Optical fiber side surface polishing device and optical fiber side surface polishing method

Abstract

This optical fiber side surface polishing device (10) comprises a holding part (11) that holds a jig (60), a light source (12) that irradiates a fixing agent (21) applied to the jig (60) with light (20) for curing the fixing agent (21), a linear motion part (14) that is provided movably toward the jig (60), a motor part (15) that is provided between the holding part (11) and the linear motion part (14), and a control unit (16) that controls the operation of at least the linear motion part (14) and the motor part (15).

Description

Optical Fiber Side Polishing Device and Optical Fiber Side Polishing Method

[0001] The present disclosure relates to an optical fiber side polishing device and an optical fiber side polishing method.

[0002] As a wiring method for an optical communication network that provides optical services at high speed and low cost, the PON (Passive Optical Network) method is known (see Non-Patent Document 1). On the other hand, as an optical multiplexing / demultiplexing technology that can demultiplex light from an optical fiber or multiplex light into an optical fiber without cutting the optical fiber during communication, a method for manufacturing an optical coupler using an optical fiber side polishing method has been studied (see Non-Patent Documents 2 and 3).

[0003] "Technical Foundation Lecture, GE-PON Technology, Lecture 1, What is PON," NTT Technical Journal, Vol. 17, No. 8, pp. 71-74, 2005Takamitsu Uematsu, "Study on In-Service Optical Branching Using Side Polishing of Optical Fiber," IEICE Technical Report, Institute of Electronics, Information and Communication Engineers, OFT2021-61 (2022-01), pp. 32-35 (2022)M. A. Uddin, M. Y. Ali and H. P. Chan, "MATERIALS AND FABRICATION ISSUES OF OPTICAL FIBER ARRAY", Rev. Adv. Mater. Sci. 21(2009) 155-164

[0004] When polishing the side surface of an optical fiber, the optical fiber is fixed to a jig and side surface polishing is performed. Dedicated devices are required for fixing the optical fiber to the jig and side surface polishing, respectively. That is, in order to perform side surface polishing, the attachment and detachment of each device to the optical fiber takes time.

[0005] The present disclosure has been made in view of such circumstances, and an object thereof is to provide an optical fiber side polishing device and an optical fiber side polishing method capable of shortening the working time in side surface polishing.

[0006] An optical fiber side polishing apparatus according to a first aspect of the present disclosure is an apparatus that uses a jig provided with a groove on which an optical fiber is placed. The optical fiber side polishing apparatus comprises a holding part for holding the jig, a light source for irradiating a fixing agent applied to the jig with light to harden the fixing agent, a linear motion part that is movable toward the jig, a motor part provided between the holding part and the linear motion part, and a control unit that controls the operation of at least the linear motion part and the motor part.

[0007] A method for polishing the side surface of an optical fiber according to a second aspect of the present disclosure is a method using a jig provided with a groove. The method for polishing the side surface of an optical fiber includes placing an optical fiber in the groove and applying a fixing agent to the jig, moving a flat plate in contact with the fixing agent toward the plane, hardening the fixing agent sandwiched between the flat plate and the jig by light irradiation, and polishing the hardened fixing agent and the side surface of the optical fiber from the side surface to a predetermined depth, wherein the movement of the flat plate, the light irradiation, and the polishing are performed by power from a portable power source.

[0008] According to this disclosure, it is possible to provide an optical fiber side polishing apparatus and an optical fiber side polishing method that can shorten the working time in side polishing.

[0009] Figure 1 is a perspective view showing an example of a jig. Figure 2 is a diagram showing the overall configuration of the polishing apparatus according to this embodiment. Figure 3 is a diagram showing an example of the configuration of the control unit. Figure 4 is a cross-sectional view showing an example of the configuration of the polishing apparatus housed in a frame. Figure 5 is a diagram of the tension-applying unit according to this embodiment, where Figure 5(a) is a front view of the tension-applying unit, Figure 5(b) is a front view showing a first example of the tension-applying unit, and Figure 5(c) is a front view showing a second example of the tension-applying unit. Figure 6 is a diagram showing the steps of a first example of the polishing method. Figure 7 is a diagram showing the steps of a first example of the polishing method. Figure 8 is a diagram showing the steps of a first example of the polishing method. Figure 9 is a diagram showing the steps of a first example of the polishing method. Figure 10 is a diagram showing the steps of a first example of the polishing method. Figure 11 is a table showing the working times for a comparative example and this embodiment. Figure 12 is a diagram showing the steps of a second example of the polishing method. Figure 13 is a diagram showing the steps of a second example of the polishing method. Figure 14 is a diagram showing the steps of a third example of the polishing method. Figure 15 is a diagram showing the steps of a third example of the polishing method.

[0010] Hereinafter, the optical fiber side polishing apparatus 10 according to an embodiment of this disclosure will be described with reference to the drawings. In addition, the same parts are denoted by the same reference numerals in the drawings and their descriptions are omitted. For the sake of explanation, mutually orthogonal X, Y, and Z directions are defined. The X direction is the width direction of the polishing apparatus 10, the Y direction is the depth direction of the polishing apparatus 10, and the Z direction is the height direction of the polishing apparatus 10. Furthermore, it is assumed that the Z direction coincides with the vertical direction, and one side is defined as upward and the other side as downward.

[0011] First, the jig 60 used in the optical fiber side polishing apparatus 10 will be described. Figure 1 is a perspective view showing an example of the jig 60. As shown in Figure 1, an optical fiber 1 is placed on the jig 60. The jig 60 is a rectangular body extending along the groove 62 and is made of a material that transmits light 20 such as ultraviolet light (UV light) emitted from the light source 12 (see Figure 4). Such a material is, for example, transparent glass or resin.

[0012] The jig 60 has a flat surface 61 to which a fixing agent 21 (see Figure 4) is applied. The fixing agent 21 applied to the flat surface 61 is a photocurable resin, for example, an ultraviolet curing resin. When the jig 60 is held by the holding part 11, the flat surface 61 faces the motor part 15 (see Figure 4). A groove 62 is formed in the flat surface 61 on which the optical fiber 1 is placed. The groove 62 has depth in the Z direction and extends along the X direction. The groove 62 is also curved with respect to the flat surface 61 with a predetermined radius of curvature, with its center on the side where the jig 60 is located. The depth of the groove 62 along the Z direction is shallowest near the center of the flat surface 61. The minimum depth of this groove 62 is set to a value that, for example, provides evanescent coupling between cores.

[0013] In a cross-section perpendicular to the X direction, the groove 62 has a V-shaped cross-section. However, the cross-sectional shape of the groove 62 is not limited to a V-shape. That is, as long as polishing is possible in which a part of the optical fiber 1 is placed and evanescent coupling is obtained between the cores, the cross-sectional shape of the groove 62 may be a semicircle, rectangle, trapezoid, or other shape.

[0014] Next, the optical fiber side polishing apparatus 10 according to this embodiment will be described. For convenience of explanation, the optical fiber side polishing apparatus 10 will be referred to as the polishing apparatus 10. As can be understood from the following description, the polishing apparatus 10 holds a jig 60 and fixes the optical fiber 1 to the jig 60 by light irradiation using a light source 12. Furthermore, while holding the jig 60, the polishing apparatus 10 polishes a part of the side surface 1c (see Figure 4) of the optical fiber 1. This polishing is performed to a depth in which the core 1a of the optical fiber 1 obtains evanescent coupling with the core (not shown) of the other side polishing fiber. This depth reaches the cladding 1b or core 1a (see Figure 4) of the optical fiber 1.

[0015] In this way, the polishing device 10 performs a series of steps, from fixing the optical fiber 1 to the jig 60 to polishing the side surface 1c. In other words, there is no need to use different devices for each step of the process for the optical fiber 1. Therefore, the working time required for side surface polishing can be shortened. In addition, errors in the work procedure can be prevented, and the occurrence of breakage of the optical fiber 1 can be suppressed. Furthermore, the above-described series of steps can also be performed using a portable battery as a power source. In this case, commercial power is not required, so the portability of the polishing device 10 is improved.

[0016] Figure 2 is a diagram showing the overall configuration of the polishing device 10. Figure 3 is a diagram showing an example of the configuration of the control unit 16. Figure 4 is a cross-sectional view showing an example of the configuration of the polishing device 10 housed in the frame 18. Figure 5 is a diagram of the tension-applying unit 13 according to this embodiment, where Figure 5(a) is a front view of the tension-applying unit 13, Figure 5(b) is a front view showing a first example of the tension-applying unit 13, and Figure 5(c) is a front view showing a second example of the tension-applying unit 13.

[0017] As shown in Figure 2, the polishing device 10 comprises a holding unit 11, a light source 12, a tensioning unit 13, a linear motion unit 14, a motor unit 15, and a control unit 16. In the example shown in Figure 4, the light source 12, the holding unit 11, the motor unit 15, and the linear motion unit 14 are arranged from top to bottom. The control unit 16 and power supply 17 are also arranged inside the frame 18. That is, the holding unit 11, the tensioning unit 13, the light source 12, the linear motion unit 14, and the motor unit 15 are housed or mounted in the frame 18 together with the control unit 16. Therefore, the polishing device 10 is configured as a portable device that performs the entire process from fixing to polishing the optical fiber 1 as described above.

[0018] Figure 2 shows the case where the optical fiber 1 being polished by the polishing device 10 is an existing optical fiber. That is, transmission devices 2 and 3 are pre-connected to both ends of the optical fiber 1, and the two communicate using communication light 4 propagating through the optical fiber 1.

[0019] As described later, a bent portion M is formed in a part of the optical fiber 1 to control side polishing. In this case, leakage light 4a of the communication light 4 leaks out from the bent portion M, and its intensity is measured by an optical intensity meter (power meter) 19. This measurement result is input to the control unit 16.

[0020] The polishing device 10 is not limited to currently used optical fibers; it may also use optical fibers that have not yet been laid in the network. In this case, a light source (not shown) that emits test light of a predetermined intensity is connected to one end of the optical fiber, and the light intensity meter 19 measures the intensity of the test light output from the other end of the optical fiber.

[0021] The holding portion 11 is located between the light source 12 and the motor portion 15 in the Z direction and detachably holds the jig 60. The holding portion 11 may be integrally formed with the frame 18, or it may be formed separately from the frame 18 and attached to the frame 18. While the holding portion 11 is holding the jig 60, the flat surface 61 of the jig 60 faces the motor portion 15. The method of holding the jig 60 by the holding portion 11 is arbitrary and may be, for example, gripping from the X or Y direction, mounting in a groove extending in the Y direction, or fixing using a predetermined attachment, screw, pin, etc.

[0022] The holding portion 11 may have an opening 11a facing the light source 12. The opening 11a has a shape that allows light 20 from the light source 12 to pass through the entire surface of the plane 61. For example, as shown in Figure 4, the opening 11a may be formed between a pair of stoppers 11b, 11b that are spaced apart in the Y direction and extend in the X direction. As described above, the jig 60 is made of a material that is transparent to light 20. Therefore, light 20 passes through the opening 11a and the jig 60, curing the fixing agent 21 applied to the plane 61. The stoppers 11b are configured as part of the holding portion 11 and contact the jig 60, restricting the upward movement of the jig 60.

[0023] The holding portion 11 may be made of a material that is transparent to light 20. In this case, light 20 passes through the holding portion 11. Therefore, the opening 11a can be omitted.

[0024] The light source 12 is provided above the holding portion 11. The light source 12 generates light 20 having a wavelength that cures the fixing agent 21 and irradiates the jig 60 with the light 20. The light 20 has a wavelength that cures the fixing agent 21. Such light 20 is, for example, ultraviolet (UV) light. Furthermore, the operation of the light source 12, such as the irradiation time, may be controlled by the control unit 16. The source of the light 20 is, for example, an LED (light-emitting diode). In this case, the light source 12 can be easily operated even if the power supply 17 is a battery.

[0025] The linear motion unit 14 is movably mounted toward the jig 60 held by the holding unit 11. In other words, the linear motion unit 14 is movably mounted along the Z-direction. The linear motion unit 14 has a well-known mechanism that is movable in the Z-direction, such as a linear guide or a Z-axis stage. The linear motion unit 14 is driven and controlled by the control unit 16.

[0026] The motor unit 15 is provided between the holding unit 11 and the linear motion unit 14 and is attached to the linear motion unit 14. The motor unit 15 may be pre-integrated with the linear motion unit 14. The motor unit 15 rotates or reciprocates the polishing sheet 23, which is placed on its upper surface, on a plane perpendicular to the direction of movement of the linear motion unit 14 (i.e., the Z direction) (i.e., a plane parallel to the plane 61). For example, the motor unit 15 rotates around an axis extending in the Z direction as its center of rotation. Similar to the linear motion unit 14, the motor unit 15 is also driven and controlled by the control unit 16.

[0027] A flat plate 22 or an abrasive sheet 23 is attached to the motor unit 15. The flat plate 22 is a plate-shaped member having a thickness that prevents it from bending when pressed by the liquid fixing agent 21. The flat plate 22 has a smooth surface that comes into contact with the fixing agent 21 when pressed. On the other hand, the abrasive sheet 23 is a plate-shaped or sheet-shaped member having a thickness that prevents it from bending when polishing the optical fiber 1 and the hardened fixing agent 21. The abrasive sheet 23 has an abrasive surface of a predetermined roughness that polishes the optical fiber 1 and the hardened fixing agent 21.

[0028] The control unit 16 controls the operation of at least the linear motion unit 14 and the motor unit 15. For example, as shown in Figure 2, the control unit 16 controls the operation of the light source 12, the linear motion unit 14, and the motor unit 15. Furthermore, the control unit 16 may control the operation of the motor unit 15 based on the measurement results from the light intensity meter 19, or it may control the driver 30 of the tension application unit 13 (see Figure 3(b)).

[0029] As shown in Figure 3, the control unit 16 is a so-called computer with a well-known configuration. For example, the control unit 16 includes a CPU 16a, a memory 16b, a storage 16c, a communication unit 16d, an input unit 16e, and an output unit 16f. The memory 16b and the storage 16c are memory devices. In the control unit 16, the CPU 16a executes a predetermined program loaded onto the memory 16b, thereby realizing various functions such as light irradiation by the light source 12, movement of the linear motion unit 14, and rotation of the motor unit 15.

[0030] The control unit 16 may be implemented on a single computer. The control unit 16 may be implemented on multiple computers. The control unit 16 may also be a virtual machine implemented on a computer. The program for the control unit 16 can be stored on a computer-readable recording medium such as an HDD, SSD, USB memory, CD, or DVD. A computer-readable recording medium is, for example, a non-transitory recording medium. The program for the control unit 16 can also be distributed via a communication network.

[0031] The light source 12, linear motion unit 14, motor unit 15, and control unit 16 described above are powered by electricity. The polishing device 10 may also be equipped with a portable power source 17 that supplies this electricity. A portable power source is, for example, a battery (primary battery, secondary battery). In other words, at least the light source 12, linear motion unit 14, motor unit 15, and control unit 16 may be configured to be powered by a portable power source 17. A portable power source 17 such as a battery eliminates the need for power supply from a commercial power source, improving the portability of the polishing device 10.

[0032] As shown in Figure 5, the polishing apparatus 10 may also include a tension-applying unit 13 for the optical fiber 1. The tension-applying unit 13 applies tension to the optical fiber 1, pressing it against the groove 62 of the jig 60 while the jig 60 is held in the holding unit 11.

[0033] The tension-applying unit 13 comprises a pair of clamping parts 25, 25 for clamping the optical fiber 1, and a guide rail 26 that movably supports each of the pair of clamping parts 25, 25. The pair of clamping parts 25, 25 are arranged in the X direction, with the jig 60 held by the holding unit 11 interposed between them. In other words, the clamping parts 25 are located on both sides of the jig 60 in the X direction. The guide rail 26 is fixed to, for example, the frame 18 and extends in the X direction. Therefore, the clamping parts 25 are supported by the guide rail 26 so as to be movable in the X direction.

[0034] Each clamping portion 25 comprises, for example, a base portion 27 and a cover portion 29 that covers the groove portion 28. The base portion 27 is movably supported by a guide rail 26. A groove portion 28 extending in the X direction is formed in the base portion 27. As shown in Figure 5(a), in the Z direction, the groove portion 28 of the base portion 27 is located higher than the groove portion 62 of the jig 60. Also, the groove portion 28 is located on the plane that includes the groove portion 62.

[0035] The optical fiber 1 is aligned with the groove 28, and the cover portion 29 further covers the optical fiber 1 located in the groove 28. A magnet (not shown) is attached to one of the cover portion 29 and the base portion 27, and a metal (not shown) that is attracted to the magnet is attached to the other. Therefore, when the cover portion 29 covers the optical fiber 1, the cover portion 29 and the base portion 27 are attracted to each other, and the optical fiber 1 is temporarily held in place by them.

[0036] The pair of clamping parts 25, 25 move away from each other along the guide rail 26, each clamping the optical fiber 1. As a result, tension is generated in the optical fiber 1 between the pair of clamping parts 25, 25, and the optical fiber 1 moves upward. The optical fiber 1, moving upward, fits into the groove 62 of the jig 60 and is pressed against the groove 62. This allows the optical fiber 1 to be accurately positioned relative to the jig 60 (groove 62).

[0037] As shown in Figure 5(b), the tension-applying unit 13 may have a driver 30, such as a motor, for moving each clamping portion 25. In this case, the tension-applying unit 13 may have, for example, a rotatably mounted lead screw 31 that screws onto each clamping portion 25. The lead screw 31 is connected to the driver 30, which is controlled by the control unit 16. When the driver 30 rotates the lead screw 31, the clamping portions 25 move along the guide rail 26.

[0038] As shown in Figure 5(c), the tension-applying section 13 may have magnets 32 and 33. In this case, magnet 32 ​​is attached to the clamping section 25, and magnet 33 is attached to the end of the guide rail 26. Also, magnets 32 and 33 are arranged so that their opposite polarities face each other. That is, magnets 32 and 33 are arranged so that they attract each other by their magnetic force. Each clamping section 25 moves freely on the guide rail 26.

[0039] With the optical fiber held in place, each clamping portion 25 is attracted by the corresponding magnet 33. As a result, the two clamping portions 25 move away from each other. Consequently, the aforementioned tension is applied to the optical fiber 1. The tension applied to the optical fiber 1 can be changed by adjusting the distance between the magnets 32 (clamping portion 25) and 33, and the magnitude of the magnetic force. The distance between the magnets 32 and 33 can be adjusted, for example, by changing the position of the magnet 33 using a screw 34. In this example, the driver 30 shown in Figure 5(b) is not used. Therefore, compared to the example in Figure 5(b), power for applying tension is not required, and the increase in power consumption by the polishing device 10 can be suppressed. Also, because the magnets 32 and 33 are relatively small, concavity of the polishing device 10 can be suppressed.

[0040] Next, a method for polishing the sides of an optical fiber using the polishing apparatus 10 will be described. For the sake of explanation, the optical fiber side polishing method will be referred to as the polishing method. Figures 6 to 10 show the steps of the first example of the polishing method. In the following example, unless otherwise specified, the operation of at least the motor unit 15 and the linear motion unit 14 is controlled by the control unit 16.

[0041] First, as shown in Figure 6(a), a jig 60 is prepared by applying the fixing agent 21 to a flat surface 61, and the jig 60 is attached to the holding part 11 through the window portion 18a of the frame 18. If the holding part 11 has a stopper 11b as shown in Figure 6(a), the jig 60 is pushed in until it contacts the stopper 11b. At this time, since the fixing agent 21 is liquid, its surface will not be flat due to surface tension or viscosity. At this point, the groove portion 62 may or may not be filled with the fixing agent 21.

[0042] Next, as shown in Figure 6(b), the optical fiber 1 is introduced from the window portion 18a to a position below the groove portion 62. Then, the optical fiber 1 is clamped between the clamping portions 25, 25 of the tensioning portion 13 (see Figure 5(a)), and tension is applied to the optical fiber 1 by moving the clamping portions 25, 25. Due to the application of tension, the optical fiber 1 is placed in the groove portion 62 of the jig 60 (see Figure 7(a)).

[0043] Next, the fixing agent 21 is flattened using the flat plate 22. If the fixing agent 21 is not flattened, when polishing the hardened fixing agent 21 with the polishing sheet 23, the polishing sheet 23 may tilt due to a decrease in the contact area between the polishing sheet 23 and the fixing agent 21. If polishing continues with the polishing sheet 23 tilted, a problem will occur where the polished surface of the optical fiber 1 is tilted (so-called uneven polishing). To prevent this problem, the fixing agent 21 is flattened to increase the contact area between the polishing sheet 23 and the fixing agent 21. Specifically, as shown in Figure 7(b), the flat plate 22 is used. The flat plate 22 is introduced through the window portion 18a and placed on the upper surface of the motor portion 15.

[0044] Next, as shown in Fig. 8(a), the flat plate 22 is moved upward (i.e., toward the jig 60). The motor unit 15 and the linear motion unit 14 are integrated, and both move upward under the control of the linear motion unit 14 by the control unit 16. That is, the flat plate 22 can be moved upward. Due to the operation of the linear motion unit 14, the flat plate 22 moves upward and comes into contact with the liquid fixing agent 21. Further, with the optical fiber 1 placed in the groove 62 and the fixing agent 21 applied to the jig 60, the flat plate 22 in contact with the fixing agent 21 is moved toward the jig 60. By further moving the flat plate 22 upward, the fixing agent 21 is pushed by the flat plate 22 and deformed so as to extend in the X and Y directions. Thereby, the surface of the fixing agent 21 is deformed from a curved surface to a flat surface by contact with the flat plate 22. Also, even if there are gaps remaining in the groove 62, the fixing agent 21 fills the groove 62 in this process, and the groove 62 is filled with the fixing agent 21.

[0045] The upward movement of the flat plate 22 can be executed, for example, by operating a switch 24 connected to the control unit 16. The switch 24 is composed of one or more switch elements or an operation panel or the like. After the flat plate 22 is brought into contact with the fixing agent 21, the flat plate 22 may be rotated or reciprocated by operating the motor unit 15. Thereby, the fixing agent 21 can be spread more uniformly over the flat surface 61, and the flattening of the fixing agent 21 can be promoted.

[0046] Next, as shown in Fig. 8(b), the fixing agent 21 sandwiched between the flat plate 22 and the jig 60 is cured by light irradiation. That is, light 20 is output from the light source 12 toward the jig 60. The operation of the light source 12 can be controlled, for example, by operating the switch 24 or by the control of the control unit 16. The light 20 output from the light source 12 passes through the opening 11a and the jig 60 and irradiates the fixing agent 21. Thereby, the fixing agent 21 undergoes a chemical reaction and cures, and the optical fiber 1 is fixed in the groove 62.

[0047] Next, by controlling the linear motion part 14, the flat plate 22 is moved downward to remove the flat plate 22 from the cured fixing agent 21. Then, the flat plate 22 is replaced with the polishing sheet 23, and the polishing sheet 23 is attached to the upper surface of the motor part 15 (see Fig. 9(a)). Then, again, the motor part 15 is moved upward to bring the polishing sheet 23 into contact with the fixing agent 21 (see Fig. 9(a)). Then, the motor part 15 is driven to reciprocate or rotate the polishing sheet 23, and the cured fixing agent 21 and the side surface 1c of the optical fiber 1 are polished from the side surface 1c to a predetermined depth. At this time, the linear motion part 14 may adjust (control) the pressure from the polishing sheet 23 toward the fixing agent 21.

[0048] Before performing the polishing, the surface of the fixing agent 21 has been pre-flattened by contact with the flat plate 22. That is, the surface of the polishing sheet 23 and the surface of the fixing agent 21 are parallel to each other. Therefore, the polishing sheet 23 contacts the surface of the fixing agent 21 over a wide range. Therefore, polishing can be continuously performed stably without bias. Note that the execution of polishing may also be controlled by operating the switch 24.

[0049] While the polishing is being performed, the light intensity meter 19 (see Fig. 2) observes the attenuation of the leakage light 4a (or test light) leaking from the bent portion M. The data of the intensity of the leakage light 4a measured by the light intensity meter 19 is input to the control unit 16. When the intensity or the ratio of the leakage light 4a has attenuated to a predetermined threshold value, the control unit 16 stops the operation of the motor part 15 and stops the polishing. This predetermined threshold value indicates that the side surface 1c of the optical fiber 1 has been polished to the above-mentioned predetermined depth. Then, the polishing sheet 23 and the motor part 15 are moved downward, and the jig 60 is taken out from the polishing apparatus 10 (see Fig. 10).

[0050] In this way, a series of operations can be daringly performed within one polishing apparatus 10. In addition, each operation such as light irradiation and polishing can be executed only by operating the switch 24.

[0051] Figure 11 is a table showing the working times for the comparative example and this embodiment. As shown in the left column of the table, the comparative example uses dedicated equipment for irradiation and polishing. Therefore, the work of attaching and detaching the jig 60 to each device is required. On the other hand, the polishing device of this embodiment also serves as the irradiation device in the comparative example. Therefore, as shown in the right column of the table, the work of removing the jig 60 from the irradiation device and then attaching the jig 60 to the polishing device in the comparative example can be omitted. Consequently, the total working time in this embodiment can be reduced to about two-thirds of that in the comparative example.

[0052] Figures 12 and 13 show the steps of a second example of the polishing method. In the second example, the step of applying the fixing agent 21 to the flat surface 61 of the jig 60 is omitted. Instead, the fixing agent 21 applied to the flat plate 22 is brought into contact with the jig 60.

[0053] First, as shown in Figure 12(a), the jig 60 is attached to the holding part 11. No fixing agent is applied to the jig 60. Next, the optical fiber 1 is introduced from the window part 18a to a position below the groove part 62. Then, the optical fiber 1 is clamped between the clamping parts 25, 25 of the tensioning part 13 (see Figure 5(a)), and tension is applied to the optical fiber 1 by moving the clamping parts 25, 25. Due to the application of tension, the optical fiber 1 is placed in the groove part 62 of the jig 60 (see Figure 12(b)).

[0054] Next, as shown in Figure 13(a), the fixing agent 21 is applied to the flat plate 22, and the flat plate 22 is placed on the motor unit 15 with the fixing agent 21 facing the jig. Then, the flat plate 22 is moved upward by the operation of the linear motion unit 14. That is, with the optical fiber 1 placed in the groove 62 and the fixing agent 21 applied to the jig 60, the flat plate 22, which is in contact with the fixing agent 21, is moved toward the jig 60. As a result, the fixing agent 21 is sandwiched between the jig 60 and the flat plate 22, and the area around the optical fiber 1 is covered with the fixing agent 21. Also, since the fixing agent 21 is applied to the flat plate 22 in advance, the interface between the fixing agent 21 and the flat plate 22 is flattened in advance. After the fixing agent 21 is brought into contact with the jig 60, the flat plate 22 may be rotated or reciprocated by the operation of the motor unit 15. This allows the fixing agent 21 to spread more uniformly across the flat surface 61, thereby promoting the flattening of the fixing agent 21.

[0055] Next, as shown in Figure 13(b), the fixing agent 21, which is sandwiched between the flat plate 22 and the jig 60, is cured by light irradiation. That is, light 20 is emitted from the light source 12 toward the jig 60. The process after the fixing agent 21 has cured is the same as in the first example. That is, as shown in Figures 9 to 10, polishing is performed with the polishing sheet 23, and the jig 60 is removed from the holding part 11 (polishing device 10).

[0056] Figures 14 and 15 show the steps of a third example of the polishing method. In the third example, a release sheet 35 is used instead of a flat plate 22. The release sheet 35 is placed on top of the polishing sheet 23. Furthermore, a fixing agent 21 is pre-applied to the release sheet 35. By omitting the step using the flat plate 22, the working time can be shortened.

[0057] In the third example, similar to the second example, the jig 60 without the fixing agent 21 applied is attached to the holding part 11, and then the optical fiber 1 is placed in the groove part 62 using the tensioning part 13. Next, with the release sheet 35 placed on top of the polishing sheet 23, the fixing agent 21 is applied to the release sheet 35, and these are attached to the upper surface of the motor part 15 (see Figure 14(a)).

[0058] Next, as shown in Figure 14(b), the linear motion unit 14 moves the polishing sheet 23, the release sheet 35, and the fixing agent 21 upward, bringing the fixing agent 21 into contact with the jig 60. That is, with the optical fiber 1 placed in the groove 62 and the fixing agent 21 applied to the jig 60, the release sheet 35 that is in contact with the fixing agent 21 is moved toward the jig 60. As a result, the fixing agent 21 is sandwiched between the jig 60 and the release sheet 35, and the area around the optical fiber 1 is covered with the fixing agent 21. Since the fixing agent 21 has been applied to the release sheet 35 in advance, the interface between the fixing agent 21 and the release sheet 35 is flattened.

[0059] Next, as shown in Figure 15(a), the fixing agent 21, which is sandwiched between the flat plate 22 and the jig 60, is cured by light irradiation. That is, light 20 is emitted from the light source 12 toward the jig 60. After the fixing agent 21 has hardened, only the release sheet 35 is removed from the polishing device 10, and polishing is performed with the polishing sheet 23 (see Figure 15(b)). The steps after the polishing is completed are the same as in the first and second examples. That is, as shown in Figure 10, the jig 60 is removed from the holding part 11 (polishing device 10).

[0060] Thus, according to the polishing method of this embodiment, the series of steps described above can be performed using a single polishing device 10. Therefore, the polishing work can be shortened. In addition, the linear motion unit 14, motor unit 15, light source 12, and control unit 16 may be operated by power supplied from a power source 17 such as a battery mounted on the polishing device 10. In this case, the portability of the polishing device 10 is improved, and the burden on the worker during side polishing work is reduced.

[0061] 1 Optical fiber 4 Communication light 4a Leaked light 10 Optical fiber side polishing device (polishing device) 11 Holding part 12 Light source 13 Tensioning part 14 Linear motion part 15 Motor part 16 Control unit 17 Power supply 18 Frame 19 Light intensity meter (power meter) 20 Light 21 Fixing agent 22 Flat plate 23 Polishing sheet 35 Release sheet 60 Jig 61 Flat surface 62 Groove part M Bending part

Claims

1. An optical fiber side polishing apparatus that uses a jig provided with a groove on which an optical fiber is placed, comprising: a holding part for holding the jig; a light source for irradiating a fixing agent applied to the jig with light to harden the fixing agent; a linear motion part that is movable toward the jig; a motor part provided between the holding part and the linear motion part; and a control unit that controls the operation of at least the linear motion part and the motor part.

2. The optical fiber side polishing apparatus according to claim 1, further comprising a tension-applying unit that applies tension to the optical fiber to press it against the groove while the jig is held in the holding unit.

3. The optical fiber side polishing apparatus according to claim 1, wherein the light source, the linear motion unit, the motor unit, and the control unit are configured to be operable by a portable power supply.

4. The optical fiber side polishing apparatus according to claim 2, wherein the holding part, the tensioning part, the light source, the linear motion part, and the motor part are housed in or mounted on a frame.

5. The optical fiber side polishing apparatus according to any one of claims 1 to 4, wherein the control unit controls the linear motion unit to move a flat plate or release sheet in contact with the fixing agent toward the jig while the optical fiber is placed in the groove and the fixing agent is applied to the jig; the light source is irradiated onto the fixing agent sandwiched between the flat plate or release sheet and the jig; and the motor unit is controlled to polish the hardened fixing agent and the side surface of the optical fiber to a predetermined depth from the side surface.

6. The optical fiber side polishing apparatus according to claim 5, wherein the control unit stops the operation of the motor unit when the intensity or ratio of light leaking from the optical fiber is attenuated to a predetermined threshold.

7. A method for polishing the side surface of an optical fiber using a jig provided with a groove, wherein an optical fiber is placed in the groove and a fixing agent is applied to the jig, a flat plate or release sheet in contact with the fixing agent is moved toward the jig, the fixing agent sandwiched between the flat plate or release sheet and the jig is cured by light irradiation, and the side surface of the cured fixing agent and the optical fiber is polished from the side surface to a predetermined depth, wherein the movement of the flat plate or release sheet, the light irradiation, and the polishing are performed by power from a portable power source.

8. The optical fiber side polishing method according to claim 7, wherein the polishing is stopped when the intensity or percentage of light leaking from the optical fiber is reduced to a predetermined threshold.

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