Welding device and welding method

Abstract

A welding device (1A) is provided with a first holding unit (11), a second holding unit (12), a light source (30), a light detection unit (40), and a heating unit (2). The first holding section (11) varies the rotation angle of the end surface (F1a) of the first optical fiber about the central axis in a state in which the first optical fiber (F1) is held. The second holding section (12) varies the rotation angle of the end surface (F2a) of the second optical fiber about the central axis in a state in which the second optical fiber (F2) is held. The light source (30) irradiates the resin coating (RS) of the first optical fiber (F1) with light, and the light source (30) is configured such that the center wavelength of the light is variable. The light detection unit (40) detects the intensity of light that passes through the resin coating (RS) of the second optical fiber (F2) and leaks in a state where the end surface of the first optical fiber (F1) and the end surface of the second optical fiber (F2) are close to each other. The heating unit (40) melts the end surface of the first optical fiber (F1) and the end surface of the second optical fiber (F2) in a state of approaching each other.

Description

Technical Field

[0001] The present disclosure relates to a welding device and a welding method. This application claims priority based on Japanese application No. 2022-090670 filed on June 3, 2022, and all the contents described in the Japanese application are cited by reference. Background Art

[0002] Patent document 1 discloses a method for connecting multi-core optical fibers. In the connection method, the connecting end faces of the first multi-core optical fiber and the second multi-core optical fiber are placed opposite to each other in such a manner that the axes of the first multi-core optical fiber and the second multi-core optical fiber are aligned with each other. Test light is injected from the side of the first multi-core optical fiber and propagated in the cladding. The axis rotation of the first multi-core optical fiber and the second multi-core optical fiber is adjusted based on the test light detected from the second multi-core optical fiber.

[0003] Patent document 2 discloses a method for connecting a first optical fiber to a second optical fiber which is a multi-core optical fiber. The method includes a facing process, a bending process, an injection process, a measuring process, a core adjustment process, and a connecting process. In the facing process, the central axes of the two optical fibers are parallel and the end faces of the two optical fibers are opposite. In the bending process, a portion of the second optical fiber is bent. In the injection process, light is injected into the core from one end of the first optical fiber, and light emitted from the other end is injected into the second optical fiber. In the measuring process, the intensity of light emitted from the bent portion of the second optical fiber is measured. In the core adjustment process, at least one of the two optical fibers is moved or rotated in a manner that keeps the central axes of the two optical fibers parallel so that the intensity of the light increases. In the connecting process, the positional relationship of the two optical fibers where the intensity of the light is maximized is maintained, and the distance between the two optical fibers is changed to connect the ends to each other.

[0004] Patent document 3 discloses a method for fusing the end faces of a pair of optical fibers. In this method, a photographing unit disposed opposite to the end faces of the optical fibers is used to photograph the end faces of the optical fibers from the front. A discharge unit discharges to the end faces of the optical fibers having notches or hackles detected by a detection unit. Thereafter, the end faces of the optical fibers are fused together.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2017-21190

[0008] Patent Document 2: Japanese Patent Application Publication No. 2015-4762

[0009] Patent Document 3: International Publication No. 2013-77002 Summary of the invention

[0010] Problems to be solved by the invention

[0011] As optical fibers that require adjustment of the rotation angle around the central axis during fusion splicing, there are, for example, multi-core optical fibers and polarization-maintaining optical fibers. When such optical fibers that require adjustment of the rotation angle are fused together, for example, any of the following methods can be adopted. In one method, light is injected from the side of one optical fiber, and the intensity of light leaked from the side of another optical fiber is detected. Then, the relative rotation angle of the optical fibers is adjusted based on the intensity. In another method, light is injected from the side of each optical fiber, and the end face of each optical fiber is observed, and the rotation angle of each optical fiber is adjusted individually. When the optical fibers are fused together, the coating resin is removed from the top portion of the optical fiber including the connected end face, so that the glass portion including the core and the cladding is exposed. As a structure for injecting light from the side of the optical fiber, there is a structure for injecting light to the side of the glass portion exposed from the resin coating and a structure for injecting light to the side of the resin coating. In the fusion splicing device, any of these structures is appropriately selected.

[0012] When light is incident on the side of the resin coating, the following problem occurs. Usually, a coloring material (such as a pigment) for identifying the type of optical fiber is mixed into the resin coating. Alternatively, in order to make the optical fiber beautiful, particles that diffuse light are mixed into the resin coating. The coloring material and particles absorb or scatter the light incident on the resin coating, thereby preventing the light from passing through the resin coating and reaching the glass part. Therefore, the following situation may occur: the intensity of light leaking from the side of another optical fiber or the brightness of the observed image of the end face of the optical fiber, which is required for adjusting the rotation angle, cannot be obtained. In this case, it becomes difficult to adjust the rotation angle.

[0013] The object of the present disclosure is to provide a fusion splicing device and a fusion splicing method, by which, when light is incident on the side of the resin coating to adjust the relative rotation angle between optical fibers, the light incident on the resin coating can easily pass through the resin coating and reach the glass portion.

[0014] Solutions for solving problems

[0015] A fusion splicing device according to one aspect of the present disclosure includes a first holding portion, a second holding portion, a light source, a light detection portion, and a heating portion. The first holding portion makes the rotation angle of the end face of the first optical fiber around the central axis variable while holding the first optical fiber. The first optical fiber includes: a glass portion having one or more cores and a cladding surrounding the one or more cores; and a resin coating surrounding the periphery of the glass portion. In the first optical fiber, the tip portion of the glass portion including the end face is exposed from the resin coating. The second holding portion makes the rotation angle of the end face of the second optical fiber around the central axis variable while holding the second optical fiber. The second optical fiber includes: a glass portion having one or more cores and a cladding surrounding the one or more cores; and a resin coating surrounding the periphery of the glass portion. In the second optical fiber, the tip portion of the glass portion including the end face is exposed from the resin coating. The light source irradiates light to the resin coating of the first optical fiber, and the light source is configured to have one or both of the characteristics that the central wavelength of the light is variable and the wavelength bandwidth of the light is 100 nm or more. The light detection unit detects the intensity of light leaked through the resin coating of the second optical fiber when the end face of the first optical fiber and the end face of the second optical fiber are close to each other. The heating unit heats the end face of the first optical fiber and the end face of the second optical fiber so that the end face of the first optical fiber and the end face of the second optical fiber are melted when they are close to each other.

[0016] A fusion splicing method according to an embodiment of the present disclosure includes the following steps: preparing a first optical fiber and a second optical fiber, the first optical fiber and the second optical fiber respectively having: a glass portion having one or more cores and a cladding surrounding the one or more cores; and a resin coating surrounding the outer periphery of the glass portion, with the top end portions of the glass portions of the first optical fiber and the second optical fiber including the end faces being exposed from the resin coating; bringing the end face of the first optical fiber and the end face of the second optical fiber close to each other; irradiating light to the resin coating of the first optical fiber using a light source having one or both of the characteristics of a variable central wavelength of output light and a wavelength bandwidth of the output light being greater than 100 nm; detecting the intensity of light leaked through the resin coating of the second optical fiber; adjusting the relative rotation angle of the first optical fiber and the second optical fiber based on the intensity of light detected in the detecting step; and heating the end face of the first optical fiber and the end face of the second optical fiber to melt them.

[0017] Effects of the Invention

[0018] According to the present disclosure, a fusion splicing device and a fusion splicing method can be provided, by which, when light is incident on the side of the resin coating to adjust the relative rotation angle between optical fibers, the light incident on the resin coating can easily pass through the resin coating and reach the glass portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a diagram for explaining the outline of the welding device according to the first embodiment.

[0020] Figure 2 is a side view of a first optical fiber and a second optical fiber.

[0021] Figure 3 yes Figure 2 A cross-sectional view of the first optical fiber and the second optical fiber in the III-III section is shown.

[0022] Figure 4 It is a diagram schematically showing a cross section of the first holding portion and the second holding portion along the YZ plane.

[0023] Figure 5 It is a diagram schematically showing a configuration example of a light source.

[0024] Figure 6 This is a diagram schematically showing another configuration example of a light source.

[0025] Figure 7 This is a flowchart showing the operation of the welding device according to the first embodiment.

[0026] Figure 8 It is a diagram showing a part of the configuration of a welding device according to a second embodiment.

[0027] Fig. 9 This is a flowchart showing the operation of the welding device according to the second embodiment. DETAILED DESCRIPTION

[0028] [Description of Embodiments of the Present Disclosure]

[0029] First, the contents of the embodiments of the present disclosure will be listed and described.

[0030] [1] A fusion splicing device according to a first aspect of the present disclosure includes a first holding portion, a second holding portion, a light source, a light detection portion, and a heating portion. The first holding portion allows the rotation angle of the end face of the first optical fiber around the central axis to be variable while holding the first optical fiber. The first optical fiber includes: a glass portion having one or more cores and a cladding surrounding the one or more cores; and a resin coating surrounding the outer periphery of the glass portion. In the first optical fiber, the top end portion of the glass portion including the end face is exposed from the resin coating. The second holding portion allows the rotation angle of the end face of the second optical fiber around the central axis to be variable while holding the second optical fiber. The second optical fiber includes: a glass portion having one or more cores and a cladding surrounding the one or more cores; and a resin coating surrounding the outer periphery of the glass portion. In the second optical fiber, the top end portion of the glass portion including the end face is exposed from the resin coating. The light source irradiates light toward the resin coating of the first optical fiber. The light source is configured to have one or both of the characteristics that the central wavelength of the light is variable and the wavelength bandwidth of the light is 100 nm or more. The light detection unit detects the intensity of light leaked through the resin coating of the second optical fiber when the end face of the first optical fiber and the end face of the second optical fiber are close to each other. The heating unit heats the end face of the first optical fiber and the end face of the second optical fiber so that the end face of the first optical fiber and the end face of the second optical fiber are melted when they are close to each other.

[0031] In the fusion splicing device, the light source for irradiating light to the resin coating of the first optical fiber is configured to have one or both of the characteristics that the central wavelength of the light is variable and the wavelength bandwidth of the light is 100nm or more. As described above, the coloring material and particles contained in the resin coating absorb or scatter the light incident to the resin coating, but the magnitude of the absorption and scattering at this time depends on the wavelength of the light. According to the fusion splicing device, a wavelength with small absorption and scattering in the resin coating is selected and the light of the wavelength is irradiated to the resin coating, so that the light easily passes through the resin coating and reaches the glass part. As a result, the intensity of the light leaked through the resin coating of the second optical fiber can be increased, so that the rotation angle can be appropriately adjusted. Alternatively, the light source is configured so that the wavelength bandwidth of the light is 100nm or more, so that such a wide-band light can be used, so that the rotation angle of multiple optical fibers with different absorption characteristics and scattering characteristics of the resin coating can be adjusted using the same wavelength of light. As a result, the frequency of changing the wavelength of the light can be reduced, and the operator's work can be reduced. In addition, by using broadband light having a bandwidth of 100 nm or more, at least one wavelength component included in the bandwidth, typically a wavelength component with the smallest absorption and scattering included in the bandwidth, easily passes through the resin coating and reaches the glass portion. Therefore, the intensity of the light leaking through the resin coating of the second optical fiber can be increased, and the rotation angle can be appropriately adjusted.

[0032] [2] In the welding device of [1] above, the light detection unit may be configured to have a variable central wavelength of a frequency band having a sensitivity. In this case, the light can be detected with an optimum sensitivity corresponding to the wavelength of the light, and the light detection efficiency can be improved, thereby enabling more accurate adjustment of the rotation angle.

[0033] [3] A fusion splicing device according to a second aspect of the present disclosure includes a first holding portion, a second holding portion, a first light source, a second light source, an imaging portion, and a heating portion. The first holding portion makes the rotation angle of the end face of the first optical fiber around the central axis variable while holding the first optical fiber. The first optical fiber includes: a glass portion having one or more cores and a cladding surrounding the one or more cores; and a resin coating surrounding the outer periphery of the glass portion. In the first optical fiber, the tip portion of the glass portion including the end face is exposed from the resin coating. The second holding portion makes the rotation angle of the end face of the second optical fiber around the central axis variable while holding the second optical fiber. The second optical fiber includes: a glass portion having one or more cores and a cladding surrounding the one or more cores; and a resin coating surrounding the outer periphery of the glass portion. In the second optical fiber, the tip portion of the glass portion including the end face is exposed from the resin coating. The first light source irradiates the resin coating of the first optical fiber with a first light. The first light source is configured to have one or both of the characteristics that the central wavelength of the first light is variable and the wavelength bandwidth of the first light is 100 nm or more. The second light source irradiates the resin coating of the second optical fiber with a second light. The second light source is configured to have one or both of the characteristics that the central wavelength of the second light is variable and the bandwidth of the wavelength of the second light is greater than 100 nm. The imaging unit obtains observation images of the end face of the first optical fiber and the end face of the second optical fiber. The heating unit heats the end face of the first optical fiber and the end face of the second optical fiber so that the end face of the first optical fiber and the end face of the second optical fiber are melted in a state close to each other.

[0034] In the fusion splicing device, the first light source for irradiating light to the resin coating of the first optical fiber is configured to have one or both of the characteristics that the central wavelength of the first light is variable and the bandwidth of the wavelength of the first light is greater than 100nm. In addition, the second light source for irradiating light to the resin coating of the second optical fiber is configured to have one or both of the characteristics that the central wavelength of the second light is variable and the bandwidth of the wavelength of the second light is greater than 100nm. As described above, the coloring material and particles contained in the resin coating absorb or scatter the light incident to the resin coating, but the magnitude of the absorption and scattering at this time depends on the wavelength of the light. According to the fusion splicing device, a wavelength with small absorption and scattering in the resin coating is selected and the first light and the second light of the wavelength are irradiated to the resin coating of the first optical fiber and the second optical fiber, respectively, so that the first light and the second light are easy to pass through the resin coating and reach the glass part. As a result, the observation image of the end face of the first optical fiber and the second optical fiber can be made brighter, so that the rotation angle can be adjusted appropriately. Alternatively, the first light source and the second light source are configured such that each wavelength bandwidth of the first light and the second light is greater than 100 nm, thereby enabling the use of such broadband light, and thus enabling the use of light of the same wavelength to adjust the rotation angle of a plurality of optical fibers having different absorption characteristics and scattering characteristics of the resin coating. Thus, the frequency of changing the wavelengths of the first light source and the second light source can be reduced, and the operator's work can be reduced. In addition, by using the broadband first light and the second light having a bandwidth of greater than 100 nm, at least one wavelength component contained in the bandwidth, typically a wavelength component with the smallest absorption and scattering contained in the bandwidth, can easily pass through the resin coating and reach the glass portion. Therefore, the observation image of the end face of the first optical fiber and the second optical fiber can be made brighter, so that the rotation angle can be appropriately adjusted.

[0035] [4] In the fusion splicing device of [3], the imaging unit may be configured to have a variable central wavelength of a frequency band having a sensitivity. In this case, the first light and the second light can be imaged with an optimal sensitivity corresponding to the wavelengths of the first light and the second light, and the observation images of the end faces of the first optical fiber and the second optical fiber can be made brighter, thereby enabling more accurate adjustment of the rotation angle.

[0036] [5] In the fusion splicing device of [1] or [2] above, the light source may be configured to have a variable intensity of light irradiated onto the resin coating of the first optical fiber. In this case, it is possible to easily adjust the intensity of the light, such as lowering the intensity of the light when the intensity of the light incident on the light detection unit exceeds the maximum amount of light allowed in the light detection unit, or increasing the intensity of the light when the intensity of the light incident on the light detection unit is too small. Therefore, the intensity of the light leaking through the resin coating of the second optical fiber can be appropriately adjusted, thereby appropriately adjusting the rotation angle.

[0037] [6] In the fusion splicing device of [3] or [4] above, the first light source may be configured to have a variable intensity of the first light irradiated onto the resin coating of the first optical fiber, and the second light source may be configured to have a variable intensity of the second light irradiated onto the resin coating of the second optical fiber. In this case, it is easy to adjust the intensities of the first light and the second light, for example, by reducing the intensities of the first light and the second light incident on the imaging unit when the intensities exceed the maximum amount of light allowed in the imaging unit, or by increasing the intensities of the first light and the second light incident on the imaging unit when the intensities are too low. Therefore, the intensities of the first light and the second light emitted from the end faces of the first optical fiber and the second optical fiber can be appropriately adjusted to appropriately obtain observation images of the end faces of the first optical fiber and the second optical fiber, thereby appropriately adjusting the rotation angle.

[0038] [7] The first aspect of the present disclosure is a fusion splicing method comprising the following steps: preparing a first optical fiber and a second optical fiber, the first optical fiber and the second optical fiber respectively comprising: a glass portion having one or more cores and a cladding surrounding the one or more cores; and a resin coating surrounding the outer periphery of the glass portion, wherein the top end portion of the glass portion including the end face of the first optical fiber and the second optical fiber is exposed from the resin coating; bringing the end face of the first optical fiber and the end face of the second optical fiber close to each other; irradiating the resin coating of the first optical fiber with light using a light source having one or both of the characteristics of a variable central wavelength of the output light and a wavelength bandwidth of the output light being greater than 100 nm; detecting the intensity of light leaked through the resin coating of the second optical fiber; adjusting the relative rotation angle of the first optical fiber and the second optical fiber based on the intensity of the light detected in the detection step; and heating the end face of the first optical fiber and the end face of the second optical fiber to melt them.

[0039] In this fusion splicing method, light is irradiated onto the resin coating of the first optical fiber using a light source having one or both of the characteristics of variable central wavelength of output light and wavelength bandwidth of output light being 100 nm or more. According to this fusion splicing method, for the same reason as the fusion splicing device of [1] described above, the intensity of light leaking through the resin coating of the second optical fiber can be increased, thereby enabling appropriate adjustment of the rotation angle.

[0040] [8] In the welding device of [7] above, in the step of detecting, the intensity of light may be detected using a photodetector configured to have a frequency band with a sensitivity whose central wavelength is variable. In this case, light can be detected with an optimum sensitivity corresponding to the wavelength of light, and the light detection efficiency can be improved, thereby enabling more accurate adjustment of the rotation angle.

[0041] [9] The fusion splicing method according to the second aspect of the present disclosure comprises the following steps: preparing a first optical fiber and a second optical fiber, wherein the first optical fiber and the second optical fiber respectively have: a glass portion having one or more cores and a cladding surrounding the one or more cores; and a resin coating surrounding the periphery of the glass portion, wherein the top end portions of the glass portions including the end faces of the first optical fiber and the second optical fiber are exposed from the resin coating; irradiating the resin coating of the first optical fiber with a first light source having one or both of the characteristics that the central wavelength of the output light is variable and the wavelength bandwidth of the output light is greater than 100 nm; A method of producing a first optical fiber and a second optical fiber comprising: producing a first optical fiber and a second optical fiber having an optical fiber end face; producing a first optical fiber and a second optical fiber by using a first optical fiber; producing a second optical fiber; and producing a first optical fiber; producing a second optical fiber; and producing a second optical fiber. The method comprises: producing a first optical fiber and a second optical fiber by using a first optical fiber; producing a first optical fiber; and producing a second optical fiber. The method comprises: producing a first optical fiber; and producing a second ...

[0042] In this fusion splicing method, the first light source and the second light source are configured to have one or both of the characteristics of variable central wavelength of output light and wavelength bandwidth of output light being 100 nm or more, and the first light and the second light are respectively irradiated onto the resin coating of each of the first optical fiber and the second optical fiber. According to this fusion splicing method, for the same reason as the fusion splicing device of [3] described above, the observation image of the end face of the first optical fiber and the second optical fiber can be made brighter, so that the rotation angle can be appropriately adjusted.

[0043]

[10] In the fusion splicing method of [9], in the step of acquiring the observation image of the end face of the first optical fiber and the step of acquiring the observation image of the end face of the second optical fiber, an imaging device configured to have a center wavelength of a frequency band with a sensitivity that is variable is used to acquire the observation image of the end face of the first optical fiber and the observation image of the end face of the second optical fiber, respectively. In this case, the first light and the second light can be detected with an optimal sensitivity corresponding to the wavelengths of the first light and the second light, and the detection efficiency of the first light and the second light can be improved, thereby enabling more accurate adjustment of the rotation angle.

[0044]

[11] In the fusion splicing method of [7] or [8] above, in the irradiation step, light may be irradiated using a light source configured to irradiate the resin coating of the first optical fiber with a variable intensity. In this case, it is easy to adjust the intensity of the light, for example, by lowering the intensity of the light when the intensity of the light incident on the light detection unit exceeds the maximum amount of light allowed in the light detection unit, or by increasing the intensity of the light when the intensity of the light incident on the light detection unit is too small. Therefore, the intensity of the light leaked through the resin coating of the second optical fiber can be appropriately adjusted, so that the rotation angle can be appropriately adjusted.

[0045]

[12] In the fusion splicing method of [9] or

[10] , in the step of obtaining an observation image of the end face of the first optical fiber, the first light may be irradiated using a first light source configured to have a variable intensity of the first light, and in the step of obtaining an observation image of the end face of the second optical fiber, the second light may be irradiated using a second light source configured to have a variable intensity of the second light. In this case, it is easy to adjust the intensities of the first light and the second light, for example, when the intensities of the first light and the second light incident on the imaging unit exceed the maximum light amount allowed in the imaging unit, or when the intensities of the first light and the second light incident on the imaging unit are too small, the intensities of the first light and the second light may be increased. Therefore, the intensities of the first light and the second light emitted from the end faces of the first optical fiber and the second optical fiber can be appropriately adjusted to appropriately obtain observation images of the end faces of the first optical fiber and the second optical fiber, thereby appropriately adjusting the rotation angle.

[0046] [Details of the embodiments of the present disclosure]

[0047] Hereinafter, specific examples of the embodiments of the present disclosure will be described with reference to the accompanying drawings. The present disclosure is not limited to these examples, but is shown by the claims, and is intended to include all changes within the meaning and scope equivalent to the claims. In the following description, the same elements are marked with the same reference numerals in the description of the drawings, and repeated descriptions are omitted.

[0048] (First Embodiment)

[0049] Figure 1 FIG. 1 is a diagram for explaining the outline of the welding device 1A according to the first embodiment. Figure 1 The XYZ orthogonal coordinate system is also shown in FIG. Figure 1 As shown, the fusion-splicing device 1A is a device for fusing the end face F1a of the first optical fiber F1 and the end face F2a of the second optical fiber F2 to each other. Figure 2 is a side view of the first optical fiber F1 and the second optical fiber F2. Figure 3 yes Figure 2The cross-sectional view of the first optical fiber F1 and the second optical fiber F2 in the III-III section shown in FIG. Figure 3 As shown, the first optical fiber F1 and the second optical fiber F2 have a glass portion GL and a resin coating RS surrounding the periphery of the glass portion GL. The glass portion GL has one or more (four in the illustrated example) cores CR, a marker MK, and a common cladding CL surrounding the core CR and the marker MK. The refractive index of the core CR is greater than the refractive index of the common cladding CL. The marker MK can be transparent or opaque. Figure 3 In the figure, a multi-core fiber (MCF: Multi Core Fiber) having multiple cores CR is shown as the first optical fiber F1 and the second optical fiber F2. The first optical fiber F1 and the second optical fiber F2 can be optical fibers that need to be rotated and adjusted during fusion splicing, and are not limited to multi-core optical fibers. The first optical fiber F1 and the second optical fiber F2 can also be optical fibers having a single core, such as polarization maintaining fibers (PMF: Polarization Maintaining Fiber).

[0050] like Figure 2 As shown, in the first optical fiber F1, the tip portion GL1 of the glass portion GL including the end face F1a is exposed from the resin coating RS. In the second optical fiber F2, the tip portion GL2 of the glass portion GL including the end face F2a is exposed from the resin coating RS. These exposed portions are formed by removing the resin coating RS around the tip portions GL1 and GL2 before the fusion operation.

[0051] Refer again Figure 1The fusion splicing device 1A includes a first holding portion 11 and a second holding portion 12. The first holding portion 11 makes the spatial position of the end face F1a of the first optical fiber F1 and the rotation angle θ around the central axis variable while holding the first optical fiber F1. The spatial position refers to the position on each of the X-axis, the Y-axis, and the Z-axis. The second holding portion 12 makes the spatial position of the end face F2a of the second optical fiber F2 and the rotation angle θ around the central axis variable while holding the second optical fiber F2. The first holding portion 11 and the second holding portion 12 are arranged along the Z-axis direction which is the central axis direction of the first optical fiber F1 and the second optical fiber F2. The first holding portion 11 has a V-groove 111 extending along the Z-axis direction. The V-groove 111 accommodates the portion of the first optical fiber F1 other than the tip portion GL1, that is, the portion of the first optical fiber F1 having the resin coating RS, and fixes the position of the first optical fiber F1 in the XY plane. The first holding portion 11 holds the first optical fiber F1 while the tip portion GL1 protrudes. The second holding portion 12 has a V-groove 121 extending along the Z-axis direction. The V-groove 121 accommodates the portion of the second optical fiber F2 other than the tip portion GL2, that is, the portion of the second optical fiber F2 having the resin coating RS, and fixes the position of the second optical fiber F2 in the XY plane. The second holding portion 12 holds the second optical fiber F2 with the tip portion GL2 protruding.

[0052] In one embodiment, the first holding part 11 and the second holding part 12 are made of resin. The first holding part 11 includes, for example, a table 112 formed with a V-groove 111 and on which the first optical fiber F1 is placed; and a cover 113 placed on the table 112. The table 112 and the cover 113 are arranged, for example, along the Y-axis direction intersecting the Z-axis direction. The second holding part 12 includes, for example, a table 122 formed with a V-groove 121 and on which the second optical fiber F2 is placed; and a cover 123 placed on the table 122. The table 122 and the cover 123 are arranged, for example, along the Y-axis direction.

[0053] The fusion splicing device 1A further includes a first drive unit 21 and a second drive unit 22. The first drive unit 21 supports the first holding unit 11, and controls the spatial position of the first holding unit 11 and the rotation angle θ of the first holding unit 11 around the Z axis. The first drive unit 21 controls the spatial position and the rotation angle θ of the first holding unit 11, thereby controlling the spatial position and the rotation angle θ of the end face F1a of the first optical fiber F1. The second drive unit 22 supports the second holding unit 12, and controls the spatial position of the second holding unit 12 and the rotation angle θ of the second holding unit 12 around the Z axis. The second drive unit 22 controls the spatial position and the rotation angle θ of the second holding unit 12, thereby controlling the spatial position and the rotation angle θ of the end face F2a of the second optical fiber F2. The first drive unit 21 and the second drive unit 22 are configured to include, for example, a motor.

[0054] The fusion splicing device 1A further includes a pair of discharge electrodes 2. The pair of discharge electrodes 2 are arranged at positions where the end face F1a of the first optical fiber F1 and the end face F2a of the second optical fiber F2 are opposite. The pair of discharge electrodes 2 are arranged to be opposite to each other along the X-axis direction intersecting both the Z-axis direction and the Y-axis direction. The pair of discharge electrodes 2 is a heating unit that heats the end face F1a of the first optical fiber F1 and the end face F2a of the second optical fiber F2 by discharge so that the end face F1a of the first optical fiber F1 and the end face F2a of the second optical fiber F2 are melted in a state close to each other.

[0055] The fusion splicing device 1A further includes a control unit 3A. The control unit 3A can be composed of, for example, a computer including a CPU (Central Processing Unit) and a memory. The control unit 3A is electrically connected to a power source that supplies power to the discharge electrode 2, and controls the discharge current and discharge time of the discharge electrode 2. Thus, fusion splicing is performed under conditions suitable for the types of the first optical fiber F1 and the second optical fiber F2. In addition, the control unit 3A controls the actions of the first drive unit 21 and the second drive unit 22. The actions of the first drive unit 21 and the second drive unit 22 include the following three actions. One action is an action of bringing the end face F1a of the first optical fiber F1 and the end face F2a of the second optical fiber F2 closer together. Another action is an action of adjusting the relative position of the end face F1a and the end face F2a in the XY plane (i.e., axial alignment). Still another action is an action of adjusting the relative rotation angle θ between the end face F1a and the end face F2a.

[0056] The axis alignment of the first optical fiber F1 and the second optical fiber F2 implemented by the control unit 3A is performed as follows. First, the end face F1a of the first optical fiber F1 and the vicinity of the end face F2a of the second optical fiber F2 are photographed using a camera arranged in the lateral direction (two directions intersecting the Z-axis direction and orthogonal to each other) relative to the end face F1a and the end face F2a. Then, the control unit 3A controls the first drive unit 21 and the second drive unit 22 in such a manner that the central axes of the first optical fiber F1 and the second optical fiber F2 included in the observation image are consistent with each other.

[0057] Figure 4 Schematically shows a cross section of the first holding portion 11 and the second holding portion 12 along the YZ plane. Figure 4As shown, the fusion splicing device 1A further includes a light source 30 and a light detection unit 40. The light source 30 irradiates light L to the resin coating RS of the first optical fiber F1. In one example, the light source 30 is disposed inside the first holding portion 11 so as to be in contact with the first optical fiber F1. The light source 30 may also be disposed to press the resin coating RS of the first optical fiber F1. The configuration of the light source 30 is not limited thereto, and the light source 30 may also be disposed outside the first holding portion 11. The light source 30 may also be configured separately from the first optical fiber F1. In this case, the light source 30 may also irradiate light L to the bent portion formed by bending the first optical fiber F1.

[0058] The light detection unit 40 is a power meter that detects the intensity of the light L that leaks through the resin coating RS of the second optical fiber F2 when the end face F1a of the first optical fiber F1 and the end face F2a of the second optical fiber F2 are close to each other. In one example, the light detection unit 40 is arranged to be connected to the second optical fiber F2 inside the second holding part 12. The configuration of the light detection unit 40 is not limited to this, and the light detection unit 40 may also be arranged outside the second holding part 12. The light detection unit 40 may also be configured separately from the second optical fiber F2. In this case, the light detection unit 40 may also detect the light L that leaks from the bent portion formed by bending the second optical fiber F2.

[0059] The light source 30 and the light detection unit 40 are Figure 1 The control unit 3A shown is electrically connected. The control unit 3A controls the output action of the light L in the light source 30. In addition, the control unit 3A inputs a signal related to the light intensity of the light L detected in the light detection unit 40 from the light detection unit 40. The light L irradiated to the resin coating RS of the first optical fiber F1 passes through the resin coating RS of the first optical fiber F1 and enters the glass portion GL, and is concentrated on each core CR. Then, after the light L propagates through each core CR of the first optical fiber F1, it propagates through each core CR of the second optical fiber F2. The leakage light of the light L leaks through the resin coating RS of the second optical fiber F2. What is detected in the light detection unit 40 is the leaked light L. Figure 4 In the figure, one core CR among a plurality of cores CR is shown as a representative.

[0060] When the position of the core CR of the first optical fiber F1 and the position of the core CR of the second optical fiber F2 are offset from each other, the greater the offset, the more difficult it is for the light L to propagate from the core CR of the first optical fiber F1 to the core CR of the second optical fiber F2. As a result, the light intensity detected in the light detection unit 40 becomes smaller. Therefore, the control unit 3A adjusts the relative rotation angle θ between the end face F1a and the end face F2a in a manner that the light intensity detected in the light detection unit 40 approaches the maximum value by controlling one or both of the first drive unit 21 and the second drive unit 22. As a result, the position of the core CR of the first optical fiber F1 and the position of the core CR of the second optical fiber F2 can be aligned with each other.

[0061] The light source 30 is configured so that the central wavelength of the light L can be varied. Figure 5 and Figure 6 Each of the diagrams schematically shows a light source 30A and a light source 30B as configuration examples of the light source 30 . Figure 5 The light source 30A shown has a plurality of light emitting elements 31. The central wavelengths of the light emitting bands of the plurality of light emitting elements 31 are different from each other. The light emitting bands of the plurality of light emitting elements 31 may overlap or may not overlap. The central wavelength of the light L is selected by selectively supplying current to any one of the plurality of light emitting elements 31. The light emitting wavelength bandwidth of each light emitting element 31 may be a wide band such as more than 100 nm, or a narrow band less than 100 nm. The light emitting bands of the plurality of light emitting elements 31 may be set, for example, in a manner of dividing a band of 400 nm to 2000 nm.

[0062] Figure 6 The light source 30B shown has a light emitting element 32 and a wavelength variable filter 33. The light emitting element 32 is an element that outputs a wide-band (e.g., 400 nm to 2000 nm) wide-spectrum (broad) light. The wavelength variable filter 33 is a bandpass filter that receives light from the light emitting element 32 and allows only a portion of the wavelength components of the light to pass through. The wavelength variable filter 33 is configured to be able to change the passing wavelength band. The passing wavelength band of the wavelength variable filter 33 is changed, thereby changing the center wavelength of the light passing through the wavelength variable filter 33, that is, the light L output from the light source 30B.

[0063] In the light source 30, the central wavelength of the light L may be fixed instead of variable. In this case, the light source 30 is configured so that the wavelength bandwidth of the light L is greater than 100 nm, for example, greater than 1000 nm. In one example, the light source 30 outputs a wide spectrum of light having a wavelength band of 400 nm to 2000 nm. In this case, the wavelength bandwidth of the light L is 1600 nm.

[0064] Alternatively, the light detection unit 40 may be configured such that the center wavelength of the wavelength band to which the light detection unit 40 has sensitivity is variable. In this case, the wavelength band to which the light detection unit 40 has sensitivity may be set to match the wavelength band of the light L output from the light source 30. In one example, the center wavelength of the wavelength band to which the light detection unit 40 has sensitivity is set to coincide with the center wavelength of the wavelength band of the light L output from the light source 30.

[0065] Figure 7 1A is a flowchart showing the operation of the welding device 1A. Figure 7The operation of the fusion splicing device 1A is described, and the fusion splicing method of the present embodiment is described. First, in step ST11, the control unit 3A controls the first drive unit 21 and the second drive unit 22 in such a manner that the end face F1a of the first optical fiber F1 and the end face F2a of the second optical fiber F2 are close to each other. As a result, the end face F1a and the end face F2a are opposite to each other. However, there is a small gap between the end face F1a and the end face F2a. Next, in step ST12, the axis alignment of the first optical fiber F1 and the second optical fiber F2 is performed. Specifically, a camera arranged on the side of the end face F1a and the end face F2a is used to shoot the vicinity of the end face F1a of the first optical fiber F1 and the end face F2a of the second optical fiber F2. Then, the control unit 3A controls the first drive unit 21 and the second drive unit 22 in such a manner that the central axes of the first optical fiber F1 and the second optical fiber F2 included in the observation image are consistent with each other.

[0066] Next, in step ST13, the light source 30 whose output light has a variable central wavelength irradiates the resin coating RS of the first optical fiber F1 with light L. Alternatively, in step ST13, the light source 30 whose output light has a fixed central wavelength irradiates the resin coating RS of the first optical fiber F1 with light L having a wavelength bandwidth of 100 nm or more. Then, in step ST14, the light detection unit 40 detects the intensity of the light L leaked through the resin coating RS of the second optical fiber F2. As described above, the light detection unit 40 may be configured such that the central wavelength of the wavelength band in which it has sensitivity is variable. Then, in step ST15, the control unit 3A adjusts the relative rotation angle θ between the first optical fiber F1 and the second optical fiber F2 based on the intensity of the light L detected in step ST14. At this time, the control unit 3A adjusts the relative rotation angle θ between the end face F1a and the end face F2a by controlling one or both of the first drive unit 21 and the second drive unit 22 in such a way that the light intensity detected in the light detection unit 40 approaches the maximum value. Then, in step ST16, discharge is generated between the pair of discharge electrodes 2 to heat and melt the end face F1a of the first optical fiber F1 and the end face F2a of the second optical fiber F2, thereby connecting the end faces F1a and F2a to each other.

[0067] The effects obtained by the fusion splicing device and the fusion splicing method of the present embodiment having the above configuration will be described. In the fusion splicing device 1A of the present embodiment, the light source 30 that irradiates the light L to the resin coating RS of the first optical fiber F1 is configured so that the central wavelength of the light L is variable. In the fusion splicing method of the present embodiment, the light source 30 whose output light has a variable central wavelength is also used to irradiate the light to the resin coating RS of the first optical fiber F1. As described above, the coloring material and particles contained in the resin coating RS absorb or scatter the light L incident to the resin coating RS, but the magnitude of the absorption and scattering at this time depends on the wavelength of the light L. According to the fusion splicing device 1A and the fusion splicing method of the present embodiment, a wavelength with small absorption and scattering in the resin coating RS is selected and the light L of the wavelength is irradiated to the resin coating RS, so that the light L is easy to pass through the resin coating RS and reach the glass portion GL. In addition, the light L is easy to leak from the resin coating RS of the second optical fiber F2. Therefore, according to the present embodiment, the intensity of the light L leaking through the resin coating RS of the second optical fiber F2 can be increased, and the rotation angle θ can be appropriately adjusted. The wavelength of the light L may be changed automatically by the control unit 3A according to the types of the first optical fiber F1 and the second optical fiber F2 input before fusion splicing. Alternatively, the wavelength of the light L may be changed by an operator through an input unit such as a switch provided in the fusion splicing apparatus 1A.

[0068] As described above, the light source 30 may be configured so that the wavelength bandwidth of the light L is 100 nm or more. By using such a wide-band light L, the rotation angle θ of a plurality of optical fibers having different absorption characteristics and scattering characteristics of the resin coating RS can be adjusted using the same wavelength of light L. Thus, the frequency of changing the wavelength of the light L can be reduced, and the operator's work can be reduced.

[0069] As described above, the light detection unit 40 may be configured to have a variable central wavelength of a band having sensitivity. In this case, the light L can be detected with an optimal sensitivity according to the wavelength of the light L. This can improve the detection efficiency of the light L and more accurately adjust the rotation angle θ.

[0070] As described above, the light source 30 may be configured such that the central wavelength of the light L is not variable but fixed, and the wavelength bandwidth of the light L is 100 nm or more. In step ST13 of the fusion method of the present embodiment, the light source 30 in which the central wavelength of the light L is not variable but fixed may be used to irradiate the resin coating RS of the first optical fiber F1 with light L having a wavelength bandwidth of 100 nm or more. As described above, the coloring material and particles contained in the resin coating RS absorb or scatter the light L incident on the resin coating RS, but the magnitude of the absorption and scattering at this time depends on the wavelength of the light L. By using the wide-band light L having a bandwidth of 100 nm or more, at least one wavelength component contained in the bandwidth, typically the wavelength component with the smallest absorption and scattering contained in the bandwidth, easily passes through the resin coating RS and reaches the glass portion GL. Therefore, the intensity of the light L leaking through the resin coating RS of the second optical fiber F2 can be increased, and the rotation angle θ can be appropriately adjusted.

[0071] In the present embodiment, the light source 30 may be configured to make the intensity of the light L irradiated to the resin coating RS of the first optical fiber F1 variable. In this case, it is easy to adjust the intensity of the light L, for example, by reducing the intensity of the light L when the intensity of the light L incident on the light detection unit 40 exceeds the maximum amount of light allowed in the light detection unit 40, or by increasing the intensity of the light L when the intensity of the light L incident on the light detection unit 40 is too small. Therefore, the intensity of the light L leaked through the resin coating RS of the second optical fiber F2 can be appropriately adjusted, so that the rotation angle θ can be appropriately adjusted. The change in the intensity of the light L can be automatically performed by the control unit 3A based on the intensity of the light L incident on the light detection unit 40. Alternatively, the change in the intensity of the light L can be performed by the operator through an input unit such as a switch provided in the fusion splicing device 1A.

[0072] (Second Embodiment)

[0073] Figure 8 This is a diagram showing a part of the structure of the fusion splicing device 1B of the second embodiment, and schematically shows a cross section of the first holding portion 11 and the second holding portion 12 along the YZ plane. The fusion splicing device 1B of this embodiment is a device for fusing the end face F1a of the first optical fiber F1 and the end face F2a of the second optical fiber F2 to each other. The fusion splicing device 1B includes a first holding portion 11, a second holding portion 12, a first driving portion 21, a second driving portion 22, and a pair of discharge electrodes 2, similarly to the first embodiment. Figure 8 As shown, the welding device 1B of this embodiment includes a first light source 51, a second light source 52, an imaging unit 60, a reflecting mirror 61, and a control unit 3B instead of the light source 30, the light detection unit 40, and the control unit 3A of the first embodiment.

[0074] The control unit 3B can be constituted by a computer including a CPU and a memory, for example. The control unit 3B is electrically connected to a power source that supplies power to the discharge electrode 2. The control unit 3B controls the discharge current and discharge time of the discharge electrode 2. Thus, the fusion is performed under conditions suitable for the types of the first optical fiber F1 and the second optical fiber F2. The control unit 3B controls the actions of the first drive unit 21 and the second drive unit 22. The actions of the first drive unit 21 and the second drive unit 22 include the following three actions. One action is an action of bringing the end face F1a of the first optical fiber F1 and the end face F2a of the second optical fiber F2 closer. Another action is an action of adjusting the relative position of the end face F1a and the end face F2a in the XY plane (i.e., axial alignment). Another action is an action of adjusting the relative rotation angle θ between the end face F1a and the end face F2a. The process of axial alignment of the first optical fiber F1 and the second optical fiber F2 implemented by the control unit 3B is the same as the process of axial alignment of the first optical fiber F1 and the second optical fiber F2 implemented by the control unit 3A in the first embodiment.

[0075] The first light source 51 irradiates the first light L1 toward the resin coating RS of the first optical fiber F1. The first light L1 irradiated to the resin coating RS of the first optical fiber F1 becomes the observation light emitted from the end face F1a of the first optical fiber F1. In one example, the first light source 51 is arranged to be connected to the first optical fiber F1 inside the first retaining portion 11. The first light source 51 may also be arranged to press the resin coating RS of the first optical fiber F1. The configuration of the first light source 51 is not limited to this, and the first light source 51 may also be arranged outside the first retaining portion 11. The first light source 51 may also be arranged separately from the first optical fiber F1. In this case, the first light source 51 may also irradiate the first light L1 into the bent portion formed by bending the first optical fiber F1. The first light source 51 is configured so that the center wavelength of the first light L1 is variable. In this case, the first light source 51 may be configured so that the bandwidth of the wavelength of the first light L1 is greater than 100 nm. The configuration example of the first light source 51 may be the same as the configuration example of the light source 30 of the first embodiment (refer to Figure 5 and Figure 6 ) is the same. Alternatively, in the first light source 51, the central wavelength of the first light L1 may not be variable but fixed. In this case, the first light source 51 is configured so that the bandwidth of the wavelength of the first light L1 is greater than 100nm, for example, greater than 1000nm. In one example, the first light source 51 outputs a wide spectrum of light having a wavelength band of 400nm to 2000nm. In this case, the bandwidth of the wavelength of the first light L1 is 1600nm.

[0076] The second light source 52 irradiates the second light L2 to the resin coating RS of the second optical fiber F2. The second light L2 irradiated to the resin coating RS of the second optical fiber F2 becomes the observation light emitted from the end face F2a of the second optical fiber F2. In one example, the second light source 52 is provided to be in contact with the second optical fiber F2 inside the second holding portion 12. The second light source 52 may also be provided to press the resin coating RS of the second optical fiber F2. The configuration of the second light source 52 is not limited thereto, and the second light source 52 may also be provided outside the second holding portion 12. The second light source 52 may also be configured separately from the second optical fiber F2. In this case, the second light source 52 may also irradiate the second light L2 to the bent portion formed by bending the second optical fiber F2. The second light source 52 is configured so that the center wavelength of the second light L2 is variable. In this case, the second light source 52 may be configured so that the bandwidth of the wavelength of the second light L2 is 100 nm or more. The configuration example of the second light source 52 may be the same as the light source 30 of the first embodiment. Alternatively, in the second light source 52, the center wavelength of the second light L2 may not be variable but may be fixed. In this case, the second light source 52 is configured so that the bandwidth of the wavelength of the second light L2 is greater than 100 nm, for example, greater than 1000 nm. In one example, the second light source 52 outputs a wide spectrum of light having a wavelength band of 400 nm to 2000 nm. In this case, the bandwidth of the wavelength of the second light L2 is 1600 nm.

[0077] The imaging unit 60 is a camera that obtains observation images of the end face F1a of the first optical fiber F1 and the end face F2a of the second optical fiber F2. In the illustrated example, the imaging unit 60 is arranged in the lateral direction (along the direction of the first optical fiber F1 and the end face F2a) with respect to the end face F1a and the end face F2a. Figure 1 The reflector 61 is arranged between the end face F1a of the first optical fiber F1 and the end face F2a of the second optical fiber F2. The angle of the reflector 61 is adjusted along the swing direction A1 between the angle when the end face F1a of the first optical fiber F1 is photographed by the imaging unit 60 and the angle when the end face F2a of the second optical fiber F2 is observed by the imaging unit 60. In a state where the reflector 61 is arranged to reflect the observation light from the end face F1a of the first optical fiber F1 toward the imaging unit 60, the imaging unit 60 outputs the observation image of the end face F1a of the first optical fiber F1. In a state where the reflector 61 is arranged to reflect the observation light from the end face F2a of the second optical fiber F2 toward the imaging unit 60, the imaging unit 60 outputs the observation image of the end face F2a of the second optical fiber F2.

[0078] The first light source 51, the second light source 52, and the imaging unit 60 are electrically connected to the control unit 3B. The control unit 3B controls the output operation of the first light L1 in the first light source 51 and the output operation of the second light L2 in the second light source 52. In addition, the control unit 3B inputs the observation images of the end face F1a and the end face F2a acquired in the imaging unit 60 from the imaging unit 60. In these observation images, the plurality of cores CR are brightly shown by the first light L1 and the second light L2. The control unit 3B adjusts the relative rotation angle θ of the first optical fiber F1 and the second optical fiber F2 based on the observation image of the end face F1a and the observation image of the end face F2a. In other words, the control unit 3B adjusts the rotation angle θ of one or both of the first optical fiber F1 and the second optical fiber F2 in such a manner that the positions of the plurality of cores CR of the first optical fiber F1 in the XY plane and the positions of the plurality of cores CR of the second optical fiber F2 in the XY plane coincide with each other.

[0079] Alternatively, the imaging unit 60 may be configured such that the center wavelength of the frequency band to which the imaging unit 60 is sensitive is variable. In this case, the frequency band to which the imaging unit 60 is sensitive may be set to match the frequency bands of the first light L1 and the second light L2 outputted from the first light source 51 and the second light source 52, respectively. In one example, the center wavelength of the frequency band to which the imaging unit 60 is sensitive is set to coincide with the center wavelength of the frequency bands of the first light L1 and the second light L2 outputted from the first light source 51 and the second light source 52, respectively.

[0080] Fig. 9 1B is a flowchart showing the operation of the welding device 1B. Fig. 9 The operation of the fusion splicing device 1B is described, and the fusion splicing method of the present embodiment is described. First, in step ST21, the first light source 51 whose output light has a variable central wavelength irradiates the resin coating RS of the first optical fiber F1 with the first light L1. Alternatively, in step ST21, the first light source 51 whose output light has a fixed central wavelength irradiates the resin coating RS of the first optical fiber F1 with the first light L1 having a wavelength bandwidth of 100 nm or more. Then, while the first light source 51 continues to irradiate the first light L1, the imaging unit 60 acquires an observation image of the end face F1a of the first optical fiber F1. Next, in step ST22, the second light source 52 whose output light has a variable central wavelength irradiates the resin coating RS of the second optical fiber F2 with the second light L2. Alternatively, in step ST22, the second light source 52 whose output light has a fixed central wavelength irradiates the resin coating RS of the second optical fiber F2 with the second light L2 having a wavelength bandwidth of 100 nm or more. Then, while the second light source 52 continues to irradiate the second light L2, the imaging unit 60 acquires an observation image of the end face F2a of the second optical fiber F2.

[0081] Next, in step ST23, the relative rotation angle between the first optical fiber F1 and the second optical fiber F2 is adjusted based on the observation image of the end face F1a of the first optical fiber F1 and the observation image of the end face F2a of the second optical fiber F2. Then, in step ST24, the control unit 3B controls the first drive unit 21 and the second drive unit 22 in such a manner that the end face F1a of the first optical fiber F1 and the end face F2a of the second optical fiber F2 are close to each other. Thus, the end face F1a and the end face F2a are opposite to each other. However, there is a small gap between the end face F1a and the end face F2a. Next, in step ST25, the axis alignment of the first optical fiber F1 and the second optical fiber F2 is performed. Specifically, a camera arranged in a horizontal direction relative to the end face F1a and the end face F2a is used to shoot the vicinity of the end face F1a of the first optical fiber F1 and the end face F2a of the second optical fiber F2. Then, the control unit 3B controls the first drive unit 21 and the second drive unit 22 in such a manner that the central axes of the first optical fiber F1 and the second optical fiber F2 included in the observation image are consistent with each other. Then, in step ST26, discharge is generated between the pair of discharge electrodes 2 to heat and melt the end face F1a of the first optical fiber F1 and the end face F2a of the second optical fiber F2, thereby connecting the end faces F1a and F2a to each other.

[0082] The effects obtained by the fusion splicing device and the fusion splicing method of the present embodiment having the above configuration are described. In the fusion splicing device 1B of the present embodiment, the first light source 51 for irradiating the first light L1 to the resin coating RS of the first optical fiber F1 and the second light source 52 for irradiating the second light L2 to the resin coating RS of the second optical fiber F2 are respectively configured so that the center wavelengths of the first light L1 and the second light L2 are variable. In the fusion splicing method of the present embodiment, the first light source 51 and the second light source 52 whose output light center wavelengths are variable are also used to irradiate the first light L1 and the second light L2 to the resin coating RS of the first optical fiber F1 and the second optical fiber F2, respectively. As described above, the coloring material and particles contained in the resin coating RS absorb or scatter the first light L1 and the second light L2 incident on the resin coating RS, but the magnitude of the absorption and scattering at this time depends on the wavelengths of the first light L1 and the second light L2. According to the fusion splicing device 1B and the fusion splicing method of the present embodiment, a wavelength with low absorption and scattering in the resin coating RS is selected and the first light L1 and the second light L2 of the wavelength are irradiated to the resin coating RS of the first optical fiber F1 and the second optical fiber F2, respectively, so that the first light L1 and the second light L2 can easily pass through the resin coating RS and reach the glass portion GL. Therefore, according to the present embodiment, the observation images of the end face F1a of the first optical fiber F1 and the end face F2a of the second optical fiber F2 can be made brighter, so that the rotation angle θ can be adjusted appropriately. The change of the wavelength of the first light L1 and the second light L2 can be automatically performed by the control unit 3B according to the type of the first optical fiber F1 and the second optical fiber F2 input before fusion splicing. Alternatively, the change of the wavelength of the first light L1 and the second light L2 can be performed by the operator through an input unit such as a switch provided in the fusion splicing device 1B.

[0083] As described above, the first light source 51 and the second light source 52 may be configured so that the wavelength bandwidth of the first light L1 and the second light L2 is 100 nm or more, respectively. By using such broadband first light L1 and second light L2, the rotation angle θ of multiple optical fibers having different absorption characteristics and scattering characteristics of the resin coating RS can be adjusted using light of the same wavelength. Thus, the frequency of changing the wavelength of the first light L1 and the second light L2 can be reduced, and the operator's work can be reduced.

[0084] As described above, the imaging unit 60 may be configured to have a variable central wavelength of a frequency band having a sensitivity. In this case, the first light L1 and the second light L2 can be photographed with an optimal sensitivity corresponding to the wavelengths of the first light L1 and the second light L2, and the observation images of the end face F1a of the first optical fiber F1 and the end face F2a of the second optical fiber F2 can be made brighter, thereby enabling more accurate adjustment of the rotation angle θ.

[0085] As described above, the first light source 51 and the second light source 52 may be configured such that the center wavelengths of the first light L1 and the second light L2 are not variable but fixed, and the wavelength bandwidth of the first light L1 and the second light L2 is greater than 100 nm. In step ST21 and step ST22 of the fusion method of the present embodiment, the first light source 51 and the second light source 52, whose center wavelengths are not variable but fixed, may be used to irradiate the resin coating RS of the first optical fiber F1 and the second optical fiber F2 with the first light L1 and the second light L2 having a wavelength bandwidth of greater than 100 nm, respectively. As described above, the coloring material and particles contained in the resin coating RS absorb or scatter the first light L1 and the second light L2 incident on the resin coating RS, but the magnitude of the absorption and scattering at this time depends on the wavelengths of the first light L1 and the second light L2. By using the first light L1 and the second light L2 of a wide band having a bandwidth of 100 nm or more, at least one wavelength component included in the band, typically a wavelength component with the smallest absorption and scattering included in the band, can easily pass through the resin coating RS and reach the glass portion GL. Therefore, the observed images of the end face F1a of the first optical fiber F1 and the end face F2a of the second optical fiber F2 can be made brighter, so that the rotation angle θ can be appropriately adjusted.

[0086] In the present embodiment, the first light source 51 may be configured to make the intensity of the first light L1 irradiated to the resin coating RS of the first optical fiber F1 variable. Similarly, the second light source 52 may be configured to make the intensity of the second light L2 irradiated to the resin coating RS of the second optical fiber F2 variable. In this case, the intensity of the first light L1 and the second light L2 can be easily adjusted. For example, when the intensity of the first light L1 and the second light L2 incident on the imaging unit 60 exceeds the maximum light amount allowed in the imaging unit 60, the intensity of the first light L1 and the second light L2 can be reduced. When the intensity of the first light L1 and the second light L2 incident on the imaging unit 60 is too small, the intensity of the first light L1 and the second light L2 can be increased. Therefore, the intensity of the first light L1 emitted from the end face F1a of the first optical fiber F1 and the intensity of the second light L2 emitted from the end face F2a of the second optical fiber F2 can be appropriately adjusted, so that the observation images of the end face F1a of the first optical fiber F1 and the end face F2a of the second optical fiber F2 can be appropriately obtained. Thus, the rotation angle θ can be appropriately adjusted. The change in the intensity of the first light L1 and the second light L2 can be automatically performed by the control unit 3B based on the intensity of the first light L1 and the second light L2 incident on the imaging unit 60. Alternatively, the change in the intensity of the first light L1 and the second light L2 can be performed by an operator through an input unit such as a switch provided in the welding device 1B.

[0087] The fusion splicing device and fusion splicing method disclosed in the present invention are not limited to the above-mentioned embodiments, and other various modifications can be made. For example, the above-mentioned embodiments can also be combined with each other according to the desired purpose and effect. In the second embodiment, a shooting unit 60 is provided for shooting the end face F1a of the first optical fiber F1 and shooting the end face F2a of the second optical fiber F2. The shooting unit for shooting the end face F1a and the shooting unit for shooting the end face F2a can also be provided separately. In this case, the reflector 61 is not required.

[0088] Description of Reference Numerals

[0089] 1A, 1B: Welding device

[0090] 2: Discharge electrode

[0091] 3A, 3B: Control unit

[0092] 11: First holding part

[0093] 12: Second holding unit

[0094] 21: First drive unit

[0095] 22: Second drive unit

[0096] 30, 30A, 30B: Light source

[0097] 31, 32: Light-emitting element

[0098] 33: Wavelength Variable Filter

[0099] 40: Light detection unit

[0100] 51: First Light Source

[0101] 52: Second light source

[0102] 60: Photography Department

[0103] 61: Reflector

[0104] 111, 121: V groove

[0105] 112, 122: Taiwan

[0106] 113, 123: Cover

[0107] A1: Swing direction

[0108] CL: Common Cladding

[0109] CR: Core

[0110] F1: First Fiber

[0111] F1a: End face

[0112] F2: Second optical fiber

[0113] F2a: End face

[0114] GL: Glass part

[0115] GL1, GL2: Top part

[0116] L: Light

[0117] L1: First Light

[0118] L2: Second Light

[0119] MK: Mark

[0120] RS: Resin coating

[0121] θ: rotation angle.

Claims

1. A welding device, comprising: The first holding portion holds the first optical fiber so that the rotation angle of the end face of the first optical fiber around the central axis is variable, wherein: The first optical fiber has: a glass portion having one or more cores and a cladding surrounding the one or more cores; and a resin coating surrounding the outer periphery of the glass portion, and a tip portion of the glass portion including the end face of the first optical fiber is exposed from the resin coating; a second holding portion that allows a rotation angle of an end face of the second optical fiber around a central axis to be variable while holding the second optical fiber, wherein the second optical fiber comprises: a glass portion having one or more cores and a cladding surrounding the one or more cores; and a resin coating surrounding an outer periphery of the glass portion, and a tip portion of the glass portion of the second optical fiber including the end face is exposed from the resin coating; a light source that irradiates light toward the resin coating of the first optical fiber, wherein the light source is configured to have one or both of the characteristics that the central wavelength of the light is variable and the bandwidth of the wavelength of the light is 100 nm or more; a light detecting unit that detects the intensity of the light leaked through the resin coating of the second optical fiber in a state where the end face of the first optical fiber and the end face of the second optical fiber are close to each other; and The heating unit heats the end face of the first optical fiber and the end face of the second optical fiber so that the end face of the first optical fiber and the end face of the second optical fiber are melted in a state of being close to each other.

2. The welding device according to claim 1, wherein: The light detection unit is configured so that the center wavelength of a frequency band having sensitivity is variable.

3. A welding device, comprising: The first holding portion holds the first optical fiber so that the rotation angle of the end face of the first optical fiber around the central axis is variable, wherein: The first optical fiber has: a glass portion having one or more cores and a cladding surrounding the one or more cores; and a resin coating surrounding the outer periphery of the glass portion, and a tip portion of the glass portion including the end face of the first optical fiber is exposed from the resin coating; a second holding portion that allows a rotation angle of an end face of the second optical fiber around a central axis to be variable while holding the second optical fiber, wherein the second optical fiber comprises: a glass portion having one or more cores and a cladding surrounding the one or more cores; and a resin coating surrounding an outer periphery of the glass portion, and a tip portion of the glass portion of the second optical fiber including the end face is exposed from the resin coating; a first light source that irradiates the resin coating of the first optical fiber with first light, wherein the first light source is configured to have one or both of the characteristics that the central wavelength of the first light is variable and the bandwidth of the wavelength of the first light is greater than 100 nm; a second light source that irradiates the resin coating of the second optical fiber with a second light, wherein the second light source is configured to have one or both of the characteristics that the central wavelength of the second light is variable and the bandwidth of the wavelength of the second light is greater than 100 nm; an imaging unit for acquiring observation images of the end face of the first optical fiber and the end face of the second optical fiber; and The heating unit heats the end face of the first optical fiber and the end face of the second optical fiber so that the end face of the first optical fiber and the end face of the second optical fiber are melted in a state of being close to each other.

4. The welding device according to claim 3, wherein: The imaging unit is configured such that a central wavelength of a frequency band having sensitivity is variable.

5. The welding device according to claim 1 or 2, wherein: The light source is configured to vary the intensity of the light irradiated onto the resin coating of the first optical fiber.

6. The welding device according to claim 3 or 4, wherein: The first light source is configured to vary the intensity of the first light irradiated onto the resin coating of the first optical fiber. The second light source is configured to vary the intensity of the second light irradiated onto the resin coating of the second optical fiber.

7. A welding method comprising the following steps: preparing a first optical fiber and a second optical fiber, wherein the first optical fiber and the second optical fiber respectively have: a glass portion having one or more cores and a cladding surrounding the one or more cores; and a resin coating surrounding the outer periphery of the glass portion, and tip portions of the glass portion including end faces of the first optical fiber and the second optical fiber are exposed from the resin coating; Bringing the end face of the first optical fiber and the end face of the second optical fiber closer to each other; irradiating light to the resin coating of the first optical fiber using a light source configured to have one or both of the characteristics of a variable central wavelength of output light and a wavelength bandwidth of the output light being 100 nm or more; detecting the intensity of the light leaked through the resin coating of the second optical fiber; adjusting a relative rotation angle between the first optical fiber and the second optical fiber based on the intensity of the light detected in the detecting step; as well as The end face of the first optical fiber and the end face of the second optical fiber are heated to be melted.

8. The welding method according to claim 7, wherein: In the step of detecting, the intensity of the light is detected using a photodetector configured to have a variable central wavelength of a frequency band of sensitivity.

9. A welding method comprising the following steps: preparing a first optical fiber and a second optical fiber, wherein the first optical fiber and the second optical fiber respectively have: a glass portion having one or more cores and a cladding surrounding the one or more cores; and a resin coating surrounding the outer periphery of the glass portion, and tip portions of the glass portion including end faces of the first optical fiber and the second optical fiber are exposed from the resin coating; Acquiring an observation image of the end face of the first optical fiber while irradiating the resin coating of the first optical fiber with first light using a first light source configured to have one or both of the characteristics of a variable central wavelength of output light and a wavelength bandwidth of output light being 100 nm or more; Acquiring an observation image of the end face of the second optical fiber while irradiating the resin coating of the second optical fiber with second light using a second light source configured to have one or both of the characteristics of a variable central wavelength of the output light and a wavelength bandwidth of the output light being 100 nm or more; adjusting a relative rotation angle between the first optical fiber and the second optical fiber based on an observed image of the end face of the first optical fiber and an observed image of the end face of the second optical fiber; bringing the end face of the first optical fiber and the end face of the second optical fiber closer to each other; and The end face of the first optical fiber and the end face of the second optical fiber are heated to be melted.

10. The welding method according to claim 9, wherein: In the step of obtaining an observation image of the end face of the first optical fiber and the step of obtaining an observation image of the end face of the second optical fiber, an imaging device configured to have a frequency band with a sensitivity whose central wavelength is variable is used to obtain the observation image of the end face of the first optical fiber and the observation image of the end face of the second optical fiber, respectively.

11. The welding method according to claim 7 or 8, wherein: In the step of irradiating, the light is irradiated using the light source configured to vary the intensity of the light irradiated to the resin coating of the first optical fiber.

12. The welding method according to claim 9 or 10, wherein: In the step of acquiring the observation image of the end face of the first optical fiber, the first light is irradiated using the first light source configured so that the intensity of the first light is variable. In the step of acquiring the observed image of the end face of the second optical fiber, the second light is irradiated using the second light source configured so that the intensity of the second light is variable.

Images