opening  121 . The diameter of the opening  121  is larger than the outside diameter of the projection  104 , so that the projection  104  can move within the opening  121  as the mount  101  moves within the recess  54 . 
     The plate  116  has two cylindrical holes  123  and  124  that extend therethrough on opposite sides of the opening  121 , and that are respectively aligned with the threaded openings  71  and  72  in the body  51 . Two screws  126  and  127  each have a threaded shank that extends through a respective one of the openings  123  and  124 , and threadedly engages a respective one of the two threaded openings  71  and  72  in the body  51 . The screws  126  and  127  thus fixedly secure the plate  116  to the body  51 . The plate  116  has two further cylindrical holes  131  and  132  that extend therethrough on opposite sides of the opening  121 , and that are each aligned with a respective one of the openings  73  and  74  in the body  51 . Two cylindrical alignment pins  133  and  134  each have one end portion that extends through a respective one of the holes  131  and  132 , and that extends into a respective one of the openings  73  and  74 . These ends of the pins  133  and  134  are fixedly secured within the openings  73  and  74  by a friction fit, and may also optionally be held in place by a suitable, conventional, commercially-available adhesive. As best seen in  FIG. 1 , the other ends of the pins  133  and  134  each project forwardly beyond the plate  116 . When the adjuster assembly  36  is secured to the bracket  16  by the screws  37 , these ends of the pins  133  and  134  extend into respective, not-illustrated openings in the vertical plate  22  of the bracket  16 , in order ensure accurate alignment of the adjusting assembly  36  with respect to the bracket  16 . 
     With reference to  FIG. 3 , the body  51  and the plate  116  keep the base  102  of the mount  101  captive within the recess  54  of the body, while permitting the previously-discussed movement of the base  102  within the recess. In particular, the mount  101  cannot move any significant distance forwardly or rearwardly with respect to the body  51  in directions parallel to the reference axis  107 , but is capable of limited movement with respect to the body in vertical and horizontal directions perpendicular to the reference axis  107 . 
     The adjuster assembly  36  includes a tubular barrel  141 , and a connector part  146 . The barrel  141  and connector part  146  are each made of aluminum, but could alternatively be made of any other suitable material. The barrel  141  is slidably disposed within the cylindrical opening  106  through the mount  101 , and has an outside diameter that is only slightly less than the inside diameter of the opening  106 . The barrel  141  has a cylindrical opening extending coaxially therethrough, with internal threads  142  at one end. 
     The connector part  146  has a cylindrical portion at its front end, with external threads  147  that engage the internal threads  142  in the barrel  141 . At its rear end, the connector part  146  has a cylindrical portion of smaller diameter that also has external threads  148 . As best seen in  FIG. 2 , a cylindrical opening  149  extends axially into the connector part  146  from the rear. An inwardly-converging frustoconical opening  151  extends from the front surface of the connector part  146  to the inner end of the opening  149 . As shown in  FIG. 3 , the front surface of the connector part  146  has two spaced recesses  153  and  154 . A not-illustrated tool can engage the recesses  153  and  154  in order to effect rotation of the connector part  146  relative to the barrel  141 . 
     With reference to  FIG. 2 , the conventional connector  12  at the end of the optical fiber  11  includes a rotatable sleeve  156  with internal threads at its forward end. The internal threads on the sleeve  156  can engage the external threads  148  on the connector part  146 , in order to releasably couple the connector  12  to the adjuster assembly  36 . When the connector  12  is releasably coupled to the connector part  146 , the end portion of optical fiber  11  extends into the opening  149  in the connector part  146 . The connector part  146  is configured so that an optical axis of the end portion of the optical fiber is coincident with the reference axis  107 , and so that a fiber axis  159  of the end portion of optical fiber  11  extends at a small acute angle  161  with respect to the reference axis  107  of the mount  101 , as defined by the structure of the APC connector  12  used in the disclosed embodiment. However, the connector part  146  could alternatively be configured so that the fiber axis  159  of the optical fiber is substantially coaxial with the reference axis  107 , and thus also coaxial with the optical axis of the fiber. 
     In operation, when the connector  12  on optical fiber  11  is fixedly coupled to the adjuster assembly  36  of the micro-adjuster  13 , the end portion of the optical fiber  11  can be very accurately positioned. With reference to  FIG. 3 , and as mentioned earlier, the spring  86  yieldably urges the base  102  of mount  101  upwardly against the inner end of the setscrew  83 , and the spring  87  yieldably urges the base  102  horizontally against the inner end of the setscrew  84 . By rotating the setscrew  83  and/or the setscrew  84 , the base  102  of mount  101  can be moved vertically and/or horizontally within the recess  54 , in directions perpendicular to the reference axis  107 , until the end of the optical fiber  11  has been accurately positioned. The setscrew  89  can then be manually tightened so that the base  102  of mount  101  is effectively captured between the ends of the three setscrews  83 ,  84  and  89 , thereby preventing the base from moving away from either of the setscrews  83  and  84  against the urging of the associated spring  86  or  87 . 
     In order to also position the end of optical fiber  11  in directions parallel to the reference axis  107 , the barrel  141  and adapter  146  can be slidably moved within the mount  101 . This movement may, for example, be used to achieve focus for radiation entering or exiting the end of the optical fiber  11 . When the barrel  141  and thus the end of the optical fiber  11  are in a desired position relative to the mount  101 , the setscrew  108  can be tightened so that its inner end snugly engages the exterior surface of the barrel  141 , thereby preventing axial movement of the barrel  141  in relation to the mount  101 . 
     Optical radiation traveling rightwardly through the optical fiber  11  as viewed in  FIG. 2  can exit the end of the optical fiber along a path of travel that is coincident with the fiber axis  159 , and then pass through the lens  31 . Alternatively, radiation traveling leftwardly along a path of travel coincident with fiber axis  159 , as viewed in  FIG. 2 , can pass through the lens  31  and then enter the end of the optical fiber  11 . 
       FIG. 4  is diagrammatic perspective exploded view similar to  FIG. 3 , but showing the optical fiber  11  and connector  12  with an adjuster assembly  201  that is an alternative embodiment of the adjuster assembly  36  of  FIG. 3 . Components in  FIG. 4  that are identical or equivalent to components in  FIG. 3  are identified in  FIG. 4  with the same reference numerals used in  FIG. 3 . The adjuster assembly  201  of  FIG. 4  is identical to the adjuster assembly  36  of  FIG. 3 , except for differences that are discussed below. 
     In  FIG. 4 , a mount  206  is provided in place of the mount  101  of  FIG. 3 . The mount  206  is identical to the mount  101 , except that the central opening through the mount  206  has internal threads  207  at its forward end. In addition, the mount  206  of  FIG. 4  does not include the setscrew  108  ( FIG. 3 ) or the associated threaded opening. 
     The adjuster assembly  201  of  FIG. 4  also does not include the tubular barrel  141  of the adjuster assembly  36  in  FIG. 3 . In  FIG. 4 , the external threads  147  at the front end of the connector part  146  directly engage the internal threads  207  provided in the cylindrical opening through the mount  206 . The adjuster assembly  201  includes a lock ring  218  with external threads  219  that engage the internal threads  207  in the opening through the mount  206 . The front side of the lock ring  218  has two diametrically opposed recesses  221  that can be engaged by a not-illustrated tool, in order to effect rotation of the lock ring  218  relative to the mount  206 . 
     In  FIG. 4 , the connector part  146  can be rotated relative to the mount  206  and, due to the cooperating threads  147  and  207 , the connector part  146  will move axially with respect to the mount  206  in directions parallel to the reference axis  107 . This permits the connector part  146  and the end of optical fiber  11  to be positioned relative to the mount  206  in directions parallel to the reference axis  107 . After the connector part  146  has been rotated and is in a desired axial position with respect to the mount  206 , the lock ring  218  can be rotated until it snugly engages the front side of the connector part  146 , so that friction holds the connector part  146  and lock ring  218  against rotation relative to each other or the mount  206 . 
       FIG. 5  is a diagrammatic, partially-exploded perspective view similar to  FIG. 1 , but showing an apparatus  239  that is an alternative embodiment of the apparatus  10  of  FIG. 1 .  FIG. 6  is a diagrammatic central sectional side view taken along the section line  6 - 6  in  FIG. 5 . Components in  FIGS. 5 and 6  that are identical or equivalent to components in  FIGS. 1 and 2  are identified in  FIGS. 5 and 6  with the same reference numerals used in  FIGS. 1 and 2 . The apparatus  239  of  FIGS. 5 and 6  is identical to the apparatus  10  of  FIGS. 1-3 , except for differences that are discussed below. 
     In  FIGS. 5 and 6 , a mount  246  is provided in place of the mount  101  of  FIGS. 1-3 . The mount  246  is identical to the mount  101 , except that external threads  247  are provided at the front end of the cylindrical projection on the mount  246 . In addition, in the apparatus  239  of  FIGS. 5-6 , a lens support  251  is provided in place of the lens support  26  of  FIGS. 1-3 . The lens support  251  is supported on the mount  246 , whereas the lens support  26  in  FIGS. 1-3  is supported on the bracket  16 . 
     In more detail, the rear end of the lens support  251  has internal threads  252  that engage the external threads  247  on the mount  246 , thereby fixedly securing the lens support  251  to the mount  246 . Alternatively, the cooperating threads could be omitted from the lens support  251  and the mount  246 , and the lens support could be affixed to the mount in any other suitable manner, for example by a friction fit and/or a suitable assembly adhesive. The lens  31  is disposed within a central opening through the mount  251 , between the shoulder  29  and the retaining ring  32 . The largest outside diameter of the lens support  251  is somewhat smaller than the inside diameter of the opening  23  through the bracket  16 , so that the lens support  251  can move within the opening  23  as the adjuster assembly  241  positions the optical fiber  11 . 
     Although selected embodiments have been illustrated and described in detail, it should be understood that a variety of substitutions and alterations are possible without departing from the spirit and scope of the present invention, as defined by the claims that follow.