JP2011209761A - Method for fusion splice of optical fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To satisfactorily achieve fusion splice by easily and correctly performing alignment (optical axis alignment) of an optical fiber of large aperture (outside diameter), which cannot fall within an imaging visual field, and an optical fiber of a low fusing point and a narrow diameter.SOLUTION: In the method for fusion splice an optical fiber, two bare optical fibers 7 and 9 of known identical outside diameter are imaged, and the two bare optical fibers 7 and 9 are aligned using the picked up image and then fusion splice is performed by a pair of opposite discharge electrodes orthogonal to the two bare optical fibers 7 and 9. In this case, if the two bare optical fibers 7 and 9 do not fall within an imaging visual field 39, the upper sides XL2 and XR2 or the lower sides XL1 and XR1 of the outer periphery of the two bare optical fibers 7 and 9 are caused to fall within the imaging visual field 39, thereby the upper sides XL2 and XR2 or the lower sides XL1 and XR1 are positioned. Thus, the two bare optical fibers 7 and 9 can be aligned.

Description

  The present invention relates to an optical fiber fusion splicing method, and more particularly to an optical fiber fusion splicing method in which an optical fiber is aligned and then spliced using an optical fiber fusion splicer.

  Conventionally, in the fusion splicing method of optical fibers, as shown in FIGS. 8 (A) and 8 (B), the left and right optical fibers 101 and 103 are coated with the distal ends removed in the longitudinal direction. When the bare optical fibers 105 and 107 are brought into contact with each other and fusion-bonded by discharge using a pair of opposed discharge electrodes, the abutting portions of the left and right bare optical fibers 105 and 107 are imaged by, for example, a CCD camera as an imaging means. Alignment is performed based on the captured image.

  At this time, as shown in FIG. 8A, the entire outer diameters of the left and right bare optical fibers 105 and 107 are shown in the screen 109 (imaging area). Software is created on the premise of this state, and the upper and lower sides are observed in the images of the left and right bare optical fibers 105 and 107, and the center between the upper and lower sides is adjusted as the center of each bare optical fiber 105 and 107. The heart is done.

  More specifically, FIG. 8C shows the luminance distribution on the straight line AA of the left bare optical fiber 105 shown in FIG. 8A, and the outer peripheral side of the left bare optical fiber 105 is dark. The central part of the bare optical fiber 105 becomes brighter. Intersection points a and b with the threshold level become the upper side XL2 and the lower side XL1 of the outer periphery of the left bare optical fiber 105. The above luminance distribution is the same for the right bare optical fiber 107.

  Therefore, as shown in FIGS. 8A and 8B, the optical axis position XL0 of the left bare optical fiber 105 is the lower side position XL1 and the upper side position XL2 of the outer periphery of the left bare optical fiber 105 in the image. The average planting, ie, XL0 = (XL1 + XL2) / 2. On the other hand, the optical axis position XR0 of the right bare optical fiber 107 is represented by an average planting of the lower side position XR1 and the upper side position XR2 of the outer circumference of the right bare optical fiber 107, that is, XR0 = (XR1 + XR2) / 2.

  When aligning and connecting a large-diameter left bare optical fiber 105 (LDF: Large Diameter Fiber), the optical fiber fusion splicer reduces the magnification of the optical system such as a camera, lens, or lens barrel, and has a large aperture. Is designed so that the outer diameter width of the left bare optical fiber 105 falls within the imaging area 109.

  In addition, an ordinary optical fiber fusion splicer has a mechanism that aligns to a position where the amount of heat given to a bare optical fiber of 125 μm (SMF: Single Mode Fiber) is optimized.

  Further, in the conventional optical fiber fusion splicer, as described above, for example, there are Patent Documents 1 to 3 regarding the method of observing the left and right bare optical fibers 105 and 107 at the time of fusion splicing. The two optical systems of magnification are used in combination, and all the optical fibers to be fusion spliced are placed in the observation field of the optical system.

  In Patent Document 4, the magnification change image is displayed in a small window in the monitor. Each display magnification of the X-axis direction image and the Y-axis direction image, the X-axis direction image display window, and the Y-axis direction image display are displayed. The size of each window can be freely set. Further, the image after the magnification change after changing the display magnification is displayed in the image display window after the magnification change. Further, only a specific image area is displayed on the extracted image display window.

  Further, in Patent Document 5, when the large-diameter and small-diameter optical fibers are fusion-spliced, only the large-diameter optical fiber is first preheated in the heating area, and then the small-diameter optical fiber is advanced. Then, both the large-diameter optical fiber and the small-diameter optical fiber are subjected to the second preheating in the heating area, and the small-diameter optical fiber is further advanced and its end surface is pressed against the end surface of the large-diameter optical fiber to perform the main heating process. It is.

  Further, in Patent Document 6, when a single mode optical fiber having an outer diameter A and an optical fiber having an outer diameter B smaller than the outer diameter A are fusion spliced, one end of the single mode optical fiber is stretched to extend the outer diameter B. A connection end face having an outer diameter of ± 2 μm or less is formed, and the connection end face and the end face of the optical fiber having the outer diameter B are fusion-connected, thereby connecting with low loss.

Japanese Patent Laid-Open No. 9-43447 JP-A-9-61661 JP-A-11-167039 JP 2006-47817 A JP 2004-325990 A JP 2005-189813 A

  By the way, in the conventional fusion splicing method of optical fibers, an optical system in which the outer diameter width of the left bare optical fiber 105 having a large aperture can be accommodated in the imaging area 109 has a low resolution because the observation magnification is low. (Length per pixel) is reduced. As a result, when the observation magnification is lowered, as shown in FIG. 8A, the lower side position XL1 and the upper side position XL2 of the outer periphery of the left bare optical fiber 105 having a large diameter can be detected. There was a problem that the ellipticity dropped. Further, when the observation magnification is lowered, there is a problem that the core observation of the thin optical fiber 107 with a small diameter cannot be performed and the connection performance itself may be deteriorated.

  On the other hand, when the observation magnification is increased, as shown in FIG. 8B, the lower side position XL1 and the upper side position XL2 of the outer periphery of the large-diameter left bare optical fiber 105 deviate from the imaging area 109, and detection is not possible. This makes it impossible to align the left and right bare optical fibers 105 and 107.

  Regarding the above problems, Patent Documents 1 to 4 are the same because the observation magnification is simply changed.

  In addition, an ordinary optical fiber fusion splicer has a mechanism for adjusting the position where the amount of heat applied to a 125 μm (SMF) bare optical fiber is optimal. However, when discharging was performed after aligning at the same alignment position as that of the bare optical fiber of 125 μm (SMF), there was a problem that even if it was discharged with a weak discharge current, it melted and disappeared. For this reason, there is a problem that the hardware needs to be changed in order to use the offset of the electrode rod or a special discharge circuit.

  Further, in Patent Document 5, since it is necessary to perform a heating process step by step in order to fuse and connect optical fibers having a large diameter and a small diameter, the conditions such as the heating temperature and the heating time are set and managed. There was a problem that it was difficult to do. Further, in Patent Document 6, in order to fuse and connect optical fibers having a large diameter and a small diameter, one end portion of the large-diameter single mode optical fiber is stretched to be within an outer diameter B ± 2 μm of the small-diameter optical fiber. There is a problem in that it takes time to form the connecting end surface of the outer diameter.

In order to achieve the problem to be solved by the above invention, an optical fiber fusion splicing method of the present invention images two bare optical fibers having the same outer diameter, and uses the captured image to perform the above-mentioned 2 When aligning two bare optical fibers and then fusion-splicing them with a pair of discharge electrodes that are orthogonally opposed to the two bare optical fibers,
When the two bare optical fibers do not fit in the imaging field, the upper sides or the lower sides of the outer circumferences of the two bare optical fibers are placed in the imaging field, and the upper sides or the lower sides are aligned. Thus, the alignment of the two bare optical fibers is performed.

Further, in the fusion splicing method of optical fibers of the present invention, two bare optical fibers having a known outer diameter are imaged, and the two bare optical fibers are aligned based on the taken image, and then the two optical fibers are aligned. When fusion-splicing with a pair of discharge electrodes facing in the X-axis direction orthogonal to the bare optical fiber,
A center position of the discharge path by the pair of discharge electrodes so that the upper and lower sides of the outer circumferences of the two first and second bare optical fibers are within the imaging field of view. From the center position to the position of the upper or lower side of the outer circumference of the first bare optical fiber (shift distance S). And the position of the upper side or the lower side of the outer circumference of the second bare optical fiber is shifted from the center position (shift distance S-radius of the second bare optical fiber). ), The two bare optical fibers are aligned.

In addition, the optical fiber fusion splicing method of the present invention images two bare optical fibers having a known large diameter and small outer diameter, and adjusts the two bare optical fibers based on the picked-up images. When fusion-bonding with a pair of discharge electrodes facing in the X-axis direction orthogonal to the two bare optical fibers from the center,
When the large-diameter bare optical fiber does not fit in the imaging field, the upper sides or the lower sides of the outer circumferences of the two bare optical fibers are placed in the imaging field, and the upper side of the outer circumference of the small-diameter bare optical fiber. Alternatively, the small-diameter bare optical fiber is positioned so that the position of the lower side is shifted by a half of the outer diameter difference between the two bare optical fibers with respect to the position of the upper or lower side of the outer periphery of the large-diameter bare optical fiber The two bare optical fibers are aligned by moving in the X-axis direction.

Also, in the fusion splicing method of optical fibers of the present invention, one or both of the two naked optical fibers having an unknown outer diameter are imaged, and the two naked optical fibers are aligned based on the captured images. When fusion splicing with a pair of discharge electrodes facing in the X-axis direction orthogonal to the two bare optical fibers,
When one or both of the two bare optical fibers do not fit within the imaging field, the upper sides or the lower sides of the outer circumferences of the two bare optical fibers are placed within the imaging field and the upper sides or the lower sides are positioned. Together
Next, the two bare optical fibers are shifted in the X-axis direction by a shift distance S so that the lower sides or the upper sides opposite to the alignment of the outer circumferences of the two bare optical fibers are within the imaging field of view. And then detecting the positions of the lower sides or the upper sides of the outer circumferences of the two bare optical fibers, and the outer circumference of the two bare optical fibers based on the difference in the positions of the detected lower sides or the upper sides. The outer diameter difference of
Next, the two bare optical fibers are adjusted by moving the bare optical fiber having the smaller outer diameter toward the upper side or the lower side in the X-axis direction by ½ of the difference in outer diameter. It is characterized by doing the mind.

  As can be understood from the means for solving the problems as described above, according to the fusion splicing method of optical fibers of the present invention, two bare optical fibers to be spliced have the same known outer diameter. Even if it does not fit in the imaging field of view, just by placing the upper sides or the lower sides of the outer circumference of the two bare optical fibers within the imaging field of view, aligning the upper sides or the lower sides, The two bare optical fibers can be easily aligned. Further, since it is not necessary to reduce the magnification of the optical system, the alignment accuracy and performance of the two bare optical fibers are not deteriorated.

  Further, according to the fusion splicing method of optical fibers of the present invention, when the two bare optical fibers to be fusion spliced have a low melting point or a small diameter, for example, the two fibers can be used without reducing the alignment accuracy. Can be moved away from the center position of the discharge path by the pair of discharge electrodes in the X-axis direction on the one electrode side by a shift distance S, and can be fusion spliced with a low heat quantity. it can.

  In addition, the position of the upper or lower side of the outer circumference of the first bare optical fiber is adjusted to the distance from the center position to (shift distance S−the radius of the first bare optical fiber), and the second bare optical fiber. The two bare optical fibers can be easily adjusted simply by moving the position of the upper or lower side of the outer periphery to match the distance from the center position to (shift distance S−the radius of the second bare optical fiber). I can do it. Further, since it is not necessary to reduce the magnification of the optical system, the alignment accuracy and performance of the two bare optical fibers are not deteriorated.

  Also, according to the fusion splicing method of optical fibers of the present invention, the two bare optical fibers to be fusion spliced have a known large diameter and a small outer diameter, and the large diameter bare optical fiber is an imaging field of view. Even if it does not fit within, the upper side or the lower side of the outer circumference of the two bare optical fibers are accommodated in the imaging field of view, the position of the upper side or the lower side of the outer circumference of the thin bare optical fiber, The small-diameter bare optical fiber is moved in the X-axis direction so as to be shifted from the position of the upper or lower side of the outer circumference of the large-diameter bare optical fiber by ½ of the outer diameter difference between the two bare optical fibers. By doing so, the two bare optical fibers can be easily aligned. Further, since it is not necessary to reduce the magnification of the optical system, the alignment accuracy and performance of the two bare optical fibers are not deteriorated.

  In addition, according to the fusion splicing method of optical fibers of the present invention, one or both of the two bare optical fibers to be fusion spliced are unknown-diameter large-diameter bare optical fibers that do not fit in the imaging field of view. Even in this case, the two bare optical fibers can be easily aligned. Further, since it is not necessary to reduce the magnification of the optical system, the alignment accuracy and performance of the two bare optical fibers are not deteriorated.

(A), (B) is a schematic explanatory drawing which shows the fusion splicing method of the optical fiber which concerns on 1st Embodiment of this invention. (A), (B) is a schematic explanatory drawing which shows the fusion splicing method of the optical fiber which concerns on the 2nd Embodiment of this invention. It is a schematic explanatory drawing which shows the fusion splicing method of the optical fiber which concerns on 3rd Embodiment of this invention. (A), (B) is a schematic explanatory drawing which shows each process of the fusion splicing method of the optical fiber which concerns on the 4th Embodiment of this invention. It is a schematic explanatory drawing which shows the process of the fusion splicing method of the optical fiber which concerns on 4th Embodiment of this invention. 1 is a schematic front view of an optical fiber fusion splicing device according to an embodiment of the present invention. 1 is a schematic plan view of an optical fiber fusion splicing device according to an embodiment of the present invention. (A), (B) is a schematic explanatory drawing which shows each process of the conventional optical fiber fusion splicing method.

  Embodiments of the present invention will be described below with reference to the drawings.

  In addition, the optical fiber applied to this invention means an optical fiber strand, an optical fiber core wire, etc. Hereinafter, this specification simply refers to “optical fiber”.

  The optical fiber fusion splicing apparatus 1 used in the optical fiber fusion splicing method according to this embodiment will be described.

  Referring to FIGS. 6 and 7, the optical fiber fusion splicing device 1 is configured so that the distal ends of the first optical fiber 3 on one side and the second optical fiber 5 on the other side extend in the longitudinal direction in advance. The first bare optical fiber 7 of the first optical fiber 3 (left side in FIGS. 6 and 7) and the second bare optical fiber 9 of the second optical fiber 5 (see FIG. 6). 6 and the right side in FIG.

  Further, the optical fiber fusion splicing device 1 has a butting portion 13 having a butting V-groove 11 for positioning the tips of the first and second optical fibers 3 and 5 so as to be butted together. 15 and optical fiber holders 17 and 19 are provided integrally on the rear side of the abutting portions 13 and 15 and grip the rear side of the first and second optical fibers 3 and 5. Yes.

  More specifically, the optical fiber holder 17 includes a holder base portion 17A for placing the first optical fiber 3 and a clamp portion 17B for pressing the first optical fiber 3 of the holder base portion 17A. Yes. On the other hand, the optical fiber holder 19 includes a holder base portion 19A for placing the second optical fiber 5 and a clamp portion 19B for pressing the second optical fiber 5 of the holder base portion 19A.

  The abutting portions 13 and 15 are substantially rectangular blocks, and a space 21 is provided in the width direction (vertical direction in FIG. 7) between the horizontal directions in FIGS. 6 and 7 of the blocks. . Further, the abutting V groove 11 described above is provided on the block upper surface of the abutting portions 13 and 15 in the front-rear direction (left-right direction in FIG. 7). In addition, the centers of the V grooves 11 facing each other on the upper surfaces of the blocks on both sides are arranged on a straight line.

  The optical fiber holders 17 and 19 are moved in the longitudinal direction of the first and second bare optical fibers 7 and 9 via a guide portion on the apparatus main body 23 by a holder movable device (not shown) (in FIG. 7). It is provided so as to be movable in the X-axis direction orthogonal to the (left-right direction), that is, the vertical direction in FIG.

  Further, the first and second optical fibers 3 and 5 which are butted against each other at the butting portions 13 and 15 are fused and connected to both sides in the vertical direction in FIG. 7 of the interval 21 between the butting portions 13 and 15. A discharge heating device 25 is provided.

  The discharge heating device 25 includes a pair of discharge electrodes 27 and 29 that are orthogonally opposed to the first and second bare optical fibers 7 and 9 to be abutted, and a space between the pair of discharge electrodes 27 and 29. And a discharge power supply device 31 for discharging the tips of the first and second bare optical fibers 7 and 9 by applying a voltage to them to cause discharge (arc generation). The discharge power supply device 31 is connected to a control device 33 in order to control the discharge power and heating time for the first and second bare optical fibers 7 and 9 to be in an optimum state.

  Further, above the abutting portions 13 and 15, for example, a CCD camera 35 is provided as an imaging means for observing and imaging the tip positions of the first and second bare optical fibers 7 and 9 to be abutted. The CCD camera 35 is connected to the control device 33 via, for example, an image processing device 37 as image processing means for processing the captured image.

  Note that the image processing device 37 determines the tip positions of the first and second bare optical fibers 7 and 9 from the image captured by the CCD camera 35. For example, the tip position of the first bare optical fiber 7 and the tip position of the second bare optical fiber 9 are determined by the position coordinates.

  The control device 33 is provided with an arithmetic device (not shown) for calculating the tip position coordinates of the first and second bare optical fibers 7 and 9 and a command corresponding to the optical fiber fusion splicing method to the corresponding means. And a command unit (not shown) for giving.

  Next, an optical fiber fusion splicing method according to an embodiment of the present invention will be described using the optical fiber fusion splicing apparatus 1 described above.

  Referring to FIG. 1A, the optical fiber fusion splicing method of the first embodiment is the first optical fiber on one side in advance as described in the optical fiber fusion splicing apparatus 1 described above. 3 and the tip of the second optical fiber 5 on the other side are covered and removed in the longitudinal direction, and the first bare optical fiber 7 (left side in FIG. 6) of the first optical fiber 3; The second bare optical fiber 9 (right side in FIG. 6) of the second optical fiber 5 is abutted. The first and second bare optical fibers 7 and 9 are fused and connected by a pair of discharge electrodes 27 and 29 that are orthogonally opposed to each other.

  In order to fusion-connect the two first and second bare optical fibers 7 and 9, the first and second bare optical fibers 7 and 9 are imaged by the CCD camera 35. The first and second bare optical fibers 7 and 9 are aligned.

  In this embodiment, optical fiber cores are used as the first and second optical fibers 3 and 5, and the first and second bare optical fibers 7 and 9 have a large diameter having the same outer diameter. It is a caliber. Therefore, a method in the case where the large-diameter first and second bare optical fibers 7 and 9 do not fit within the imaging area 39 (imaging field of view; monitor range, position detection range) is shown.

  In the image, the optical axis position XL0 of the first bare optical fiber 7 on the left is an average planting of the lower side position XL1 and the upper side position XL2 of the outer circumference of the first bare optical fiber 7, that is, XL0 = (XL1 + XL2) / 2. Indicated. On the other hand, the optical axis position XR0 of the right second bare optical fiber 9 in the image is an average planting of the lower side position XR1 and the upper side position XR2 of the outer circumference of the second bare optical fiber 9, that is, XR0 = (XR1 + XR2) / 2. Indicated.

  In FIG. 1A, the lower sides XL1 and XR1 of the outer circumferences of the first and second bare optical fibers 7 and 9 are placed in the imaging area 39, and the arithmetic unit of the control device 33 sets the lower sides XL1 and XR1. The first and second naked lights are calculated so as to align the lower sides XL1 and XR1 with a holder movable device (not shown) according to a command given from the command unit of the control device 33 based on the position coordinates. The fibers 7 and 9 are moved. As a result, since the first and second bare optical fibers 7 and 9 have the same known outer diameter, the optical axis position XL0 of the first bare optical fiber 7 and the light of the second bare optical fiber 9 inevitably exist. The first and second bare optical fibers 7 and 9 are aligned by matching the axial position XR0.

  Alternatively, as shown in FIG. 1B, the upper sides XL2 and XR2 of the outer circumferences of the first and second bare optical fibers 7 and 9 are stored in the imaging area 39, and the arithmetic unit of the control device 33 is used. Is used to calculate the position coordinates of the upper sides XL2 and XR2, and in accordance with a command given from the command unit of the control device 33 based on the position coordinates, the holder movable device (not shown) aligns the upper sides XL2 and XR2. 1. Move the second bare optical fibers 7 and 9. As a result, the first and second bare optical fibers 7 and 9 are necessarily aligned as in the case of FIG.

  The first and second bare optical fibers 7 and 9 aligned as described above are fusion-bonded by an arc discharged from the discharge electrodes 27 and 29.

  From the above, the first and second bare optical fibers 7 and 9 have the same known outer diameter, and the large-diameter first and second bare optical fibers 7 and 9 are not accommodated in the imaging area 39. Even if not, the lower sides XL1, XR1 (or the upper sides XL2, XR2) of the outer circumferences of the first and second bare optical fibers 7, 9 are placed in the imaging area 39 and then the lower sides XL1, XR1 are placed. The first and second bare optical fibers 7 and 9 can be easily aligned by simply aligning (or the upper sides XL2 and XR2). Further, since it is not necessary to reduce the magnification of the optical system, the alignment accuracy and performance of the first and second bare optical fibers 7 and 9 are not reduced.

  Next, an optical fiber fusion splicing method according to the second embodiment will be described. Note that the same components as those in the first embodiment described above are described with the same reference numerals.

  Similarly to the first embodiment described above, the first and second bare optical fibers 7 and 9 are imaged by the CCD camera 35, and the first and second bare optical fibers 7, 9 is aligned and then fused and connected by the discharge electrodes 27 and 29.

  2A and 2B, the optical fiber fusion splicing method of the second embodiment is different from the first embodiment described above in that the first and second bare lights are as follows. Although the outer diameters of the fibers 7 and 9 are known, they are bare optical fibers having a low melting point or a small diameter. Further, the present invention is applicable even when the outer diameters of the first and second bare optical fibers 7 and 9 are the same or different. 2B shows a case where the first and second bare optical fibers 7 and 9 have different diameters.

  The two first and second bare optical fibers 7 and 9 are in the X-axis direction from the center position OO ′ of the discharge path formed by the pair of discharge electrodes 27 and 29, as shown in FIG. If the optical fiber is moved downward by the shift distance S in FIG. 2, the optical fiber is shifted downward by S / COSθ in FIG. θ is an angle formed by the optical axis of the camera and the discharge path O-O ′.

  Note that the amount of heat decreases as the distance from the center position O-O ′ increases. 2A and 2B, the upper sides XL1 and XR1 of the outer circumferences of the two first and second bare optical fibers 7 and 9 are moved so as to fit in the imaging area 39.

  That is, in FIG. 2B, the position coordinates of XL1 and XR1 between the upper sides of the outer circumferences of the first and second bare optical fibers 7 and 9 are calculated by the arithmetic unit of the control device 33. Based on the command given from the command unit of the control device 33 based on this position, the first bare optical fiber 7 moves the upper side position XL1 of the outer periphery thereof from the center position OO ′ by a holder movable device (not shown). It is moved so as to match the distance up to the shift distance S−the radius of the first bare optical fiber 7. On the other hand, the second bare optical fiber 9 moves so that the upper side position XR1 of the outer periphery thereof matches the distance from the center position OO ′ to (shift distance S−radius of the second bare optical fiber 9). Is done.

  As a result, the optical axis position XL0 of the first bare optical fiber 7 and the optical axis position XR0 of the second bare optical fiber 9 inevitably coincide with each other to align the first and second bare optical fibers 7, 9. Will be done.

  The first and second bare optical fibers 7 and 9 aligned as described above are fusion-bonded by an arc discharged from the discharge electrodes 27 and 29.

  From the above, when the first and second bare optical fibers 7 and 9 have a low melting point and a small diameter, the first and second bare optical fibers 7 and 9 are discharged without reducing the alignment accuracy. It is possible to move away from the center position OO ′ of the road by the shift distance S / COSθ and move away from the center, and fusion splicing can be performed with a low amount of heat.

  In addition, the upper side position XL1 of the outer circumference of the first bare optical fiber 7 is moved so as to match the distance from the center position O-O 'to (shift distance S-radius of the first bare optical fiber 7). On the other hand, only by moving the upper side position XR1 of the outer circumference of the second bare optical fiber 9 so as to match the distance from the center position OO ′ to (shift distance S−radius of the second bare optical fiber 9), The first and second bare optical fibers 7 and 9 can be easily aligned. Further, since it is not necessary to reduce the magnification of the optical system, the alignment accuracy and performance of the first and second bare optical fibers 7 and 9 are not reduced.

  Next, an optical fiber fusion splicing method according to the third embodiment will be described. Note that the same components as those in the first embodiment described above are described with the same reference numerals. Further, as in the first embodiment described above, the first and second bare optical fibers 7 and 9 are aligned and then fused and connected by the discharge electrodes 27 and 29.

  For example, in FIG. 3, the case where the outer diameter of the first bare optical fiber 7 is a large diameter and the outer diameter of the second bare optical fiber 9 is a small diameter will be described. When 7 does not fit in the imaging area 39, the lower sides of the outer circumferences of the first and second bare optical fibers 7 and 9 are arranged so as to fit in the imaging area 39.

  Next, in FIG. 3, the position coordinates of the lower sides XL <b> 1 and XR <b> 1 of the outer circumferences of the first and second bare optical fibers 7 and 9 are calculated by the arithmetic unit of the control device 33. Based on a command given from the command unit of the control device 33 based on the position coordinates, the lower side position XR1 of the outer circumference of the second bare optical fiber 9 having the small diameter is changed to the lower side of the outer circumference of the first bare optical fiber 7 having the larger diameter. The small-diameter second bare optical fiber 9 is moved in the X-axis direction so as to be shifted by a half of the outer diameter difference between the first and second bare optical fibers 7 and 9 with respect to the position XL1.

  For example, when the outer diameter DL of the first bare optical fiber 7 having a large diameter is 400 μm and the outer diameter DR of the second bare optical fiber 9 having a small diameter is 80 μm, the 1/2 outer diameter difference ΔD is ( DL-DR) / 2 = (400-80) / 2 = 160 μm. Therefore, the lower side position XR1 of the outer periphery of the second bare optical fiber 9 having a small diameter moves upward in FIG. 3 in the X-axis direction by 160 μm with respect to the lower side position XL1 of the outer circumference of the first bare optical fiber 7 having a large diameter. Will be. The normal diameters of the first and second bare optical fibers 7 and 9 are 125 μm, the small diameter is 80 μm, and the large diameters are 140 μm, 250 μm, 300 μm, 400 μm, and the like.

  As a result, the optical axis position XL0 of the first bare optical fiber 7 and the optical axis position XR0 of the second bare optical fiber 9 inevitably coincide with each other to align the first and second bare optical fibers 7, 9. Will be done.

  Alternatively, after arranging the upper sides XL2 and XR2 of the outer circumferences of the two first and second bare optical fibers 7 and 9 in the imaging area 39, the second bare light having the small diameter is arranged. The upper side position XR2 of the outer periphery of the fiber 9 is 1/2 of the outer diameter difference between the first and second bare optical fibers 7 and 9 with respect to the upper side position XL2 of the outer periphery of the first bare optical fiber 7 having the large diameter. The small-diameter second bare optical fiber 9 may be moved in the X-axis direction so as to be displaced by a distance.

  The first and second bare optical fibers 7 and 9 aligned as described above are fusion-bonded by an arc discharged from the discharge electrodes 27 and 29.

  From the above, the outer diameters of the first and second bare optical fibers 7 and 9 are known, but the different diameters of the large-diameter first bare optical fiber 7 and the small-diameter second bare optical fiber 9 are different. Even if the first bare optical fiber 7 having a large diameter does not fit within the imaging area 39, the first and second bare optical fibers 7 and 9 can be easily aligned. Further, since it is not necessary to reduce the magnification of the optical system, the alignment accuracy and performance of the first and second bare optical fibers 7 and 9 are not reduced.

  Next, an optical fiber fusion splicing method according to the fourth embodiment will be described. Note that the same components as those in the first embodiment described above are described with the same reference numerals. Similarly to the first embodiment described above, the first and second bare optical fibers 7 and 9 are imaged by the CCD camera 35, and the first and second bare optical fibers 7, 9 is aligned and then fused and connected by the discharge electrodes 27 and 29.

  Referring to FIG. 4A, the optical fiber fusion splicing method according to the fourth embodiment is different from the first, second, and third embodiments described above. This is applied when one or both of the bare optical fibers 7 and 9 is a bare optical fiber having an unknown outer diameter that does not fit in the imaging area 39.

  For example, in FIG. 4A, the outer diameters of the first and second bare optical fibers 7 and 9 are both unknown large diameters, but the outer diameter of the first bare optical fiber 7 is the second bare light. In the case where the diameter is larger than the outer diameter of the fiber 9, as a step 1, when the large-diameter first and second bare optical fibers 7 and 9 do not fit in the imaging area 39, a holder movable not shown is movable. By moving the first and second bare optical fibers 7 and 9 upward in FIG. 4A by the apparatus, the lower sides XL1 and XR1 of the outer circumferences of the first and second bare optical fibers 7 and 9 are Arranged so as to be within the imaging area 39.

  Next, in FIG. 4A, the position coordinates of the lower sides XL <b> 1 and XR <b> 1 of the outer circumferences of the first and second bare optical fibers 7 and 9 are calculated by the arithmetic unit of the control device 33. The first and second bare optical fibers 7 and 9 are moved so as to align the lower sides XL1 and XR1 according to a command given from the command unit of the control device 33 based on the position coordinates. That is, in FIG. 4A, the second bare optical fiber 9 is moved downward, and the lower sides XL1 and XR1 are aligned.

  Next, as Step 2, as shown in FIG. 4B, the upper sides XL2 ′ and XR2 ′ of the outer circumferences of the first and second bare optical fibers 7 and 9 are within the imaging area 39. Thus, the first and second bare optical fibers 7 and 9 are translated in the X-axis direction downward in FIG. 4B, that is, from the position of the two-dot chain line to the position of the solid line by the shift distance S, The upper side positions XL2 ′ and XR2 ′ of the outer circumferences of the first and second bare optical fibers 7 and 9 are detected. That is, the position coordinates of the upper side positions XL2 'and XR2' are calculated by the arithmetic unit of the control device 33. The difference in outer diameter ΔD between the outer circumferences of the first and second bare optical fibers 7 and 9 is calculated based on the difference between the detected upper side positions XL2 'and XR2'.

  If the calculation method based on said example is shown, each outer diameter of the said 1st, 2nd bare optical fibers 7 and 9 can be represented with the following formula | equation.

Outer diameter DL of the left first optical fiber 7 = (XL2′−XL1) + S
Outer diameter DR of the second optical fiber 9 on the right side = (XR2′−XR1) + S
From this, the outer diameter difference ΔD (= DL−DR) is calculated.

Since XL1 = XR1,
The outer diameter difference ΔD = DL−DR = XL2′−XR2 ′.

  If the outer diameter DL of the unknown first large-diameter optical fiber 7 is 400 μm, for example, and the outer diameter DR of the second large-diameter bare optical fiber 9 is 300 μm, each upper side position XL2 From the position coordinates of “, XR2”, the outer diameter difference ΔD is calculated as (DL−DR) = (400−300) = 100 μm.

  Next, as step 3, as shown in FIG. 5, the second bare optical fiber 9 having the smaller outer diameter is moved to the upper side in the X-axis direction by 1/2 of the outer diameter difference ΔD. Moved.

  In the above example, 1/2 of the outer diameter difference ΔD is 50 μm, so that the upper side position XR2 ″ of the outer circumference of the second bare optical fiber 9 having the large diameter is the outer circumference of the first bare optical fiber 7 having the large diameter. 5 is moved upward in FIG. 5 in the X-axis direction by 50 μm (= ΔD / 2) with respect to the upper side position XL2 ′.

  Alternatively, the movement direction is opposite to the above, and the upper sides XL2 and XR2 of the outer circumferences of the two first and second bare optical fibers 7 and 9 are arranged in the imaging area 39, The first and second bare optical fibers 7 and 9 are moved so that the upper sides XL2 and XR2 are aligned, and then the lower sides XL1 of the outer circumferences of the first and second bare optical fibers 7 and 9 are moved. The respective lower sides XL1 ′ and XR1 ′ are detected by translation by the shift distance S so that XR1 falls within the imaging area 39, and the first and second nakednesses are detected by the difference between the lower side positions XL1 ′ and XR1 ′. Even if the outer diameter difference ΔD of the outer circumferences of the optical fibers 7 and 9 is calculated and the second bare optical fiber 9 having the smaller outer diameter is moved to the lower side in the X-axis direction by 1/2 of the outer diameter difference ΔD. good.

  As a result, the optical axis position XL0 of the first bare optical fiber 7 and the optical axis position XR0 of the second bare optical fiber 9 inevitably coincide with each other to align the first and second bare optical fibers 7, 9. Will be done.

  The first and second bare optical fibers 7 and 9 aligned as described above are fusion-bonded by an arc discharged from the discharge electrodes 27 and 29.

  From the above, even if one or both of the first and second bare optical fibers 7 and 9 are bare optical fibers having an unknown outer diameter that do not fit in the imaging area 39, it is easy to do. The first and second bare optical fibers 7 and 9 can be aligned. Further, since it is not necessary to reduce the magnification of the optical system, the alignment accuracy and performance of the first and second bare optical fibers 7 and 9 are not reduced.

DESCRIPTION OF SYMBOLS 1 Optical fiber fusion splicer 3 1st optical fiber 5 2nd optical fiber 7 1st bare optical fiber 9 2nd bare optical fiber 11 Butting V-grooves 13 and 15 Butting parts 17 and 19 Optical fiber Holder 17A, 19A Holder base part 17B, 19B Clamp part 21 Spacing 23 Device body part 25 Discharge heating device 27, 29 Discharge electrode 31 Discharge power supply device 33 Control device 35 CCD camera (imaging means)
37 Image processing device (image processing means)
39 Imaging area

Claims (1)

Two bare optical fibers having a known outer diameter are imaged, and the two bare optical fibers are aligned based on the picked-up images, and then faced in the X-axis direction orthogonal to the two bare optical fibers. When fusion splicing with a pair of discharge electrodes,
A center position of the discharge path by the pair of discharge electrodes so that the upper and lower sides of the outer circumferences of the two first and second bare optical fibers are within the imaging field of view. From the center position to the position of the upper or lower side of the outer circumference of the first bare optical fiber (shift distance S). And the position of the upper side or the lower side of the outer circumference of the second bare optical fiber is shifted from the center position (shift distance S-radius of the second bare optical fiber). The optical fiber fusion splicing method is characterized in that alignment of the two bare optical fibers is performed by adjusting the distance to the distance to the optical fiber.

Images