Grinding control system and method

Abstract

The purpose of the present disclosure is to provide polishing control in which propagation loss of an optical fiber which was laterally polished is equalized, by providing a function for monitoring the propagation loss of the optical fiber during polishing.　According to this polishing control system and this method, in a polishing control system and a method for controlling polishing in lateral-polishing of an optical fiber, light enters the optical fiber toward a point where the lateral-polishing is being performed, the optical fiber receives the light passing through the point where a lateral surface is polished, changes in light intensity of the received light are monitored, and the lateral-surface polishing is stopped on the basis of the changes in light intensity of the received light.

Description

[Technical field]

[0001] The present disclosure relates to polishing control in side polishing of an optical fiber that is equipped with a function for monitoring the propagation loss of the optical fiber during polishing. [Background technology]

[0002] Conventional polishing control will be described. Conventionally, a method of controlling the amount of polishing has been widely used for polishing control. For example, Patent Document 1 discloses a polishing method that controls the amount of polishing on the order of μm. More generally, as in Non-Patent Document 1, the amount of polishing h is expressed by Preston's formula (1). h=η v p t (1) where η is the Preston constant, v is the polishing speed, p is the load on the sample during polishing, and t is the polishing time. As can be seen from formula (1), the amount of polishing can be controlled by the polishing speed, the load on the sample during polishing, and the polishing time.

[0003] Conventional polishing control was to control the amount of polishing. Therefore, when side-polishing an optical fiber with manufacturing errors in the outer diameter or refractive index distribution, there was a problem that the propagation loss of the side-polished optical fiber could not be made the same every time. For example, the outer diameter of a coated optical fiber conforming to JIS C6835 varies from 235 μm to 265 μm. On the other hand, the typical outer diameter of a commercially available coated optical fiber is 250 μm. In this case, when polishing to 5 μm from the center of the optical fiber, it is necessary to polish the side 120 μm. When considering the case of polishing an optical fiber conforming to the JIC standard to 120 μm, the distance from the center of the optical fiber to the polished surface is -2.5 μm to 12.5 μm.

[0004] Now consider the case where light propagates within a range of 5 μm from the center of the optical fiber. When the distance from the center of the optical fiber to the polished surface is in the range of -2.5 μm to 5 μm, there is no path for the light to propagate, so the propagation loss becomes large. When the distance from the center of the optical fiber to the polished surface is in the range of 5 μm to 12.5 μm, there is still a path for the light to propagate, so the propagation loss becomes small. Thus, when only the amount of polishing is controlled, there is a problem in that the propagation loss cannot be kept constant due to manufacturing errors in the outer diameter of the optical fiber, etc.

[0005] On the other hand, side-polished optical fibers are expected to be applied to sensor networks that connect multiple sensors in series with optical fibers. In addition, by bonding the polished surfaces of two side-polished optical fibers together, it is possible to create an optical coupler at any point on the optical fiber. As described above, there are many different applications, but in any application, it is important to match the propagation loss of side-polished optical fibers for the accuracy of the sensor and the optical characteristics of the optical coupler. For example, side-polished optical fibers are expected to be used to detect changes in the refractive index, and in this case, too, the distance from the center of the optical fiber to the polished surface affects the measurement sensitivity. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Utility model registration No. 3161598 [Non-patent literature]

[0007] [Non-Patent Document 1] Atsuo Une and Toshio Kasai, "Theories and Calculation Methods of Polishing for Use on the Job", October 27, 2010, p.28-29 Summary of the Invention [Problem to be solved by the invention]

[0008] Therefore, in order to solve the problems of the above-mentioned conventional examples, the present disclosure aims to provide polishing control that makes the propagation loss of side-polished optical fibers the same by providing a function for monitoring the propagation loss of the optical fiber during polishing. [Means for solving the problem]

[0009] The polishing control system and method of the present disclosure include: A polishing control system and method for controlling side polishing of an optical fiber, comprising: Incidentally, light is incident on the optical fiber toward the point where the side polishing is being performed; receiving light that has passed through the point where the side polishing is performed on the optical fiber; Monitor the change in the light intensity of the received light, stopping the side polishing based on a change in the light intensity of the received light; It is characterized by:

[0010] In the polishing control system and method disclosed herein, before the side polishing is stopped, the polishing amount per unit time may be reduced in response to a change in the light intensity of the received light. For example, the polishing speed during the side polishing may be changed, the load on the optical fiber during the side polishing may be changed, or the abrasive grains during the side polishing may be changed.

[0011] In the polishing control system and method disclosed herein, a first bent portion of the optical fiber may be provided downstream of the point where the side polishing is performed on the optical fiber, and leakage light leaking from a side portion of the optical fiber bent by the first bent portion may be received, and a change in light intensity of the received leakage light may be monitored. Here, the optical fiber may be an optical fiber transmitting communication light, and the leakage light may be the communication light.

[0012] In the polishing control system and method disclosed herein, a second bending portion of the optical fiber may be provided upstream of the point where the side polishing is performed on the optical fiber, and light may be incident from a side portion of the optical fiber bent by the second bending portion. Here, if the optical fiber is an optical fiber transmitting communication light, test light of a specific wavelength different from the communication light may be incident from the side portion of the optical fiber bent by the second bending portion.

[0013] In the polishing control system and method of the present disclosure, the light to be received may be divided by wavelength, and the light intensity changes of the divided lights may be monitored. For example, in the present disclosure, when the optical fiber is an optical fiber transmitting communication light and the leaked light is the communication light, the leaked light may be divided by wavelength, and the light intensity changes of the divided leaked light may be monitored.

[0014] In the polishing control system and method of the present disclosure, the light to be received may be continuous light or modulated light. When the light to be received is modulated light, the light may be received using a light receiving element having a response speed slower than the modulation speed of the modulated light. For example, in the present disclosure, when the optical fiber is an optical fiber transmitting communication light and the leaking light is the communication light, the leaking light may be received using a light receiving element having a response speed slower than the communication speed of the communication light.

[0015] The above disclosures may be combined to the greatest extent possible. Effect of the Invention

[0016] According to the present disclosure, it is possible to control polishing so that the propagation loss of the optical fiber becomes a desired value. [Brief description of the drawings]

[0017] [Figure 1] 1 is a configuration example of a polishing control system having a function of monitoring the propagation loss of an optical fiber during polishing according to an embodiment of the present disclosure. [Diagram 2]1 is an example of a sequence of a polishing control method for performing propagation loss monitoring of an optical fiber during polishing according to an embodiment of the present disclosure. [Diagram 3] 1 is a configuration example of a polishing control system having a function of monitoring the propagation loss of an optical fiber during polishing according to a first embodiment of the present disclosure. [Figure 4] 13 is a configuration example of a polishing control system having a function of monitoring the propagation loss of an optical fiber during polishing according to a second embodiment of the present disclosure. [Diagram 5] 13 is a configuration example of a polishing control system having a function of monitoring the propagation loss of an optical fiber during polishing according to a third embodiment of the present disclosure. [Figure 6] 13 is a configuration example of a polishing control system having a function of monitoring the propagation loss of an optical fiber during polishing according to a fourth embodiment of the present disclosure. [Figure 7] 13 is a configuration example of a polishing control system having a function of monitoring the propagation loss of an optical fiber during polishing according to a fifth embodiment of the present disclosure. [Figure 8] 13 is a configuration example of a polishing control system having a function of monitoring the propagation loss of an optical fiber during polishing according to a sixth embodiment of the present disclosure. [Figure 9] An example of the measurement result of a photoelectric conversion element when using the polishing control system shown in FIG. 1 is shown. [Figure 10] An example of the measurement result of the photoelectric conversion element when using the polishing control system shown in FIG. 3 is shown. [Figure 11] A comparative example of the measurement results of the photoelectric conversion element having the configuration shown in FIG. 1 and the configuration shown in FIG. 3 will be shown. [Figure 12] 13 is a configuration example of a polishing control system having a function of monitoring the propagation loss of an optical fiber during polishing according to a seventh embodiment of the present disclosure. [Figure 13] 1 is an example of a sequence of a polishing control method for performing propagation loss monitoring of an optical fiber during polishing according to an embodiment of the present disclosure. [Figure 14] 13 is a configuration example of a polishing control system having a function of monitoring the propagation loss of an optical fiber during polishing according to an eighth embodiment of the present disclosure. [Figure 15] 13 is a configuration example of a polishing control system having a function of monitoring the propagation loss of an optical fiber during polishing according to a ninth embodiment of the present disclosure. [Figure 16] 13 is a configuration example of a polishing control system having a function of monitoring the propagation loss of an optical fiber during polishing according to a tenth embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the embodiments shown below. These implementation examples are merely illustrative, and the present disclosure can be implemented in various forms with various modifications and improvements based on the knowledge of those skilled in the art. Note that components with the same reference numerals in this specification and drawings are assumed to indicate the same components.

[0019] The polishing control system of the present disclosure comprises: A polishing control method for controlling a means for polishing a side surface of an optical fiber is carried out, The function of injecting light into the optical fiber toward the point where side polishing is being performed, receiving light that passes through a point where the side polishing is being performed on the optical fiber and is emitted from the optical fiber; A function for monitoring changes in the light intensity of the received light; The present invention is characterized by comprising:

[0020] In addition, the grinding control system of the present disclosure includes: a bending portion of the optical fiber is provided downstream of a point where the side polishing is performed on the optical fiber; a function of receiving leakage light leaking from a side portion of the optical fiber bent by the bending portion; A function for monitoring the change in the light intensity of the received leaked light; A configuration including the above may be adopted.

[0021] In addition, the polishing control system of the present disclosure can be configured to include a bending portion of the optical fiber upstream of the point at which the side polishing is performed on the optical fiber, and to have the function of introducing light into the side portion of the optical fiber bent by the bending portion.

[0022] The polishing control system of the present disclosure may be an in-communication polishing control system that polishes the side surface of an optical fiber that is transmitting communication light. In this case, the communicating grinding control system of the present disclosure is A function to divide leakage light by wavelength; A function to monitor the change in the light intensity of each of the split leaked light, A configuration including the above may be adopted.

[0023] Furthermore, the communicating polishing control system of the present disclosure may employ a configuration in which the leaked light is received using a light receiving element having a response speed slower than the communication speed of the communication light.

[0024] In addition, the communicating grinding control system of the present disclosure includes: a bending portion of the optical fiber is provided upstream of a point where the side polishing is performed on the optical fiber; A configuration can be employed that has a function of inputting light having a wavelength different from the communication light, which does not affect communication, from the side portion of the optical fiber bent by the bending portion.

[0025] A polishing control method for polishing an optical fiber side surface according to an embodiment of the present disclosure, which has a function of monitoring the propagation loss of the optical fiber during polishing, will be described below.

[0026] 1 shows an example of a polishing control system equipped with a function of monitoring the propagation loss of an optical fiber during polishing. The polishing control system according to this embodiment includes a light source 4, a photoelectric conversion element 5, and a control unit 6. The light source 4 has a function of irradiating light into the optical fiber 1. The photoelectric conversion element 5 has a function of receiving light emitted from the optical fiber 1. The control unit 6 has a function of monitoring changes in the light intensity of the received light.

[0027] An optical fiber 1 is fixed to a grooved optical fiber fixing jig 2 with an adhesive 3. A light source 4 is connected to one end of the optical fiber 1, and a photoelectric conversion element 5 is connected to the other end. Light emitted from the light source 4 propagates through the optical fiber 1 and is incident on the photoelectric conversion element 5. The light incident on the photoelectric conversion element 5 is converted into information on light intensity, and the information on light intensity is input to a control unit 6. The control unit 6 stores the light intensity in the state before polishing. Thereafter, the optical fiber 1 and the optical fiber fixing jig 2 are polished with a polishing sheet 7.

[0028] During polishing, the control unit 6 continues to compare the light intensity stored in the control unit 6 with the light intensity measured by the control unit 6 during polishing. When the comparison result becomes equal to or less than the threshold value, the control unit 6 completes polishing. The completion of polishing may be determined by visually checking whether the light intensity has become equal to or less than the threshold value, and polishing may be stopped, or, if the operation during polishing is controlled by a computer, polishing may be stopped by sending an operation stop signal from the control unit 6 to the computer when the light intensity has become equal to or less than the threshold value. An example of the use of the polishing control method having the function of monitoring the propagation loss of the optical fiber during polishing shown in FIG. 1 will be described below.

[0029] FIG. 2 shows the sequence of the control unit 6 for monitoring the propagation loss of the optical fiber during polishing. First, the control unit 6 stores the light intensity before polishing (S11). Then, polishing begins (S12). During polishing, the control unit 6 measures the light intensity (S13). Then, the control unit 6 calculates the rate of change between the measured light intensity and the light intensity before polishing, and compares the calculated rate of change in light intensity with a threshold (S14). If the comparison result is greater than the threshold (No in S14), polishing continues. If the comparison result is equal to or less than the threshold (Yes in S14), polishing ends. In this manner, it is possible to polish the side surface of the optical fiber with a constant propagation loss.

[0030] In addition, when polishing, water or oil may be dropped onto the polishing sheet 7, a polishing liquid (slurry) and a polishing pad may be used instead of the polishing sheet 7, or a polishing wheel may be pressed against the stretched optical fiber without using the optical fiber fixing jig 2. In addition, if it is desired to make the polished surface flat, a polishing device of a type in which the optical fiber 1 does not rotate may be used. The groove of the optical fiber fixing jig 2 may be a V-groove. In addition, the optical fiber 1 may be in a coated state or in a state in which the coating is removed, and may be a glass type optical fiber or a plastic type optical fiber that guides light. In addition, the adhesive 3 may be an ultraviolet-curing resin, a general instant adhesive or a two-liquid mixed adhesive, or a heat-curing adhesive.

[0031] Figure 9 shows the measurement results of the photoelectric conversion element 5 during polishing in the configuration of Figure 1. As can be seen from Figure 9, the propagation loss during polishing changes gradually over time. This makes it possible to complete polishing at the desired propagation loss. Several example embodiments for implementing the above disclosure are described below.

[0032] [Embodiment Example 1] 3 shows an example of the configuration of a polishing control system having a function of monitoring the propagation loss of an optical fiber during polishing according to the first embodiment of the present disclosure. The polishing control system of this embodiment includes a light source 4, a bending unit 8, a photoelectric conversion element 5, and a control unit 6. The bending unit 8 has a function of bending the optical fiber. The bending unit 8 is disposed downstream of the point where side polishing is being performed on the optical fiber 1. The photoelectric conversion element 5 has a function of receiving leakage light leaking from the side portion of the optical fiber 1 bent by the bending unit 8.

[0033] 3, a part of the light from the light source 4 leaks from the side of the optical fiber 1 bent by the bending portion 8. In the polishing control system of this embodiment, the photoelectric conversion element 5 receives this leaked light, and the control unit 6 monitors the propagation loss of the optical fiber 1. The control unit 6 determines the completion of polishing in a sequence similar to that of FIG.

[0034] In this embodiment, the propagation loss of the optical fiber 1 is monitored by using the leaked light from the side portion of the optical fiber 1. Therefore, in this embodiment, it is possible to monitor the propagation loss of the optical fiber even when one end of the optical fiber 1 is not nearby. Note that the bending portion 8 and the photoelectric conversion element 5 may use a commercially available optical fiber core wire identifier.

[0035] Figure 10 shows the measurement results of the photoelectric conversion element 5 during polishing in the configuration of Figure 3. As can be seen from Figure 10, the tendency of the change in propagation loss over time during polishing coincides with that in Figure 9.

[0036] Fig. 11 shows a comparison example of the propagation loss difference when using the configuration of Fig. 3 and the propagation loss difference when using the configuration of Fig. 1. As shown in Fig. 11, the difference in propagation loss over time with respect to the first embodiment was ±0.04 dB. This means that polishing can be completed within a range of ±0.04 dB from the desired propagation loss.

[0037] [Embodiment Example 2] 4 shows an example of the configuration of a polishing control system having a function of monitoring the propagation loss of an optical fiber during polishing according to the second embodiment of the present disclosure. The polishing control system of this embodiment includes transmission devices 9 and 10, a bending unit 8, a photoelectric conversion element 5, and a control unit 6.

[0038] In Fig. 4, a transmission device 9 and a transmission device 10 communicate with each other using communication light, and the communication light is emitted from each device. A part of the communication light emitted from the transmission device 9 leaks from the side of the optical fiber 1 bent by the bending section 8. In the polishing control system of this embodiment, the photoelectric conversion element 5 receives this leaked light, and the control section 6 monitors the propagation loss of the optical fiber 1. The control section 6 determines the completion of polishing in a sequence similar to that of Fig. 2.

[0039] In this embodiment, the propagation loss of the optical fiber 1 is monitored using light leaking from the side of the optical fiber 1. Therefore, in this embodiment, when polishing the optical fiber 1 during communication, it becomes possible to determine the completion of polishing at the polishing work site. In addition, by increasing the threshold value in Fig. 2 to an extent that does not affect communication and setting the propagation loss between the transmission device 9 and the transmission device 10 within the dynamic range, it becomes possible to polish the side of the optical fiber 1 even during communication, and it becomes possible to retrofit an optical coupler or the like even during communication.

[0040] [Embodiment 3] 5 shows an example of the configuration of a polishing control system having a function of monitoring the propagation loss of an optical fiber during polishing according to embodiment 3 of the present disclosure. The polishing control system of this embodiment includes a light source 4, bending units 8 and 11, a photoelectric conversion element 5, and a control unit 6. The bending unit 11 has a function of bending the optical fiber. The bending unit 11 is disposed upstream of the point where side polishing is performed on the optical fiber 1. The light source 4 has a function of irradiating light into the optical fiber 1 from the side portion of the optical fiber 1 bent by the bending unit 11.

[0041] In Fig. 5, light from a light source 4 is incident from an upper bent portion 11. A part of the light incident from the upper bent portion 11 leaks from a bent portion 8. This leaked light is received by a photoelectric conversion element 5, and a control unit 6 monitors the propagation loss of the optical fiber 1. The control unit 6 determines the completion of polishing in a sequence similar to that in Fig. 2.

[0042] In this embodiment, light is incident on the side of the optical fiber 1, and the propagation loss of the optical fiber 1 is monitored using the leaked light from the side of the optical fiber 1. Therefore, in this embodiment, it is possible to monitor the propagation loss of the optical fiber 1 even when both ends of the optical fiber 1 are not close to each other.

[0043] In the present embodiment, the light from the light source 4 is incident on the optical fiber 1 using the upper bending portion 11 functioning as the second bending portion, and the leaked light is received from the bending portion 8, but the present disclosure is not limited to this. For example, as shown in FIG. 1, the light may be received by a photoelectric conversion element 5 connected to the optical fiber 1.

[0044] [Embodiment 4] Fig. 6 shows an example of the configuration of a polishing control system having a function of monitoring the propagation loss of an optical fiber during polishing according to embodiment 4 of the present disclosure. The polishing control system of this embodiment includes a plurality of photoelectric conversion elements 5A and 5B and a wavelength separator 12 in the polishing control system shown in Fig. 4. The wavelength separator 12 has a function of dividing the leaked light by wavelength. The electrical conversion elements 5A and 5B receive the leaked light divided by the wavelength separator 12. The control unit 6 has a function of monitoring the change in light intensity of each light received by the electrical conversion elements 5A and 5B.

[0045] In Fig. 6, a part of communication light emitted from transmission devices 9 and 10 leaks from the side of optical fiber 1 bent by bending portion 8. This leaked light is coupled to optical fiber 15 and propagates through different paths depending on the wavelength by wavelength separator 12. The leaked light propagating through different paths is received by photoelectric conversion element 5A or 5B, respectively. Control unit 6 monitors the propagation loss of optical fiber 1 using the light intensities received by photoelectric conversion element 5A or 5B. Control unit 6 selects a wavelength that is an indicator of the completion of polishing based on the wavelength received by photoelectric conversion element 5A or 5B, and determines the completion of polishing at the selected wavelength in a sequence similar to that of Fig. 2.

[0046] In this embodiment, the propagation loss of the optical fiber 1 is monitored for each wavelength divided by the wavelength separator 12. Therefore, in this embodiment, it is possible to monitor the propagation loss of the optical fiber even when the downstream transmission device 9 and the upstream transmission device 10 are performing communication by wavelength multiplexing. Note that the wavelength separator 12 may use a fused optical coupler to separate only a specific wavelength.

[0047] In this embodiment, the leaked light from the bent portion 8 is split by the wavelength separator 12, but the present disclosure is not limited to this. For example, the light received by the photoelectric conversion element 5 shown in FIG. 1 may be split by wavelength, and the change in the light intensity of each of the split lights may be monitored.

[0048] [Embodiment 5] 7 shows a configuration example of a polishing control system having a function of monitoring the propagation loss of an optical fiber during polishing according to a fifth embodiment of the present disclosure. The polishing control system of this embodiment includes transmission devices 9 and 10, a bending unit 8, a low-speed photoelectric conversion element 13, and a control unit 6. The low-speed photoelectric conversion element 13 is a light-receiving element with a response speed slower than the communication speed of communication light.

[0049] In FIG. 7, a part of the communication light emitted from the transmission device 9 leaks from the side of the optical fiber 1 bent by the bending portion 8. In the polishing control system of this embodiment, this leaked light is incident on a low-speed photoelectric conversion element 13 having the same function as that of FIG. 3 and having a response speed slower than the transmission speed of the transmission devices 9 and 10. Since the response speed of the low-speed photoelectric conversion element 13 is slow, the leaked light incident on the low-speed photoelectric conversion element 13 is converted into information on light intensity in an averaged state. The information on the averaged light intensity is input to the control unit 6 having the same function as that of FIG. 3. The control unit 6 uses this averaged light intensity to monitor the propagation loss of the optical fiber 1. The control unit 6 determines the completion of polishing in a sequence similar to that of FIG. 2.

[0050] This embodiment uses a low-speed photoelectric conversion element 13 whose response speed is slower than the communication speed of the communication light. Therefore, in this embodiment, in a sequence for determining the completion of polishing in communication in which the communication signals are 0 and 1, even if the optical output power of the transmission devices 9 and 10 decreases when the communication signal is 0, the completion of polishing can be correctly determined.

[0051] In the present embodiment, the light transmitted through the optical fiber is communication light, but the present disclosure is not limited to this. For example, the present disclosure can be applied to any modulated light instead of communication light, and the response speed of the low-speed photoelectric conversion element 13 is slower than the modulation speed of the modulated light, so that monitoring based on the averaged light intensity can be performed.

[0052] [Embodiment 6] 8 shows a configuration example of a polishing control system having a function of monitoring the propagation loss of an optical fiber during polishing according to the sixth embodiment of the present disclosure. The polishing control system of this embodiment includes transmission devices 9 and 10, a light source 4, bending units 8 and 11, a plurality of photoelectric conversion elements 5A and 5B, a wavelength separator 12, a control unit 6, and test light blocking filters 14A and 14B.

[0053] 8, test light blocking filters 14A and 14B are installed immediately before the transmission device 9 and the transmission device 10. The test light blocking filters 14A and 14B block the test light incident on the transmission device 9 and the transmission device 10.

[0054] In FIG. 8, light is incident from the side of the optical fiber 1 bent by the upper bending portion 11 having the same function as the upper bending portion 11 in FIG. 5. A part of the light incident from the upper bending portion 11 leaks from the side of the optical fiber 1 bent by the bending portion 8, similar to the bending portion 8 in FIG. 3. This leaked light propagates through different paths depending on the wavelength by a wavelength separator 12 having the same function as the wavelength separator 12 in FIG. 6. The leaked light propagated through different paths is received by the photoelectric conversion elements 5A and 5B, respectively. The control unit 6 monitors the propagation loss of the optical fiber 1 using the light intensity received by the photoelectric conversion element 5A or 5B. The control unit 6 selects the wavelength of the test light based on the wavelength received by the photoelectric conversion element 5A or 5B, and judges the completion of polishing at the selected wavelength in a sequence similar to the sequence in FIG. 2.

[0055] This embodiment includes test light blocking filters 14A and 14B, and a test light is incident on the side portion of the optical fiber 1 bent by the bending portion 11, and the test light is used to monitor the propagation loss of the optical fiber 1. Therefore, this embodiment makes it possible to monitor the propagation loss of the optical fiber even when communication is not performed between the transmission device 9 and the transmission device 10.

[0056] (Effects of disclosure) According to the present disclosure, by providing a function for monitoring the propagation loss of an optical fiber during polishing, polishing control is provided that makes the propagation loss of side-polished optical fibers uniform. When there is no portion into which light is incident on the optical fiber, polishing control is provided that makes the propagation loss uniform by injecting light from a bent portion of the optical fiber. Furthermore, for optical fibers in communication, polishing control is provided that makes the propagation loss uniform by utilizing communication light. Furthermore, when the communication light is wavelength multiplexed, polishing control is provided that makes the propagation loss uniform by dividing the leaked light by wavelength.

[0057] [Embodiment 7] When polishing the side of an optical fiber, the amount of polishing has a large effect on the propagation loss of the optical fiber. Therefore, in order to make the propagation loss uniform above a certain level, it is necessary to reduce the amount of polishing per unit time. However, if the amount of polishing per unit time is reduced, it takes a very long time to polish the side of the optical fiber.

[0058] Therefore, in order to solve this problem, the present embodiment has a function of monitoring the propagation loss of the optical fiber being polished before stopping polishing, and changing the polishing conditions related to the amount of polishing per unit time, such as the polishing rate shown in formula (1), depending on the amount of change in the propagation loss. As a result, in the following embodiment, the propagation loss of the side-polished optical fiber is made uniform, and polishing is completed in a short time.

[0059] FIG. 12 shows an example of the configuration of a polishing control system having a function of monitoring the propagation loss of an optical fiber during polishing and a function of changing the polishing conditions according to the change in the propagation loss. The polishing control system according to this embodiment includes a light source 4, a photoelectric conversion element 5, an optical fiber fixing jig 2, a polishing sheet 7, a rotating table 18, and a control unit 6. In this embodiment, the control unit 6 monitors the change in the light intensity of the light received by the photoelectric conversion element 5, and changes the number of rotations per unit time of the rotating table 18 according to the change in the light intensity of the monitored light, thereby changing the polishing speed. The light received by the photoelectric conversion element 5 represents the influence of the propagation loss of the optical fiber. Therefore, in this disclosure, an example of monitoring the propagation loss of an optical fiber during polishing by measuring the change in light intensity will be described.

[0060] An optical fiber 1 is fixed to a grooved optical fiber fixing jig 2 with an adhesive 3. A light source 4 is connected to one end of the optical fiber 1, and a photoelectric conversion element 5 is connected to the other end. Light emitted from the light source 4 propagates through the optical fiber 1 and is incident on the photoelectric conversion element 5. The light incident on the photoelectric conversion element 5 is converted into information on light intensity, and the information on light intensity is input to a control unit 6. The control unit 6 stores the light intensity in the state before polishing. Thereafter, the optical fiber 1 and the optical fiber fixing jig 2 are polished simultaneously on a rotating table 18 to which a polishing sheet 7 is attached.

[0061] During polishing, the control unit 6 continues to compare the light intensity A stored in the control unit 6 with the light intensity B measured by the control unit 6 during polishing. Any method of comparison can be used, but for example, when the units of light intensities A and B are W, calculation of B / A can be used. When the comparison result shows that B / A is equal to or less than the polishing condition change threshold C, the control unit 6 reduces the number of rotations per unit time of the turntable 18 and continues polishing. Even after the number of rotations is reduced, the control unit 6 continues to compare the light intensity A stored in the control unit 6 with the light intensity B measured by the control unit 6 during polishing. When the comparison result shows that B / A is equal to or less than the polishing completion threshold D, the control unit 6 completes polishing.

[0062] The polishing condition change threshold and the polishing completion threshold can be determined by any method capable of determining the propagation loss. For example, the control unit 6 may display the change in light intensity on a display unit, and the user may visually determine the threshold and reduce the rotation speed or stop polishing. If the operation during polishing is computer-controlled, the control unit 6 may control the computer to reduce the rotation speed or stop polishing when the rotation speed falls below the threshold. This also applies to the following embodiments.

[0063] Hereinafter, an example of using the polishing control method having the function of monitoring the propagation loss of the optical fiber during polishing shown in Fig. 12 will be described. Fig. 13 shows a sequence of the control unit 6 in the polishing control method having the function of monitoring the propagation loss of the optical fiber during polishing. First, the control unit 6 stores the light intensity A before polishing (S11). Then, polishing is started (S12). During polishing, the control unit 6 measures the light intensity B (S13). Thereafter, the change rate B / A between the measured light intensity B and the light intensity A before polishing is calculated (S14). Thereafter, the calculated change rate B / A of the light intensity is compared with a polishing condition change threshold C (S14). If the comparison result is greater than the polishing condition change threshold C (No in S14), polishing is continued (S13).

[0064] If the comparison result is equal to or less than the polishing condition change threshold C (Yes in S14), the polishing conditions are changed in a direction that reduces the amount of polishing per unit time (S21), and polishing is continued (S22). How the polishing conditions are changed is arbitrary, but in this embodiment, for example, the number of rotations per unit time of the turntable 18 is reduced. Thereafter, the control unit 6 continues to measure the light intensity during polishing (S22), and calculates the rate of change between the measured light intensity B and the light intensity A before polishing (S23). The calculated change rate B / A of the light intensity is compared with a polishing completion threshold D (S23), and if the comparison result is greater than the polishing completion threshold D (No in S23), polishing is continued (S22). If the comparison result is equal to or less than the polishing completion threshold D (Yes in S23), polishing is completed.

[0065] In this way, the optical fiber is polished under the polishing conditions where the polishing amount per unit time of formula (1) is large until the propagation loss of the side polishing of the optical fiber changes, and after the propagation loss of the side polishing of the optical fiber changes, the optical fiber is polished under the polishing conditions where the polishing amount per unit time of formula (1) is small until the desired propagation loss is reached. As a result, this embodiment makes it possible to polish the optical fiber in a uniform and short time to reduce the propagation loss of the side polishing of the optical fiber.

[0066] Furthermore, when further polishing accuracy is required, two or more polishing condition change thresholds for changing the polishing conditions may be provided, and the polishing conditions in formula (1) may be changed each time. In this case, each time the polishing conditions are changed, they are changed in a direction that gradually reduces the amount of polishing per unit time. Furthermore, the polishing conditions in formula (1) may be changed continuously according to the change rate B / A between the measured light intensity B and the light intensity A before polishing.

[0067] In addition, when polishing, water or oil may be dropped on the polishing sheet 7, a polishing liquid (slurry) and a polishing pad may be used instead of the polishing sheet 7, or a polishing wheel may be pressed against the stretched optical fiber without using the optical fiber fixing jig 2. In addition, the rotating table 18 may be a polishing device that polishes the optical fiber 1 while drawing a figure of eight so that the optical fiber 1 does not rotate, if the polishing surface is to be flat, or a polishing device that simply rotates using a motor may be used. The groove of the optical fiber fixing jig 2 may be a V groove or a U groove, and the entire groove may be uniformly bent in order to prevent the optical fiber 1 from breaking or to polish only a part of the optical fiber 1. In addition, the optical fiber 1 may be in a coated state or in a state where the coating has been removed, and may be a glass type optical fiber or a plastic type optical fiber that guides light. In addition, the adhesive 3 may be an ultraviolet curing resin, a general instant adhesive or a two-liquid mixed adhesive, or a heat-curing adhesive.

[0068] Figure 9 shows the measurement results of the photoelectric conversion element during side polishing of the optical fiber. As can be seen from Figure 9, the propagation loss during polishing increases rapidly over time once the propagation loss starts to increase. This shows that it is possible to complete polishing at the desired propagation loss by changing the polishing conditions to a direction that reduces the amount of polishing per unit time at least once before the desired polishing loss is reached.

[0069] In the present embodiment, an example in which the light from the light source 4 is received by the photoelectric conversion element 5 has been shown, but the method of inputting light into the optical fiber 1 and the method of receiving light in the present disclosure are arbitrary. For example, as shown in FIG. 3, a bending portion 8 functioning as a first bending portion may be used, and the photoelectric conversion element 5 may receive leaked light from the bending portion 8. Also, as shown in FIG. 4, the light source 4 may be a transmission device 9, and the photoelectric conversion element 5 may receive leaked light from the bending portion 8. Also, as shown in FIG. 5 and FIG. 8, a bending portion 11 functioning as a second bending portion may be used to input light from the light source 4 into the optical fiber 1. Also, as shown in FIG. 6, FIG. 7, and FIG. 8, the optical fiber 1 may transmit communication light from the transmission device 9, and the photoelectric conversion element 5 may receive leaked light from the bending portion 8. Below, some more specific embodiment examples for carrying out the embodiment example 7 will be described.

[0070] [Embodiment 8] 14 shows an example of the configuration of a polishing control system having a function of monitoring the propagation loss of an optical fiber during polishing and a function of changing the load on an optical fiber 1, which is a polishing sample, depending on the amount of change in the propagation loss according to an eighth embodiment of the present disclosure. The polishing control system of this embodiment includes a light source 4, a photoelectric conversion element 5, an optical fiber fixing jig 2, a polishing sheet 7, a rotating table 18, a load adjustment unit 2A, and a control unit 6. In this embodiment, the control unit 6 monitors the change in the light intensity of the received light, and changes the load applied by the load adjustment unit 2A to the optical fiber 1 according to the change in the light intensity of the monitored light.

[0071] In FIG. 14, the load on the polished sample can be changed using the load adjustment unit 2A. As a result, when the control unit 6 compares the light intensity stored in the control unit 6 during polishing with the light intensity measured by the control unit 6 during polishing, and B / A becomes equal to or less than the polishing condition change threshold C, the control unit 6 reduces the load on the polished sample using the load adjustment unit 2A and continues polishing. Even after reducing the load on the polished sample, the control unit 6 continues to compare the light intensity A stored in the control unit 6 with the light intensity B measured by the control unit 6 during polishing. When the control unit 6 compares the light intensity B / A becomes equal to or less than the polishing completion threshold D, the control unit 6 completes the polishing. The sequence at this time is the same as the sequence in FIG. 13 to determine the completion of polishing. As a result, the polishing amount per unit time decreases as can be seen from formula (1).

[0072] The load adjustment unit 2A may be configured to adjust the load on the polished sample by expanding and contracting a spring 2B as shown in FIG. 14, or may be configured to change the weight of a weight that applies a load to the polished sample. The load adjustment unit 2A may be automatically controlled by the control unit 6 while monitoring the propagation loss, or may be manually adjusted by visually checking the propagation loss. The amount of polishing per unit time may be reduced by combining the load adjustment unit 2A and the rotating table 18.

[0073] [Embodiment 9] 15 shows an example of the configuration of a polishing control system having a function of monitoring the propagation loss of an optical fiber during polishing and a function of changing the polishing abrasive grains depending on the amount of change in the propagation loss according to an eighth embodiment of the present disclosure. In the polishing control system of this embodiment, a rotating table 18 is provided with a plurality of polishing sheets 7A and 7B using abrasive grains of different grain sizes, and a moving stage 17 for moving the plurality of polishing sheets 7A and 7B. A control unit 6 monitors the change in the light intensity of the received light, and changes the polishing sheets 7A and 7B according to the change in the light intensity of the monitored light.

[0074] In FIG. 15, the moving stage 17 is installed on the rotating table 18, and the coarse polishing sheet 7B and the normal polishing sheet 7A are installed on the moving stage 17, and the polishing conditions can be changed by changing the polishing sheet to be used using the moving stage 17. As a result, the control unit 6 uses the coarse polishing sheet 7B to perform polishing at first, and when the result of comparing the light intensity A stored in the control unit 6 before polishing with the light intensity B measured by the control unit 6 during polishing becomes equal to or less than the polishing condition change threshold C, the control unit 6 changes the polishing sheet to the polishing sheet 7A using the moving stage 17 and continues polishing. Even after changing the polishing sheet, the control unit 6 continues to measure the light intensity B during polishing and compares the light intensity A stored in the control unit 6 with the light intensity B measured by the control unit 6 during polishing. The control unit 6 completes polishing when the result of the comparison, B / A, becomes equal to or less than the polishing completion threshold D. The sequence at this time is the same as the sequence in FIG. 13 to determine the completion of polishing. As a result, the Preston constant in formula (1) decreases, and the amount of polishing per unit time decreases.

[0075] The moving stage 17 may be an electric stage as shown in FIG. 15, or may be a stage that is moved manually. The moving stage 17 may be controlled automatically while the control unit 6 monitors the propagation loss, or the control unit 6 may display the propagation loss on a display unit so that the user can visually check and manually adjust it. The rough polishing sheet 7B may have a different grain size of abrasive grains, a different type of abrasive grains, or a different grain size and type of abrasive grains at the same time. The polishing amount per unit time may be reduced by combining the rough polishing sheet 7B, the load adjustment unit 2A, and the rotating table 18.

[0076] [Embodiment 10] 16 shows an example of the configuration of a polishing control system having a function of monitoring the propagation loss during polishing of an optical fiber in communication according to the best embodiment of the present disclosure and the seventh and eighth embodiments. The polishing control system of this embodiment further includes a bending unit 8 in addition to the configuration of the ninth embodiment.

[0077] In Fig. 16, light used for communication is emitted from a transmission device 9. A part of the communication light emitted from the transmission device 9 leaks from the bending portion 8 in Fig. 16. The propagation loss of the optical fiber is monitored for this leaked light using the photoelectric conversion element 5 and the control unit 6, and the completion of polishing is determined by a sequence similar to that of Fig. 13. Therefore, when polishing an optical fiber during communication, it is possible to determine the completion of polishing at the polishing work site.

[0078] Furthermore, by making the polishing completion threshold D in FIG. 13 small enough so as not to affect communication and keeping the propagation loss of the transmission device 9 within the dynamic range, it becomes possible to perform side polishing of the optical fiber even during communication, making it possible to retrofit an optical coupler or the like even during communication.

[0079] The control unit 6 of the present disclosure can also be realized by a computer and a program, and the program can be recorded on a recording medium or provided via a network. The program of the present disclosure is a program for realizing a computer as the control unit 6 included in the system according to the present disclosure, and is a program for causing a computer to execute each step included in the method executed by the system according to the present disclosure. [Industrial Applicability]

[0080] Since the present disclosure is characterized by a propagation loss monitoring function, it can be used for light-guiding objects such as plastic optical fibers in addition to the glass optical fibers generally used in long-distance communications. [Explanation of symbols]

[0081] 1, 15 Optical fiber 2 Optical fiber fixing fixture 2A load adjustment section 2B Spring 3. Glue 4 light source 5 Photoelectric conversion element 6 Control section 7, 7A, 7B Polishing Sheet 8 Bending section 9, 10 Transmission Equipment 11 Upper bend 12 wavelength separator 13 Low-speed photoelectric conversion element 14A, 14B Test light blocking filter 17 Moving Stage 18 Rotating table

Claims

1. A polishing control system for controlling side polishing of an optical fiber, comprising: a first bent portion of the optical fiber is provided downstream of a point where the side polishing is performed on the optical fiber; A light is incident on the optical fiber toward a point where the side polishing is being performed; receiving leakage light that passes through a point where the side polishing is being performed on the optical fiber and leaks from a side portion of the optical fiber bent by the first bending portion; The change in the light intensity of the received leaked light is monitored. stopping the side polishing based on a change in the light intensity of the received leakage light; A polishing control system comprising:

2. A polishing control system for controlling side polishing of an optical fiber, comprising: A light is incident on the optical fiber toward a point where the side polishing is being performed; receiving light that has passed through the point where the side polishing is performed on the optical fiber; Monitor the change in the light intensity of the received light, Stopping the side polishing based on a change in the light intensity of the received light; A light receiving element with a response speed slower than the transmission speed of the incident light is used to monitor the averaged light intensity. A polishing control system comprising:

3. a first bent portion of the optical fiber is provided downstream of a point where the side polishing is performed on the optical fiber; receiving leakage light leaking from a side portion of the optical fiber bent by the first bending portion; monitoring a change in the light intensity of the received leaked light; 3. The grinding control system according to claim 2.

4. the optical fiber is an optical fiber transmitting communication light, the leakage light is the communication light, 4. The grinding control system according to claim 1 or 3.

5. a second bent portion of the optical fiber is provided upstream of a point where the side polishing is performed on the optical fiber; Light is made incident from a side portion of the optical fiber bent by the second bending portion.

3. The grinding control system according to claim 1 or 2.

6. the optical fiber is an optical fiber transmitting communication light, a test light having a specific wavelength different from the communication light is inputted from a side portion of the optical fiber bent by the second bending portion; The grinding control system according to claim 5 .

7. The light to be received is divided according to wavelength; The change in the light intensity of each of the split lights is monitored.

3. The grinding control system according to claim 1 or 2.

8. A light receiving element having a response speed slower than the transmission speed of the incident light is used to monitor the averaged light intensity. The grinding control system according to claim 1 .

9. before stopping the side polishing, reducing the polishing amount per unit time in response to the monitored change in light intensity; 3. The grinding control system according to claim 1 or 2.

10. The polishing speed for polishing the side surface is changed to reduce the polishing amount. The grinding control system according to claim 9 .

11. The amount of polishing is reduced by changing the load on the optical fiber subjected to the side polishing. The grinding control system according to claim 9 .

12. The amount of polishing is reduced by changing the abrasive grains used for the side polishing. The grinding control system according to claim 9 .

13. 1. A polishing control method executed by a polishing control system that controls side polishing of an optical fiber and has a first bent portion of the optical fiber downstream of a point on the optical fiber where the side polishing is being performed, the method comprising: A light is incident on the optical fiber toward a point where the side polishing is being performed; receiving leakage light that passes through a point where the side polishing is being performed on the optical fiber and leaks from a side portion of the optical fiber bent by the first bending portion; The change in the light intensity of the received leaked light is monitored. stopping the side polishing based on a change in the light intensity of the received leakage light; A polishing control method comprising:

14. A polishing control method executed by a polishing control system that controls side polishing of an optical fiber, comprising: A light is incident on the optical fiber toward a point where the side polishing is being performed; receiving light that has passed through the point where the side polishing is performed on the optical fiber; Monitor the change in the light intensity of the received light, Stopping the side polishing based on a change in the light intensity of the received light; A light receiving element with a response speed slower than the transmission speed of the incident light is used to monitor the averaged light intensity. A polishing control method comprising:

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