Patent Publication Number: US-2022221651-A1

Title: Cutting jig and cutting method of optical fiber

Description:
TECHNICAL FIELD 
     The present invention relates to a cutting jig and a method for cutting an optical fiber, specifically, a cutting jig and a method for cutting an optical fiber using the cutting jig. 
     BACKGROUND ART 
     Conventionally, it has been known that a distal end portion of an optical fiber is cut so that its cut surface (end surface) is vertical in a transmission direction, and the end surface is connected to another optical member. 
     Recently, as a cutting method for the distal end portion of the optical fiber, a method for obliquely cutting the distal end portion has been proposed (ref: for example, Patent Document 1). According to this method, light is reflected on the end surface, and it is possible to prevent the reflected light due to this from returning to an optical device connected to a rear end portion. 
     In Patent Document 1, after fixing two different locations in an axial direction of the optical fiber with a holding tool, the optical fiber is deformed upwardly by pressing a pushing tool to the lower surface of the optical fiber between the two fixed points, and then, a blade edge of a blade is applied to the upper surface of the optical fiber from a vertical direction to cut the optical fiber. 
     CITATION LIST 
     Patent Document 
     
         
         Patent Document 1: Japanese Unexamined Patent Publication No. 2005-300597 
       
    
     SUMMARY OF THE INVENTION 
     Problem to be Solved by the Invention 
     However, in the device described in Patent Document 1, the movement of the pushing tool to the optical fiber, and the movement of the blade to the optical fiber are separately carried out. Therefore, each driving device for driving the pushing tool and the blade is required. As a result, there is a problem that a device configuration, and the control become complicated. 
     Further, when a movement amount (pushing amount) of the pushing tool cannot be accurately controlled for each operation, there is a problem that an angle formed between the deformed optical fiber and a moving direction of the blade tends to be easily different for each operation, and therefore, the formation accuracy of the end surface is lowered. 
     The present invention provides a cutting jig capable of simplifying a device configuration, easily cutting a free end portion so as to be inclined with respect to a perpendicular direction of a proximal end portion, and furthermore, improving the formation accuracy of a cut surface of an optical fiber, and a method for cutting an optical fiber. 
     Means for Solving the Problem 
     The present invention (1) includes a cutting jig including a fixing member for inserting a distal end portion of an optical fiber, and a cutting unit movable with respect to the fixing member for cutting the distal end portion, wherein the distal end portion is configured to be defined into a proximal end portion fixed to the fixing member, and a free end portion located at the front side with respect to the proximal end portion and not fixed to the fixing member; the cutting unit includes an inclination imparting portion and a blade portion incapable of relative movement to each other; the cutting unit is capable of carrying out a first movement of moving with respect to the fixing member, and following the first movement, a second movement of moving with respect to the fixing member with a larger movement amount than the first movement; the inclination imparting portion is configured so that the inclination imparting portion is brought into contact with the free end portion based on the first movement of the cutting unit, and the free end portion moves to be inclined with respect to an extension line of the proximal end portion extending along a transmission direction of light; and the blade portion is configured so that a blade edge of the blade portion is brought into contact with the free end portion based on the second movement of the cutting unit. 
     In this cutting jig, the distal end portion of the optical fiber is inserted into the fixing member to be fixed, and the inclination imparting portion is brought into contact with the free end portion based on the first movement of the cutting unit with respect to the fixing member to incline the free end portion, and following the first movement, the blade edge is brought into contact with the free end portion based on the second movement of the cutting unit with respect to the fixing member to cut the free end portion. Therefore, it is possible to form the cut surface along a direction along the moving direction of the second movement, that is, a direction inclining toward the moving direction of the fixing member in the free end portion in the free end portion of the optical fiber. 
     Further, since the cutting jig includes the cutting unit including the inclination imparting portion and the blade portion incapable of relative movement to each other, the configuration is simple as compared with the device of Patent Document 1 including a pushing tool and the blade portion each of which moves independently. 
     Furthermore, since the inclination imparting portion and the blade portion incapable of relative movement to each other are moved with respect to the fixing member, it is possible to easily cut the free end portion with the blade edge as compared with a case including the inclination imparting portion and the blade portion capable of relative movement to each other. 
     Moreover, since the inclination imparting portion and the blade portion are incapable of relative movement to each other, it is possible to make an inclined state of the free end portion uniform at the time of a contact of the blade edge with the free end portion. Therefore, it is possible to improve the formation accuracy of the cut surface of the optical fiber. 
     The present invention (2) includes the cutting jig described in (1), wherein the cutting unit further includes a holding member for holding the blade portion, and the fixing member is movably attached to the holding member. 
     In the cutting jig, since the holding member holds the blade portion in the cutting unit, it is possible to reliably move the blade portion with respect to the fixing member by the holding member. 
     The present invention (3) includes the cutting jig described in (2), wherein the inclination imparting portion is attached to the holding member. 
     In the cutting jig, since the inclination imparting portion is attached to the holding member, the configuration is simple. 
     The present invention (4) includes the cutting jig described in (3), wherein the holding member has a slit capable of guiding the free end portion along with the first movement and the second movement. 
     In the cutting jig, since the free end portion can be guided by the slit in the first movement and the second movement, it is possible to smoothly incline and cut the free end portion. 
     The present invention (5) includes the cutting jig described in (4) further including a closing member for closing a portion of an open end edge of the slit, wherein an end portion of the closing member is the inclination imparting portion. 
     In the cutting jig, it is possible to easily configure the inclination imparting portion by the closing member. 
     The present invention (6) includes the cutting jig described in (4) further including a filling member for filling a portion of the slit, wherein an end portion of the filling member is the inclination imparting portion. 
     In the cutting jig, it is possible to easily configure the inclination imparting portion by the filling member. 
     The present invention (7) includes the cutting jig described in (4), wherein an inner end edge defining one end edge in an extending direction of the slit in the holding member is the inclination imparting portion. 
     In the jig, since the holding member does not need to include the closing member of (5) or the filling member of (6) described above, it is possible to easily configure the inclination imparting portion by the inner end edge of the holding member, while reducing the number of components. 
     The present invention (8) includes the cutting jig described in any one of (1) to (7), wherein the blade edge is inclined with respect to a direction perpendicular to a transmission direction of light in the free end portion, and a moving direction of the blade portion. 
     In the cutting jig, since the blade edge is inclined with respect to the perpendicular direction, it is possible to cut the optical fiber with a small pressure as compared with a case of being along the perpendicular direction. 
     The present invention (9) includes the cutting jig described in any one of (1) to (8), wherein an anchor member anchored to the periphery of the proximal end portion is fitted into the fixing member. 
     In the cutting jig, since the anchor member anchored to the periphery of the proximal end portion is fitted into the fixing member, it is possible to cut the free end portion, while reliably fixing the proximal end portion to the fixing member. Therefore, it is possible to further ensure the formation accuracy of the cut surface of the optical fiber. 
     The present invention (10) includes a method for cutting an optical fiber using the cutting jig described in any one of (1) to (9) including a first step of inserting a distal end portion into a fixing member to fix a proximal end portion to the fixing member, a second step of moving a cutting unit with respect to the fixing member, and bringing an inclination imparting portion into contact with a free end portion to incline the free end portion, and a third step of further moving the cutting unit with respect to the fixing member, and bringing a blade edge of a blade portion into contact with the free end portion to cut the free end portion. 
     In the method for cutting an optical fiber, since the inclination imparting portion and the blade portion are moved together with respect to the fixing member, it is possible to easily carry out the inclination and the cutting of the free end portion. Therefore, it is possible to easily and accurately form the inclined cut surface. 
     Effect of the Invention 
     The cutting jig of the present invention has a simple configuration, and it is possible to easily cut a free end portion by a blade edge. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a perspective view of a cutting jig of one embodiment of a cutting jig of the present invention when viewed from a rear side. 
         FIG. 2  shows a disassembled perspective view of the cutting jig shown in  FIG. 1 . 
         FIG. 3  shows the cutting jig shown in  FIG. 1 , and a perspective view in which a rear wall is omitted. 
         FIG. 4  shows the cutting jig shown in  FIG. 3 , and a perspective view in which a rear wall and a fixing unit are omitted. 
         FIG. 5  shows a side cross-sectional view of the cutting jig shown in  FIG. 1 . 
         FIGS. 6A to 6D  show process views for illustrating a method for cutting an optical fiber using the cutting jig shown in  FIG. 5 : 
         FIG. 6A  illustrating a preparation step of preparing the cutting jig and an optical connector, 
         FIG. 6B  illustrating a second step of inclining a free end portion, 
         FIG. 6C  illustrating a third step of cutting the free end portion, and 
         FIG. 6D  illustrating a step of housing a fixing unit in a case. 
         FIG. 7  shows a one side view (view of seeing through a front wall) of a closing plate, the front wall, and a blade portion of the cutting jig shown in  FIG. 2 . 
         FIG. 8  shows an other side view of a closing plate, a front wall, and a blade portion of the cutting jig shown in  FIG. 2 . 
         FIG. 9  shows a modified example of the cutting jig shown in  FIG. 7 , and a one side view of the front wall and a filling portion. 
         FIGS. 10A to 10D  show process views of a modified example of a method for cutting an optical fiber using the cutting jig shown in  FIG. 9 : 
         FIG. 10A  illustrating a preparation step of preparing the cutting jig and an optical connector, 
         FIG. 10B  illustrating a second step of inclining a free end portion, 
         FIG. 10C  illustrating a third step of cutting the free end portion, and 
         FIG. 10D  illustrating a step of housing a fixing unit in a case. 
         FIGS. 11A to 11D  show process views of a modified example of a method for cutting an optical fiber using the cutting jig shown in  FIGS. 6A to 6D : 
         FIG. 11A  illustrating a preparation step of preparing the cutting jig and an optical connector, 
         FIG. 11B  illustrating a second step of inclining a free end portion, 
         FIG. 11C  illustrating a third step of cutting the free end portion, and 
         FIG. 11D  illustrating a step of housing a fixing unit in a case. 
         FIGS. 12A to 12B  show process views for connecting two optical fibers: 
         FIG. 12A  illustrating a step of allowing two cut surfaces to face each other and 
         FIG. 12B  illustrating a step of brining two cut surfaces into contact with each other. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     One embodiment of a cutting jig and a method for cutting an optical fiber of the present invention is described with reference to  FIGS. 1 to 8 . 
     In  FIG. 5 , a right-left direction on the plane of the sheet is a front-rear direction (first direction), a right side on the plane of the sheet is a front side, and a left side on the plane of the sheet is a rear side. An up-down direction on the plane of the sheet is a moving direction (second direction perpendicular to the front-rear direction) with respect to a holding cutting unit  2  (described later) of a fixing unit  3  (described later), a lower side on the plane of the sheet is an other side in the moving direction, and an upper side on the plane of the sheet is one side in the moving direction. In  FIG. 7 , the right-left direction on the plane of the sheet is a width direction (third direction perpendicular to the front-rear direction and the moving direction). Each direction conforms to a direction described in each view. 
     As shown in  FIGS. 1 and 5 , a cutting jig  1  includes the holding cutting unit  2  and the fixing unit  3 . Further, the cutting jig  1  includes the holding cutting unit  2  and the fixing unit  3  movably to each other, and in this embodiment, the fixing unit  3  is movable with respect to the holding cutting unit  2 . 
     That is, in the cutting jig  1  of this embodiment, an embodiment in which the fixing unit  3  is used so as to move with respect to the holding cutting unit  2  is described. In this embodiment, as shown in  FIGS. 6A to 6D , when an optical fiber  31  is cut using the cutting jig  1 , the fixing unit  3  moves from the other side (lower side on the plane of the sheet) toward one side (upper side on the plane of the sheet).  FIGS. 5 and 6A  show the cutting jig  1  before the above-described movement. 
     The holding cutting unit  2  is a unit for cutting a distal end portion  32  of the optical fiber  31 . The holding cutting unit  2  includes a case  4  as one example of a holding member, and an inclination cutting unit  5  as one example of a cutting unit. 
     As shown in  FIG. 1 , the case  4  has a generally box shape which is thin in the front-rear direction. The case  4  has a generally rectangle shape when viewed from the front. As shown in  FIG. 5 , the case  4  includes a front case member  7  and a rear case member  6 . 
     As shown in  FIGS. 2 and 3 , the front case member  7  includes a front wall  10 , a peripheral wall  11 , and a locking portion  14 . 
     As shown in  FIGS. 2 and 4 , the front wall  10  has a plate shape. The front wall  10  has a slit  12 . 
     The slit  12  penetrates the front wall  10  in the front-rear direction. The slit  12  extends along the moving direction. A width of the slit  12  is set to allow the movement of the distal end portion  32  of the optical fiber  31  in the slit  12 , and specifically, is longer than the maximum length (specifically, the outer diameter) in a cross-sectional view of the optical fiber  31 . 
     As shown in  FIGS. 3 and 4 , the locking portion  14  has a hook shape protruding rearwardly from the rear surface of the front wall  10 , and is disposed on the rear surface of the front wall  10 . The plurality of (two) locking portions  14  are disposed spaced apart from each other in a plane direction (direction along the rear surface of the front wall  10 ). As shown in  FIG. 4 , for example, a phantom line extending from the slit  12  toward one side in the moving direction intersects a line segment connecting the two locking portions  14 . 
     The peripheral wall  11  is a side wall extending rearwardly from the peripheral end portion of the rear surface of the front wall  10 . An intermediate portion in the width direction of the other end portion in the moving direction of the peripheral wall  11  is cut out. Thus, an opening portion  15  for opening the intermediate portion in the width direction of the other end portion in the moving direction thereof is defined in the case  4 . 
     As shown in  FIGS. 1 and 2 , the rear case member  6  is located on the rear side of the front case member  7 . As shown in  FIG. 2 , the rear case member  6  is a rear wall  8  having a generally plate shape which is thin in the front-rear direction. The rear wall  8  has a first hole  9  penetrating the rear wall in the front-rear direction. 
     The first hole  9  has a generally rectangular shape when viewed from the front. The first hole  9  is an opening having a generally rectangular shape which is long in the moving direction. As shown in  FIGS. 2 and 5 , a first surface  51  and a second surface  52  for defining the other end portion and one end portion in the moving direction of the first hole  9 , respectively, are included in the rear wall  8 . 
     A material for the case  4  is not particularly limited, and examples thereof include resins, ceramics, and metals, and preferably, from the viewpoint of moldability, a resin is used. Examples of the resin include transparent resins such as an acrylic resin, an epoxy resin, and a silicone resin from the viewpoint of easily grasping an insertion state and a cutting state of the optical fiber  31 . 
     As shown in  FIGS. 2 and 5 , the inclination cutting unit  5  includes a blade portion  17 , and a closing plate  21  as one example of a closing member. Preferably, the inclination cutting unit  5  includes only the blade portion  17  and the closing plate  21 . 
     As shown in  FIGS. 2 and 3 , the blade portion  17  is disposed on the rear side of the front wall  10 . The blade portion  17  has a generally rectangular shape when viewed from the front, and has a blade edge  18  located on one long side. The blade edge  18  is inclined with respect to the slit  12  (moving direction). Further, the blade edge  18  is also inclined with respect to the width direction. An angle formed between the blade edge  18  and the slit  12  has a sharp angle of, for example, 20 degrees or more, preferably 30 degrees or more, and for example, 70 degrees or less, preferably 50 degrees or less. The above-described angle is most preferably 45 degrees. 
     Further, the blade portion  17  has a cut-out portion  19  obtained by cutting out each of the intermediate portions of two short sides facing each other. Each of the two cut-out portions  19  is locked by each of the two locking portions  14 . Thus, the blade portion  17  is fixed to the front wall  10  of the case  4 . A material for the blade portion  17  is not particularly limited, and examples thereof include metals and ceramics. Preferably, a metal is used. 
     As shown in  FIGS. 1 and 5 , the closing plate  21  is disposed on the front surface of the front wall  10 . As shown in  FIGS. 1 and 7 , the closing plate  21  has a plate shape in a generally rectangular shape when viewed from the front. The closing plate  21  has a one end edge  22  facing the opening portion  15  when viewed from the front. The one end edge  22  is one side surface connecting one end portion of the front surface (one surface in the thickness direction) of the closing plate  21  to one end portion of the rear surface (the other surface in the thickness direction) thereof. 
     Further, as shown in  FIG. 8 , a width directional intermediate portion  46  of the other end portion in the moving direction of the closing plate  21  is overlapped with one end portion in the moving direction of the slit  12  when projected in the front-rear direction. Thus, the width directional intermediate portion  46  of the other end portion in the moving direction of the closing plate  21  closes the front end edge of one end portion in the moving direction of the slit  12 . The one end edge  22  in the width directional intermediate portion  46  of one end portion of the closing plate  21  is one example of an inclination imparting portion. 
     As shown in  FIGS. 6A and 8 , the one end edge  22  is located on the other side in the moving direction of the blade edge  18  when projected in the front-rear direction. In other words, the one end edge  22  and the blade edge  18  are disposed in order toward one side in the moving direction. Further, when projected in the front-rear direction, the one end edge  22  and the blade edge  18  are separated with an interval L therebetween. The interval L is appropriately set by a distance between a free end portion  34  and the one end edge  22  and/or the inclination as a target of the cut surface when cutting the free end portion  34 . Specifically, the interval L between the one end edge  22  and a midpoint of the blade edge  18  is, for example, 0.1 mm or more, preferably 1 mm or more, and for example, 10 mm or less, preferably 5 mm or less. 
     The closing plate  21  is not disposed at the inside (space) of the slit  12 . The front surface of the periphery of the slit  12  in the front wall  10  is in contact with the closing plate  21 . 
     The closing plate  21  is fixed (adhered) (attached) to the front wall  10 . Thus, the closing plate  21  is fixed to the case  4 . 
     Then, both the blade portion  17  and the closing plate  21  are fixed to the case  4 . That is, the blade portion  17  and the closing plate  21  are incapable of relative movement to each other. Thus, the inclination cutting unit  5  is fixed to the case  4 . 
     A material for the closing plate  21  is not particularly limited, and the same material as that for the case  4  is used. Preferably, the material for the case  4  and the material for the closing plate  21  are the same. 
     As shown in  FIG. 5 , the fixing unit  3  is movable with respect to the holding cutting unit  2 . The fixing unit  3  includes a fixing member  23  and a guiding member  24 . 
     The fixing member  23  is a rear portion in the fixing unit  3 . The fixing member  23  fixes the distal end portion  32  of the optical fiber  31 . As shown in  FIGS. 2 and 5 , the fixing member  23  integrally includes a fixing plate  25  and a fixing cylindrical portion  27 . 
     The fixing plate  25  has a generally flat plate shape which is thin in the front-rear direction. Further, the fixing plate  25  has a generally rectangular shape which is long in the moving direction. The fixing plate  25  is parallel to the rear wall  8 . The fixing plate  25  has a through hole  26 . 
     The through hole  26  penetrates the fixing plate  25  in the front-rear direction. The through hole  26  is disposed in one end portion in the moving direction in the fixing plate  25 . The through hole  26  is, for example, a round hole. The through hole  26  has a size (inner diameter) capable of inserting a proximal end portion  33  of the distal end portion  32  of the optical fiber  31 , and the distal end portion of the connector  35  (both are described later). 
     The fixing cylindrical portion  27  is disposed on the rear surface of the fixing plate  25 . The fixing cylindrical portion  27  extends rearwardly from the rear surface of the fixing plate  25 . The fixing cylindrical portion  27  surrounds the through hole  26 . The fixing cylindrical portion  27  has a double cylindrical structure including an inner cylinder  41  and an outer cylinder  42 . Preferably, the fixing cylindrical portion  27  includes only the inner cylinder  41  and the outer cylinder  42 . 
     The inner cylinder  41  defines the through hole  26 . The inner cylinder  41  has a generally cylindrical shape having the shaft thereof common with that of the through hole  26 . 
     The outer cylinder  42  is disposed spaced apart from the outside of the inner cylinder  41 . The outer cylinder  42  has, for example, a square cylindrical shape. The outer cylinder  42  extends longer than the inner cylinder  41  toward the rear side. Further, the outer cylinder  42  is also a holding portion which is held by the user when the fixing unit  3  is moved with respect to the holding cutting unit  2 . Furthermore, the outer cylinder  42  has a first fitting portion  28  provided on its inner surface. 
     The guiding member  24  is disposed on the front side of the fixing member  23 . The guiding member  24  has a thin plate shape in the front-rear direction. The guiding member  24  is parallel to the fixing plate  25 . The guiding member  24  integrally includes a thick portion  30  and a thin portion  20 . 
     The thick portion  30  is located in the other end portion in the moving direction of the guiding member  24 . The rear surface of the thick portion  30  is fixed to the front surface of the fixing plate  25 . The other end surface in the moving direction of the thick portion  30 , and the other end surface in the moving direction of the fixing plate  25  are flush with each other to form one other end surface in the moving direction of the fixing unit  3 . 
     The thin portion  20  is located on one side in the moving direction of the thick portion  30 . The thin portion  20  is thinner than the thick portion  30 . Specifically, the front surface of the thin portion  20  is flush with the front surface of the thick portion  30 . The rear surface of the thin portion  20  is disposed spaced apart from the front side of the rear surface of the thick portion  30 . Further, a guiding groove  16  is formed between the rear surface of the thin portion  20  and the front surface of the fixing plate  25 . The guiding groove  16  is a receiving groove  16  which is capable of receiving the entry of the blade edge  18 . The fixing plate  25 , the thin portion  20 , and the thick portion  30  form a generally U-shape in a side view having an opening toward one side in the moving direction by the guiding groove  16 . 
     Further, the thin portion  20  has a guiding hole  29 . The guiding hole  29  penetrates the thin portion  20  in the front-rear direction. The thin portion  20  is overlapped with the through hole  26  when viewed from the front. The guiding hole  29  is, for example, a round hole. The guiding hole  29  has a size (inner diameter) in which the free end portion  34  is movably inclined. Preferably, the guiding hole  29  has the same size as the through hole  26 . 
     The fixing member  23  is movable with respect to the blade edge  18 , while the fixing plate  25  and the thin portion  20  of the guiding member  24  sandwich the blade portion  17  in the front-rear direction therebetween. As long as the fixing cylindrical portion  27  moves inside the first hole  9 , the fixing member  23  is movable with respect to the blade portion  17 . 
     To obtain the cutting jig  1 , as shown in  FIG. 2 , each of the rear case member  6 , the front case member  7 , the fixing member  23 , the guiding member  24 , the blade portion  17 , and the closing plate  21  is prepared. Thereafter, for example, the thin portion  20  of the guiding member  24  is disposed with respect to the front wall  10  of the front case member  7 , subsequently, the cut-out portion  19  of the blade portion  17  is locked to the locking portion  14  of the front case member  7  (ref:  FIGS. 3 and 4 ), and the thick portion  30  of the guiding member  24  and the fixing plate  25  are bonded by an adhesive which is not shown. In this manner, the fixing unit  3  is produced. 
     Thereafter, the rear case member  6  is disposed with respect to the front case member  7  so that the fixing cylindrical portion  27  is inserted into the first hole  9 . At this time, the rear wall  8  and the front wall  10  sandwich the fixing member  23 , the blade portion  17 , and the guiding member  24  therebetween. Further, the rear wall  8  of the rear case member  6  and the peripheral wall  11  of the front case member  7  are bonded (attached) by an adhesive which is not shown. 
     Thereafter, as shown in  FIGS. 1 and 2 , the closing plate  21  is disposed on the front wall  10 . For example, the front wall  10  is bonded to the closing plate  21  by an adhesive which is not shown so that the one end edge  22  traverses one end portion in the moving direction of the slit  12 . Thus, the holding cutting unit  2  is produced. 
     Thus, the cutting jig  1  including the holding cutting unit  2  and the fixing unit  3  is obtained. 
     &lt;Cutting Method&gt; 
     Next, a method for cutting the distal end portion  32  of the optical fiber  31  using the cutting jig  1  is described. 
     This method includes a preparation step of preparing each of the cutting jig  1  and the optical fiber  31  (ref:  FIG. 5 ), a first step of fixing the proximal end portion  33  of the optical fiber  31  to the fixing member  23  (ref:  FIG. 6A ), a second step of inclining the free end portion  34  (ref:  FIG. 6B ), and a third step of cutting the free end portion  34  (ref:  FIG. 6C ) in order. 
     &lt;Preparation Step&gt; 
     As shown in  FIG. 5 , in the preparation step, for example, the fixing cylindrical portion  27  is held to be moved to the other end portion in the moving direction in the first hole  9 . At this time, the fixing cylindrical portion  27  is slid toward the other side in the moving direction in the first hole  9 . Specifically, the other end portion in the moving direction of the fixing cylindrical portion  27  is brought into contact with the first surface  51  of the rear wall  8 . On the other hand, one end portion in the moving direction of the fixing cylindrical portion  27  is spaced apart from the second surface  52  of the rear wall  8 . 
     When projected in the front-rear direction. the through hole  26  and the guiding hole  29  are overlapped with the other end portion in the moving direction of the slit  12 , and are deviated from the closing plate  21 . In the movement of the fixing cylindrical portion  27  described above, the through hole  26  and the guiding hole  29  move with respect to the holding cutting unit  2  so as to move away from the one end edge  22  and the blade edge  18  corresponding to the slit  12  (ref:  FIG. 8 ). 
     As shown in  FIG. 3 , even after the movement of the fixing unit  3  described above, one end portions in the width direction of one end portions in the moving direction of the thin portion  20  and the fixing plate  25  sandwich the blade portion  17  therebetween in the front-rear direction. The other end portions in the width direction of one end portions in the moving direction of the thin portion  20  and the fixing plate  25  are deviated from the blade portion  17 . 
     As shown in  FIG. 5 , the optical fiber  31  extends long along the transmission direction of the light. The optical fiber  31  has, for example, a generally circular shape in a cross-sectional view. Examples of a material for the optical fiber  31  include resins such as an acrylic resin and an epoxy resin, and transparent materials such as glass and ceramics. As the transparent material, preferably, from the viewpoint of ensuring excellent handling properties, a resin is used. 
     A connector  35  as one example of an anchor member is attached to the distal end portion  32  (one end portion in the transmission direction) of the optical fiber  31 . 
     The connector  35  is a joint for connecting the distal end portion  32  of the optical fiber  31  to another optical member (not shown). The connector  35  has a generally cylindrical (specifically, circular cylindrical) shape. The connector  35  is anchored to the periphery of the proximal end portion  33  of the distal end portion  32 , and is not anchored to the periphery of the free end portion  34  located on the front side (one side in the transmission direction) from the proximal end portion  33  in the distal end portion  32 . The distal end portion  32  of the optical fiber  31  is defined into the proximal end portion  33  and the free end portion  34  described above depending on a presence or absence of the above-described anchor of the connector  35 . The optical fiber  31 , together with the connector  35 , is prepared as an optical fiber connector  37 . The optical fiber connector  37  includes the distal end portion  32  of the optical fiber  31 , and the connector  35 . 
     The distal end portion of the connector  35  has a double cylindrical structure including a connector inner tip cylinder  43 , and a connector outer tip cylinder  44  which is disposed spaced apart in the radially outer side thereof. 
     The optical fiber connector  37  is, for example, prepared in accordance with the descriptions of Japanese Unexamined Patent Publications No. 2014-71174, 2013-257366, 2016-9041, 2013-68668, 2010-286795, 2010-511439, and 2011-75743. 
     A second fitting portion  36  which can be fitted into the first fitting portion  28  is provided on the outer peripheral surface of the connector  35 . The second fitting portion  36  may be referred to as a latch. The second fitting portion  36  may be provided on one side in the moving direction of the connector  35 . 
     &lt;First Step&gt; 
     As shown by an arrow of  FIG. 5 , and  FIG. 6A , in the first step, the proximal end portion  33  is fixed to the fixing member  23 . In the first step, specifically, first, the free end portion  34  of the optical fiber  31  passes through the through hole  26 , the guiding hole  29 , and the slit  12  in order from the rear side of the fixing unit  3  toward the front side. 
     At this time, the free end portion  34  traverses the guiding groove  16 . The free end portion  34  traversing the guiding groove  16  passes through the slit  12 , while the movement in all directions of a direction perpendicular to the transmission direction of the light in the optical fiber  31  (for example, a radial direction of the optical fiber  3 ) is restricted by the guiding hole  29 . 
     The movement of the free end portion  34  in all directions of the direction perpendicular to the transmission direction of the light (for example, the radial direction) is restricted by the through hole  26  and the guiding hole  29 . Therefore, the free end portion  34  traversing the guiding groove  16  is along the front-rear direction. In other words, the free end portion  34  is not yet substantially inclined in at least the moving direction. 
     A distal end edge  38  of the free end portion  34  is disposed at the front side with respect to the closing plate  21 . 
     Then, the proximal end portion  33  is fixed to the fixing member  23 . Specifically, as shown by the arrow of  FIG. 5 , the connector inner tip cylinder  43  is inserted into the inner cylinder  41 , and the connector outer tip cylinder  44  of the connector  35  is inserted into the outer cylinder  42 . In short, the connector inner tip cylinder  43  and the connector outer tip cylinder  44  are fitted into the inner cylinder  41  and the outer cylinder  42 , respectively. Further, the second fitting portion  36  is fitted into the first fitting portion  28  of the fixing cylindrical portion  27 . 
     Thus, the proximal end portion  33  is firmly fixed to the fixing member  23 . 
     In the first step, the free end portion  34  is disposed spaced apart from the other side in the moving direction with respect to the blade edge  18  of the blade portion  17  and the one end edge  22  of the closing plate  21 . A length between the free end portion  34  and the one end edge  22  is shorter than the length between the free end portion  34  and the blade edge  18 . 
     &lt;Second Step&gt; 
     As shown in  FIG. 6B , in the second step, the free end portion  34  is inclined. 
     The fixing unit  3  is moved with respect to the holding cutting unit  2  (first movement). The one end edge  22  of the closing plate  21  is brought into contact with the free end portion  34  of the optical fiber  31  based on the first movement. 
     Specifically, the fixing cylindrical portion  27  is moved from the other end portion in the moving direction thereof to the intermediate portion in the moving direction in the first hole  9 . 
     Then, the free end portion  34  of the optical fiber  31  is brought into contact (contact with no load) with the one end edge  22  of the closing plate  21 . 
     Subsequently, when the fixing cylindrical portion  27  is further moved (when the first movement is carried out), the free end portion  34  is moved so as to be inclined with respect to an extension line EL obtained by extending the proximal end portion  33  in the front-rear direction. More specifically, the distal end edge  38  of the free end portion  34  is moved toward the other side in the moving direction with respect to the extension line EL. That is, the free end portion  34  is inclined with respect to the extension line EL so as to be away from the extension line EL toward the distal end edge  38 . 
     However, in the second step, the free end portion  34  is not yet in contact with the blade edge  18  and is spaced apart therefrom in the moving direction in the guiding groove  16 . 
     An angle formed between the free end portion  34  and the extension line EL is, for example, 1 degree or more, preferably 5 degrees or more, and for example, 30 degrees or less, preferably 15 degrees or less. 
     Also, the free end portion  34  moves in the slit  12  during the first movement of the second step. Specifically, the free end portion  34  moves toward the other side in the moving direction in the slit  12 , while the movement in the width direction is restricted. 
     &lt;Third Step&gt; 
     Subsequently, as shown in  FIG. 6C , the inclined free end portion  34  is cut. 
     The fixing cylindrical portion  27  is further moved toward one side in the moving direction in the first hole  9  (second movement). 
     Then, the free end portion  34  in the guiding groove  16  is brought into contact with the blade edge  18 , thereby being cut. Specifically, the free end portion  34  is first brought into contact with the blade edge  18 , and the free end portion  34  traverses the blade edge  18  along the moving direction. 
     In the second movement of the third step, since the fixing unit  3  is moved with a larger movement amount than the first movement of the second step, a degree of inclination of the free end portion  34  when cut is large as compared with the inclination of the free end portion  34  before being cut. 
     In the second to the third steps described above, the blade edge  18  is immovable with respect to the one end edge  22 , and specifically, the interval L between the one end edge  22  and the blade edge  18  (ref:  FIGS. 6A and 8 ) is invariant during at least the first to the third steps. 
     Since the free end portion  34  is inclined with respect to the extension line EL, as shown by an enlarged view of  FIG. 6C , by the transverse of the blade edge  18 , a cut surface CL formed in the distal end portion  32  is inclined with respect to the direction perpendicular to the transmission direction of the light in the free end portion  34 . An angle formed between the cut surface CL and the above-described perpendicular direction is, for example, 1 degree or more, preferably 5 degrees or more, and for example, 30 degrees or less, preferably 15 degrees or less. 
     Further, as shown in  FIG. 6D , the blade edge  18  cuts the free end portion  34  by leaving the rear end edge  39  thereof. 
     The second and the third steps are carried out in a series of operations. 
     Thus, the free end portion  34  is separated from the proximal end portion  33  by leaving the rear end edge  39  thereof. 
     A length of the remaining rear end edge  39  is, for example, 0.01 mm or more, preferably 0.1 mm or more, and for example, 20 mm or less, preferably 5 mm or less. 
     Thereafter, as shown in  FIG. 6D , by further moving the fixing unit  3  with respect to the holding cutting unit  2 , the other end portions in the moving direction of the fixing member  23  and the guiding member  24  are housed (retracted) in the case  4 . Thus, the other end surface in the moving direction of the fixing unit  3  is flush with the other end surface in the moving direction of the case  4 . 
     Thereafter, by releasing the fitting of the first fitting portion  28  and the second fitting portion  36  to detach the optical fiber connector  37  from the fixing unit  3 , the optical fiber  31  having the distal end portion  32  with the inclined surface formed is produced. 
     &lt;Function and Effect of One Embodiment&gt; 
     Then, the cutting jig  1  includes the one end edge  22  of the closing plate  21 , and the blade portion  17  which are incapable of relative movement to each other. The distal end portion  32  of the optical fiber  31  is inserted into the fixing member  23  to be fixed, and the one end edge  22  is brought into contact with the free end portion  34  based on the first movement of the fixing member  23  with respect to the inclination cutting unit  5  to incline the free end portion  34 . Following the first movement, the blade edge  18  is brought into contact with the free end portion  34  based on the second movement of the fixing member  23  with respect to the inclination cutting unit  5  to cut the free end portion  34  in an inclined state. Therefore, it is possible to form the cut surface CL along the direction inclining in the second direction of the free end portion  34  in the free end portion  34  of the optical fiber  31 . 
     Further, since the cutting jig  1  includes the inclination cutting unit  5  including the one end edge  22  and the blade portion  17  which are incapable of relative movement to each other, the configuration is simple as compared with the device of Patent Document 1 including a pushing tool and a blade each of which moves independently. 
     Furthermore, since the fixing member  23  is moved with respect to the one end edge  22  and the blade portion  17  which are incapable of relative movement to each other, it is simple as compared with the device of Patent Document 1 including a pushing tool and a blade each of which moves independently. 
     Moreover, since the one end edge  22  and the blade portion  17  are incapable of relative movement to each other, it is possible to make an inclination state of the free end portion  34  uniform at the time of a contact of the blade edge  18  of the blade portion  17  with the free end portion  34 . Therefore, it is possible to improve the formation accuracy of the cut surface CL of the optical fiber  31 . 
     Further, in the cutting jig  1 , the case  4  holds the blade portion  17  in the inclination cutting unit  5 . Therefore, it is possible to reliably move the fixing member  23  with respect to the blade portion  17  by the case  4 . 
     Furthermore, in the cutting jig  1 , since the closing plate  21  is attached to the case  4 , the configuration is simple. 
     Further, in the cutting jig  1 , it is possible to smoothly incline and cut the free end portion  34 , while the free end portion  34  is guided by the slit  12  in the first movement and the second movement. 
     Further, in the cutting jig  1 , it is possible to easily configure one example of the inclination imparting portion by the one end edge  22  of the closing plate  21 . 
     Further, in the cutting jig  1 , since the blade edge  18  is inclined with respect to the width direction, it is possible to cut the optical fiber  31  with a small pressure as compared with a case of being along the width direction. 
     Further, in the cutting jig  1 , since the connector  35  anchored to the periphery of the proximal end portion  33  is fitted into the fixing cylindrical portion  27  of the fixing member  23 , it is possible to cut the free end portion  34 , while the proximal end portion  33  is reliably fixed to the connector  35 . Therefore, it is possible to furthermore ensure the formation accuracy of the cut surface CL of the cutting jig  1 . 
     In the method for cutting the optical fiber  1 , since the one end edge  22  and the blade portion  17  are moved together with respect to the inclination cutting unit  5 , it is possible to easily carry out the inclination and the cutting of the free end portion  34 . Therefore, it is possible to easily and accurately form the inclined cut surface CL. 
     MODIFIED EXAMPLES 
     In each modified example below, the same reference numerals are provided for members and steps corresponding to each of those in the above-described one embodiment, and their detailed description is omitted. Each modified example can achieve the same function and effect as that of one embodiment unless otherwise specified. Furthermore, one embodiment and each modified example thereof can be appropriately used in combination. 
     In one embodiment, the fixing unit  3  is moved with respect to the holding cutting unit  2 . Alternatively, for example, though not shown, it is also possible to move the holding cutting unit  2  with respect to the fixing unit  3 . 
     Further, the fixing unit  3  includes the guiding member  24 . Alternatively, for example, though not shown, only the fixing member  23  can be also provided without including the guiding member  24 . 
     As shown in  FIGS. 9 to 10D , the inclination cutting unit  5  can also include a filling portion  61  which fills one end portion in the moving direction of the slit  12  instead of the closing plate  21 . 
     As shown in  FIGS. 9 to 10A , the filling portion  61  is one example of a filling member, and is disposed in one end portion in the moving direction of the inside of the slit  12 . The one end edge  22  of the filling portion  61  is one example of an inclination imparting portion. The front surface of the filling portion  61  is, for example, flush with the front surface of the front wall  10 . A material for the filling portion  61  is, for example, the same as the material for the case  4 . 
     Also, by the cutting jig  1 , in the second step, as shown in  FIG. 10B , the one end edge  22  of the filling portion  61  is moved based on the contact with the free end portion  34  so as to incline the free end portion  34 . 
     In the modified example, it is possible to easily configure the one end edge  22  which is an inclination imparting portion by the filling portion  61 . Furthermore, since the filling portion  61  fills a portion of the slit  12 , it is possible to reduce the size of the cutting jig  1 . 
     As shown in  FIGS. 11A to 11D , the inclination cutting unit  5  may be included in the front wall  10  without including the closing plate  21  or the filling portion  61 , and an inner end edge  63  for defining one end in the moving direction of the slit  12  may be an inclination imparting portion. 
     The inner end edge  63  is located at the same position as the one end edge  22  in the filling portion  61 . 
     In the modified example, since the case  4  does not need to include the closing plate  21  or the filling portion  61 , it is possible to reduce the number of components. At the same time, it is possible to easily configure the inclination cutting unit  5  by the inner end edge  63  of the front wall  10 . 
     In one embodiment, the free end portion  34  is cut to be separated from the proximal end portion  33  by leaving the rear end edge  39 . Alternatively, for example, though not shown, it is also possible to cut the boundary between the free end portion  34  and the proximal end portion  33 , and separate the entire free end portion  34  from the proximal end portion  33  without leaving the rear end edge  39 . 
     Next, a method for optically connecting the two optical fiber connectors  37  to each other is described with reference to  FIGS. 12A to 12B . In  FIGS. 12A to 12B , the connector  35  is simply drawn. 
     As shown in  FIG. 12A , each of the two optical fibers  31 , together with the connector  35 , is provided in each of the two optical fiber connectors  37 . A latch  36  disposed on the near side on the plane of the sheet is provided in the connector  35 . In the optical fiber  31  in each of the two optical fiber connectors  37 , in the cutting method of one embodiment, the optical fiber connector  37  is rotated at 90 degrees with the optical fiber  31  as a center, and thereafter, the free end portion  34  is cut. By the rotation of the optical fiber connector  37  described above, the latch  36  is disposed on one side in the moving direction. In this case, the first fitting portion  28  into which the latch  36  is fitted (ref:  FIG. 5 , however, not shown in  FIG. 12 ) is located on one side in the moving direction of the inner surface of the outer cylinder  42 . The latch  36  and the first fitting portion  28  face the same side. 
     Subsequently, the cut surfaces CL of the two optical fibers  31  face each other. As shown in  FIG. 12A , the two cut surfaces CL are parallel to each other. 
     As shown in  FIG. 12B , next, the cut surfaces CL of the two optical fibers  31  are brought into contact with each other. The entire cut surface CL of the optical fiber  31  of the one optical fiber connector  37  is in contact with the entire cut surface CL of the optical fiber  31  of the other optical fiber connector  37 . 
     Thus, it is possible to improve a connection loss between the two optical fibers  31 . 
     The above-described connection is, for example, applied in the case of extending the one optical fiber  31 . 
     While the illustrative embodiments of the present invention are provided in the above description, such is for illustrative purpose only and it is not to be construed as limiting the scope of the present invention. Modification and variation of the present invention that will be obvious to those skilled in the art is to be covered by the following claims. 
     INDUSTRIAL APPLICATION 
     The cutting jig of the present invention is used for cutting an optical fiber. 
     DESCRIPTION OF REFERENCE NUMERALS 
     
         
         
           
               1  Cutting jig 
               4  Case 
               5  Inclination cutting unit 
               12  Slit 
               17  Blade portion 
               18  Blade edge 
               23  Fixing member 
               31  Optical fiber 
               32  Distal end portion 
               33  Proximal end portion 
               34  Free end portion 
               61  Filling portion 
               63  Inner end edge