FUSION SPLICER, AND METHOD FOR CONNECTING OPTICAL FIBER

A fusion splicer (1) for fusion-splicing a plurality of optical fibers (3L), arranged side by side along a direction intersecting a longitudinal direction, with respective other optical fibers (3R) includes a base member (11L) with a groove portion (17L) having a plurality of V-grooves formed therein for setting the plurality of optical fibers (3L), and a pair of guide walls (12FL, 12BL) configured to guide setting of the plurality of optical fibers (3L) into the plurality of V-grooves, wherein the pair of guide walls (12FL, 12BL) are disposed at an interval in a width direction of the groove portion (17L), one (12FL) of the guide walls constituting the pair has a guide surface (GF1) capable of coming into contact with one of the plurality of optical fibers (3L), another one (12BL) of the guide walls constituting the pair has a guide surface (GF2) capable of coming into contact with another one of the plurality of optical fibers (3L), and each guide surface (GF1, GF2) includes a portion inclined toward the groove portion (17L) when viewed along a direction of extension of the plurality of V-grooves.

FIELD OF THE INVENTION

The present disclosure relates to fusion splicers and methods of splicing optical fibers.

The present application is based on and claims priority to Japanese application No. 2021-101985 filed on Jun. 18, 2021, and the entire contents of this Japanese application are incorporated herein by reference.

BACKGROUND ART

A fusion splicer as conventionally known in the art fusion-splices a plurality of optical fibers arranged side by side along a width direction intersecting the longitudinal direction (see Patent Document 1). The fusion splicer includes a fiber placement table that has a groove portion having a plurality of V-grooves formed therein in which a plurality of optical fibers are placed.

The coating material at the distal end of the optical fibers is removed at the time of fusion-splicing. A portion of an optical fiber where the coating material is removed to expose glass fiber is referred to as a bare fiber portion, and a portion coated with the coating material is referred to as an optical fiber element or an optical fiber cable. The bare fiber portions, not coated with the coating material, of a plurality of optical fibers easily spread in the width direction.

PRIOR ART DOCUMENT

Patent Document

SUMMARY OF THE INVENTION

Means for Solving the Problem

A fusion splicer according to an embodiment of the present disclosure is a fusion splicer for fusion-splicing a plurality of optical fibers, arranged side by side along a direction intersecting a longitudinal direction, with respective other optical fibers, including a base member with a groove portion having a plurality of V-grooves formed therein for setting the plurality of optical fibers, and a pair of guide walls configured to guide setting of the plurality of optical fibers into the plurality of V-grooves, wherein the pair of guide walls are disposed at an interval in a width direction of the groove portion, one of the guide walls constituting the pair has a guide surface capable of coming into contact with one of the plurality of optical fibers, another one of the guide walls constituting the pair has a guide surface capable of coming into contact with another one of the plurality of optical fibers, and each guide surface includes a portion inclined toward the groove portion when viewed along a direction of extension of the plurality of V-grooves.

DETAILED DESCRIPTION OF THE INVENTION

Problems to be Solved by the Present Disclosure

The groove portion of a fiber placement table is configured such that a plurality of V-grooves for setting the bare fiber portions of a plurality of optical fibers, i.e., glass fibers, are arranged parallel to each other. Because of this, the orientation of the glass fibers positioned at the outermost positions, among the plurality of glass fibers spread in the width direction, may deviate from the orientation of the corresponding V-grooves. Some of the bare fiber portions of the plurality of optical fibers spread in the width direction may fail to be fit in the corresponding V-grooves, and may slide out of the corresponding V-grooves.

Accordingly, it is desirable to prevent the bare fiber portions of optical fibers from sliding out of the V-grooves.

Effects of the Present Disclosure

According to the present disclosure, it is possible to prevent the bare fiber portions of optical fibers from sliding out of the V-grooves.

Description of Embodiments of the Present Disclosure

Embodiments of the present disclosure will first be listed and described. In the following description, the same or corresponding elements are referred to by the same reference numerals, and a duplicate description thereof will not be provided.

(1) A fusion splicer according to an aspect of the present disclosure is a fusion splicer for fusion-splicing a plurality of optical fibers, arranged side by side along a direction intersecting direction, with respective other a longitudinal optical fibers, which includes a base member with a groove portion having a plurality of V-grooves formed therein for setting the plurality of optical fibers, and a pair of guide walls configured to guide setting of the plurality of optical fibers into the plurality of V-grooves, wherein the pair of guide walls are disposed at an interval in a width direction of the groove portion, one of the guide walls constituting the pair has a guide surface capable of coming into contact with one of the plurality of optical fibers, another one of the guide walls constituting the pair has a guide surface capable of coming into contact with another one of the plurality of optical fibers, and each guide surface includes a portion inclined toward the groove portion when viewed along a direction of extension of the plurality of V-grooves. This configuration has the pair of guide walls, and can thus narrow the spread of the bare fiber portions in the width direction when the bare fiber portions of the plurality of optical fibers are set in the plurality of V-grooves. This is because the bare fiber portions spread outward in the width direction come into contact with the guide surfaces of the guide walls when approaching the V-grooves, thereby to be pushed back inward in the width direction. Consequently, this configuration brings about the result that the bare fiber portions are prevented from sliding out of the V-grooves when the bare fiber portions of the plurality of optical fibers are set in the plurality of V-grooves.

(2) Each guide surfaces may be disposed as a continuous extension of a groove surface of one of the plurality of V-grooves when viewed along the direction of extension of the plurality of V-grooves. The fact that the guide surface and the groove surface are continuous with each other means that, for example, the inclination angle of the guide surface and the inclination angle of the groove surface are equal to each other where the guide surface and the groove surface meet when viewed along the direction of extension of the V-grooves. It may be noted that the guide surface and the groove surface do not need to be physically connected. This is because the guide surface and the groove surface may be spaced apart from each other in the direction of extension of the V-grooves. The inclination angle of the guide surface is the angle formed between the guide surface and an imaginary vertical plane, and the inclination angle of the groove surface is the angle formed between the groove surface and an imaginary vertical plane. The fact that the inclination angle of the guide surface and the inclination angle of the groove surface are equal to each other may include a situation in which an angular difference between the inclination angle of the guide surface and the inclination angle of the groove surface is less than or equal to a predetermined minute angle. This configuration brings about the result that, for example, the bare fiber portions readily enter the V-grooves upon moving along the guide surfaces while being pushed back by the guide surfaces.

(3) The pair of guide walls may be formed as a member separate from the base member. This configuration yields the advantage that the guide walls can be newly added to an existing fusion splicer without removing or replacing an existing base member in the existing fusion splicer. This configuration also allows the guide walls and the base member to be made of different materials. This configuration thus brings about the advantage that the manufacturing cost of the fusion splicer can be reduced as compared with, for example, the case in which the guide walls and the base member are integrally formed of the same material and the material of the base member is expensive.

(4) The pair of guide walls may be integrated with the base member. This configuration brings about the advantage that the positioning accuracy of the guide walls with respect to the V-grooves can be improved as compared with the case in which the guide walls are formed as a member separate from the base member, for example.

(5) At least one of the guide walls constituting the pair may be configured to be movable relative to the groove portion in the width direction. This configuration brings about the advantage that, for example, the guide walls can cope with optical fibers having various numbers of cores. For example, this configuration achieves the advantage that the guide walls configured to correct the widthwise spread of bare fiber portions of a 24-core ribbon cable can be used to correct the widthwise spread of a ribbon cable having a smaller number of cores (for example, a 16-core ribbon cable, an 8-core ribbon cable, or the like).

(6) An optical fiber splicing method according to an aspect of the present disclosure fusion-spices a plurality of optical fibers with respective other optical fibers by using a fusion-splicer that includes a base member with a groove portion having a plurality of V-grooves formed therein for setting a plurality of optical fibers, and a pair of guide walls configured to guide setting of the plurality of optical fibers into the plurality of V-grooves, the optical fiber splicing method including placing the plurality of optical fibers in the plurality of V-grooves while bringing one of the plurality of optical fibers into contact with a guide surface of one of the guide walls constituting the pair, the guide walls being disposed at an interval in a width direction of the groove portion, and fusion-splicing the plurality of optical fibers with respective other optical fibers. By including the step of placing the plurality of optical fibers in the plurality of V-grooves while bringing one of the plurality of optical fibers into contact with a guide surface of one of the guide walls constituting the pair, this method can narrow the spread of bare fiber portions in the width direction when the bare fiber portions of the plurality of optical fibers are set in the plurality of V-grooves. This is because the bare fiber portions spread outward in the width direction come into contact with the guide surfaces of the guide walls when approaching the V-grooves, thereby to be pushed back inward in the width direction. Consequently, this configuration brings about the result that the bare fiber portions are prevented from sliding out of the V-grooves when the bare fiber portions of the plurality of optical fibers are set in the plurality of V-grooves.

Details of Embodiments of the Present Disclosure

In the following, specific examples of a fusion splicer1and an optical fiber splicing method according to an embodiment of the present disclosure will be described with reference to the accompanying drawings.

FIG.1is an axonometric view illustrating part of the fusion splicer1. InFIG.1, X1 represents one direction along an X-axis of a three-dimensional orthogonal coordinate system, and X2 represents the opposite direction along the X-axis. Y1 represents one direction along a Y-axis of the three-dimensional orthogonal coordinate system, and Y2 represents the opposite direction along the Y-axis. Similarly, Z1 represents one direction along a Z-axis of the three-dimensional orthogonal coordinate system, and Z2 represents the opposite direction along the Z-axis. In the present embodiment, the X1 side of the fusion splicer1corresponds to the front side (front surface side) of the fusion splicer1, and the X2 side of the fusion splicer1corresponds to the rear side (rear surface side) of the fusion splicer1. The Y1 side of the fusion splicer1corresponds to the left-hand side of the fusion splicer1, and the Y2 side of the fusion splicer1corresponds to the right-hand side of the fusion splicer1. The Z1 side of the fusion splicer1corresponds to the upper side of the fusion splicer1, and the Z2 side of the fusion splicer1corresponds to the lower side of the fusion splicer1. The same applies to other drawings.

The fusion splicer1is a device configured to be able to fusion-splice, by arc discharge, a plurality of optical fiber pairs arranged with the end faces abutting against each other. In the illustrated example, the fusion splicer1is configured to be able to fusion-splice four optical fiber pairs. To be specific, the fusion splicer1includes a pair of electrode rods5(i.e., a rear electrode rod5B and a front electrode rod5F), a pair of base members11(i.e., a left base member11L and a right base member11R), a pair of clamps21(i.e., a left clamp21L and a right clamp21R), and a pair of fiber holders31(i.e., a left fiber holder31L and a right fiber holder31R).

The pair of electrode rods5includes the rear electrode rod5B and the front electrode rod5F spaced apart from each other in the X-axis direction. The pair of electrode rods5are arranged such that the distal end5Ba of the rear electrode rod5B and the distal end5Fa of the front electrode rod5F oppose each other. In the illustrated example, the rear electrode rod5B includes a generally conical portion whose diameter decreases toward the distal end5Ba. The same applies to the front electrode rod5F.

The plurality of optical fiber pairs arranged on the pair of base members11are glass fibers, and are arranged between the rear electrode rod5B and the front electrode rod5F for generating arc discharge. The portions of the plurality of optical fiber pairs disposed on the pair of base members11are bare fiber portions in which the coating material is removed to expose the glass.

To be specific, the plurality of pairs of bare fiber portions include bare fiber portions of a left optical fiber group3L belonging to a left ribbon cable4L and bare fiber portions of a right optical fiber group3R belonging to a right ribbon cable4R. Hereinafter, the left optical fiber group3L and the right optical fiber group3R may be referred to as an optical fiber group3for the sake of convenience of description.

The ribbon cable is formed by arranging a plurality of optical fibers (optical fiber elements) in parallel and coating the optical fibers collectively with, for example, an ultraviolet curable resin (i.e., coating material). Both the left ribbon cable4L and the right ribbon cable4R in the illustrated example are a four-core ribbon cable in which four optical fibers (i.e., optical fiber elements) are arranged in parallel and collectively coated with an ultraviolet curable rein (i.e., coating material).

The pair of base members11is a member for supporting the plurality of optical fiber pairs, and includes a left base member11L and a right base member11R between which the pair of electrode rods5is interposed. In other words, the pair of electrode rods5is disposed between the left base member11L and the right base member11R that are spaced apart from each other in the Y-axis direction. The right base member11R of the illustrated example has a right V-groove group17R, which is also referred to as a right optical fiber placement portion or a right groove portion. The left base member11L has a left V-groove group17L, which is also referred to as a left optical fiber placement portion or a left groove portion. Hereinafter, the left V-groove group17L and the right V-groove group17R may be referred to as a V-groove group17for the sake of convenience of description.

The left V-groove group17L has a plurality of V-grooves for arranging a plurality of optical fibers (i.e., the left optical fiber group3L), and the right V-groove group17R has a plurality of V-grooves for arranging a plurality of optical fibers (i.e., the right optical fiber group3R). In the illustrated example, the left V-groove group17L has four V-grooves for arranging four optical fibers. The four V-grooves are arrayed at equal intervals in the X-axis direction and are formed to linearly extend along the Y-axis direction. Similarly, the right V-groove group17R has four V-grooves for arranging four optical fibers. The four V-grooves are arrayed at equal intervals in the X-axis direction, and are formed to linearly extend along the Y-axis direction.

The plurality of V-grooves in the right V-groove group17R and the plurality of V-grooves in the left V-groove group17L are configured such that positioning of the plurality of optical fiber pairs is performed simultaneously. In the illustrated example, the four V-grooves in the right V-groove group17R and the four V-grooves in the left V-groove group17L are arranged in an opposing relationship in the direction of extension (i.e., the Y-axis direction), and are configured such that positioning of the four optical fiber pairs is performed simultaneously.

With this arrangement, four optical fibers positioned by the four V-grooves in the right V-groove group17R and four optical fibers positioned by the four V-grooves in the left V-groove group17L are caused to abut against each other in the region between the right base member11R (or the right V-groove group17R) and the left base member11L (or the left V-groove group17L).

In the following, details of the V-groove group17in which the four optical fiber pairs are positioned will be described with reference toFIG.2AthroughFIG.2C.FIG.2AthroughFIG.2Care top views illustrating part of the fusion splicer1. Specifically,FIG.2AthroughFIG.2Care top views of the electrode rods5, the base members11, and guide walls12. To be more specific,FIG.2Aillustrates the situation before the optical fiber group3is placed above the V-groove group17.FIG.2Billustrates the situation when the optical fiber group3is placed above the V-groove group17(i.e., the situation before the optical fiber group3is set in the V-groove group17).FIG.2Cillustrates the situation after the optical fiber group3is set in the V-groove group17. It may be noted that inFIG.2AthroughFIG.2C, a coarse dot pattern is applied to the groove surfaces of the V-groove group17, and a fine dot pattern is applied to guide surfaces GF (which will be described later) of the guide walls12, for the sake of increased clarity. The bottom of each V-groove is indicated by a dashed line.

As illustrated inFIG.2A, the left V-groove group17L includes a first left V-groove17AL, a second left V-groove17BL, a third left V-groove17CL, and a fourth left V-groove17DL, and the right V-groove group17R includes a first right V-groove17AR, a second right V-groove17BR, a third right V-groove17CR, and a fourth right V-groove17DR. The first left V-groove17AL and the first right V-groove17AR constitute a first V-groove pair17A. The second left V-groove17BL and the second right V-groove17BR constitute a second V-groove pair17B. The third left V-groove17CL and the third right V-groove17CR constitute a third V-groove pair17C. The fourth left V-groove17DL and the fourth right V-groove17DR constitute a fourth V-groove pair17D.

Further, as illustrated inFIG.2B, the left optical fiber group3L includes a first left optical fiber3AL, a second left optical fiber3BL, a third left optical fiber3CL, and a fourth left optical fiber3DL as bare fiber portions, and the right optical fiber group3R includes a first right optical fiber3AR, a second right optical fiber3BR, a third right optical fiber3CR, and a fourth right optical fiber3DR as bare fiber portions. The first left optical fiber3AL and the first right optical fiber3AR constitute a first optical fiber pair3A. The second left optical fiber3BL and the second right optical fiber3BR constitute a second optical fiber pair3B. The third left optical fiber3CL and the third right optical fiber3CR constitute a third optical fiber pair3C. The fourth left optical fiber3DL and the fourth right optical fiber3DR constitute a fourth optical fiber pair3D.

The guide walls12are configured to guide the setting of the optical fiber group3into the V-groove group17. In the illustrated example, the guide walls12include left guide walls12L and right guide walls12R, as illustrated inFIG.2A. The left guide walls12L include a left rear guide wall12BL and a left front guide wall12FL, and the right guide walls12R include a right rear guide wall12BR and a right front guide wall12FR.

To be specific, the guide walls12include the left guide walls12L that guide the setting of the left optical fiber group3L into the left V-groove group17L, and include the right guide walls12R that guide the setting of the right optical fiber group3R into the right V-groove group17R.

The left guide walls12L include the left rear guide wall12BL and the left front guide wall12FL formed at positions corresponding to the left end of the left V-groove group17L situated toward the left fiber holder31L. Similarly, the right guide walls12R include the right rear guide wall12BR and the right front guide wall12FR formed at positions corresponding to the right end of the right V-groove group17R situated toward the right fiber holder31R.

The guide walls12have guide surfaces GF. InFIG.2AthroughFIG.2C, a fine dot pattern is applied to the guide surfaces GF for the sake of increased clarity. To be more specific, as illustrated inFIG.2B, the left front guide wall12FL has a first guide surface GF1that comes into contact with the first left optical fiber3AL located furthest to the front (toward the X1 side) in the left optical fiber group3L, and the left rear guide wall12BL has a second guide surface GF2that comes into contact with the fourth left optical fiber3DL located furthest to the rear (toward the X2 side) in the left optical fiber group3L. Similarly, the right front guide wall12FR has a third guide surface GF3that comes into contact with the first right optical fiber3AR located furthest to the front (toward the X1 side) in the right optical fiber group3R, and the right rear guide wall12BR has a fourth guide surface GF4that comes into contact with the fourth right optical fiber3DR located furthest to the rear (toward the X2 side) in the right optical fiber group3R.

In the illustrated example, the first guide surface GF1of the left front guide wall12FL is formed as a continuous extension of the first left V-groove17AL located furthest to the front in the left V-groove group17L, and the second guide surface GF2of the left rear guide wall12BL is formed as a continuous extension of the fourth left V-groove17DL located furthest to the rear in the left V-groove group17L. Similarly, the third guide surface GF3of the right front guide wall12FR is formed as a continuous extension of the first right V-groove17AR located furthest to the front in the right V-groove group17R, and the fourth guide surface GF4of the right rear guide wall12BR is formed as a continuous extension of the fourth right V-groove17DR located furthest to the rear in the right V-groove group17R.

In the following, an operation of setting the optical fiber group3in the V-groove group17will be described. Although the following description is directed to the operation of setting the left optical fiber group3L in the left V-groove group17L, it is similarly applied to the operation of setting the right optical fiber group3R in the right V-groove group17R.

In order to set the left optical fiber group3L in the left V-groove group17L, the operator places the left optical fiber group3L spread in the width direction of the left ribbon cable4L (i.e., X-axis direction) directly above the left V-groove group17L as illustrated inFIG.2B. Thereafter, the operator moves the left optical fiber group3L downward (toward the direction of the left V-groove group17L).

As the left optical fiber group3L is moved downward (toward the direction of the left V-groove group17L), the first left optical fiber3AL located furthest to the front (i.e., toward the X1 side) in the left optical fiber group3L comes into contact with the first guide surface GF1of the left front guide wall12FL, and the fourth left optical fiber3DL located furthest to the rear (i.e., toward the X2 side) in the left optical fiber group3L comes into contact with the second guide surface GF2of the left rear guide wall12BL.

The first left optical fiber3AL located furthest to the front among the four optical fibers constituting the left optical fiber group3L is guided by the first guide surface GF1of the left front guide wall12FL inclined toward the first left V-groove17AL, and is moved further rearward (in the X2 direction) as it moves further downward (in the Z2 direction), as indicated by the arrow AR1inFIG.2B. That is, the first guide surface GF1of the left front guide wall12FL enables the first left optical fiber3AL spread in the width direction (i.e., forward (in the X1 direction)) to move backward (in the X2 direction) so that the first left optical fiber3AL comes closer to the widthwise center of the left ribbon cable4L as the first left optical fiber3AL moves further downward (in the Z2 direction). In other words, the first guide surface GF1serves to make the first left optical fiber3AL curved in the width direction (i.e., forward (in the X1 direction)) straight again such that the longitudinal direction (i.e., axial direction) of the first left optical fiber3AL coincides with the direction of extension of the first left V-groove17AL.

Although the second left optical fiber3BL extends straight along the second left V-groove17BL in the example illustrated inFIG.2B, it may alternatively be spread in the width direction (i.e., forward (in the X1 direction)), that is, may be curved in the width direction (i.e., forward (in the X1 direction)) in the same manner as the first left optical fiber3AL.

In such a case, the second left optical fiber3BL is moved rearward by being pushed by the first left optical fiber3AL that is moved rearward by the left front guide wall12FL. As a result, the second left optical fiber3BL extends straight along the second left V-groove17BL.

Similarly, the fourth left optical fiber3DL located furthest to the rear among the four optical fibers constituting the left optical fiber group3L is guided by the second guide surface GF2of the left rear guide wall12BL inclined toward the fourth left V-groove17DL, and is moved further forward (in the X1 direction) as it moves further downward (in the Z2 direction) as indicated by the arrow AR2inFIG.2B. That is, the second guide surface GF2of the left rear guide wall12BL enables the fourth left optical fiber3DL spread in the width direction (i.e., rearward (in the X2 direction) to move forward (in the X1 direction) so that the fourth left optical fiber3DL comes closer to the widthwise center of the left ribbon cable4L as the fourth left optical fiber3DL moves further downward (in the Z2 direction). In other words, the second guide surface GF2serves to make the fourth left optical fiber3DL curved in the width direction (i.e., backward (in the X2 direction)) straight again such that the longitudinal direction (i.e., axial direction) of the fourth left optical fiber3DL coincides with the direction of extension of the fourth left V-groove17DL.

Although the third left optical fiber3CL extends straight along the third left V-groove17CL in the example illustrated inFIG.2B, it may alternatively be spread in the width direction (i.e., rearward (in the X2 direction)), that is, may be curved in the width direction (i.e., rearward (in the X2 direction)), similarly to the fourth left optical fiber3DL.

In such a case, the third left optical fiber3CL is moved forward by being pushed by the fourth left optical fiber3DL that is moved forward by the left rear guide wall12BL. As a result, the third left optical fiber3CL extends straight along the third left V-groove17CL.

Thereafter, as the left optical fiber group3L is moved downward to such an extent as to come into contact with the left V-groove group17L as illustrated inFIG.2C, the spread in the width direction is narrowed by the left rear guide wall12BL and the left front guide wall12FL. That is, the spread of the left optical fiber group3L in the width direction is narrowed such that the respective axial lines of the first left optical fiber3AL through the fourth left optical fiber3DL become parallel to each other. As a result, the first left optical fiber3AL is set in the first left V-groove17AL while the longitudinal direction thereof is parallel to the direction of extension of the first left V-groove17AL. The same applies to the second left optical fiber3BL through the fourth left optical fiber3DL.

In the following, movements of the pair of clamps21(i.e., the left clamp21L and the right clamp21R) will be described with reference toFIG.3.FIG.3is a cross-sectional view illustrating part of the fusion splicer1. To be more specific,FIG.3is a cross-sectional view taken along the line III-III inFIG.2Cas viewed from the X1 direction as indicated by arrows. The cross section inFIG.2Cincludes a cross section of the base member11.

The left clamp21L is configured to press the left optical fiber group3L set in the left V-groove group17L relatively against the left V-groove group17L. Similarly, the right clamp21R is configured to press the right optical fiber group3R installed in the right V-groove group17R relatively against the right V-groove group17R. In the illustrated example, the left clamp21L includes a left arm portion21La and a left pressing portion21Lb, and the right clamp21R includes a right arm portion21Ra and a right pressing portion21Rb. The left arm portion21La is disposed above the left V-groove group17L, and the right arm portion21Ra is disposed above the right V-groove group17R. Further, the left arm portion21La and the right arm portion21Ra are configured to be movable in the vertical direction. The left arm portion21La and the right arm portion21Ra may have, for example, a substantially rectangular parallelepiped exterior shape as illustrated inFIG.1. The left pressing portion21Lb may be attached to the lower end of the left arm portion21La, and the right pressing portion21Rb may be attached to the lower end of the right arm portion21Ra. In the illustrated example, the left pressing portion21Lb is movable in the vertical direction (i.e., Z direction) at the lower end of the left arm portion21La, and the right pressing portion21Rb is movable in the vertical direction (i.e., Z direction) at the lower end of the right arm portion21Ra. Although in the state illustrated inFIG.3the left pressing portion21Lb is situated apart from the left optical fiber group3L set in the left V-groove group17L, the left pressing portion21Lb may come into contact with the left optical fiber group3L and press the left optical fiber group3L toward the left V-groove group17L by downward movement of the left arm portion21La. The same applies to the right pressing portion21Rb.

In the illustrated example, further, the left clamp21L may be configured to have adjustable clamp pressure. The clamp force is a force that the left optical fiber group3L set in the left V-groove group17L receives from the left pressing portion21Lb of the left clamp21L. An elastic body such as a spring that urges the left pressing portion21Lb downward may be disposed between the left arm portion21La and the left pressing portion21Lb. In this case, the left clamp21L is capable of controlling clamp pressure by controlling the position of the left arm portion21La in the vertical direction. The same applies to the right clamp21R.

As illustrated inFIG.1, the left fiber holder31L is configured to hold the left optical fiber group3L, and the right fiber holder31R is configured to hold the right optical fiber group3R. To be specific, the left holder31L is configured to hold the left ribbon cable4L including the left optical fiber group3L, and the right fiber holder31R is configured to hold the right ribbon cable4R including the right optical fiber group3R. To be more specific, the left fiber holder31L includes a left fiber holder body31La having a recess (not shown) for housing the left ribbon cable4L, and includes a left lid31Lb attached to the left fiber holder body31La. Similarly, the right fiber holder31R includes a right fiber holder body31Ra having a recess (not shown) for housing the right ribbon cable4R, and includes a right lid31Rb attached to the right fiber holder body31Ra.

By closing the left lid31Lb while the left ribbon cable4L is housed in the left fiber holder body31La, the left ribbon cable4L is secured in the left fiber holder31L. The left fiber holder31L is movable in a direction along the axial direction of the secured left optical fiber group3L. That is, the left fiber holder31L is movable along the direction of extension of the left V-groove group17L (i.e., the Y-axis direction). When the left fiber holder31L holding the left optical fiber group3L moves, the secured left optical fiber group3L is allowed to move along the left V-groove group17L.

Similarly, by closing the right lid31Rb while the right ribbon cable4R is housed in the right fiber holder body31Ra, the right ribbon cable4R is secured in the right fiber holder31R. The right fiber holder31R is movable in a direction along the axial direction of the secured right optical fiber group3R. That is, the right fiber holder31R is movable along the direction of extension of the right V-groove group17R (Y-axis direction). When the right fiber holder31R holding the right optical fiber group3R moves, the secured right optical fiber group3R is allowed to move along the right V-groove group17R.

In the following, a control system for controlling the fusion splicer1will be described with reference toFIG.4.FIG.4is a block diagram illustrating the control system for controlling the fusion splicer1.

As illustrated inFIG.4, the fusion splicer1includes an imaging device51, a fusion device52, a clamp driving device53, a fiber holder driving device54, a display device55, and a control device60. In the present embodiment, the imaging device51, the fusion device52, the clamp driving device53, the fiber holder driving device54, and the display device55are controlled by the control device60.

The control device60is, for example, a computer including a CPU (central processing unit), a RAM (random access memory), a ROM (read only memory), a communication module, an external storage device, and the like.

The imaging device51is configured to include, for example, a pair of cameras (an X camera and a Y camera). The X camera and the Y camera are each arranged to be able to simultaneously image the end of the left optical fiber group3L set in the left V-groove group17L and the end of the right optical fiber group3R set in the right V-groove group17R. Further, the viewing direction of the X camera and the viewing direction of the Y camera are orthogonal to each other. The control device60is capable of specifying the position of the optical fiber group3based on the images of the optical fiber group3captured from two different directions by the pair of cameras.

The fusion device52is one which fusion-splices the end of the left optical fiber group3L and the end of the right optical fiber group3R. In the present embodiment, the pair of electrode rods5belongs to the fusion device52.

The clamp driving device53is one which presses the optical fiber group3relatively against the V-groove group17. In the present embodiment, the clamp driving device53includes actuators that vertically move the left arm portion21La belonging to the left clamp21L and the right arm portion21Ra belonging to the right clamp21R.

The fiber holder driving device54is one which moves the optical fiber group3in a direction along the axial direction thereof (i.e., Y-axis direction). In the present embodiment, the fiber holder driving device54includes an actuator that moves the left fiber holder31L in a direction along the axial direction (i.e., Y-axis direction) of the left optical fiber group3L and an actuator that moves the right fiber holder31R in a direction along the axial direction (i.e., Y-axis direction) of the right optical fiber group3R.

The display device55is one which displays various kinds of information. In the present embodiment, the display device55is configured to display images captured by the imaging device51. In the present embodiment, the display device55is a liquid crystal display.

The control device60is one which controls the imaging device51, the fusion device52, the clamp driving device53, the fiber holder driving device54, and the display device55. In the present embodiment, the control device60acquires images captured by the imaging device51by controlling the imaging device51. The control device60can cause, for example, the display device55to display the acquired image. In addition, the control device60may determine the state of one pair or a plurality of pairs of optical fibers by performing image processing on the acquired images. Further, the control device60may cause arc discharge to be generated between the rear electrode rod5B and the front electrode rod5F by controlling the fusion device52. Moreover, the control device60may cause the left arm portion21La of the left clamp21L and the right arm portion21Ra of the right clamp21R to be moved in the vertical direction by controlling the clamp driving device53. Under the control of the control device60, the left clamp21L may change the press state of the left optical fiber group3L disposed in the left V-groove group17L, and the right clamp21R may change the press state of the right optical fiber group3R disposed in the right V-groove group17R. Further, the control device60may control the positions of the left fiber holder31L and the right fiber holder31R in the Y-axis direction by controlling the fiber holder driving device54. To be more specific, the control device60may cause the left optical fiber group3L held by the left fiber holder31L to move in the right-left direction (i.e., Y-axis direction) by moving the left fiber holder31L in the right-left direction (i.e., Y-axis direction), and may cause the right optical fiber group3R held by the right fiber holder31R to move in the right-left direction (i.e., Y-axis direction) by moving the right fiber holder31R in the right-left direction (i.e., Y-axis direction).

In the following, the guide walls12will be described in detail with reference toFIG.5andFIG.6.FIG.5is a top axonometric view of the base member11having the V-groove group17in which the optical fibers of a 16-core ribbon cable may be set.FIG.6is a cross-sectional view taken along the line VI-VI inFIG.5and viewed from the Y2 direction as indicated by arrows. The cross section inFIG.5includes a cross section of the right base member11R having the 16 V-grooves (the first right V-groove17R1to the sixteenth right V-groove17R16) formed therein and cross sections of the bare fiber portions of the 16 optical fibers (the first right optical fiber3R1to the sixteenth right optical fiber3R16) belonging to the 16-core right ribbon cable4R.

In recent years, not only a 16-core ribbon cable as illustrated inFIG.5, but also a rollable ribbon cable (pliable ribbon cable) and an ultra-high-count ribbon cable having a larger number of optical fibers have been put into practical use. The characteristics of these ribbon cables include the fact that the bare fiber portions obtained by removing the coating material are more likely to be spread in the width direction (i.e., X-axis direction) than in a 4-core ribbon cable as illustrated inFIG.1. One of the causes in the case of the ultra-high-count ribbon cable is arguably the fact that the removal of the coating material causes the coating edge to be crushed thereby to slightly widen the intervals between the adjacent optical fibers. Further, one of the causes in the case of a rollable ribbon cable made by loosely connecting two or four optical fibers (optical fiber elements) in pairs in a mesh form is arguably the fact that setting the rollable ribbon cable in the fiber holder is likely to cause the optical fibers to be oriented in various directions, which results in the optical fibers being likely to point to sideways where no obstruction exists.

Because of this, also in the example illustrated inFIG.5andFIG.6, the bare fiber portions of the 16 optical fibers belonging to the 16-core ribbon cable are more likely to be spread in the width direction (i.e., X-axis direction) than the bare fiber portions of the 4 optical fibers belonging to the 4-core ribbon cable as illustrated inFIG.1.

When the bare fiber portions spread in the width direction are set in the V-groove group17engraved in the flat surface as illustrated inFIG.5andFIG.6, the orientations of the outermost cores of the ribbon cable would not be regulated in the configuration having no guide walls12. Here, the “orientations of the outermost cores of the ribbon cable” refer to the orientations of the bare fiber portions of the outermost optical fibers in the width direction among the plurality of optical fibers belonging to the ribbon cable. In the example illustrated inFIG.5andFIG.6, the orientations of the outermost cores of the right ribbon cable4R refer to the orientation of the first right optical fiber3R1and the orientation of the sixteenth right optical fiber3R16.

In the configuration including no guide walls12, the deviation between the orientations of the V-groove group17structured to be straight and the orientations of the outermost cores of the ribbon cable would become large, which would result in the optical fiber group3failing to be fit in the V-groove group17, and the optical fiber group3sliding out of the V-groove group17. Such a situation leads to failure and redoing of fusion splicing. Redoing the fusion splicing requires redoing the cutting of a ribbon cable, the removing of a coating material, and the like, thereby needing extra time. The guide walls12serve to reduce the occurrence of such a situation.

It may be noted that the following description given with reference toFIG.5andFIG.6is directed to the right guide walls12R that come in contact with the right optical fiber group3R, but equally applies to the left guide walls12L that come in contact with the left optical fiber group3L.

The bare fiber portions of the 16 optical fibers (i.e., the first right optical fiber3R1to the sixteenth right optical fiber3R16) belonging to the right ribbon cable4R are spread in the width direction (i.e., X-axis direction) when disposed above the right V-groove group17R as illustrated inFIG.5andFIG.6, that is, before coming into contact with the right guide walls12R.

It may be noted thatFIG.5andFIG.6illustrate a situation in which the first right optical fiber3R1to the sixteenth right optical fiber3R16are disposed higher than the height H1 of the right guide walls12R. The height H1 of the right guide walls12R refers to the distance in the Z-axis direction between the upper surface TF1of the right base member11R (i.e., the right optical fiber arrangement portion) and the upper surface TF2of the right guide walls12R.

InFIG.6, dotted arrows indicate the respective paths of movement of the right optical fiber group3R moved downward from the position at the height H1. Further, inFIG.6, the right optical fiber group3R that has been moved downward to the position at the height H2 is depicted in dash dot lines, and the right optical fiber group3R set in the right V-groove group17R is depicted in thick dotted lines. It may be noted that the height H2 is equal to the height of the upper surface TF1(seeFIG.5) of the right base member11R (right optical fiber arrangement portion).

As depicted in the dash dot line inFIG.6, the first right optical fiber3R1comes into contact with the third guide surface GF3of the right front guide wall12FR when moved downward to the position at the height H2. With further downward movement, the first right optical fiber3R1moves inward (i.e., in the X2 direction) along the third guide surface GF3, and is set in the first right V-groove17R1in the end as depicted in the thick dotted line inFIG.6. This is because the third guide surface GF3is structured to be inclined toward the right V-groove group17R when viewed from the right-hand side (from the X2 side) along the direction of extension of the right V-groove group17R (i.e., Y-axis direction). That is, this is because the third guide surface GF3is inclined such as to approach the right V-groove group17R, and is formed as a continuous extension of the first groove surface GS1of the first right V-groove17R1in the right side elevation view.

Similarly, the sixteenth right optical fiber3R16comes into contact with the fourth guide surface GF4of the right rear guide wall12BR when moved downward to the position at the height H2 as depicted in the dash dot line inFIG.6. With further downward movement, the sixteenth right optical fiber3R16moves inward (i.e., in the X1 direction) along the fourth guide surface GF4, and is set in the sixteenth right V-groove17R16in the end as depicted in the thick dotted line inFIG.6. This is because the fourth guide surface GF4is inclined such as to approach the right V-groove group17R in the right side elevation view, and is formed as a continuous extension of the sixteenth groove surface GS16of the sixteenth right V-groove17R16.

The second right optical fiber3R2when positioned below the height H2 moves inward (i.e., in the X2 direction) as indicated by the dotted arrow inFIG.6by being pushed by the first right optical fiber3R1moving inward (i.e., in the X2 direction) along the third guide surface GF3. The second right optical fiber3R2is set in the second right V-groove17R2in the end as depicted in the thick dotted line inFIG.6. The third right optical fiber3R3when positioned below the height H2 moves inward (i.e., in the X2 direction) as indicated by the dotted arrow inFIG.6by being pushed by the second right optical fiber3R2, which moves inward (i.e., in the X2 direction) by being pushed by the first right optical fiber3R1. The third right optical fiber3R3is set in the third right V-groove17R3in the end as depicted in the thick dotted line inFIG.6.

Similarly, the fifteenth right optical fiber3R15when positioned below the height H2 moves inward (i.e., in the X1 direction) as indicated by the dotted arrow inFIG.6by being pushed by the sixteenth right optical fiber3R16moving inward (i.e., in the X1 direction) along the fourth guide surface GF4. The fifteenth right optical fiber3R15is set in the fifteenth right V-groove17R15in the end as depicted in the thick dotted line inFIG.6. The fourteenth right optical fiber3R14when positioned below the height H2 moves inward (i.e., in the X1 direction) as indicated by the dotted arrow inFIG.6by being pushed by the fifteenth right optical fiber3R15, which moves inward (i.e., in the X1 direction) by being pushed by the sixteenth right optical fiber3R16. The fourteenth right optical fiber3R14is set in the fourteenth right V-groove17R14in the end as depicted in the thick dotted line inFIG.6.

In the example illustrated inFIG.5andFIG.6, the fourth right optical fiber3R4through the thirteenth right optical fiber3R13are not spread in the width direction even at the position at the height H1. Therefore, the fourth right optical fiber3R4through the thirteenth right optical fiber3R13are each moved downward without coming into contact with an adjacent optical fiber, followed by being set in the fourth right V-groove17R4through the thirteenth right V-groove17R13, respectively, as indicated by the dotted arrows inFIG.6.

With this configuration, even when the bare fiber portions of the right optical fiber group3R (i.e., the first right optical fiber3R1through the sixteenth right optical fiber3R16) are spread in the width direction (i.e., the X-axis direction), the worker can place the bare fiber portions in the right V-groove group17R without letting them slide out of the right V-groove group17R.

Further, in the example illustrated inFIG.5andFIG.6, the right guide walls12R are configured such that their height H1 is significantly greater than the depth of the right V-groove group17R. The depth of the right V-groove group17R refers to the distance in the Z-axis direction between the upper surface TF1of the right base member11R (i.e., the right optical fiber arrangement portion) and the bottom of the right V-groove group17R. The right guide walls12R are further configured such that the inclination angle of the third guide surface GF3is the same as the inclination angle of the first groove surface GS1, and the inclination angle of the fourth guide surface GF4is the same as the inclination angle of the sixteenth groove surface GS16. The depth of the right V-groove group17R and the inclination angles of the groove surfaces are suitably determined such that when the bare fiber portions of the right optical fiber group3R are set in the V-grooves, the bare fiber portions protrude above the upper surface TF1of the right base member11R.

However, the height H1 of the right guide walls12R and the inclination angles of their guide surfaces GF may be set to any values as long as the right guide walls12R are configured to cause the spread of the bare fiber portions to converge when the right optical fiber group3R spread in the width direction (i.e., the X-axis direction) is moved vertically downward. That is, the height H1 of the right guide walls12R and the inclination angles of the guide surfaces GF thereof may be set to any values as long as the right guide walls12R are configured to cause the bare fiber portions to extend straight. For example, the height H1 of the right guide walls12R may be substantially the same as (slightly greater than) the depth of the right V-groove group17R. Further, the inclination angles of the guide surfaces GF are about 25 degrees in the illustrated example, but may be set to a larger or smaller value.

In the illustrated example, further, the right guide walls12R are configured such that the distance between the right front guide wall12FR and the right rear guide wall12BR at the same level (height) as the upper surface TF1of the right base member11R is the same as the width of the right V-groove group17R. In addition to this arrangement, the right guide walls12R are configured to have the distance therebetween increasing upward. Alternatively, the right guide walls12R may be configured such that the distance between the right front guide wall12FR and the right rear guide wall12BR at the same level (height) as the upper surface TF1of the right base member11R is greater than the width of the right V-groove group17R.

In the illustrated example, moreover, the guide surfaces GF are flat surfaces, and are configured such that the direction normal thereto is perpendicular to the direction of extension of the right V-groove group17R (i.e., the Y-axis direction) in a top view. Alternatively, the guide surfaces GF may be configured such that the direction normal thereto obliquely crosses the direction of extension of the right V-groove group17R (i.e., the Y-axis direction) in a top view.

In the following, another example of the configuration of the guide walls12will be described with reference toFIG.7throughFIG.9.FIG.7throughFIG.9are partial cross-sectional views of the right base member11R including the right V-groove group17R, and correspond toFIG.6. The following description given with reference toFIG.7throughFIG.9relates to the right guide walls12R functioning together with the right V-groove group17R, but similarly applies to the left guide walls12L functioning together with the left guide walls12L (not visible inFIG.7throughFIG.9) functioning together with the left V-groove group17L.

The right guide walls12R illustrated inFIG.7differ from the right guide walls12R illustrated inFIG.6in that the third guide surface GF3and the fourth guide surface GF4each include a vertical face (i.e., middle vertical surface VS), but is the same as the right guide walls12R illustrated inFIG.6in other aspects. In the following be description, thus, different aspects will described in detail while omitting a description of the common aspects.

In the example illustrated inFIG.7, the third guide surface GF3of the right front guide wall12FR includes an upper inclined surface US, the middle vertical surface VS, and a lower inclined surface LS. Both the upper inclined surface US and the lower inclined surface LS are structured to be inclined toward the right V-groove group17R. The same applies to the fourth guide surface GF4of the right rear guide wall12BR.

In the third guide surface GF3, the inclination angle of the upper inclined surface US and the inclination angle of the lower inclined surface LS are the same. Alternatively, the inclination angle of the upper inclined surface US and the inclination angle of the lower inclined surface LS may differ from each other. In this specification, the inclination angle of the upper inclined surface US refers to an angle formed between the upper inclined surface US and a vertical plane. The same applies to the inclination angle of the lower inclined surface LS.

An increase in the inclination angles of the upper inclined surface US and the lower inclined surface LS serves to increase the distance of inward movement (toward the X2 direction) of the first right optical fiber3R1caused by the downward movement of the right optical fiber group3R. This yields the result that the deviation of the first right optical fiber3R1in the width direction quickly converges.

Conversely, a decrease in the inclination angles of the upper inclined surface US and the lower inclined surface LS serves to decrease the distance of inward movement (toward the X2 direction) of the first right optical fiber3R1caused by the downward movement of the right optical fiber group3R. This achieves the result that the spread of the right optical fiber group3R in the width direction gradually converges.

Accordingly, the inclination angles of both the upper inclined surface US and the lower inclined surface LS are suitably set according to the circumstances or the like in which of the fusion splicer1is used.

In the example illustrated inFIG.7, the fourth guide surface GF4of the right rear guide wall12BR includes an upper inclined surface US, the middle vertical surface VS, and a lower inclined surface LS, like the third guide surface GF3of the right front guide wall12FR. Both the upper inclined surface US and the lower inclined surface LS are structured to be inclined toward the right V-groove group17R. In the fourth guide surface GF4, unlike the third guide surface GF3, the upper inclined surface US is structured such that the inclination angle thereof is greater than the inclination angle of the lower inclined surface LS. Alternatively, the upper inclined surface US may be structured such that the inclination angle thereof is smaller than the inclination angle of the lower inclined surface LS, or may be structured such that the inclination angle thereof is the same as the inclination angle of the lower inclined surface LS.

In the example illustrated inFIG.7, the right guide walls12R are structured such that the shape of the third guide surface GF3of the right front guide wall12FR and the shape of the fourth guide surface GF4of the right rear guide wall12BR are asymmetric with respect to the YZ plane. Alternatively, t guide walls12R may be structured such that the shape of the third guide surface GF3of the right front guide wall12FR and the shape of the fourth guide surface GF4of the right rear guide wall12BR are symmetrical with respect to the YZ plane, similarly to the example illustrated inFIG.6.

The right guide walls12R illustrated inFIG.8differ from the right guide walls12R illustrated inFIG.7in that the third guide surface GF3and the fourth guide surface GF4each include a curved surface (i.e., upper curved surface WS) and a horizontal surface (i.e., lower horizontal surface HS), but are the same as the right guide walls12R illustrated inFIG.7in other aspects. In the following description, different aspects will be described in detail while omitting a description of the common aspects.

In the example illustrated inFIG.8, the third guide surface GF3of the right front guide wall12FR includes the upper curved surface WS, a middle vertical surface VS, and the lower horizontal surface HS. The upper curved surface WS is structured to be inclined toward the right V-groove group17R. The same applies to the fourth guide surface GF4of the right rear guide wall12BR. The right guide walls12R are structured such that the shape of the third guide surface GF3of the right front guide wall12FR and the shape of the fourth guide surface GF4of the right rear guide wall12BR are symmetrical with respect to the YZ plane. Alternatively, the right guide walls12R may be structured such that the shape of the third guide surface GF3of the right front guide wall12FR and the shape of the fourth guide surface GF4of the right rear guide wall12BR are asymmetric with respect to the YZ plane.

The upper curved surface WS is structured such that the inclination angle gradually decreases, but may include a portion in which the inclination angle gradually increases.

The configuration of the third guide surface GF3including the lower horizontal surface HS is intended to clearly indicate that the vertical surface or the inclined surface belonging to the third guide surface GF3and the first groove surface GS1of the first right V-groove17R1may not be continuous with each other.

In this case, the lower horizontal surface HS is structured such that the length (i.e., span) thereof in the width direction (i.e., X-axis direction) is smaller than the diameter of the first right optical fiber3R1. This is to prevent the first right optical fiber3R1from remaining on the lower horizontal surface HS when the right optical fiber group3R is set in the right V-groove group17R. Preferably, the lower horizontal surface HS is structured such that the length (i.e., span) thereof in the width direction (i.e., X-axis direction) is smaller than the radius of the first right optical fiber3R1. It may be noted that either the middle vertical surface VS, the lower horizontal surface HS, or both may be omitted. That is, the third guide surface GF3may be constituted only by the upper curved surface WS, constituted by the combination of the upper curved surface WS and the middle vertical surface VS, or constituted by the combination of the upper curved surface WS and the lower horizontal surface HS.

The right guide walls12R illustrated inFIG.9differ from the right guide walls12R illustrated inFIG.6in that the third guide surface GF3and the fourth guide surface GF4each include a plurality of inclined surfaces, but are the same as the right guide walls12R illustrated inFIG.6in other aspects. In the following description, thus, different aspects will be described in detail while omitting a description of the common aspects.

In the example illustrated inFIG.9, the third guide surface GF3of the right front guide wall12FR includes an upper inclined surface US, a middle inclined surface MS, and a lower inclined surface LS. The upper inclined surface US, the middle inclined surface MS, and the lower inclined surface LS are each structured to be inclined toward the right V-groove group17R. The same applies to the fourth guide surface GF4of the right rear guide wall12BR. The right guide walls12R are structured such that the shape of the third guide surface GF3of the right front guide wall12FR and the shape of the fourth guide surface GF4of the right rear guide wall12BR are symmetrical with respect to the YZ plane. Alternatively, the right guide walls12R may be structured such that the shape of the third guide surface GF3of the right front guide wall12FR and the shape of the fourth guide surface GF4of the right rear guide wall12BR are asymmetric with respect to the YZ plane.

In the third guide surface GF3, the upper inclined surface US is structured such that the inclination angle thereof is greater than the inclination angle of the middle inclined surface MS, and the middle inclined surface MS is structured such that the inclination angle thereof is greater than the inclination angle of the lower inclined surface LS. Alternatively, the inclination angles of the upper inclined surface US, the middle inclined surface MS, and the lower inclined surface LS may be set to have any relative magnitude. For example, the upper inclined surface US may be structured such that the inclination angle thereof is smaller than the inclination angle of the middle inclined surface MS, and the middle inclined surface MS may be structured such that the inclination angle thereof is smaller than the inclination angle of the lower inclined surface LS.

In the following, still another example of the configuration of the guide walls12will be described with reference toFIG.10AthroughFIG.10I.FIG.10AthroughFIG.10Iare top views of the right base member11R including the right V-groove group17R. The following description referring toFIG.10AthroughFIG.10Iis directed to the right guide walls12R that function together with the right V-groove group17R. The same also applies to the left guide walls12L that function together with the left guide walls12L (not visible inFIG.10AthroughFIG.10I) functioning together with the left V-groove group17L.

The right guide walls12R illustrated inFIG.10Adiffer from the right guide walls12R illustrated inFIG.5, which are disposed at the right end (i.e., the end toward the Y2 direction) of the right base member11R in the right-left direction (i.e., the Y-axis direction), in that right guide walls are disposed at the center of the right base member11R in the right-left direction (i.e., the Y-axis direction).

The right guide walls12R illustrated inFIG.10Bdiffer from the right guide walls12R illustrated inFIG.5, which are disposed at the right end (i.e., the end toward the Y2 direction) of the right base member11R in the right-left direction (i.e., Y-axis direction), in that right guide walls are disposed at the left end (i.e., the end toward the Y1 direction) of the right base member11R in the right-left direction (Y-axis direction).

The right guide walls12R illustrated inFIG.10Cdiffer from the right guide walls12R illustrated inFIG.5, which are disposed only at the right end (i.e., the end toward the Y2 direction) of the right base member11R in the right-left direction (i.e., Y-axis direction), in that right guide walls are disposed at both the left end and the right end of the right base member11R in the right-left direction (i.e., Y-axis direction).

Further, the right guide walls12R illustrated inFIG.10Cdiffer from the right guide walls12R illustrated inFIG.5, which are constituted by two parts (i.e., the right front guide wall12FR and the right rear guide wall12BR), in that right guide walls are constituted by four parts (i.e., the first right front guide wall12FR1, the second right front guide wall12FR2, the first right rear guide wall12BR1, and the second right rear guide wall12BR2).

In the example illustrated inFIG.10C, the right guide walls12R may be configured such that the inclination angle of the guide surface of the first right front guide wall12FR1and the first right rear guide wall12BR1differs from the inclination angle of the guide surface of the second right front guide wall12FR2and the second right rear guide wall12BR2. This is because the degree of spread in the width direction of the bare fiber portions at the left end (i.e., end towards Y1 direction) of the right base member11R is larger than the degree of spread in the width direction of the bare fiber portions at the right end (i.e., the end toward Y2 direction) of the right base member11R. For the same reason, the right guide walls12R may be configured such that the distance between the guide surface of the first right front guide wall12FR1and the guide surface of the first right rear guide wall12BR1is smaller than the distance between the guide surface of the second right front guide wall12FR2and the guide surface of the second right rear guide wall12BR2at the same height.

The right guide walls12R illustrated inFIG.10Ddiffer from the right guide walls12R illustrated inFIG.5, which have both the right front guide wall12FR and right rear guide wall12BR disposed at the right end (i.e., the end toward the Y2 direction) of the right base member11R in the right-left direction (i.e., Y-axis direction), in that the right front guide wall12FR is disposed at the left end of the right base member11R and the right rear guide wall12BR is disposed at the center of the right base member11R in the right-left direction (i.e., Y-axis direction).

The right guide walls12R illustrated inFIG.10Ddiffer from the right guide walls12R ofFIG.5, which have the right front guide wall12FR and the right rear guide wall12BR facing each other in the front-rear direction (i.e., X-axis direction), in that the right front guide wall12FR and the right rear guide wall12BR do not face each other in the front-rear direction (i.e., X-axis direction).

In the example illustrated inFIG.10AtoFIG.10D, the right guide walls12R are configured such that the thickness thereof (i.e., length in the Y-axis direction) is significantly smaller than the entire length (i.e., length in the Y-axis direction) of the right V-groove group17R. Alternatively, the right guide walls12R may be configured to have any thickness. For example, the thickness of the right guide walls12R may be configured to be the same as the entire length of the right V-groove group17R, or may be configured to be about one half or one third of the entire length of the right V-groove group17R.

The right guide walls12R illustrated inFIG.10EandFIG.10Fdiffer from the right guide walls12R illustrated inFIG.5, which are disposed alongside the right V-groove group17R in the front-rear direction (i.e., X-axis direction), in that the right guide walls are not alongside the right V-groove group17R in the front-rear direction (i.e., X-axis direction).

To be more specific, the right guide walls12R illustrated inFIG.10Ediffer from the right guide walls12R illustrated inFIG.5, which are disposed alongside the right V-groove group17R in the front-rear direction (i.e., X-axis direction), in that the right guide walls are disposed to protrude rightward (i.e., in the Y2 direction) from the right end of the right base member11R.

Moreover, the right guide walls12R illustrated inFIG.10Fdiffer from the right guide walls12R illustrated inFIG.5, which are disposed alongside the right V-groove group17R in the front-rear direction (i.e., X-axis direction), in that the right guide walls are disposed to protrude leftward (i.e., in the Y1 direction) from the left end of the right base member11R.

As described above, the right guide walls12R do not have to be structured to be alongside the right V-groove group17R in the front-rear direction (i.e., X-axis direction), and may be disposed to protrude leftward (i.e., in the Y1 direction) from the left end of the right base member11R or rightward (i.e., in the Y2 direction) from the right end of the right base member11R.

The right guide walls12R illustrated inFIG.10GandFIG.10Hdiffer from the right guide walls12R illustrated inFIG.5, which are formed as part of the right base member11R, in that the right guide walls are formed as a member separate from the right base member11R.

To be more specific, the right guide walls12R illustrated inFIG.10Gdiffer from the right guide walls12R illustrated inFIG.5, which are integrally formed as part of the right base member11R, in that the right guide walls are disposed apart, to the right (i.e., in the Y2 direction), from the right end of the right base member11R.

Moreover, the right guide walls12R illustrated in theFIG.10Hdiffer from the right guide walls12R illustrated inFIG.5, which are integrally formed as part of the right base member11R, in that the right guide walls are disposed apart, to the right (i.e., in the Y1 direction), from the left end of the right base member11R.

As described above, the right guide walls12R may be disposed apart from the right base member11R. Further, the right guide walls12R may be formed of a material different from that of the right base member11R.

In the example illustrated inFIG.10G, the right base member11R is formed of a heat-resistant ceramic such as zirconia. This is because of exposure to high temperature due to arc discharge generated by the electrode rod5. On the other hand, the right guide walls12R are formed of a metal such as stainless steel because the right guide walls are positioned not to be exposed to high temperature caused by the arc discharge and also positioned not to affect the arc discharge electromagnetically. The right guide walls12R may be formed of a synthetic resinous material.

The right guide walls12R illustrated inFIG.10Idiffer from the right guide walls12R ofFIG.10E, which are structured to be immovable in the front-rear direction (i.e., X-axis direction), in that the right guide walls are structured to be movable in the front-rear direction (i.e., X-axis direction).

FIG.10Iillustrates the right guide walls12R in the state in which the distance between the right front guide wall12FR and the right rear guide wall12BR is minimum. Figures depicted in the dotted lines inFIG.10Iillustrate the right guide walls12R in the state in which the distance between the right front guide wall12FR and the right rear guide wall12BR is maximum. The double-headed arrows inFIG.10Iindicate the directions of respective movement of the right front guide wall12FR and the right rear guide wall12BR.

This configuration is suitably used when fusion splicing is performed by using less than 16 (for example, 4, 8, or 12) V-grooves among the 16 V-grooves with respect to a ribbon cable having a smaller number of fibers (e.g., a ribbon cable having 4 fibers, 8 fibers, or 12 fibers) than the 16-core ribbon cable.

To be specific, when performing fusion splicing of a 4-core ribbon cable, the operator moves the right front guide wall12FR and the right rear guide wall12BR such that the distance between the right front guide wall12FR and the right rear guide wall12BR becomes equal to the width of 4 V-grooves. To be more specific, the operator moves the right front guide wall12FR rearward (i.e., in the X2 direction) and moves the right rear guide wall12BR forward (i.e., in the X1 direction). The right guide walls12R depicted in solid lines inFIG.10Iare in a state suitable for fusion splicing of a 4-core ribbon cable.

When performing fusion splicing of a 16-core ribbon cable, the operator moves the right front guide wall12FR and the right rear guide wall12BR such that the distance between the right front guide wall12FR and the right rear guide wall12BR is equal to the width of 16 V-grooves. To be more specific, the operator moves the right front guide wall12FR forward (i.e., in the X1 direction) and moves the right rear guide wall12BR rearward (i.e., in the X2 direction). The right guide walls12R depicted in the dotted lines inFIG.10Iare in a state suitable for fusion splicing of a 16-core ribbon cable.

In the example illustrated inFIG.10I, the right guide walls12R are configured such that both the right front guide wall12FR and the right rear guide wall12BR are movable in the front-rear direction (i.e., X-axis direction). Alternatively, the right guide walls12R may be configured such that either the right front guide wall12FR or the right rear guide wall12BR is movable in the front-rear direction (i.e., X-axis direction). The right guide walls12R movable in the front-rear direction as illustrated inFIG.10Imay be applied to the configurations illustrated inFIG.5toFIG.9andFIG.10AtoFIG.10H.

As described above, the fusion splicer1according to the embodiment of the present disclosure is configured such that the optical fibers (i.e., the first right optical fiber3AR through the fourth right optical fiber3DR) arranged in side by side along the direction (i.e., X-axis direction) intersecting the longitudinal direction (i.e., Y-axis direction) are fusion-spliced to the respective other optical fibers (i.e., the first left optical fiber3AL through the fourth left optical fibers3DL), as illustrated inFIG.1andFIG.2AtoFIG.2C. To be specific, the fusion splicer1includes the right base member11R with a groove portion (i.e., the right V-groove group17R) having V-grooves (i.e., the first right V-groove17AR through the fourth right V-groove17DR) formed therein for setting optical fibers (i.e., the first right optical fiber3AR through the fourth right optical fiber3DR), and includes a pair of guide walls (i.e., the right front guide wall12FR and the right rear guide wall12BR) for guiding the setting of the optical fibers (i.e., the first right optical fiber3AR through the fourth right optical fiber3DR) into the V-grooves (i.e., the first right V-groove17AR through the fourth right V-groove17DR). The pair of guide walls (i.e., the right front guide wall12FR and the right rear guide wall12BR) are disposed at an interval in the width direction (i.e., X-axis direction) of the right V-groove group17R. The right front guide wall12FR has the third guide surface GF3which comes into contact with the first right optical fiber3AR, which is one of the optical fibers (i.e., the first right optical fiber3AR through the fourth right optical fiber3DR), and the right rear guide wall12BR has the fourth guide surface GF4which comes into contact with the fourth right optical fiber3DR, which is another one of the optical fibers (i.e., the first right optical fiber3AR through the fourth right optical fiber3DR). The third guide surface GF3and the fourth guide surface GF4each include a portion inclined toward the right V-groove group17R when viewed along the direction of extension (i.e., Y-axis direction) of the V-grooves (i.e., the first right V-groove17AR through the fourth right V-groove17DR), that is, in the right side elevation view.

The optical fibers fusion-spliced by the fusion splicer1are the bare fiber portions of the four optical fibers belonging to the 4-core ribbon cable in the example illustrated inFIG.1andFIG.2AtoFIG.2C, but may alternatively be the bare fiber portions of optical fibers belonging to a rollable ribbon cable. The number of optical fibers of a ribbon cable may be 8 fibers, 12 fibers, 16 fibers, 24 fibers, or the like. In the example illustrated inFIG.5andFIG.6, the number of optical fibers of the ribbon cable is 16.

In this configuration, the guide walls12push back, inward in the width direction, the bare fiber portions of the optical fiber group3that have been spread outward in the width direction (i.e., X-axis direction) as illustrated inFIG.2B, thereby realizing a correct state in which the bare fiber portions extend straight as illustrated inFIG.2C. This configuration thus serves to prevent the bare fiber portions from sliding out of the V-grooves.

Further, when viewed along the direction of extension (i.e., Y-axis direction) of the V-grooves (i.e., the first right V-groove17R1through the sixteenth right V-groove17R16) as illustrated inFIG.6, namely, in the right side elevation view as illustrated inFIG.6, the guide surfaces GF may each be disposed as a continuous extension of one of the groove surfaces of the V-grooves. To be more specific, as illustrated inFIG.6, the third guide surface GF3may be disposed as a continuous extension of the first groove surface GS1of the first right V-groove17R1, and the fourth guide surface GF4may be disposed as a continuous extension of the sixteenth groove surface GS16of the sixteenth right V-groove17R16.

In the above-noted configuration in which the third guide surface GF3and the first groove surface GS1are continuous with each other, the right front guide wall12FR is able to guide the first right optical fiber3R1into the first right V-groove17R1without disturbing the movement of the first right optical fiber3R1moving along the third guide surface GF3. This configuration can thus further reduce the likelihood of the bare fiber portion sliding out of the V-groove.

The pair of guide walls may be formed as members separate from the base member11, or may be integrated with the base member11. For example, the right front guide wall12FR and the right rear guide wall12BR, which are a pair of guide walls, may be integrated with the right base member11R as illustrated inFIG.10AthroughFIG.10F, or may be formed as a member separate from the right base member11R as illustrated inFIG.10GthroughFIG.10I.

Further, at least one of guide walls constituting the pair may be configured to be movable relative to the groove portion such that the size of the gap in the width direction of the groove portion is adjustable. For example, the right front guide wall12FR and the right rear guide wall12BR, which are a pair of guide walls, may be configured to be movable in the X-axis direction relative to the right V-groove group17R such that the size of the interval in the width direction (i.e., X-axis direction) of the right V-groove group17R is adjustable as illustrated inFIG.10I.

As illustrated inFIG.1andFIG.2AthroughFIG.2C, the method of splicing optical fibers according to the embodiment of the present disclosure is an optical fiber splicing method by which optical fibers (i.e., the first right optical fiber3AR through the fourth right optical fiber3DR) are fusion-spliced to respective other optical fibers (i.e., the first left optical fiber3AL through the fourth left optical fiber3DL) by using the fusion splicer1, which includes the right base member11R with a groove portion (i.e., the right V-groove group17R) having V-grooves (i.e., the first right V-groove17AR through the fourth right V-groove17DR) formed therein for setting optical fibers (i.e., the first right optical fiber3AR through the fourth right optical fiber3DR), and includes a pair of guide walls (i.e., the right front guide wall12FR and the right rear guide wall12BR) for guiding the setting of the optical fibers (i.e., the first right optical fiber3AR through the fourth right optical fiber3DR) to the V-grooves (i.e., the first right V-groove17AR through the fourth right V-groove17DR).

This splicing method includes a step of placing a plurality of optical fibers in a plurality of V-grooves while bringing one of the plurality of optical fibers into contact with one guide surface of a pair of the guide walls disposed at an interval in the width direction of a groove portion, and a step of fusion-splicing the optical fibers to respective other optical fibers.

To be more specific, as illustrated inFIGS.2A through2C, the splicing method includes a step of placing a plurality of optical fibers (i.e., the first right optical fiber3AR through the fourth right optical fiber3DR) in a plurality of V-grooves (i.e., the first right V-groove17AR through the fourth right V-groove17DR) while bringing the first right optical fiber3AR into contact with the third guide surface GF3of the right front guide wall12FR, or bringing the fourth right optical fiber3DR into contact with the fourth guide surface GF4of the right rear guide wall12BR, and a step of fusion-splicing the optical fibers (i.e., the first right optical fiber3AR through the fourth right optical fiber3DR) to respective other optical fibers (i.e., first left optical fiber3AL through the fourth left optical fiber3DL).

By this method, the bare fiber portions of the optical fiber group3(i.e., the left optical fiber group3L or the right optical fiber group3R) spread outward in the width direction (i.e., X-axis direction) as illustrated inFIG.2Bare push back inward in the width direction to cause a correct state in which the bare fiber portions extend straight as illustrated inFIG.2C, followed by fusion-splicing the left optical fiber group3L and the right optical fiber group3R. This method can thus reduce the likelihood of the bare fiber portions sliding out of the V-grooves, and can thereby reduce the likelihood of a failure or redoing of fusion splicing.

Preferred embodiments of present the disclosure have heretofore been described in detail. The disclosed embodiments are, however, to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the appended claims rather than by the foregoing description, and is intended to include all modifications within the scope and meaning equivalent to the appended claims. That is, the present invention is not limited to the above-described embodiments. Various modifications, substitutions, and the like may be made to the above-described embodiments without departing from the scope of the present invention. In addition, each of the features described with reference to the embodiments described above may suitably be combined as long as there is no technical contradiction.

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