Fusion splicer

Abstract

The present invention provides a fusion splicer that allows for end-face observation and enables fusion splicing using three electrode rods. [Solution] When the reflective member 23 is raised towards the space between the optical fibers 21, the shoulder portion 27 of the reflective member 23 comes into contact with the tapered portion 29, and the shielding member 25 is pushed down. That is, the shielding member 25 rotates and tilts around the rotation axis 31. Also, since the third electrode 7c is fixed to the shielding member 25, the third electrode 7c rotates along with the rotational movement of the shielding member 25. In this way, when the shielding member 25 opens, the third electrode 7c moves laterally together with the shielding member 25, and the top of the reflective member 23 is opened, thus preventing interference between the rising reflective member 23, the shielding member 25 and the third electrode 7c.

Description

Technical Field

[0001] The present invention relates to a fusion splicer having three electrodes and excellent centering workability.

Background Art

[0002] A fusion splicer is used to connect optical fibers. The fusion splicer abuts optical fibers held by a pair of holders, places them between electrodes, and fuses the tips of the optical fibers by an arc to connect the optical fibers.

[0003] When fusing optical fibers, centering work to align the tip positions of the optical fibers is necessary. For this reason, conventionally, while the optical fibers are arranged facing each other, the tip positions of the optical fibers are imaged by an imaging unit from the side (a direction perpendicular to the axial direction of the optical fibers) for centering.

[0004] On the other hand, when there is a circumferential directionality with respect to the cross-sectional form, such as in a so-called polarization-maintaining fiber, a multi-core fiber, or a hollow-core fiber, rather than a general single-core optical fiber, not only centering in the tip position but also centering in the rotational direction is required. That is, not only centering in the X-Y direction of the optical fiber, but also rotational centering in the circumferential direction with the axial direction of the optical fiber as the central axis is required.

[0005] In order to perform such rotational centering of an optical fiber, for example, there is a method of arranging a reflecting member between the opposing portions of the optical fiber, reflecting the end face of the optical fiber to the imaging unit for imaging, and performing rotational centering by observing the end face (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] As mentioned earlier, fusion splicing of optical fibers is generally performed by applying high pressure between two electrode rods and utilizing the heat generated by the resulting discharge. However, for fusion splicing of large-diameter optical fibers, multi-core fibers, and hollow-core fibers, a fusion splicing method using three electrode rods has also been proposed. In this case, a triangular discharge is performed between the three electrode rods, surrounding the entire circumference of the optical fiber, and fusion is achieved. This allows for uniform heating around the optical fiber, resulting in lower loss fusion splicing compared to using two electrodes.

[0008] However, as mentioned above, when rotational alignment is required, such as with multicore fibers, the end face is observed by reflecting the light from the end face of the optical fiber with a reflective element such as a prism. That is, a reflective element is inserted between two opposing optical fibers, and the end face is observed by an imaging element positioned opposite the reflective element.

[0009] In this case, the reflective element and imaging device are positioned approximately perpendicular to the two electrode rods. Therefore, if one attempts to discharge the optical fiber junction using three electrode rods, the position of the third electrode rod interferes with the position of the reflective element and imaging device. For this reason, no fusion splicer existed that could combine a rotational centering mechanism using a reflective element and imaging device with a fusion splicing mechanism using three electrode rods.

[0010] This invention has been made in view of the above problems, and aims to provide a fusion machine that allows end face observation and enables fusion bonding with three electrode rods. [Means for solving the problem]

[0011] To achieve the aforementioned objectives, the present invention provides a fusion splicer for connecting optical fibers, comprising: an optical fiber holding section for holding a pair of optical fibers facing each other; a first electrode, a second electrode, and a third electrode arranged in a direction substantially perpendicular to the opposing direction of the pair of optical fibers; a reflective member that is movable between the optical fibers when the pair of optical fibers are arranged facing each other; and an imaging section for capturing an image reflected by the reflective member, wherein the reflective member has a reflective surface that reflects the image of the end face of each optical fiber toward the imaging section, and has a shielding member that is positioned between the reflective member and the optical fiber when the reflective member is retracted from the opposing position of the optical fiber, and is configured to close in conjunction with the movement of the reflective member when the reflective member is retracted from the opposing position of the optical fiber, the third electrode is fixed to the shielding member, and when the shielding member is closed, the third electrode is positioned toward the opposing part of the pair of optical fibers, and when the shielding member is opened, the third electrode moves together with the shielding member to avoid interference with the reflective member.

[0012] The device has a moving mechanism for moving the first electrode, the second electrode, and the third electrode, and the distance between the first electrode, the second electrode, and the third electrode and the opposing portions of the pair of optical fibers may be variable.

[0013] The control unit has an input section for inputting the type of optical fiber to be connected, and the control unit may operate the moving mechanism according to the type of optical fiber input in the input section.

[0014] It may be possible to switch between a first condition in which discharge occurs between the two electrodes, the first electrode and the second electrode, and a second condition in which discharge occurs between the three electrodes, the first electrode, the second electrode and the third electrode.

[0015] According to the present invention, by using a reflective member capable of reflecting the end face of an optical fiber, rotational alignment can be reliably performed when connecting optical fibers that require rotational alignment. Furthermore, when the reflective member is moved away from between opposing optical fibers, the shielding member closes in conjunction with the movement of the reflective member, so that the reflective member can be reliably protected from contamination by the shielding member during discharge.

[0016] In this configuration, a third electrode is positioned on the shielding member, and by closing the shielding member, the third electrode can be positioned facing the opposite end of the optical fiber. Therefore, the first, second, and third electrodes can discharge electricity around the junction of the optical fiber. Furthermore, when using a reflective member, the third electrode can be tilted together with the shielding member to avoid interference with the reflective member, thus preventing interference with the rotational alignment of the optical fibers.

[0017] Furthermore, by making the first, second, and third electrodes movable relative to the opposing portions of the pair of optical fibers, an appropriate distance between the electrodes can be set according to the type and diameter of the optical fibers.

[0018] In this process, the control unit automatically moves the first electrode, second electrode, and third electrode according to the type of optical fiber, thereby ensuring that fusion splicing suitable for the optical fiber is reliably set.

[0019] Furthermore, if it is possible to switch between a first condition in which discharge occurs between the two electrodes, the first and second electrodes, and a second condition in which discharge occurs between the three electrodes, the first, second, and third electrodes, then it is possible to perform appropriate fusion splicing depending on the diameter and type of optical fiber. [Effects of the Invention]

[0020] According to the present invention, it is possible to provide a fusion machine that allows for end-face observation and fusion bonding using three electrode rods. [Brief explanation of the drawing]

[0021] [Figure 1] Perspective view showing the fusing machine 1. [Figure 2] Schematic enlarged view of the vicinity of the fusing section. [Figure 3] View seen from the axial direction of the optical fiber 21. [Figure 4] Enlarged view of the vicinity of the third electrode 7c, the reflecting member 23, and the shielding member 25. [Figure 5] An enlarged view of the vicinity of the third electrode 7c, the reflecting member 23, and the shielding member 25 seen from a direction orthogonal to FIG. 4. (a) is a view showing the state where the shielding member 25 is closed, and (b) is a view showing the state where the reflecting member 23 has risen and the shielding member 25 is open. [Figure 6] View seen from the axial direction of the second electrode 7b. (a) is a view showing the state where the reflecting member 23 is retracted from between the optical fibers 21, and (b) is a view showing the state where the reflecting member 23 is moved between the optical fibers 21. [Figure 7] (a) is a view showing the step of performing focus adjustment, and (b) is a view showing the step of performing rotational centering. [Figure 8] (a) is a view showing another embodiment, a view corresponding to FIG. 4(a), and (b) is a view showing the state where fine adjustment in the direction of the third electrode 7c has been performed. [Figure 9] (a) is a view showing the state where discharge is being performed using the first electrode 7a, the second electrode 7b, and the third electrode 7c. (b) is a view showing the state where discharge is being performed by moving the first electrode 7a, the second electrode 7b, and the third electrode 7c with respect to (a). (c) is a view showing the state where discharge is being performed using only the first electrode 7a and the second electrode 7b with respect to (a).

Embodiments for Carrying Out the Invention

[0022] Embodiments of the present invention will be described below with reference to the drawings. Figure 1 is a perspective view showing a fusion splicer 1 for connecting optical fibers. The fusion splicer 1 includes a holder mounting section 11 on which a holder for holding optical fibers is mounted, an optical fiber holding section 5 on which optical fibers are arranged, a lid section 3, an input section 15 for inputting operation of the fusion splicer 1 and various information, and a display section 17 for displaying various information. The display section 17 may be made into a touch panel, thereby integrating the display section 17 and the input section 15.

[0023] The optical fiber is held in the V-groove on the optical fiber holder 5. In addition, a pair of first electrodes 7a and second electrodes 7b are arranged to face each other in a direction substantially perpendicular to the opposing direction of the pair of optical fibers.

[0024] The lid 3 is rotatable around the rotation axis 9. A clamp 13 is provided on the back surface of the lid 3, and when the lid 3 is closed, the tip of the clamp 13 is positioned at a location corresponding to the position of the optical fiber on the optical fiber holding section 5. In other words, the clamp 13 provided on the back surface of the lid 3 allows a pair of optical fibers to be held facing each other in the optical fiber holding section 5. Furthermore, an end-face imaging unit, which will be described later, is built between the clamps 13, and when the lid 3 is closed, it is positioned to image the vicinity of the tips of the pair of optical fibers.

[0025] Figure 2 is a schematic diagram of the vicinity of the fusion splice with the optical fiber installed, and Figure 3 is a side view of the optical fiber 21 as seen from the axial direction (Z direction in Figure 2).

[0026] In the following explanation, as shown in Figure 2, the direction in which the first electrode 7a and the second electrode 7b face each other is defined as the X direction, the direction perpendicular to the X direction and in which the optical fibers 21 face each other is defined as the Z direction, and the direction perpendicular to the X and Z directions (up and down in the figure) is defined as the Y direction. Furthermore, the direction of rotation with the Z direction as the axis of rotation is defined as the R direction. Also, in the following figures, components that are not necessary for the explanation are omitted from the illustration.

[0027] As mentioned above, a pair of optical fibers 21 are arranged facing each other. A reflective member 23 is positioned below the opposing portion of the pair of optical fibers 21. Note that the state shown in Figures 2 and 3 is the state in which the reflective member 23 is retracted. When the reflective member 23 is retracted, the shielding member 25 is closed, and the reflective member 23 is covered from above by the shielding member 25. In other words, when the reflective member 23 is retracted from the position opposite the optical fibers 21, the shielding member 25 is positioned between the reflective member 23 and the optical fibers 21. The operation of the reflective member 23 and the shielding member 25 will be described later.

[0028] An end-face imaging unit 19a is positioned above the opposing portion of the optical fiber 21. That is, the reflective member 23 and the end-face imaging unit 19a are positioned opposite each other in the vertical direction (Y direction) of the optical fiber 21. Furthermore, a first lateral imaging unit 19b and a second lateral imaging unit 19c are positioned below the opposing portion of the optical fiber 21. That is, the end-face imaging unit 19a, the first lateral imaging unit 19b, and the second lateral imaging unit 19c can image the tip positions of the pair of optical fibers 21 from a direction (side) substantially perpendicular to the opposing direction of the optical fiber 21. Also, as shown in Figure 3, the first lateral imaging unit 19b and the second lateral imaging unit 19c can image the tip positions of the optical fiber 21 from, for example, two different directions that are orthogonal to each other.

[0029] Furthermore, the first electrode 7a and the second electrode 7b are positioned opposite each other in a direction approximately perpendicular to the opposing direction of the pair of optical fibers 21 (a direction approximately parallel to the X direction). In addition, the third electrode 7c is positioned in a direction approximately perpendicular to the opposing direction of the optical fibers 21 and approximately perpendicular to the opposing direction of the first electrode 7a and the second electrode 7b (a direction approximately parallel to the Y direction).

[0030] The third electrode 7c is fixed to the upper surface of the shielding member 25. That is, when the reflective member 23 is retracted from the position opposite the optical fiber 21 and the shielding member 25 is closed, the third electrode 7c is positioned toward the opposing portions of the pair of optical fibers 21.

[0031] Furthermore, the tips of the first electrode 7a and the second electrode 7b only need to be positioned opposite each other, with the opposing ends of the pair of optical fibers in between; the axes of the first electrode 7a and the second electrode 7b do not necessarily have to be on the same axis. For example, in the example shown in Figure 3, the first electrode 7a and the second electrode 7b are positioned approximately on the same axis, and the third electrode 7c is positioned at approximately 90° from the first electrode 7a and the second electrode 7b. However, for example, the first electrode 7a, the second electrode 7b, and the third electrode 7c may be positioned at equal intervals (120° intervals) around the optical fiber 21.

[0032] When performing the fusion splicing operation, first, the optical fiber is held by a pair of holders (not shown in the diagram), and the holders are placed on the holder mounting section 11. With the lid 3 closed in this state, the tip of the optical fiber 21 is aligned and the tips are brought together, and an arc is generated between the first electrode 7a, the second electrode 7b, and the third electrode 7c, thereby melting and fusing the tip of the optical fiber 21.

[0033] In the illustrated example, the reflective member 23 is positioned downwards (towards the first lateral imaging unit 19b and the second lateral imaging unit 19c), and the end face imaging unit 19a is positioned upwards (towards the lid unit 3, which is not shown in the illustration). However, the arrangement may be reversed. Furthermore, the end face imaging unit 19a and the reflective member 23 do not necessarily have to be in positions facing each other.

[0034] Next, the details of the reflective member 23 and the shielding member 25 will be described. Figure 4 is an enlarged view of the vicinity of the third electrode 7c, the reflective member 23, and the shielding member 25 when the shielding member 25 is closed, and Figure 5(a) is a view from a direction perpendicular to Figure 4. Figure 5(b) shows the state in which the reflective member 23 has risen and the shielding member 25 has opened, compared to Figure 5(a). Note that the support portion 33 in Figure 4 may be omitted in other figures.

[0035] As shown in Figure 4, the reflective member 23 has reflective surfaces 27a and 27b. The reflective surfaces 27a and 27b are arranged facing opposite directions, and each can reflect light incident from, for example, the Z direction in a direction of 90 degrees (upward in the Y direction). The reflective member 23 can be moved between the optical fibers 21 by a drive unit when a pair of optical fibers 21 are placed facing each other (in the Y direction in the figure). The drive unit is composed of, for example, a rack and pinion mechanism and a motor. The end face imaging unit 19a (see Figure 3) can capture the image reflected by the reflective member 23.

[0036] When the reflective member 23 is retracted from the position opposite the optical fiber 21, the reflective member 23 is covered by the shielding member 25. In this state, the third electrode 7c is positioned straight toward the opposite part of the optical fiber 21 (i.e., in the vertical direction). The state shown in Figures 4 and 5(a) is maintained by an elastic member such as a torsion spring, which is not shown in the illustration.

[0037] As shown in Figure 4, the reflective member 23 is provided with shoulder portions 24 that protrude on both sides. A pair of side walls of the shielding member 25 are positioned opposite each other above the shoulder portions 24, sandwiching the reflective member 23. As shown in Figure 5(a), the side walls of the shielding member 25 are provided with tapered portions 29 above the shoulder portions 24. A rotating shaft 31 is positioned near the end of the shielding member 25 and connected to a support portion 33 (see Figure 4). As shown in Figure 5(b), the shielding member 25 can rotate relative to the support portion 33 (see Figure 4) by means of the rotating shaft 31.

[0038] As shown in Figure 5(b), when the reflective member 23 is raised towards the space between the optical fibers 21 (arrow A in the figure), the shoulder portion 24 of the reflective member 23 comes into contact with the tapered portion 29, and the shielding member 25 is pushed down (arrow B in the figure). That is, the shielding member 25 rotates and tilts around the rotation axis 31. Also, as mentioned above, since the third electrode 7c is fixed to the shielding member 25, the third electrode 7c rotates along with the rotational movement of the shielding member 25. In this way, when the shielding member 25 opens, the third electrode 7c moves laterally together with the shielding member 25, opening up the top of the reflective member 23, thus avoiding interference between the rising reflective member 23, the shielding member 25 and the third electrode 7c.

[0039] When the reflective member 23 rises to the point between the opposing portions of the optical fiber 21, its upward movement stops. In this way, when the reflective member 23 moves to the position opposite the optical fiber 21, the shielding member 25 opens in conjunction with the reflective member 23. Similarly, when the shielding member 25 is lowered, the force of the elastic spring member described above returns the shielding member 25 to its closed state again. In other words, when the reflective member 23 moves away from the position opposite the optical fiber 21, the shielding member 25 closes in conjunction with the movement of the reflective member 23. Note that the opening and closing mechanism of the shielding member 25 is not limited to this example, and any mechanism that can open and close in conjunction with the movement of the reflective member 23 when the reflective member 23 rises or falls may be used.

[0040] Furthermore, the spring's elastic force required to maintain the shielding member 25 in the closed position (Figure 5(a)) is such that, even if the fusion splicer is positioned horizontally (Figure 5(a) rotated 90° clockwise), it will not rotate due to the weight of the third electrode 7c and the shielding member 25. For example, considering a safety factor, it is desirable to have an elastic force (moment) of 1.8 times or more the maximum rotational force (moment) due to the weight of the third electrode 7c and the shielding member 25, centered on the rotation axis 31.

[0041] Next, the detailed fusion splicing process using the fusion splicer 1 will be described. Figure 6(a) shows the view from the second electrode 7b side. As mentioned above, first, the holder holding the pair of optical fibers 21 is placed in the holder mounting section 11 (see Figure 1) and held in the optical fiber holding section 5 (see Figure 1).

[0042] Next, the tip position of the optical fiber 21 is adjusted. The alignment of the tip position (XY direction) of the optical fiber 21 can be performed using conventional methods. For example, the tip position of the optical fiber 21 can be imaged from each direction by the first lateral imaging unit 19b and the second lateral imaging unit 19c and displayed on the display unit 17 (see Figure 1). By moving the position and orientation of the optical fiber holding unit 5 or the holder mounting unit 11 so that the positions of the two align, the XY positions of the optical fiber 21 can be aligned, thereby enabling alignment of the X and Y directions of the optical fiber 21.

[0043] For connecting single-core optical fibers, the alignment process can be completed by XY alignment alone. On the other hand, when aligning multi-core fibers or hollow-core fibers, where the arrangement of cores etc. in the cross-section has directionality in the circumferential direction, alignment of the optical fiber 21 in the rotational direction R is required in addition to alignment in the XY direction. For this reason, the present invention uses a reflective member 23 and an end face imaging unit 19a that can observe the end face of the optical fiber 21.

[0044] The operation of each of the following parts is controlled by an internal control unit (not shown) either by input from the input unit 15 (operation unit) of the fusion splicer 1 or automatically. Figure 6(b) shows the state in which the reflective member 23 is raised and the reflective surfaces 27a and 27b are positioned between the optical fibers 21. At this time, a gap is formed between the optical fibers 21 to the extent that the reflective member 23 can be inserted. This gap can be formed by moving the optical fibers 21 backward in the axial direction. Also, in this state, the shielding member 25 opens and the third electrode 7c is moved to the side (towards the front in the figure).

[0045] Next, as shown in Figure 7(a), the image of the optical fiber 21 obtained by the reflective member 23 is captured by the end face imaging unit 19a. At this time, by irradiating the optical fiber 21 with light from the opposite end face or side, the arrangement of the core and other components at the end face can be clearly captured.

[0046] As described above, the reflective member 23 has a reflective surface 27a that reflects the image of the end face of one optical fiber 21 toward the end face imaging unit 19a (arrow I in the figure), and a reflective surface 27b that reflects the image of the end face of the other optical fiber 21 toward the end face imaging unit 19a (arrow H in the figure). Therefore, it is possible to simultaneously image the end face of one optical fiber 21 and the end face of the other optical fiber 21 with the end face imaging unit 19a.

[0047] In this embodiment, the reflection direction at the reflection surface 27a of the image at the end face of one optical fiber 21 and the reflection direction at the reflection surface 27b of the image at the end face of the other optical fiber 21 are the same. Therefore, it is possible to simultaneously image the end faces of both optical fibers 21 using a single end face imaging unit 19a.

[0048] Here, the focus adjustment of the end face of each optical fiber 21 is performed by moving each optical fiber 21 in the axial direction (arrows J and K in the figure). During fusion splicing of the optical fibers 21, the optical fibers 21 can be moved in the axial direction in order to perform butt joints with each other and post-fusion screening. Therefore, in this embodiment, the focus adjustment of each end face can be performed by moving the optical fiber 21 in the Z direction.

[0049] As shown in Figure 7(b), after focus adjustment is complete, the rotation direction R is adjusted based on the obtained image (arrows L and M in the figure). As mentioned above, the end-face imaging unit 19a can simultaneously acquire end-face images of each optical fiber 21 in real time. Therefore, the control unit can adjust the rotation direction R of each optical fiber 21 by rotating each optical fiber 21 individually, either automatically or manually.

[0050] Furthermore, by determining the position of the end face of the optical fiber 21 in the image captured by the end face imaging unit 19a, it is possible to perform alignment in the XY direction solely by end face observation using the end face imaging unit 19a. In other words, since the position in the XY direction and the direction of rotation R can be determined from the position of the end face of the optical fiber 21 in the captured image, all alignment work can be performed by end face observation.

[0051] After alignment in the rotational direction R is complete, the reflective member 23 is lowered to the state shown in Figure 6(a). That is, the reflective member 23 is retracted from the position opposite the optical fiber 21. At this time, the shielding member 25 is closed by an elastic member or the like (not shown) in conjunction with the retraction of the reflective member 23.

[0052] Subsequently, the ends of the optical fibers 21 are brought together, and an arc is generated between the first electrode 7a, the second electrode 7b, and the third electrode 7c under predetermined conditions to perform fusion splicing of the optical fibers 21. In this way, the optical fibers 21 can be aligned and connected.

[0053] Furthermore, by using a sensor capable of detecting the state of the reflective member 23 or the shielding member 25, the control unit enables discharge between each electrode when it detects that the reflective member 23 has retracted from the position opposite the optical fiber or that the shielding member 25 is closed. In this way, by providing a protection mechanism that prohibits the start of discharge if the retracted state of the reflective member 23 or the closed state of the shielding member 25 is not detected, it is possible to prevent discharge from being started by mistake when the reflective member 23 is not shielded.

[0054] As described above, according to this embodiment, the end faces of a pair of optical fibers 21 can be simultaneously imaged by the reflective member 23 and the end face imaging unit 19a, making alignment work easier. Furthermore, since the shielding member 25 closes in conjunction with the retraction of the reflective member 23, there is no need to separately arrange the lifting / lowering drive unit for the reflective member 23 and the opening / closing drive unit for the shielding member 25. When the reflective member 23 is retracted, the reflective member 23 is reliably shielded by the shielding member 25, preventing foreign matter generated during the fusion splicing process from adhering to the reflective member 23.

[0055] Furthermore, by retracting the reflective member 23 and closing the shielding member 25, the third electrode 7c can be positioned facing the opposite portion of the optical fiber 21. Therefore, fusion splicing of the optical fiber 21 can be performed using three electrodes.

[0056] Furthermore, the third electrode 7c is movable together with the shielding member 25, and there is a risk that the tip position of the third electrode 7c may shift when attaching the third electrode 7c to the shielding member 25. For this reason, it may be necessary to adjust the tip position of the third electrode 7c.

[0057] Figure 8(a) shows the angle fine adjustment mechanism for the third electrode 7c. As mentioned above, the shielding member 25 is connected to the support part 33 by a rotating shaft 31. In addition, the shielding member 25 is pressed in the closing direction (direction of arrow C in the figure) by the elastic force of a spring (not shown). At this time, a stopper 35 is provided on the side of the shielding member 25 so as to protrude outward, and the stopper 35 contacts the end of the support part 33. That is, the shielding member 25 rotates due to the elastic force of the spring until the stopper 35 contacts the support part 33, and the closed state is maintained.

[0058] Here, as shown in Figure 8(a), the stopper 35 is a flat screw. A flat screw is a screw whose head is not round but has a flat shape such as an ellipse. Therefore, as shown in Figure 8(b), the stopping position of the shielding member 25 can be adjusted by rotating the stopper 35. In other words, the angle of the shielding member 25 when it is closed can be finely adjusted. Since the third electrode 7c is fixed to the upper surface of the shielding member 25, the position (direction) of its tip can be finely adjusted by adjusting the angle of the shielding member 25 (arrow D in the figure). Therefore, if the position of the tip of the third electrode 7c is misaligned when it is attached to the shielding member 25, it is not necessary to remove the third electrode 7c again, adjust its position, and reattach it, making position adjustment easy.

[0059] Furthermore, the fusion conditions differ depending on the diameter and type of the optical fiber 21 to be fused. For example, the appropriate voltage and inter-electrode distance will differ when fusion-fusing a small-diameter optical fiber 21 (e.g., 100 μm or less) compared to a large-diameter optical fiber 21 (e.g., 125 μm or more). For this reason, the inter-electrode distances may be made variable.

[0060] For example, Figure 9(a) is a conceptual diagram of fusion splicing of small-diameter optical fibers 21, and Figure 9(b) is a conceptual diagram of fusion splicing of large-diameter optical fibers 21. As shown in the diagram, by varying the distance between the first electrode 7a, the second electrode 7b, and the third electrode 7c relative to the opposing parts of the pair of optical fibers 21 (arrow E in the figure), the high-temperature region due to discharge can be changed, and fusion splicing can be performed with an appropriate inter-electrode distance depending on the diameter and type of optical fiber 21. That is, the fusion splicer 1 has an electrode movement mechanism that allows the first electrode 7a, the second electrode 7b, and the third electrode 7c to move toward the opposing parts of the optical fibers, respectively.

[0061] This adjustment of the distance between electrodes may be done manually or automatically. For example, the electrode movement mechanism may be manually operated from the input unit 15 to change its position. Alternatively, the control unit may input the diameter and type of the optical fiber 21 to be connected from the input unit 15, read the fusion splicing conditions for each optical fiber stored in the memory unit, and operate each electrode movement mechanism according to those conditions. In this way, the control unit can move the first electrode, second electrode, and third electrode to change the distance to the optical fiber according to the type of optical fiber input from the input unit 15.

[0062] Furthermore, although the above-described embodiment described a method of performing fusion with three electrodes, it may be possible to switch between a first condition in which discharge occurs between two electrodes, the first electrode 7a and the second electrode 7b, and a second condition in which discharge occurs between three electrodes, the first electrode 7a, the second electrode 7b, and the third electrode 7c.

[0063] For example, FIG. 9(c) is a diagram showing a state changed from the state of FIG. 9(a) (first condition) to the second condition. In this case, for example, the fusion machine 1 has an optical fiber holding part moving mechanism capable of changing the heights of the optical fiber holding part 5 and the holder placement part 11.

[0064] Also in this case, the setting of such an optical fiber holding part moving mechanism may be manual or automatic. For example, the first condition and the second condition may be manually selected from the input unit 15. Alternatively, when the diameter and type of the optical fiber 21 to be connected are input from the input unit 15, the control unit may read out the fusion conditions of each optical fiber stored in the storage unit in advance and operate the optical fiber holding part moving mechanism according to the conditions. Thus, the first condition and the second condition can be changed by the control unit according to the type of the optical fiber input in the input unit 15.

[0065] As described above, the embodiments of the present invention have been described with reference to the accompanying drawings. However, the technical scope of the present invention is not limited by the foregoing embodiments. It is obvious that those skilled in the art can conceive of various modification examples or correction examples within the scope of the technical idea described in the claims, and it is naturally understood that they also belong to the technical scope of the present invention.

Explanation of Reference Numerals

[0066] 1………Fusion machine 3………Cover part 5………Optical fiber holding part 7a………First electrode 7b………Second electrode 7c………Third electrode 9………Rotating shaft 11………Holder placement part 13………Clamp 15………Input unit 17………Display unit 19a………End face imaging part 19b………First side imaging part 19c………Second side imaging part 21………Optical fiber 23………Reflective material 24...Shoulder 25... Shielding member 27a, 27b……Reflective surface 29... Tapered section 31... Rotation axis 33......Support part 35... Stopper

Claims

1. A fusion splicer that connects optical fibers together, An optical fiber holding section that holds a pair of optical fibers facing each other, A first electrode, a second electrode, and a third electrode are arranged in a direction substantially perpendicular to the opposing direction of the pair of optical fibers, When a pair of optical fibers are arranged facing each other, a movable reflective member is provided between the optical fibers, An imaging unit that captures the image reflected by the reflective member, It is equipped with, The reflective member has a reflective surface that reflects the image of the end face of each optical fiber toward the imaging unit. The shielding member is positioned between the reflective member and the optical fiber when the reflective member is retracted from the position opposite the optical fiber, and is configured to close in conjunction with the movement of the reflective member when the reflective member is retracted from the position opposite the optical fiber. A fusion splicer characterized in that the third electrode is fixed to the shielding member, and when the shielding member is closed, the third electrode is positioned toward the opposing portions of the pair of optical fibers, and when the shielding member is opened, the third electrode moves together with the shielding member to avoid interference with the reflecting member.

2. The fusion splicer according to claim 1, having a moving mechanism for moving the first electrode, the second electrode, and the third electrode, wherein the distance between the first electrode, the second electrode, and the third electrode and the opposing portions of the pair of optical fibers is variable.

3. The fusion splicer according to claim 2, having an input unit for inputting the type of optical fiber to be connected, and a control unit which operates the moving mechanism according to the type of optical fiber input in the input unit.

4. The fusion splicer according to claim 1, characterized in that it is possible to switch between a first condition in which discharge occurs between the two electrodes, the first electrode and the second electrode, and a second condition in which discharge occurs between the three electrodes, the first electrode, the second electrode and the third electrode.

Images