Fusion splicing method for optical fibers and fusion splicing device for optical fibers

Abstract

In this fusion splicing method for optical fibers, a first optical fiber (3a) and a second optical fiber (3b) arranged along a first direction are positioned in a V-groove (17a), and the first optical fiber (3a) is fusion-spliced to the second optical fiber (3b). The fusion splicing method comprises: a step in which the second optical fiber (3b) placed in the V-groove (17a) is moved in a first direction, and the first optical fiber (3a) placed in a V-groove (16a) is moved in a first direction; a step in which the first optical fiber (3a) is moved in a second direction opposite to the first direction, and the second optical fiber (3b) is moved in the second direction; and a step in which the first optical fiber (3a) and the second optical fiber (3b) are pressed relative to the V-grooves (16a, 17a) by clamps (21, 22).

Description

Optical fiber fusion splicing method and optical fiber fusion splicing device

[0001] The present disclosure relates to a method and an apparatus for fusion splicing optical fibers. This application claims priority to Japanese Patent Application No. 2023-113691 filed on July 11, 2023, and incorporates by reference the entire contents of said Japanese application.

[0002] Patent Document 1 describes a method for fusion splicing optical fibers. This fusion splicing method positions an optical fiber to be spliced ​​in a V-groove and performs fusion splicing. This fusion splicing method includes the steps of pressing the optical fiber placed in the V-groove relatively toward the V-groove with a clamp, changing the clamp pressure of the clamp pressing the optical fiber, and moving the optical fiber placed in the V-groove relatively to the V-groove along the axial direction.

[0003] International Publication No. 2020 / 162044

[0004] An optical fiber fusion splicing method according to the present disclosure is a method for positioning a first optical fiber and a second optical fiber aligned along a first direction in a V-groove and fusion splicing the first optical fiber to the second optical fiber, the method comprising the steps of: moving the second optical fiber placed in the V-groove in a first direction and moving the first optical fiber placed in the V-groove in the first direction; moving the first optical fiber in a second direction opposite the first direction and moving the second optical fiber in the first direction; and pressing the first optical fiber and the second optical fiber relatively toward the V-groove using a clamp.

[0005] FIG. 1 is a perspective view showing a portion of a fusion splicing device according to an embodiment. FIG. 2 is a cross-sectional view schematically showing a portion of the fusion splicing device. FIG. 3 is a block diagram showing a control system of the fusion splicing device. FIG. 4 is a flowchart showing an example of the operation of the fusion splicing device. FIG. 5 is a diagram schematically showing a state in which a foreign object is present in a V-groove of the fusion splicing device. FIG. 6 is a diagram schematically showing an example of an image acquired by an imaging device of the fusion splicing device. FIG. 7 is a diagram schematically showing an example of an image acquired by an imaging device of the fusion splicing device. FIG. 8 is a flowchart showing an example of a removal operation performed by the fusion splicing device. FIG. 9 is a diagram for explaining the movement of a first optical fiber and a second optical fiber during the removal operation performed by the fusion splicing device. FIG. 10 is a flowchart showing an example of a change in clamp pressure during the removal operation performed by the fusion splicing device. FIG. 11 is a flowchart showing a modified example of the removal operation performed by the fusion splicing device.

[0006] [Problem to be Solved by the Present Disclosure] In a fusion splicing device, cleaning the optical fibers and the V-groove before performing fusion splicing can enable highly accurate splicing. However, if foreign matter such as dust remaining in the V-groove during the process of cleaning the optical fibers or the like adheres to the V-groove, it may be impossible to align the end faces of a pair of optical fibers perpendicularly. In this case, it may be impossible to perform a highly accurate splice. A method is known in which the optical fibers placed in the V-groove are moved relative to each other to remove dust and the like from the V-groove. In this field, there is a demand for more efficient and reliable removal of foreign matter from the V-groove.

[0007] An object of the present disclosure is to provide an optical fiber fusion splicing method and optical fiber fusion splicing device that can more efficiently and reliably remove foreign matter from a V-groove.

[0008] [Description of Embodiments of the Present Disclosure] First, embodiments of an optical fiber fusion splicing method and an optical fiber fusion splicing device according to the present disclosure will be listed and described. (1) An optical fiber fusion splicing method according to one embodiment is an optical fiber fusion splicing method in which a first optical fiber and a second optical fiber aligned along a first direction are positioned in a V-groove and the first optical fiber is fusion spliced ​​to the second optical fiber. The optical fiber fusion splicing method includes the steps of: moving the second optical fiber placed in the V-groove in a first direction and moving the first optical fiber placed in the V-groove in the first direction; moving the first optical fiber in a second direction opposite the first direction and moving the second optical fiber in the second direction; and pressing the first optical fiber and the second optical fiber relatively toward the V-groove using a clamp.

[0009] (6) According to one embodiment, an optical fiber fusion splicing device includes a pair of V-grooves in which a first optical fiber and a second optical fiber aligned along a first direction are placed, and a pair of clamps that relatively press the first optical fiber and the second optical fiber placed in each V-groove against each V-groove. The fusion splicing device includes a movement mechanism that moves the second optical fiber placed in the V-groove in the first direction, moves the first optical fiber placed in the V-groove in the first direction, and moves the first optical fiber in a second direction opposite the first direction, and moves the second optical fiber in the second direction.

[0010] In the above-described fusion splicing method and fusion splicing device, the second optical fiber placed in the V-groove is moved in a first direction, and the first optical fiber placed in the V-groove is moved in the first direction. Then, the first optical fiber is moved in a second direction opposite to the first direction, and the second optical fiber is moved in the second direction. By moving the first optical fiber and the second optical fiber in the same direction, either the first direction or the second direction, even if a foreign object is present in at least one of the V-groove in which the first optical fiber is placed or the V-groove in which the second optical fiber is placed, the foreign object can be reliably removed. By moving both the first optical fiber and the second optical fiber in the same direction, the foreign object can be efficiently removed.

[0011] (2) In the above (1), the method may include the steps of simultaneously moving the first optical fiber and the second optical fiber in a first direction and simultaneously moving the first optical fiber and the second optical fiber in a second direction. By simultaneously moving the first optical fiber and the second optical fiber in the same direction, the foreign matter can be efficiently removed.

[0012] (3) In the above (1) or (2), a step of changing the clamping pressure of the clamp pressing the first optical fiber and the clamp pressing the second optical fiber may be included. In this case, the direction of the force applied to the first optical fiber and the second optical fiber by changing the clamping pressure differs from the movement of the first optical fiber and the second optical fiber. Since forces are also applied to the foreign matter from multiple directions, the foreign matter can be moved (removed) more effectively.

[0013] (4) In the above (3), the changing step may include a step of increasing the clamping pressure of the clamp pressing the first optical fiber and the clamp pressing the second optical fiber, and a step of decreasing the clamping pressure of the clamp pressing the first optical fiber and the clamp pressing the second optical fiber. In this case, by increasing or decreasing the clamping pressure on the first optical fiber and the second optical fiber, foreign matter in the V-groove can be more effectively moved (removed).

[0014] (5) In the above (3) or (4), the step of moving in the first direction and / or the step of moving in the second direction may be performed simultaneously with the step of changing. In this case, two forces acting in different directions can be applied to the foreign matter simultaneously or successively, thereby more effectively moving (removing) the foreign matter.

[0015] [Details of the Embodiments of the Present Disclosure] Specific examples of an optical fiber fusion splicing method and an optical fiber fusion splicing device according to embodiments will be described in detail below with reference to the drawings. Note that the present disclosure is not limited to these examples, but is intended to include all modifications set forth in the claims and within the meaning and scope equivalent to the claims. In the description of the drawings, identical or corresponding elements are designated by the same reference numerals, and redundant description will be omitted as appropriate. For ease of understanding, some of the drawings may be simplified or exaggerated, and dimensional ratios and the like are not limited to those shown in the drawings. Below, reference may be made to the XYZ Cartesian coordinate system shown in the drawings.

[0016] FIG. 1 is a perspective view showing a portion 1 of an optical fiber fusion splicing device. FIG. 2 is an enlarged cross-sectional view of the portion 1 of the fusion splicing device. FIG. 3 is a block diagram showing a control system for controlling the fusion splicing device. In this embodiment, the fusion splicing device fusion-splices multiple pairs of first optical fibers 3 a and second optical fibers 3 b arranged with the first end face 3 c of the first optical fiber 3 a and the second end face 3 d of the second optical fiber 3 b butted together by arc discharge. The first optical fibers 3 a and the second optical fibers 3 b are glass fibers. The fusion splicing device includes electrode rods 5 and 6, bases 11 and 12, clamps 21 and 22, and holders 31 and 32.

[0017] The electrode rods 5, 6 are arranged at positions spaced apart from each other in the X direction. The electrode rods 5, 6 are arranged at positions where the tip 5a of the electrode rod 5 and the tip 6a of the electrode rod 6 face each other. The electrode rods 5, 6 include conical portions whose diameters decrease toward the tips 5a, 6a. Multiple pairs of optical fibers 3 are arranged between the pair of electrode rods 5, 6 for generating arc discharge. Multiple pairs of first optical fibers 3a and second optical fibers 3b face each other along the Y direction. Hereinafter, when it is not necessary to distinguish between the first optical fibers 3a and the second optical fibers 3b, these may be collectively referred to as optical fibers 3.

[0018] The bases 11 and 12 are arranged at positions sandwiching the electrode rods 5 and 6. The electrode rods 5 and 6 are arranged between the bases 11 and 12, which are spaced apart in the Y direction. For example, the base 11 has an optical fiber arrangement section 16, and the base 12 has an optical fiber arrangement section 17. The optical fiber arrangement section 16 has a plurality of V-grooves 16a for arranging each of the plurality of first optical fibers 3a. The V-grooves 16a are aligned along the X direction and extend along the Y direction. The optical fiber arrangement section 17 has a plurality of V-grooves 17a for arranging each of the plurality of second optical fibers 3b. The V-grooves 17a are aligned along the X direction and extend along the Y direction.

[0019] The Y direction is the direction in which the first optical fiber 3a extends in the V groove 16a and the direction in which the second optical fiber 3b extends in the V groove 17a. The Y direction coincides with the direction in which the V grooves 16a and 17a extend and the axial direction of the optical fibers 3 arranged in the V grooves 16a and 17a. In this embodiment, the direction in which the second optical fiber 3b arranged in the V groove 17a is viewed from the first optical fiber 3a arranged in the V groove 16a is defined as a first direction D1, and the direction opposite to the first direction D1 is defined as a second direction D2.

[0020] The V-groove 16a of the optical fiber positioning section 16 positions the first optical fiber 3a, and the V-groove 17a of the optical fiber positioning section 17 positions the second optical fiber 3b. For example, each of the multiple V-grooves 16a of the optical fiber positioning section 16 and each of the multiple V-grooves 17a of the optical fiber positioning section 17 face each other in the Y direction. The first optical fiber 3a positioned by the V-groove 16a and the second optical fiber 3b positioned by the V-groove 17a are butted against each other in the region between the optical fiber positioning section 16 and the optical fiber positioning section 17.

[0021] The clamp 21 presses the first optical fiber 3a placed in the V-groove 16a relatively against the V-groove 16a. The clamp 22 presses the second optical fiber 3b placed in the V-groove 17a relatively against the V-groove 17a. For example, the clamps 21 and 22 include arm portions 21a and 22a and pressing portions 21b and 22b. The arm portion 21a is disposed above the optical fiber placement section 16, and the arm portion 22a is disposed above the optical fiber placement section 17.

[0022] The arm portions 21 a and 22 a are movable in the up and down direction. For example, the arm portions 21 a and 22 a are rectangular pillar-shaped. The pressing portion 21 b is attached to the lower end of the arm portion 21 a, and the pressing portion 22 b is attached to the lower end of the arm portion 22 a. In this embodiment, the pressing portion 21 b is movable in the up and down direction (Z direction) at the lower end of the arm portion 21 a, and the pressing portion 22 b is movable in the up and down direction (Z direction) at the lower end of the arm portion 22 a.

[0023] When the arm portion 21a moves downward from a state in which the pressing portion 21b is spaced apart from the first optical fiber 3a arranged in the V-groove 16a, the pressing portion 21b presses the first optical fiber 3a toward the V-groove 16a. Similarly, when the arm portion 22a moves downward from a state in which the pressing portion 22b is spaced apart from the second optical fiber 3b arranged in the V-groove 17a, the pressing portion 22b presses the second optical fiber 3b toward the V-groove 17a.

[0024] In this embodiment, the clamping pressure of the clamps 21 and 22 can be changed. The clamping pressure refers to the pressure that the first optical fiber 3a arranged in the V-groove 16a receives when pressed by the pressing portion 21b of the clamp 21, and the pressure that the second optical fiber 3b arranged in the V-groove 17a receives when pressed by the pressing portion 22b of the clamp 22. As an example, an elastic body such as a spring that urges the pressing portions 21b and 22b downward may be disposed between the arm portions 21a and 22a and the pressing portions 21b and 22b. In this case, the clamping pressure can be controlled by controlling the positions of the arm portions 21a and 22a in the vertical direction.

[0025] The holder 31 holds the first optical fiber 3 a, and the holder 32 holds the second optical fiber 3 b. For example, a ribbon fiber 4 including a plurality of first optical fibers 3 a is held by the holder 31, and a ribbon fiber 4 including a plurality of second optical fibers 3 b is held by the holder 32. For example, the holders 31 and 32 include holder bodies 31 a and 32 a having recesses for accommodating the ribbon fiber 4, and lids 31 b and 32 b attached to the holder bodies 31 a and 32 a.

[0026] The lids 31b, 32b are closed with the ribbon fiber 4 housed in the holder bodies 31a, 32a. This holds each ribbon fiber 4 in the holders 31, 32. The holders 31, 32 are movable in both the first direction D1 and the second direction D2. When the holders 31, 32 holding the optical fibers 3 move, the held optical fibers 3 can move forward and backward along the V-grooves 16a, 17a. Forward movement refers to movement of the held first optical fiber 3a and second optical fiber 3b toward each other. Backward movement refers to movement of the held first optical fiber 3a and second optical fiber 3b away from each other.

[0027] The fusion splicing apparatus includes an imaging device 51, a fusion splicing mechanism 52, a clamp driving mechanism 53, a holder driving mechanism 54, and a display device 55. The imaging device 51, the fusion splicing mechanism 52, the clamp driving mechanism 53, the holder driving mechanism 54, and the display device 55 are controlled by a control unit 60. The control unit 60 may be a computer including a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), a communication module, a hard disk, etc.

[0028] The imaging device 51 includes, for example, a pair of cameras. The pair of cameras capture images of the end of the first optical fiber 3 a and the end of the second optical fiber 3 b placed in the V-grooves 16 a, 17 a. For example, the imaging direction of the pair of cameras may be a direction intersecting the axial direction (Y direction) of the first optical fiber 3 a and the second optical fiber 3 b placed in the V-grooves 16 a, 17 a. The imaging directions of the pair of cameras may intersect with each other. As an example, the imaging direction of the pair of cameras is a direction perpendicular to the Y direction. The imaging directions of the pair of cameras may be perpendicular to each other. By using the pair of cameras to capture images of the optical fiber 3 from two different directions, the position of the optical fiber 3 can be identified.

[0029] The fusion splicing mechanism 52 is a mechanism that fusion-splices the end of the first optical fiber 3 a and the end of the second optical fiber 3 b to each other, and includes electrode rods 5 and 6. The clamp driving mechanism 53 includes an actuator that moves the arms 21 a and 22 a of the clamps 21 and 22 in the vertical direction. The holder driving mechanism 54 includes an actuator that moves the holders 31 and 32 in the first direction D1 and the second direction D2. The holder driving mechanism 54 corresponds to a moving mechanism that moves the holders 31 and 32 to move the first optical fiber 3 a and the second optical fiber 3 b in the first direction D1 and the second direction D2. The display device 55 displays an image captured by the imaging device 51.

[0030] The control unit 60 controls the imaging device 51 to acquire an image captured by the imaging device 51. The image acquired by the control unit 60 is displayed on, for example, the display device 55. The control unit 60 processes the acquired image to determine the state of the first optical fiber 3a and the state of the second optical fiber 3b. The control unit 60 controls the fusion splicing mechanism 52 to generate an arc discharge between the electrode rods 5, 6. The control unit 60 controls the clamp drive mechanism (clamp pressure control mechanism) 53 to move the arms 21a, 22a of the clamps 21, 22 in the vertical direction.

[0031] Under the control of the control unit 60, the clamps 21, 22 change the pressure applied to the first optical fiber 3 a and the second optical fiber 3 b placed in the V-grooves 16 a, 17 a. The control unit 60 controls the holder drive mechanism 54 to control the positions of the holders 31, 32 in the Y direction. Under the control of the control unit 60, the holders 31, 32 move in the first direction D1 and the second direction D2, respectively, and move the first optical fiber 3 a held in the holder 31 and the second optical fiber 3 b held in the holder 32 in the first direction D1 and the second direction D2, respectively.

[0032] Next, the operation of the fusion splicing device will be described. Fig. 4 is a flowchart showing an example of the operation of the fusion splicing device. When fusion splicing the first optical fiber 3a and the second optical fiber 3b using the fusion splicing device, a user first sets the first optical fiber 3a in the holder 31 and the second optical fiber 3b in the holder 32. At this time, the first optical fiber 3a is placed in the V-groove 16a, and the second optical fiber 3b is placed in the V-groove 17a. The first optical fiber 3a is pressed against the pressing portion 21b of the clamp 21 while placed in the V-groove 16a, and the second optical fiber 3b is pressed against the pressing portion 22b of the clamp 22 while placed in the V-groove 17a.

[0033] When the first optical fiber 3a is set in the holder 31 and the second optical fiber 3b is set in the holder 32, the control unit 60 drives the holder drive mechanism 54 to move the holders 31 and 32 along the Y direction. At this time, the first end face 3c of the first optical fiber 3a set in the holder 31 and the second end face 3d of the second optical fiber 3b set in the holder 32 move inside the imaging range of the imaging device 51, and end face butting is performed (step S1).

[0034] In step S1, the distance from the first end face 3c to the second end face 3d is adjusted to a predetermined distance suitable for fusion splicing. First, the holders 31 and 32 are moved so that the first end face 3c and the second end face 3d approach each other. Next, an axial misalignment inspection is performed (step S2). In step S2, based on an image captured by the imaging device 51, it is determined whether the amount of misalignment of the axis of the second optical fiber 3b with respect to the axis of the first optical fiber 3a is equal to or less than a predetermined amount.

[0035] Fig. 5 is a diagram schematically showing the first optical fiber 3a and the second optical fiber 3b when a foreign object G such as dust is present in one of the V-grooves 17a. Fig. 6 is a diagram schematically showing an image captured by the imaging device 51 in the state shown in Fig. 5. Fig. 7 is a diagram schematically showing an image captured by the imaging device 51 when the axial centers of the first optical fiber 3a and the second optical fiber 3b are aligned. In Figs. 6 and 7, the cladding portion of the optical fiber that surrounds the core is hatched.

[0036] If a foreign object G is present in the V-groove 17a, the second optical fiber 3b may not be positioned in the V-groove 17a, causing the second end face 3d of the second optical fiber 3b to tilt upward. In this case, as shown in FIG. 6 , a misalignment occurs between the axial center direction of the first optical fiber 3a and the axial center direction of the second optical fiber 3b in the image captured by the imaging device 51. As an example, the amount of misalignment may be the amount of misalignment of the optical fiber core in the vertical direction of the paper surface of FIG. 6 . The core position is identified, for example, from the brightness value of the image. If the amount of misalignment is determined to be greater than a predetermined amount in the axial misalignment inspection of step S2, i.e., if the amount of misalignment is determined to be greater than or equal to the predetermined amount, the process proceeds to the removal operation of step S3.

[0037] 7 , if the amount of misalignment between the first optical fiber 3 a and the second optical fiber 3 b is equal to or less than a predetermined amount, i.e., if the amount of misalignment is determined to be equal to or less than a predetermined amount in the axial misalignment inspection of step S2, discharge is generated between the electrode rods 5, 6. Then, the first optical fiber 3 a and the second optical fiber 3 b are heated and fusion-spliced ​​(step S4). Thereafter, the imaging device 51 images the fusion-spliced ​​first optical fiber 3 a and second optical fiber 3 b, and a post-fusion inspection is performed based on the image obtained as a result of the imaging (step S5).

[0038] Fig. 8 is a flowchart showing an example of the removal operation. In the removal operation of Fig. 8, first, the first optical fiber 3a and the second optical fiber 3b are moved (step S11). In step S11, the control unit 60 controls the holder driving mechanism 54 to move the first optical fiber 3a placed in the V-groove 16a and the second optical fiber 3b placed in the V-groove 17a along the Y direction.

[0039] 9 is a diagram schematically illustrating the movement of the first optical fiber 3a and the second optical fiber 3b. As shown in FIG. 9, the second optical fiber 3b placed in the V-groove 17a is moved in the first direction D1. The first optical fiber 3a placed in the V-groove 16a is moved in the first direction D1 (step of moving the first optical fiber and the second optical fiber in the first direction). The movements of the first optical fiber 3a and the second optical fiber 3b may be performed simultaneously.

[0040] At this time, the holder driving mechanism 54 may move the holders 31, 32 a certain amount in the first direction D1 so that the first end face 3 c located at the end of the first optical fiber 3 a in the first direction D1 and the second end face 3 d located at the end of the second optical fiber 3 b in the second direction D2 move simultaneously while maintaining the distance K from their original positions. In this manner, the first optical fiber 3 a and the second optical fiber 3 b are moved simultaneously or continuously in the same direction. The original position refers, for example, to a position where the first optical fiber 3 a and the second optical fiber 3 b are symmetrical to each other with respect to a reference line L (see FIG. 1 ) that passes through the electrode rods 5, 6 and extends in the X direction.

[0041] Next, the first optical fiber 3a is moved in the second direction D2. The second optical fiber 3b is moved in the second direction D2. The first optical fiber 3a and the second optical fiber 3b may be moved simultaneously. Alternatively, the first optical fiber 3a and the second optical fiber 3b are moved in the second direction D2 while maintaining the distance K between the first end face 3c and the second end face 3d (step of moving the first optical fiber and the second optical fiber in the second direction). The holder driving mechanism 54 may move the holders 31 and 32 a certain amount in the second direction D2 so that the first optical fiber 3a and the second optical fiber 3b move simultaneously while maintaining the distance K. For example, the first optical fiber 3a and the second optical fiber 3b may move in the second direction D2 from their original positions. Alternatively, they may be stopped at their original positions, and step S11 in FIG. 8 may be completed. In this manner, the first optical fiber 3a and the second optical fiber 3b are moved simultaneously or consecutively in the same direction.

[0042] Thereafter, the first optical fiber 3a is moved in the first direction D1. The second optical fiber 3b is moved in the first direction D1. The first optical fiber 3a and the second optical fiber 3b may be moved simultaneously. Alternatively, the first optical fiber 3a and the second optical fiber 3b are returned to their original positions by moving them in the first direction D1 while maintaining the distance K between the first end face 3c and the second end face 3d (the step of moving the first optical fiber and the second optical fiber to their original positions). At this time, the holder driving mechanism 54 may move the holders 31 and 32 a certain amount in the first direction D1 so that the first optical fiber 3a and the second optical fiber 3b move simultaneously while maintaining the distance K, thereby returning the first optical fiber 3a and the second optical fiber 3b to their original positions. In this way, the first optical fiber 3a and the second optical fiber 3b are moved simultaneously or continuously in the same direction. Through the above steps, step S11 in FIG. 8 is completed. In either case, the movement is performed within a range that prevents the first optical fiber 3a and the second optical fiber 3b from coming out of the V-groove 16a and the V-groove 17a, respectively.

[0043] Next, an axial misalignment inspection is performed (step S12). This axial misalignment inspection is the same as the axial misalignment inspection in step S2 described above. If the result of this axial misalignment inspection indicates that the amount of misalignment between the first optical fiber 3 a and the second optical fiber 3 b is equal to or less than a predetermined amount, the removal operation ends and the process proceeds to step S4 in Fig. 4. On the other hand, if the axial misalignment inspection in step S12 indicates that the amount of misalignment is greater than the predetermined amount, i.e., if the amount of misalignment is not equal to or less than the predetermined amount, the process proceeds to step S13.

[0044] In step S13, the clamp pressure is changed (a process of changing the clamp pressure). In step S13, as an example, the control unit 60 controls the clamp drive mechanism 53 so as to temporarily change the clamp pressure of the clamps 21 and 22. FIG. 10 is a flowchart showing an example of the process of changing the clamp pressure. As shown in FIG. 10, first, the clamps 21 and 22 are moved to a clamp release position so as to release the first optical fiber 3a pressed toward the V-groove 16a and the second optical fiber 3b pressed toward the V-groove 17a (step S21). For example, the clamp drive mechanism 53 raises the clamps 21 and 22.

[0045] Thereafter, the clamps 21 and 22 are returned to their normal positions (step S22). The normal positions refer to the position where the clamp 21 presses the first optical fiber 3a toward the V-groove 16a, and the clamp 22 presses the second optical fiber 3b toward the V-groove 17a. Then, the process proceeds to step S23, where an axial misalignment inspection is performed. The axial misalignment inspections of step S23 and steps S25 and S27, which will be described later, are similar to the axial misalignment inspections of steps S2 and S12, and therefore will not be described here.

[0046] If it is determined as a result of the axial misalignment inspection in step S23 that the amount of misalignment between the first optical fiber 3 a and the second optical fiber 3 b is equal to or less than a predetermined amount (YES in step S23), the process of changing the clamp pressure ends and the process proceeds to step S14 in Fig. 8. On the other hand, if it is determined as a result of the axial misalignment inspection in step S23 that the amount of misalignment between the first optical fiber 3 a and the second optical fiber 3 b is not equal to or less than the predetermined amount (NO in step S23), the process proceeds to step S24 to increase the clamp pressure (process of increasing the clamp pressure).

[0047] In step S24, the clamping pressure of clamp 21 pressing against first optical fiber 3a and the clamping pressure of clamp 22 pressing against second optical fiber 3b are increased. At this time, clamp drive mechanism 53 applies a downward force to clamps 21 and 22, thereby pressing first optical fiber 3a and second optical fiber 3b into V-grooves 16a and 17a and increasing the clamping pressure. Then, the process proceeds to step S25, where an axial misalignment inspection is performed.

[0048] If the result of the axial misalignment inspection in step S25 indicates that the amount of misalignment between the first optical fiber 3 a and the second optical fiber 3 b is equal to or less than a predetermined amount, the process of changing the clamp pressure is terminated and the process proceeds to step S14 in Fig. 8. On the other hand, if the result of the axial misalignment inspection in step S23 indicates that the amount of misalignment between the first optical fiber 3 a and the second optical fiber 3 b is not equal to or less than the predetermined amount (NO in step S25), the process proceeds to step S26, where the clamp pressure is reduced (process of reducing the clamp pressure).

[0049] In step S26, the clamping pressure of the clamp 21 pressing against the first optical fiber 3a and the clamping pressure of the clamp 22 pressing against the second optical fiber 3b are reduced. At this time, the clamp drive mechanism 53 applies an upward force to the clamps 21 and 22, thereby loosening the pressure on the first optical fiber 3a and the second optical fiber 3b and reducing the clamping pressure. The clamp drive mechanism 53 may also raise the clamps 21 and 22 from the first optical fiber 3a and the second optical fiber 3b. At this time, the clamps 21 and 22 may also be moved upward from their normal positions described above. After that, the process proceeds to step S27, where an axial misalignment inspection is performed.

[0050] If, as a result of the axial misalignment inspection in step S27, it is determined that the amount of misalignment between the first optical fiber 3 a and the second optical fiber 3 b is equal to or less than a predetermined amount (YES in step S27), the process of changing the clamp pressure ends, and the process proceeds to step S29, where the first optical fiber 3 a and the second optical fiber 3 b are butted together. On the other hand, if, as a result of the axial misalignment inspection in step S27, it is determined that the amount of misalignment between the first optical fiber 3 a and the second optical fiber 3 b is not equal to or less than the predetermined amount (NO in step S27), the process proceeds to step S28, where an error is displayed (a process of notifying that an error has occurred). At this time, an error message is displayed on the display device 55, for example.

[0051] The axial misalignment inspection in step S14 in Fig. 8 is the same as the axial misalignment inspection in step S2. If it is determined in this axial misalignment inspection that the amount of misalignment between the first optical fiber 3 a and the second optical fiber 3 b is equal to or less than a predetermined amount (YES in step S14), the removal operation is terminated and the process proceeds to step S4 in Fig. 4. Then, discharge is generated between the pair of electrode rods 5, 6, the first optical fiber 3 a and the second optical fiber 3 b are heated and fusion-spliced, and a post-fusion inspection is performed (step S5), completing the series of processes.

[0052] 8, if it is determined that the amount of misalignment is greater than the predetermined amount, i.e., if it is determined that the amount of misalignment is not equal to or less than the predetermined amount (NO in step S14), the process may return to step S11. Note that if a problem occurs in the misalignment inspection even after the removal operation in step S3 has been performed, an error message may be displayed on the display device 55 and the process may end. The removal operation in step S3 may be performed once or multiple times.

[0053] Next, the effects obtained by the optical fiber fusion splicing method and optical fiber fusion splicing device according to this embodiment will be described. In the above-described fusion splicing method and fusion splicing device, the second optical fiber 3b placed in the V-groove 17a is moved in a first direction D1, and the first optical fiber 3a placed in the V-groove 16a is moved in the first direction D1. Then, the first optical fiber 3a is moved in a second direction D2, which is the opposite direction to the first direction D1, and the second optical fiber 3b is moved in the second direction D2.

[0054] The first optical fiber 3a and the second optical fiber 3b may be moved in the first direction D1 while maintaining the distance K between the first end face 3c of the first optical fiber 3a placed in the V-groove 16a and the second end face 3d of the second optical fiber 3b placed in the V-groove 17a, or the first optical fiber 3a and the second optical fiber 3b may be moved in the second direction D2 while maintaining the distance K between the first end face 3c and the second end face 3d. By simultaneously or continuously moving the first optical fiber 3a and the second optical fiber 3b in the same direction, the first direction D1 and the second direction D2, foreign matter G can be reliably removed by the above movement even if foreign matter G is present in at least one of the V-groove 16a in which the first optical fiber 3a is placed and the V-groove 17a in which the second optical fiber 3b is placed. Moving both the first optical fiber 3a and the second optical fiber 3b in the same direction allows foreign matter G to be efficiently removed.

[0055] As described above, the optical fiber fusion splicing method may include a step of changing the clamping pressure of the clamp 21 pressing the first optical fiber 3a and the clamping pressure of the clamp 22 pressing the second optical fiber 3b. In this case, the change in clamping pressure causes the force applied to the first optical fiber 3a and the second optical fiber 3b to move in a different direction than the movement of the first optical fiber 3a and the second optical fiber 3b. That is, the movement of the first optical fiber 3a and the second optical fiber 3b acts along the first direction D1 and the second direction D2, while the change in clamping pressure acts along the Z direction. Since forces act on the foreign matter G from multiple directions, the foreign matter can be moved (removed) more effectively.

[0056] As described above, the changing step may include the steps of increasing the clamping pressure of the clamp 21 pressing the first optical fiber 3 a and the clamping pressure of the clamp 22 pressing the second optical fiber 3 b, and decreasing the clamping pressure of the clamp 21 pressing the first optical fiber 3 a and the clamping pressure of the clamp 22 pressing the second optical fiber 3 b. In this case, by increasing or decreasing the clamping pressure on the first optical fiber 3 a and the second optical fiber 3 b, the foreign matter G in the V-grooves 16 a, 17 a can be more effectively moved (removed). Note that the order in which the step of increasing the clamping pressure and the step of decreasing the clamping pressure are performed may be reversed from the example described above.

[0057] Fig. 11 is a flowchart showing a modified example of the removal operation. In this embodiment, the removal operation shown in Fig. 11 may be performed instead of the removal operation of step S3. In the removal operation shown in Fig. 11, the change in clamping pressure and the movement of the first optical fiber 3a and the second optical fiber 3b are performed in parallel (step S31). For example, in the removal operation, the first optical fiber 3a and the second optical fiber 3b may be moved in the first direction D1 while the clamping pressure is increased, and then the first optical fiber 3a and the second optical fiber 3b may be moved in the second direction D2 while maintaining the high clamping pressure, returning the first optical fiber 3a and the second optical fiber 3b to their original positions.

[0058] As an example different from the above, in the removal operation, the first optical fiber 3 a and the second optical fiber 3 b may be moved in the first direction D1 without changing the clamping pressure, and then the first optical fiber 3 a and the second optical fiber 3 b may be moved in the second direction D2 with the clamping pressure increased. Thus, in the removal operation in step S31, a state in which the clamping pressure is increased, a state in which the clamping pressure is not changed, a state in which the optical fibers are released (a state in which the clamping pressure is reduced, for example, a state in which the clamping pressure is zero), and the movement of the first optical fiber 3 a and the second optical fiber 3 b in the first direction D1 and the second direction D2 may be appropriately combined. Furthermore, the magnitude of the clamping pressure may be changed while the first optical fiber 3 a and the second optical fiber 3 b are moving in the first direction D1 or the second direction D2. As an example, a state in which the clamping pressure is high and a state in which the clamping pressure is low may be alternated while the first optical fiber 3 a and the second optical fiber 3 b are moving in the first direction D1 or the second direction D2.

[0059] After step S31, an axial misalignment inspection is performed (step S32). This axial misalignment inspection is similar to the axial misalignment inspection in step S2, and therefore a description thereof will be omitted. If the result of the axial misalignment inspection in step S32 indicates that the amount of misalignment between the first optical fiber 3 a and the second optical fiber 3 b is equal to or less than a predetermined amount, the series of steps in the removal operation is completed. On the other hand, if the result of the axial misalignment inspection in step S32 indicates that the amount of misalignment between the first optical fiber 3 a and the second optical fiber 3 b is not equal to or less than the predetermined amount (NO in step S32), the process proceeds to step S31, where the clamp pressure is changed again and the first optical fiber 3 a and the second optical fiber 3 b are moved again.

[0060] As described above, in the removal operation shown in Fig. 11, the step of changing the clamping pressure and the step of moving the first optical fiber 3a and the second optical fiber 3b in the first direction D1 and the second direction D2 are performed simultaneously. At least one of the steps of moving the first optical fiber 3a and the second optical fiber 3b in the first direction D1 and the step of moving the first optical fiber 3a and the second optical fiber 3b in the second direction D2 is performed simultaneously with the step of changing the clamping pressure. In this case, two forces acting in different directions can be applied to the foreign matter G simultaneously or successively. By combining a force acting in the Z direction and a force acting in the Y direction, a force can be applied to the foreign matter G obliquely upward or obliquely downward. As a result, the foreign matter G can be moved (removed) more effectively.

[0061] The above describes embodiments of the optical fiber fusion splicing method and optical fiber fusion splicing device according to the present disclosure. However, the present invention is not limited to the above-described embodiments. In other words, it will be readily understood by those skilled in the art that various modifications and variations are possible within the scope of the gist of the claims. For example, the shape, size, number, materials, and arrangement of each part of the fusion splicing device, as well as the content and order of the steps of the fusion splicing method, can be modified as appropriate within the scope of the gist. For example, in the above-described embodiments, a fusion splicing device for fusion splicing multi-core fibers having multiple optical fibers was described. However, the fusion splicing device may also be a device for fusion splicing single-core optical fibers formed from a single optical fiber.

[0062] DESCRIPTION OF SYMBOLS 1...Part of fusion splicing device 3...Optical fiber 3a...First optical fiber 3b...Second optical fiber 3c...First end face 3d...Second end face 4...Core ribbon 5...Electrode rod 5a...Tip 6...Electrode rod 6a...Tip 11, 12...Base 16...Optical fiber placement section 16a...V-groove 17...Optical fiber placement section 17a...V-groove 21...Clamp 21a...Arm section 21b...Pressing section 22...Clamp 22a...Arm section 22b...Pressing section 31...Holder 31b...Cover 32...Holder 32b...Cover 51...Imaging device 52...Fusion splicing mechanism 53...Clamp driving mechanism 54...Holder driving mechanism (moving mechanism) 55...Display device 60...Control section G...Foreign matter

Claims

1. A method for fusion splicing optical fibers, comprising positioning a first optical fiber and a second optical fiber aligned along a first direction in a V-groove and fusion splicing the first optical fiber to the second optical fiber, A step of moving the second optical fiber placed in the V groove in the first direction, and moving the first optical fiber placed in the V groove in the first direction, The process involves moving the first optical fiber in a second direction opposite to the first direction, and moving the second optical fiber in the second direction. A step of pressing the first optical fiber and the second optical fiber relative to each other toward the V-groove by clamping, Equipped with, A method for fusion splicing optical fibers.

2. A step of moving the first optical fiber and the second optical fiber simultaneously in the first direction, A step of moving the first optical fiber and the second optical fiber simultaneously in the second direction, including, The fusion splicing method for optical fibers according to claim 1.

3. The process includes a step of changing the clamping pressure of the clamp that presses the first optical fiber and the clamping pressure of the clamp that presses the second optical fiber. A method for fusion splicing optical fibers according to claim 1 or claim 2.

4. The aforementioned process of making changes is A step of increasing the clamping pressure of the clamp that presses the first optical fiber and the clamping pressure of the clamp that presses the second optical fiber, A step of reducing the clamping pressure of the clamp that presses the first optical fiber and the clamping pressure of the clamp that presses the second optical fiber, including, The fusion splicing method for optical fibers according to claim 3.

5. The step of moving in the first direction and the step of moving in the second direction are performed simultaneously with the step of changing. The fusion splicing method for optical fibers according to claim 3.

6. A pair of V-grooves on which the first optical fiber and the second optical fiber, which are aligned along the first direction, are placed, A pair of clamps that press the first optical fiber and the second optical fiber, which are placed in each of the V-grooves, against each of the V-grooves, A moving mechanism that moves the second optical fiber placed in the V-groove in the first direction, moves the first optical fiber placed in the V-groove in the first direction, moves the first optical fiber in the second direction opposite to the first direction, and moves the second optical fiber in the second direction, Equipped with, A fusion splicing device for optical fibers.