Optical fiber alignment instrument, fiber holder having an alignment instrument attached, optical fiber alignment method, and optical fiber retention method

Abstract

An optical fiber alignment instrument includes a placement surface onto which a plurality of optical fibers included in an intermittently-fixed optical fiber ribbon are placed thereon, and a clamp that sandwiches and retains the plurality of optical fibers therebetween with the placement surface. A retention force with which the clamp retains the plurality of optical fibers has a gradient in an extension direction in which the plurality of the optical fibers extend.

Description

OPTICAL FIBER ALIGNMENT INSTRUMENT, FIBER HOLDER HAVING AN ALIGNMENT INSTRUMENT ATTACHED, OPTICAL FIBER ALIGNMENT METHOD, AND OPTICAL FIBER RETENTION METHOD

[0001] The present invention relates to an optical fiber alignment instrument, a fiber holder having an alignment instrument attached, an optical fiber alignment method, and an optical fiber retention method.

[0002] In Patent Document 1, a method for fusion splicing a plurality of optical fibers all at once using a fiber holder is disclosed. The plurality of optical fibers are attached to a fusion splicer in state where all of the plurality of optical fibers are held together.

[0003] Japanese Unexamined Patent, First Publication No. 2011-002858

[0004] There are cases where the plurality of optical fibers configure what is known as an intermittently-fixed optical fiber ribbon. The intermittently-fixed optical fiber ribbon has a construction where the plurality of optical fibers are fixed intermittently in a lengthwise direction by a plurality of fixing portions. In a case where a pitch of the fixing portions (intervals in the lengthwise direction) is large, or in a case where some of the fixing portions are partially omitted, restraints of the optical fibers become weaker. Therefore, the optical fibers may not be aligned in order, and adjacent optical fibers intersect one another for example. At such case, work efficiency decreases if a worker tries to pinch the optical fibers using their fingers in order to align the optical fibers for example.

[0005] The present invention is made with the above problem in mind, and an object thereof is to provide an optical fiber alignment instrument, a fiber holder having an alignment instrument attached, an optical fiber alignment method, and an optical fiber retention method, where it is possible to cause an intermittently-fixed optical fiber ribbon to efficiently align.

[0006] To solve the problem above, an embodiment of an optical fiber alignment instrument according to the present invention includes a placement surface onto which a plurality of optical fibers included in an intermittently-fixed optical fiber ribbon are placed thereon, and a clamp that sandwiches and retains the plurality of optical fibers therebetween with the placement surface. A retention force with which the clamp retains the plurality of optical fibers has a gradient in an extension direction in which the plurality of the optical fibers extend.

[0007] An embodiment of fiber holder having an alignment instrument attached according to the present invention includes the optical fiber alignment instrument mentioned above, and a fiber holder that retains the plurality of optical fibers which extend from the optical fiber alignment instrument.

[0008] An alignment method of an optical fiber according to an embodiment of the present invention includes preparing an optical fiber alignment instrument that includes a placement surface and a clamp, on which a plurality of optical fibers included in an intermittently-fixed optical fiber ribbon are placed, and a retention force with which the clamp retains the plurality of the optical fibers has a gradient that extends in the extension direction in which the plurality of optical fibers extend, sandwiching and retaining the plurality of optical fibers between the placement surface and the clamp, and causing the intermittently-fixed optical fiber ribbon to slide in the extension direction, in a state where the plurality of optical fibers are retained by the placement surface and the clamp.

[0009] A retention method of an optical fiber according to an embodiment of the present invention includes retaining the plurality of optical fibers that extend from the optical fiber alignment instrument, after causing the plurality of optical fibers to align using the optical fiber alignment method mentioned above.

[0010] According to the aforementioned, it is possible to provide an optical fiber alignment instrument, a fiber holder having an alignment instrument attached, an optical fiber alignment method, and an optical fiber retention method, that cause an intermittently-fixed optical fiber ribbon to efficiently align.

[0011] Fig. 1 is a perspective view showing a fiber holder having an alignment instrument attached, according to the present embodiment.Fig. 2 is a perspective view showing a condition where a lid of the fiber holder having an alignment instrument attached of FIG. 1 is closed.Fig. 3 is a view explaining an example of a configuration of an intermittently-fixed optical fiber ribbon.Fig. 4 is a view of the fiber holder having an alignment instrument attached of FIG. 2 as seen from above.Fig. 5 is a view of the fiber holder having an alignment instrument attached of FIG. 2 as seen from the front.Fig. 6 is a view explaining a method of using the fiber holder having an alignment instrument attached of the present embodiment.Fig. 7 is a cross-sectional view showing a situation where optical fibers are caused to be aligned.Fig. 8 is a side cross-sectional view showing a situation where the optical fibers are caused to be aligned.

[0012] Hereinafter an alignment instrument of an optical fiber of the present embodiment, and a fiber holder having an alignment instrument attached of the present embodiment are explained. As shown in FIG. 1, a fiber holder having an alignment instrument attached 3 includes an optical fiber alignment instrument 1, a base 2, and a fiber holder 100. The base 2 supports the optical fiber alignment instrument 1 and the fiber holder 100. The optical fiber alignment instrument 1 and the fiber holder 100 are detachable, with respect to the base 2. The optical fiber alignment instrument 1 has a main body 10, and a lid 20. The main body 10 is attached to the base 2, and is a part that does not move. The lid 20 is rotatable with respect to the main body 10. FIG. 1 shows the lid 20 in an open state. FIG. 2 shows the lid 20 in a closed state.

[0013] The optical fiber alignment instrument 1 is used with an intermittently-fixed optical fiber ribbon T, as an object of use thereof shown in FIG. 3. The intermittently-fixed optical fiber ribbon T has a plurality of optical fibers F, and a plurality of connectors C. The entirety of the plurality of optical fibers F or a number of the optical fibers F are intermittently connected in the lengthwise direction of an optical fiber F, using the plurality of connectors C. A portion of the optical fiber F may be continuously connected in the lengthwise direction of the optical fiber F. For example, two optical fibers F which are continuously connected at the connector C in the lengthwise direction of the optical fiber F, form a sub-unit, and may be intermittently connected in the lengthwise direction of the optical fiber F between adjacent sub-units, or between adjacent sub-units and the optical fiber F. For example, in a case where the intermittently-fixed optical fiber ribbon T is included in an optical fiber cable, the intermittently-fixed optical fiber ribbon T is removed from a mid-section of the optical fiber cable, and there is a case where the intermittently-fixed optical fiber ribbon T is fusion spliced with another intermittently-fixed optical fiber ribbon T. As such, when fusion splicing two intermittently-fixed optical fiber ribbons T, the optical fiber alignment instrument 1 or the fiber holder having an alignment instrument attached 3 is used.

[0014] When fusion splicing the intermittently-fixed optical fiber ribbon T, the fiber holder 100 is removed from the base 2, and is set onto the fusion splicer. At such time, the fiber holder 100 is in a state of having the plurality of optical fibers F supported. In a state of having the plurality of optical fibers F supported by the fiber holder 100, there is a need to align the plurality of optical fibers F in a certain predetermined order. This is because, correct fusion splicing cannot be conducted in a case where the order of the optical fibers F is changed.

[0015] (Definition of Directions) As shown in FIG. 1, the optical fiber alignment instrument 1 has a placement surface 12. The plurality of optical fibers F included in the intermittently-fixed optical fiber ribbon T are placed on the placement surface 12 (see FIG. 6). When the plurality of optical fibers F are placed on the placement surface 12, a direction in which the plurality of optical fibers F extend is referred to as the “extension direction X”. The extension direction X is the same direction in which the optical fiber alignment instrument 1 and the fiber holder 100 are aligned in. One side (-X side) in the extension direction X is referred to as “left”, while the opposite side is referred to as “right” (+X side). When the plurality of optical fibers F are placed on the placement surface 12, a direction in which the plurality of optical fibers F are aligned in is referred to as an “alignment direction Y”. One side (+Y side) in the alignment direction Y is referred to as “rear”, while the opposite side (-Y side) is referred to as “front”.

[0016] The alignment direction Y is orthogonal to the extension direction X. A direction that is orthogonal to both the extension direction X and the alignment direction Y is referred to as a “top-bottom direction Z”. One side (+Z side) in the top-bottom direction Z is referred to as a top side, while the opposite side (-Z side) is referred to as a “bottom side”. A view seen from the top-bottom direction Z is also referred to as a “plane view”. A cross-sectional that is orthogonal to the extension direction X is referred to as a “cross-sectional surface”. In other words, the cross-sectional surface is parallel with the alignment direction Y and the top-bottom direction Z.

[0017] The main body 10 of the optical fiber alignment instrument 1 has a main body member 11, the placement surface 12, and a first locking portion 13. The main body member 11 is a part that is attached to the base 2. The placement surface 12 is placed on a center of the main body member 11, in the alignment direction Y. A position of the placement surface 12 however, need not be at the center of the main body member 11 in the alignment direction Y. The placement surface 12 may be formed of material that has a smaller coefficient of friction than that of the main body member 11. Since the optical fiber F and the placement surface 12 slide against one another, it is preferable that the coefficient of friction of the placement surface 12 be small.

[0018] The lid 20 of the optical fiber alignment instrument 1 has a lid main body 21, a clamp 22, and a second locking portion 23. The main body 10 and the lid 20 are connected at a hinge 24. It is possible for the lid 20 to rotate about the main body 10, with the hinge 24 as a center thereof. A torsion spring is disposed in a vicinity of the hinge 24. The torsion spring causes a force in an opening direction of the lid 20 to be generated. Therefore, even in a situation where a user is not touching the lid 20 by hand, the lid 20 remains in the open state. The main body 10 and the lid 20 may be configured so as to be connected at a component other than the hinge 24. Or, the main body 10 and the lid 20 need not be connected.

[0019] Along with the placement surface 12, the clamp 22 is a part that sandwiches the plurality of optical fibers F. A construction of the clamp 22 is mentioned later on. Along with the main body 10 and the first locking portion 13, the second locking portion 23 has a function of retaining the lid 20 in a closed position. For example, either one or both of the first locking portion 13 and the second locking portion 23 may be a magnet. In such case, when the lid 20 closes, the first locking portion 13 and the second locking portion 23 attract one another due to magnetic force. Therefore, the position of the lid 20 is retained. A construction of the first locking portion 13 and / or the second locking portion 23 may also be changed. For example, a hook and a protrusion to which the hook hooks onto may be used. In such case, one of the hook or the protrusion is made to be the first locking portion 13, while the other is made to be the second locking portion 23.

[0020] In FIG. 1, the optical fiber alignment instrument 1 is disposed on the left (-X side) with respect to the fiber holder 100. In other words, the base 2 supports the optical fiber alignment instrument 1 on a left of the fiber holder 100. The optical fiber alignment instrument 1 may also be disposed on a right side (+X side) with respect to the fiber holder 100. In other words, the base 2 may support the optical fiber alignment instrument 1 from a right side of the fiber holder 100. The base 2 may be configured so as to support the optical fiber alignment instrument 1 with respect to the fiber holder 100 from both the right and the left. In other words, a configuration thereof may be such that the user is able to choose a disposition of the optical fiber alignment instrument 1 with respect to the fiber holder 100.

[0021] The fiber holder 100 has a holder main body 101 and a holder lid 102. The holder main body 101 has a retention surface 101a. The retention surface 101a is a portion that supports the plurality of optical fibers F that extend from the optical fiber alignment instrument 1 (refer to FIG. 6). It is preferable that the retention surface 101a be disposed on the same plane as the placement surface 12. The base 2 may support the optical fiber alignment instrument 1 and the fiber holder 100, such that the placement surface 12 and the retention surface 101a are located on the same plane.

[0022] As shown in FIG. 1, the holder lid 102 has a holder clamp 103, and a holder hinge 104. The holder clamp 103 is a part that sandwiches the plurality of optical fibers F therebetween with the retention surface 101a. When the fiber holder 100 is setup in the fusion splicer, the plurality of optical fibers F are sandwiched between the holder clamp 103 and the retention surface 101a. The holder hinge 104 is connected to the holder main body 101. The holder lid 102 is rotatable about the holder main body 101, with the holder hinge 104 as a center thereof.

[0023] As shown in FIG. 4 and FIG. 5, a force applying member 25 is provided on the lid 20 of the optical fiber alignment instrument 1. The force applying member 25 is accommodated on the inside of the lid main body 21. The force applying member 25 applies a force to the clamp 22, towards the main body 10. For example, it is possible to use a compression coil spring as the force applying member 25. By having the force applying member 25 apply a force to the clamp 22, a retention force is generated as the plurality of optical fibers F are retained between the clamp 22 and the placement surface 12.

[0024] In FIG. 5, a dash-dotted line L shows a position of a center of the clamp 22 in the extension direction X. Hereinafter, the said dash-dotted line is referred to as “center line L”. In FIG. 5, the force applying member 25 is located to the left, more than the center line L. As such, a gradient is generated in the retention force of the clamp 22. Specifically, the retention force on the left (-X side) of the center line L becomes larger than the retention force on the right (+X side) of the center line L.

[0025] A direction of the gradient however, may be changed. In other words, the force applying member 25 may be disposed to the right, more than the center line L. In such case, the retention force on the right (+X side) of the center line L becomes larger than the retention force on the left (-X side) of the center line L. It is also possible to have a position of the force applying member 25 be changeable in the extension direction X. In such case, it is possible to change how large the gradient is in the retention force. Specifically, the closer the force applying member 25 is to the center line L, the smaller the gradient becomes. The more the force applying member 25 separates from the center line L, the larger the gradient becomes. In the aforementioned embodiment, since a number of the force applying member 25 is one, a positional relationship between the center line L and the force applying member 25 is explained. However, there may be a plurality of force applying members 25. For example, if two springs having the same spring constants and natural lengths or the like are used as the force applying members 25, so long as a disposition of the two force applying members 25 is asymmetrical with respect to the center line L, it is possible to adjust the gradient of the retention force. When using the force applying members 25 which have differing spring constants and natural lengths or the like, a degree of freedom in disposing each of the force applying member 25 increases.

[0026] Next, a method of using the optical fiber alignment instrument 1 as configured above, and effects thereof are explained.

[0027] As shown in FIG. 6, the intermittent fixation tape core T is disposed so as to straddle between the optical fiber alignment instrument 1 and the fiber holder 100. The user has the intermittently-fixed optical fiber ribbon T in a state of being sandwiched between the placement surface 12 and the clamp 22. The user causes the intermittently-fixed optical fiber ribbon T to move to the right (+X side) with respect to the optical fiber alignment instrument 1. In FIG. 6, and to the left (-X side) more than the clamp 22, a case where a portion of the optical fiber F overrides the other optical fibers F exists. In other words, in a plane view, a case where the portion of the optical fiber F crosses the other optical fibers F exists. In contrast to the above, in the right (+X side) more than the clamp 22, the override of the optical fiber F is neutralized, and all the optical fibers F are aligned in single row in the alignment direction Y.

[0028] As such, by sandwiching the intermittently-fixed optical fiber ribbon T between the placement surface 12 and the clamp 22, and causing the intermittently-fixed optical fiber ribbon T to move in the extension direction X with respect to the optical fiber alignment instrument 1, an override of the optical fibers F is neutralized. The larger a pitch of the connector C is in the extension direction X, the easier it is for the override of the optical fiber F to occur. Also, in order to fusion splice the intermittently-fixed optical fiber ribbon T, even if stripping of the connector C is caused on a portion of the intermittently-fixed optical fiber ribbon T, it is still easy for the override of the optical fiber F to occur. The aforementioned is due to positional relationships of the plurality of optical fibers F not having any constraints in regions where the connector C is not provided. A mechanism of how the override in the optical fiber F is neutralized using the optical fiber alignment instrument 1, is explained using FIG. 7 and FIG. 8.

[0029] FIG. 7 shows a schematic diagram of the optical fiber alignment instrument 1, and is a cross-sectional view along the extension direction X and the top-bottom direction Z. In the example of FIG. 7, one force applying member 25 is disposed on the left (-X side) of the center line L. Therefore, the gradient of the retention force of the clamp 22 becomes stronger when as the left is approached, and becomes weaker as the right is approached. As shown in FIG. 7, a portion of the optical fiber F overrides the other optical fibers F. At such time, by causing the intermittently-fixed optical fiber ribbon T to move in the extension direction X with respect to the optical fiber alignment instrument 1, a force acts to move said fiber to the correct position. In the example of FIG. 7, the intermittently-fixed optical fiber ribbon T is pulled to the right (+X side). As such, in a region more to the left than the center line L, the overriding optical fiber F moves to the correct position on a region more to the right than the center line L.

[0030] FIG. 8 is a schematic diagram that shows a side cross-sectional view of the optical fiber alignment instrument 1. FIG. 8 (a), (b), and (c) show a plurality of optical fibers F that are sandwiched by the plurality of placement surface 12 and the clamp 22, and that are being aligned in the correct position. For explanation purposes, the optical fibers F in FIG. 8 have numbers “1” to “6” assigned thereto. Said numbers reflect the predetermined alignment order of each optical fiber F, in the alignment direction Y. In FIG. 8 (a), the optical fiber F number 5 is overriding on the optical fibers F number 3 and number 4.

[0031] In the above example, the optical fiber alignment instrument 1 of the present embodiment includes a swing mechanism M that causes the clamp 22 to swing. By having the optical fiber alignment instrument 1 include the swing mechanism M, it is possible to increase the alignment effect of the optical fibers F. However, it is not necessary to have the swing mechanism M. In FIG. 8, the swing mechanism M has a swing shaft 22a provided on the clamp 22. It is possible for the clamp 22 to swing with the swing shaft 22a as a center thereof. By swinging the clamp 22, an angle formed by a clamp surface 22b (bottom surface of the clamp 22) and the placement surface 12 in the cross sectional surface varies. The clamp 22 has a force applied thereto by the force applying member 25, towards the placement surface 12. The applied force using the force applying member 25 has a gradient. Considerations conducted by the inventors of the present invention revealed that an applied force having a gradient causes a return force to be generated, which returns the optical fiber F that overrides the other optical fibers F to a predetermined position thereof.

[0032] In a state where the plurality of optical fibers F are sandwiched by the clamp 22 and the placement surface 12 (FIG. 8 (a)), the user pulls the intermittently-fixed optical fiber ribbon T in the extension direction X. Accordingly, as shown in FIG. 8 (b), the optical fiber F number 5 moves towards the optical fibers F number 4 and number 6. Furthermore, as shown in FIG. 8 (c), the optical fiber F number 5 enters between the optical fibers F number 4 and number 6. Accordingly, alignment of the plurality of optical fibers F is complete.

[0033] Although a number of the optical fibers F is six in FIG. 8, the number which includes the optical fiber F in the intermittently-fixed optical fiber ribbon T is not limited. For example, experiments conducted by the inventors of the present invention revealed that even in when the intermittently-fixed optical fiber ribbon T had twelve optical fibers F, it was possible to cause intersecting optical fibers F to align in predetermined positions thereof using the optical fiber alignment instrument 1. In the aforementioned experiments, a maximum value of the retention force of the clamp 22 used was in a range of 0.294N to 1.471N. A minimum value of the retention force was in the range of 0.196N to 1.176N. A point where the retention force was a maximum value and a point where the retention force was a minimum value were separated by at least 5 mm in the extension direction X. When such conditions were met, it was confirmed that it is possible to smoothly align the optical fibers F, without having the connector C break.

[0034] In the aforementioned, as shown in FIG. 1, the “retention force of the clamp 22” was measured by applying a force gauge to the clamp 22, where the lid 20 was in the open state. In other words, in the above experiment, the “retention force” is the same as the applied force of the force applying member 25. In the above experiment, it was possible to disregard a weight of the clamp 22 itself, seeing as how the weight thereof is very small compared to the applied force of the force applying member 25. For example, the weight of the clamp 22 itself, or a weights or the like may be used in place of the force applying member 25. The same results are believed to be achievable when using a retention force caused by using gravity. By adjusting a shape of the clamp 22, or by adjusting locations of the weights used to generate the retention force or the like, it is also possible to provide a gradient for the retention force of the clamp 22. There is also a case where moving the intermittently-fixed optical fiber ribbon T, with respect to the optical fiber alignment instrument 1, in a direction where the gradient of the retention force of the clamp 22 becomes higher, as opposed to the opposite direction, increases the alignment effect. In other words, the direction of the gradient of the retention force may be such that the retention force becomes larger as the fiber holder 100 is approached from the optical fiber alignment instrument 1.

[0035] After the optical fiber F is aligned using the optical fiber alignment instrument 1, the holder lid 102 is closed, and the optical fiber F may be retained by the holder clamp 103 and the retention surface 101a. The fiber holder 100 may be removed from the base 2, and may be set in the fusion splicer. Fusion splicing with respect to a mating intermittently-fixed optical fiber ribbon T may also be conducted. The same alignment of the optical fibers F using the optical fiber alignment instrument 1 may be conducted with respect to the mating intermittently-fixed optical fiber ribbon T. According to this method, it is possible to efficiently conduct fusion splicing in a state where the plurality of optical fibers F are correctly aligned.

[0036] As explained above, the optical fiber alignment instrument 1 according to the present embodiment includes the placement surface 12 in which the plurality of optical fibers F included in the intermittently-fixed optical fiber ribbon T are placed, and the clamp 22 that sandwiches the plurality of optical fibers F therebetween with the placement surface 12. The retention force with which the clamp 22 retains the plurality of optical fibers F has a gradient in the extension direction X, in which the plurality of the optical fibers F extend. With such configuration, it is possible to cause the optical fiber F to align by sandwiching the plurality of optical fibers using the placement surface 12 and the clamp 22, and by pulling the intermittently-fixed optical fiber ribbon T. Therefore, compared to a case where for example, the optical fibers F that intersect one another are pinched by fingers so as to be moved to predetermined positions thereof, it is possible to efficiently cause the intermittently-fixed optical fiber ribbon T to align.

[0037] The optical fiber alignment instrument 1 also includes the swing mechanism M. As for the swing mechanism M in a cross-sectional view (FIG. 8) that is orthogonal to the extension direction X, the clamp 22 is able to swing so that the angle between the placement surface 12 and the clamp surface 22b of the clamp 22 varies. With such configuration, it is possible to cause the optical fiber F that overrides on the other optical fibers F to move more smoothly to the predetermined position thereof.

[0038] The optical fiber alignment instrument 1 includes the force applying member 25 which applies a force to the clamp 22 in the direction towards the placement surface 12. The gradient of the retention force of the clamp 22 varies according to the change in position of the force applying member 25 in the extension direction X. Accordingly, it is possible to adjust the retention force without having the connector C break, while causing the optical fibers F to align.

[0039] The fiber holder having an alignment instrument attached 3 includes the optical fiber alignment instrument 1, the fiber holder 100, and the base 2. The fiber holder 100 retains the plurality of optical fibers F that extend from the optical fiber alignment instrument 1. The base 2 supports the optical fiber alignment instrument 1 and the fiber holder 100. According to the fiber holder having an alignment instrument attached 3, it is possible to retain the optical fibers F in a state of being aligned using the fiber holder 100. By attaching the fiber holder 100 having the optical fibers F retained therein to the fusion splicer or the like, it is also possible to smoothly conduct fusion splicing work.

[0040] The fiber holder 100 has the retention surface 101a that retains the plurality of optical fibers F. The base 2 supports the optical fiber alignment instrument 1 and the fiber holder 100 so as to align locations of the placement surface 12 and the retention surface 101a. With such configuration, it is possible to smoothly hand over the optical fibers F that are aligned using the optical fiber alignment instrument 1 to the fiber holder 100. The placement surface 12 and the retention surface 101a need not be strictly located on the same plane. So long as the retention surface 101a is disposed in a location where it is possible to retain the optical fibers F that extend from the optical fiber alignment instrument 1, a function of the fiber holder 100 is realized.

[0041] The optical fiber alignment instrument 1 may be disposable on both sides in the extension direction X, with respect to the fiber holder 100. During fusion splicing of two intermittently-fixed optical fiber ribbons T, there are cases where the two intermittently-fixed optical fiber ribbons T are attached to the fusion splicer. In such case, each of the two fiber holders 100, for the left side and for the right side, is caused to retain the intermittently-fixed optical fiber ribbon T. It is possible to increase work efficiency by causing the optical fibers F to be aligned using the optical fiber alignment instrument 1, with respect to the fiber holders 100 of both the left side and the right side.

[0042] An optical fiber alignment method according to the present embodiment includes preparing an optical fiber alignment instrument 1 that includes a placement surface 12 and a clamp 22, on which a plurality of optical fibers F included in an intermittently-fixed optical fiber ribbon T are placed, and a retention force with which the clamp 22 retains the plurality of the optical fibers F has a gradient that extends in the extension direction in which the plurality of optical fibers F extend, sandwiching and retaining the plurality of optical fibers F between the placement surface 12 and the clamp 22, and causing the intermittently-fixed optical fiber ribbon T to slide in the extension direction, in a state where the plurality of optical fibers F are retained by the placement surface 12 and the clamp 22. According to such alignment method, compared to a case where for example, the optical fibers F that intersect one another are pinched by fingers so as to be moved to predetermined positions thereof, it is possible to efficiently cause the intermittently-fixed optical fiber ribbon T to align.

[0043] A retention method of the optical fiber according to the present embodiment retains the plurality of optical fibers F that extend from the optical fiber alignment instrument 1, after causing the plurality of optical fibers F to align using the aforementioned optical fiber alignment method. According to the retention method above, it is easy to retain the optical fibers F that are in a state of being aligned. Therefore, it is possible to increase work efficiency of fusion splicing or the like.

[0044] The technical scope of the present invention is not limited to the aforementioned embodiments, and various changes may be made so long as the scope of the present invention is not departed from.

[0045] For example, in FIG. 6, the fiber holder 100 is located on the right (+X side) of the optical fiber alignment instrument 1, and the intermittently-fixed optical fiber ribbon T is pulled to the right with respect to the optical fiber alignment instrument 1. However, the fiber holder 100 may be located on the left (-X side) of the optical fiber alignment instrument 1. Furthermore, the intermittently-fixed optical fiber ribbon T may be pulled from the left with respect to the optical fiber alignment instrument 1. Even in such case, it is still possible to neutralize the override of the optical fiber F on the other optical fibers F.

[0046] In FIG. 8 the swing mechanism M other than the swing shaft 22a may be adopted. For example, the shape of the clamp 22 may be an upside down shape of the character “T”. In such a case, it is possible for the clamp 22 to swing with an end point of the character T being a base point thereof. In the aforementioned embodiments, the optical fiber alignment instrument 1 and the fiber holder 100 are supported by the base 2. However, a construction where the optical fiber alignment instrument 1 and the fiber holder 100 are directly connected without using the base 2, may be adopted. A method where optical fiber alignment instrument 1 alone is used to cause the optical fiber F to align is possible. After causing the optical fiber F to align using the optical fiber alignment instrument 1 alone, the intermittently-fixed optical fiber ribbon T may be placed on top of the fiber holder 100 which is not connected to the optical fiber alignment instrument 1.

[0047] Besides the aforementioned, so long as the technical scope of the present invention is not departed from, configuration components of the aforementioned embodiments may be replaced with well-known configuration components. Embodiments and modification examples may be suitably changed or combined. Reference Signs List

[0048] 1…Optical Fiber Alignment Instrument, 2…Base, 3…Fiber Holder Having An Alignment Instrument Attached, 12…Placement Surface, 22…Clamp, 25…Force Applying Member, 100…Fiber Holder, 101a…Retention Surface, F…Optical Fiber, M…Swing Mechanism, T…Intermittently-fixed optical fiber ribbon Core, X…Extension Direction

Claims

1. An optical fiber alignment instrument comprising: a placement surface onto which a plurality of optical fibers included in an intermittently-fixed optical fiber ribbon are placed thereon; and a clamp that sandwiches and retains the plurality of optical fibers therebetween with the placement surface, wherein a retention force with which the clamp retains the plurality of optical fibers has a gradient in an extension direction in which the plurality of the optical fibers extend.

2. The optical fiber alignment instrument according to claim 1, wherein the clamp is configured to swing, so that an angle between the placement surface and the clamp varies in a cross-sectional view that is orthogonal to the extension direction.

3. The optical fiber alignment instrument according to claim 1 or 2 further comprising: a force applying member that applies a force to the clamp, towards the placement surface, wherein the gradient of the retention force varies according to a change in a position of the force applying member in the extension direction.

4. The optical fiber alignment instrument according to any one of claims 1 to 3, wherein a maximum value of the retention force of the clamp is in a range of 0.294N to 1.471N.

5. The optical fiber alignment instrument according to any one of claims 1 to 4, wherein a minimum value of the retention force is in the range of 0.196N to 1.176N.

6. The optical fiber alignment instrument according to any one of claims 1 to 5, wherein a point where the retention force is a maximum value and a point where the retention force is a minimum value are separated by at least 5 mm in the extension direction.

7. A fiber holder having an alignment instrument attached comprising: the optical fiber alignment instrument according to any one of claims 1 to 6; and a fiber holder that retains the plurality of optical fibers which extend from the optical fiber alignment instrument.

8. The fiber holder having an alignment instrument attached according to claim 7, wherein a direction of the gradient of the retention force is such that the retention force becomes larger as the fiber holder is approached from the optical fiber alignment instrument.

9. The fiber holder having an alignment instrument attached according to claim 7 further comprising: a base that supports the optical fiber alignment instrument and the fiber holder, wherein the fiber holder has a retention surface that retains the plurality of the optical fibers, and the base supports the optical fiber alignment instrument and the fiber holder so as to align locations of the placement surface and the retention surface.

10. The fiber holder having an alignment instrument attached according to any one of claims 7 to 9, wherein the optical fiber alignment instrument is disposable on both sides in the extension direction, with respect to the fiber holder.

11. An optical fiber alignment method, the method comprises: preparing an optical fiber alignment instrument that includes a placement surface and a clamp, on which a plurality of optical fibers included in an intermittently-fixed optical fiber ribbon are placed, and a retention force with which the clamp retains the plurality of the optical fibers has a gradient that extends in the extension direction in which the plurality of optical fibers extend, sandwiching and retaining the plurality of optical fibers between the placement surface and the clamp, and causing the intermittently-fixed optical fiber ribbon to slide in the extension direction, in a state where the plurality of optical fibers are retained by the placement surface and the clamp.

12. A retention method of an optical fiber comprises: retaining the plurality of optical fibers that extend from the optical fiber alignment instrument, after causing the plurality of optical fibers to align using the optical fiber alignment method according to claim 11.

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