Optical fiber measuring device and method for applying bend to optical fiber

Abstract

The optical fiber measuring device comprises: a light source that emits light toward the optical fiber; a light receiving unit that receives light propagating in the optical fiber; a direction changing component that changes the direction in which the optical fiber, whose two ends are optically connected to the light source and the light receiving unit, extends downward; and a tension applying component that applies tension to the optical fiber hanging from the direction changing component.

Description

Technical Field

[0001] The invention relates to an optical fiber measuring device and an optical fiber bending applying method.

[0002] This application claims priority based on Japanese Patent Application No. 2019-166336 filed on September 12, 2019, and the contents are cited here. Background Art

[0003] Patent Document 1 discloses an optical fiber measuring device including a light source, a photodetector, and a roller for bending the optical fiber. In the optical fiber measuring device, the light source, the photodetector, and the roller are arranged on substantially the same plane.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2-50412 Summary of the invention

[0007] 1. Technical issues to be resolved

[0008] In the structure of Patent Document 1, when the optical fiber is wound on the roller, the position of the optical fiber in the vertical direction is easily deviated due to the weight of the optical fiber, and the optical fiber is easily wound with an inclination relative to the roller. When it is difficult to set the optical fiber in this way, the posture (position) of the optical fiber relative to the roller is easily deviated. As a result, the curvature radius of the bend applied to the optical fiber may deviate each time it is set, making the measurement accuracy unstable.

[0009] The present invention has been made in view of this problem, and its object is to provide an optical fiber measuring device or an optical fiber bending application method, which can improve the ease of optical fiber installation and stabilize the measurement accuracy.

[0010] (II) Technical solution

[0011] In order to solve the above technical problems, the first mode of the optical fiber measuring device of the present invention comprises: a light source, which emits light toward the optical fiber; a light receiving unit, which receives the light propagating in the optical fiber; a direction changing component, which suspends the optical fiber so that the direction in which the optical fiber, whose two ends are optically connected to the light source and the light receiving unit, extends is changed to downward; and a tension applying component, which applies tension to the optical fiber hanging from the direction changing component.

[0012] In addition, in the second mode of the method for applying a bend to an optical fiber of the present invention, an optical fiber with both ends fixed is suspended on a direction changing component, a tension applying component is used to apply tension to the optical fiber hanging from the direction changing component, and a bend is applied to the optical fiber using a plurality of reels arranged between the direction changing component and the tension applying component.

[0013] (III) Beneficial effects

[0014] According to the above aspect of the present invention, it is possible to provide an optical fiber measuring device or an optical fiber bending method that can improve the ease of optical fiber installation and stabilize the measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1A It is a perspective view of the measuring device according to the first embodiment.

[0016] Figure 1B Observed from the left Figure 1A Diagram of the measuring device.

[0017] Figure 1C Observe from the front Figure 1A Diagram of the measuring device.

[0018] Figure 1D This is a diagram showing a measurement device according to a modified example of the first embodiment when viewed from the left.

[0019] Figure 1E This is a diagram showing a measuring device according to another modified example of the first embodiment as viewed from the front.

[0020] Figure 2A This is a diagram showing the measuring device according to the second embodiment as viewed from the front.

[0021] Figure 2B Observed from the left Figure 2A Diagram of the measuring device.

[0022] Figure 3A It is a figure which shows the 1st example of the shape of a roll.

[0023] Figure 3B It is a diagram showing a second example of the shape of the roll.

[0024] Figure 3C It is a diagram showing a third example of the shape of the roll.

[0025] Figure 4A It means in Figure 2A A diagram of the measuring device in which each roll moves.

[0026] Figure 4B It means in Figure 4AFigure 3. Measurement device with the reels moved.

[0027] Figure 4C It means in Figure 4A FIG. 1 is a diagram showing a situation in which the optical fiber is not normally wound around the reel in the measurement device.

[0028] Figure 5A It is a diagram showing a modified example of the arrangement of the reels.

[0029] Figure 5B This is a diagram showing a state where the reel is moved parallel to the left-right direction.

[0030] Figure 5C This is a diagram showing a state where the reel is moved obliquely with respect to the left-right direction.

[0031] Fig. 6A This is a diagram showing the measuring device of the embodiment as seen from the front.

[0032] Figure 6B It means in Fig. 6A FIG. 1 is a diagram showing a measurement device in which the roll is moved.

[0033] Figure 7 This is a diagram showing the measuring device of the embodiment as seen from the front.

[0034] Fig. 8A This is a diagram showing the measuring device of the embodiment as viewed from the front.

[0035] Figure 8B Observed from the left Fig. 8A Diagram of the measuring device. DETAILED DESCRIPTION

[0036] (First Embodiment)

[0037] Hereinafter, an optical fiber measuring device and a method for applying a bend according to a first embodiment will be described with reference to the drawings.

[0038] like Figure 1A to Figure 1C As shown, the optical fiber measuring device (hereinafter referred to as the measuring device 10A) includes a stage S, a light source 1, a light receiving unit 2, a direction changing member 3, and a tension applying member 4. The measuring device 10A is a device for applying a bend to the optical fiber F and measuring the characteristics of the optical fiber F. In addition, the light source 1 and the light receiving unit 2 may be provided inside a single analysis device.

[0039] (Direction definition)

[0040] In the present embodiment, an XYZ orthogonal coordinate system is set to illustrate the positional relationship of each structure. In each figure, the Z axis represents the up-down direction, the X axis represents a direction orthogonal to the up-down direction, and the Y axis represents a direction orthogonal to both the Z axis and the X axis. Hereinafter, the Z axis direction is referred to as the up-down direction, the X axis direction is referred to as the left-right direction, and the Y axis direction is referred to as the front-back direction. In addition, in the up-down direction, the +Z side represents the top, and the -Z side represents the bottom. In the left-right direction, one side (+X side) is referred to as the right, and the other side (-X side) is referred to as the left. In the front-back direction, one side (+Y side) is referred to as the front, and the other side (-Y side) is referred to as the back.

[0041] The optical fiber F to be measured may be a single-mode optical fiber. The specific type of the optical fiber F can be changed as appropriate.

[0042] The mounting table S is a table or the like. A light source 1 and a light receiving unit 2 are mounted on the mounting table S. The light source 1 and the light receiving unit 2 are arranged with a gap in the left-right direction. The light source 1 is arranged on the left, and the light receiving unit 2 is arranged on the right. In addition, the positions of the light source 1 and the light receiving unit 2 may be reversed.

[0043] The light source 1 emits light toward the optical fiber F. The first end of the optical fiber F is optically connected to the emission-side connecting portion 1a of the light source 1. The wavelength of the light emitted by the light source 1 can be appropriately changed according to the characteristics of the optical fiber F as a measurement object. That is, the light source 1 is configured to be able to appropriately change the wavelength of the light. In addition, the emission-side connecting portion 1a and the first end of the optical fiber F can be directly connected or connected via other optical paths (optical fibers, optical waveguides). In each case, the optical fiber F is optically connected to the light source 1.

[0044] The light receiving unit 2 receives the light propagating in the optical fiber F. The second end of the optical fiber F is optically connected to the incident side connecting unit 2a of the light receiving unit 2. The light receiving unit 2 is configured to be able to analyze the characteristics of the optical fiber F based on the received light. In addition, the incident side connecting unit 2a and the second end of the optical fiber F can be directly connected or connected via other optical paths (optical fiber, optical waveguide). In each case, the optical fiber F is optically connected to the light receiving unit 2.

[0045] The direction changing component 3 is closer to the front than the light source 1 and the light receiving part 2. A part of the optical fiber F connected to the light source 1 and the light receiving part 2 is suspended on the direction changing component 3. Thus, the direction changing component 3 changes the direction of the optical fiber F extending forward from the light source 1 and the light receiving part 2 to downward. The direction changing component 3 extends in the left-right direction. The left end of the direction changing component 3 is closer to the left than the emitting side connection part 1a, and the right end of the direction changing component 3 is closer to the right than the incident side connection part 2a. That is, the direction changing component 3 is arranged across the emitting side connection part 1a and the incident side connection part 2a in the left-right direction. The direction changing component 3 is fixed to the mounting table S. However, the direction changing component 3 may also be fixed to a place other than the mounting table S (for example, the ground, etc.).

[0046] The direction-changing component 3 of the present embodiment is formed into a cylindrical shape. In addition, the diameter of the cylinder is smaller than φ280 mm, and a portion of the optical fiber F is bent along the outer peripheral surface of the direction-changing component 3. Therefore, the direction-changing component 3 is used to apply a bend with a curvature radius smaller than 140 mm to the optical fiber F. Generally speaking, a bend with a curvature radius of more than 140 mm is not considered as a bend when measuring the characteristics of the optical fiber F. This is because a bend with such a small curvature is unlikely to affect the characteristics of the optical fiber F. In other words, the direction-changing component 3 of the present embodiment intentionally applies a bend of a size that needs to be considered when measuring the characteristics of the optical fiber F.

[0047] The tension applying component 4 is located below the direction changing component 3. Figure 1B As shown in FIG. 1 , the position of the tension applying member 4 in the front-back direction coincides with the position of the front end of the direction changing member 3. The tension applying member 4 is configured to be movable in the up-down direction relative to the mounting table S and the direction changing member 3. When measuring the optical fiber F, the tension applying member 4 is suspended by the optical fiber F hanging downward from the direction changing member 3. The tension applying member 4 applies tension to the optical fiber F by its own weight, for example. The tension can be appropriately changed, but is preferably, for example, 20 gf or less.

[0048] The tension applying member 4 is formed in a substantially disk shape. Figure 1B As shown, a groove 4a is formed in the center of the tension applying member 4 in the front-rear direction. The optical fiber F passes through the inner side of the groove 4a. The position of the optical fiber F is restricted by the groove 4a, so that the posture of the optical fiber F can be stabilized and the optical fiber F can be prevented from being separated from the tension applying member 4.

[0049] Figure 1CThe diameter of the bottom surface of the groove 4a shown is smaller than φ280 mm, and a part of the optical fiber F is bent along the bottom surface of the groove 4a. Therefore, the tension applying member 4 applies a bend having a radius of curvature smaller than 140 mm to the optical fiber F. That is, similarly to the direction changing member 3, the tension applying member 4 also applies a bend of a size that is considered when measuring the characteristics of the optical fiber F. In addition, the tension applying member 4 may not have the groove 4a. In this case, the radius of the outer peripheral surface of the tension applying member 4 is made consistent with the required radius of curvature of the optical fiber F.

[0050] In the present embodiment, tension is applied to the optical fiber F only by the weight of the disk-shaped tension applying member 4. However, the structure for applying tension, the shape of the tension applying member 4, and the like can be changed as appropriate.

[0051] For example, Figure 1D As shown in FIG. 1 , a spring 4b for applying an upward force is provided on the tension applying member 4. In this case, the tension of the optical fiber F is the difference between the weight of the tension applying member 4 and the elastic force of the spring 4b. In addition, a so-called constant force spring can be used as the spring 4b. A constant force spring is a spring whose load does not change due to the amount of deformation. When a constant force spring is used, the tension of the optical fiber F can be kept constant regardless of the position of the tension applying member 4 in the vertical direction.

[0052] In addition, you can also use Figure 1E The balance structure 7 is as shown. The balance structure 7 includes a balance rod 7a, a support portion 7b, and a weight 7c. The balance rod 7a is supported by the support portion 7b so as to be rotatable about a fulcrum C. The first end of the balance rod 7a is rotatably fixed to the tension applying member 4, and the weight 7c is mounted on the second end of the balance rod 7a. According to this structure, the tension of the optical fiber F is the difference between the weight of the tension applying member 4 and the upward force applied to the tension applying member 4 by the weight 7c.

[0053] according to Figure 1D By changing the strength of the spring 4b, the tension of the optical fiber F can be easily changed. In addition, by providing a load sensor to detect the load applied to the spring 4b, the tension applied to the optical fiber F can be monitored.

[0054] according to Figure 1E The structure can easily change the tension of the optical fiber F by changing the position and mass of the weight 7c. In addition, by setting a load sensor below the weight 7c and setting a torque sensor to detect the torque around the fulcrum C, the tension applied to the optical fiber F can be monitored.

[0055] Furthermore, the tension applied to the optical fiber F can also be changed by adding or removing weights from the tension applying member 4 itself.

[0056] Alternatively, the tension applied to the optical fiber F can be changed by changing the shape of the tension applying member 4 such as by making the tension applying member 4 semicircular, thereby changing the weight of the tension applying member 4.

[0057] Next, a method of applying a bend to the optical fiber F in the present embodiment will be described.

[0058] First, the optical fiber F to be measured is cut into a predetermined length.

[0059] Next, both ends of the optical fiber F are connected to the emission side connection portion 1a of the light source 1 and the incident side connection portion 2a of the light receiving portion 2. At this time, both ends of the optical fiber F are fixed to the emission side connection portion 1a and the incident side connection portion 2a in such a manner that the optical fiber F is prevented from being detached from the emission side connection portion 1a and the incident side connection portion 2a due to the tension applied by the tension applying member 4.

[0060] Next, the optical fiber F connected to the light source 1 and the light receiving unit 2 at both ends is suspended from above the direction changing member 3 and hangs downward by its own weight. Thus, the direction of the optical fiber F extending forward from the light source 1 and the light receiving unit 2 toward the direction changing member 3 becomes downward.

[0061] Next, the tension applying member 4 is brought close from above to the optical fiber F hanging from the direction changing member 3. In the present embodiment, the tension applying member 4 has a groove 4a, so the optical fiber F is placed inside the groove 4a. A predetermined tension is applied to the optical fiber F by the tension applying member 4, and a bend is applied to the optical fiber F along the direction changing member 3 and the tension applying member 4.

[0062] Next, light for measurement is emitted from the light source 1. The light enters the light receiving unit 2 through the optical fiber F. When the light passes through the portion of the optical fiber F that is bent by the direction changing component 3 and the tension applying component 4, the intensity of the light changes. Therefore, by analyzing the light that enters the light receiving unit 2, the characteristics of the optical fiber F with respect to bending can be evaluated.

[0063] As described above, the measuring device 10A of the present embodiment comprises: a light source 1 that emits light toward the optical fiber F; a light receiving unit 2 that receives light propagating in the optical fiber F; a direction changing component 3 that suspends the optical fiber F so that the direction in which the optical fiber F, whose two ends are optically connected to the light source 1 and the light receiving unit 2, extends is changed downward; and a tension applying component 4 that applies tension to the optical fiber F hanging from the direction changing component 3.

[0064] According to this configuration, the position of the portion of the optical fiber F that is bent by contact with the direction changing member 3 and the tension applying member 4 in the vertical direction is less likely to deviate due to the weight of the optical fiber F. Therefore, it is easy to set the optical fiber F. Therefore, the curvature radius of the bend applied to the optical fiber is stable, so the measurement accuracy can be stabilized.

[0065] In addition, the tension applying member 4 is provided with a groove 4a for limiting the position of the optical fiber F. This further improves the ease with which the optical fiber F can be placed on the tension applying member 4. In addition, since the shape of the optical fiber F at the portion bent along the tension applying member 4 is stable, the accuracy of measurement can be further stabilized.

[0066] (Second Embodiment)

[0067] Next, a second embodiment of the present invention will be described. The basic structure is the same as that of the first embodiment. Therefore, the same reference numerals are given to the same structures and the description thereof is omitted, and only the differences will be described.

[0068] like Figure 2A , Figure 2B As shown, in addition to the mounting table S, the light source 1 , the light receiving unit 2 , the direction changing member 3 , and the tension applying member 4 , the measuring device 10B of the present embodiment further includes a plurality of reels 5 and a position detecting unit 6 .

[0069] Figure 2B The position detection unit 6 shown is configured to detect the position of the tension applying member 4 in the up-down direction.

[0070] The plurality of reels 5 are disposed between the direction changing member 3 and the tension applying member 4. The plurality of reels 5 are configured to apply a bend to the optical fiber F. Figure 2A As shown, a part of the reels 5 is arranged to clamp the portion of the optical fiber F located on the left side of the tension applying member 4 in the left-right direction. In addition, the remaining reels 5 are arranged to clamp the portion of the optical fiber F located on the right side of the tension applying member 4 in the left-right direction. In addition, the same number of reels 5 may be arranged on the left and right sides of the tension applying member 4. In addition, the reels 5 arranged on the left side of the tension applying member 4 and the reels 5 arranged on the right side of the tension applying member 4 may be respectively arranged in the same vertical direction.

[0071] Alternatively, at least one reel 5 may be provided on the left side of the tension applying member 4 and at least one reel 5 may be provided on the right side of the tension applying member 4 in the left-right direction.

[0072] By arranging the plurality of reels 5 in this manner, it is possible to compactly gather the trajectory of the optical fiber F. That is, it is possible to shorten the dimension of the optical fiber along the vertical direction of the measuring device.

[0073] like Figure 2B As shown in FIG. 1 , the position of each reel 5 in the front-to-back direction coincides with the position of the tension applying member 4 in the front-to-back direction. Figure 2AIn the example, the diameter of each reel 5 is smaller than the diameter of the tension applying member 4. However, the diameter of each reel 5 may be the same as the diameter of the tension applying member 4, or may be larger than the diameter of the tension applying member 4. In other words, the curvature (diameter) of each part can be appropriately set according to the characteristics to be measured.

[0074] Figure 3A to Figure 3C An example of the shape of the reel 5 is shown.

[0075] like Figure 3A As shown, the reel 5 can be a cylindrical (disk-shaped) shape without grooves. Figure 3A In the case of the reel 5, the optical fiber F is bent along the outer peripheral surface of the reel 5. In this case, the radius of the outer peripheral surface of the reel 5 is made consistent with the required curvature radius of the optical fiber F. In this case, the diameter of the outer peripheral surface of the reel 5 is smaller than φ280 mm.

[0076] like Figure 3B or Figure 3C As shown, the reel 5 may have a groove (second groove) 5a. Figure 3B or Figure 3C In the case of the reel 5, the optical fiber F is bent along the bottom surface of the groove 5a. In this case, the radius of the bottom surface of the groove 5a is made consistent with the required curvature radius of the optical fiber F. In this case, the diameter of the bottom surface of the groove 5a is smaller than φ280 mm.

[0077] In addition, when both the reel 5 and the tension applying member 4 have grooves, the position of the groove 5a of the reel 5 in the front-to-back direction is made to coincide with the position of the groove 4a of the tension applying member 4 in the front-to-back direction. This prevents the portion of the optical fiber F that contacts the reel 5 and the tension applying member 4 from being unnecessarily bent in the front-to-back direction. In addition, the grooves of both the reel 5 and the tension applying member 4 can prevent the trajectory of the optical fiber F from being deviated in the front-to-back direction.

[0078] like Figure 3C As shown, the reel 5 may have a notch 5b. Figure 3C In the case of the reel 5, it is possible to prevent the reels 5 from contacting each other. In addition, the shape of the reel 5 is not limited to Figure 3A to Figure 3C , can be changed appropriately. For example, Figure 3A The reel 5 is formed as follows Figure 3C The notch portion 5b is shown.

[0079] In addition, the plurality of reels 5 provided in the measuring device 10B may be combined. Figure 3A to Figure 3C The reel 5 shown is used.

[0080] Next, a method of applying a bend to the optical fiber F in the present embodiment will be described.

[0081] First, similarly to the first embodiment, the optical fiber F having both ends connected to the light source 1 and the light receiving unit 2 is suspended from the direction changing member 3 and made to hang downward. In addition, tension is applied to the optical fiber F by the tension applying member 4. By applying the tension, the slack of the optical fiber F is eliminated.

[0082] Then, if Figure 4A As shown in FIG. 1 , each reel 5 is moved so as to sandwich the optical fiber F therebetween. Figure 4A In the figure, each reel 5 moves in the left-right direction, but the direction of movement of the reel 5 can be changed appropriately. In the case where the reel 5 has a groove 5a, the optical fiber F is placed inside the groove 5a.

[0083] By moving the reel 5, Figure 4B As shown, the optical fiber F is bent along each winding drum 5. Thus, the optical fiber F is bent with a desired curvature radius based on the radius of the outer peripheral surface of the winding drum 5 or the bottom surface of the groove 5a.

[0084] about Figure 4B For example, among the five reels 5 arranged on the left side of the tension applying member 4, the optical fiber F is bent at an angle of 90° along the upper reel 5 and the lower reel 5. In addition, the optical fiber F is bent at an angle of 180° along the three reels 5 arranged between the upper reel 5 and the lower reel 5. The five reels 5 arranged on the right side of the tension applying member 4 also bend the optical fiber F in the same manner.

[0085] By combining the reel 5 for bending the optical fiber F at an angle of 90° and the reel 5 for bending the optical fiber F at an angle of 180°, it is possible to bend the optical fiber F at a desired angle. Thus, it is possible to easily adjust the angle of the bend applied to the optical fiber F. In addition, it is easy to design the path (trajectory) of the optical fiber F from the light source 1 to the light receiving unit 2.

[0086] Furthermore, the angle of the bend applied to the optical fiber F can be adjusted by using either the reel 5 that bends the optical fiber F at an angle of 90° or the reel 5 that bends the optical fiber F at an angle of 180°.

[0087] In a state where the tension applying member 4 generates tension in the optical fiber F, since the reel 5 is in contact with the optical fiber F, it is possible to suppress the optical fiber F from remaining slack or twisting.

[0088] In this state, by emitting light from the light source 1 and analyzing the light in the light receiving unit 2 , the characteristics of the optical fiber F with respect to bending can be measured.

[0089] Here, for example Figure 4CAs shown, if the optical fiber F is not properly wound around a part of the reel 5, the tension applying member 4 may be moved downward from a predetermined position. Therefore, the position detecting unit 6 detects the position of the tension applying member 4, thereby determining whether the optical fiber F is properly wound around all the reels 5.

[0090] In addition, the arrangement of the reel 5 can be changed appropriately, and for example Figure 5A Here, in order to become Figure 5A state, assuming that Figure 5B If the lower reel 5 moves in parallel in the left-right direction, the reels 5 will contact each other. This situation is particularly likely to occur when the reel 5 is formed with a groove 5a. Figure 5C As shown in FIG. 1 , by moving the reels 5 obliquely relative to the left and right directions, it is possible to suppress the reels 5 from contacting each other. Figure 5C In the example of FIG. 1 , the lower reel 5 moves obliquely toward the +Z axis direction side relative to the left-right direction when viewed from the front.

[0091] As described above, the measurement device 10B of the present embodiment includes a plurality of reels 5 for applying bends to the optical fiber F. Thus, more bends can be applied to the optical fiber F.

[0092] In addition, in the case of the present embodiment, since the optical fiber F can be bent by the winding drum 5, it is not necessary to use the direction changing member 3 and the tension applying member 4 to apply the bending to be measured to the optical fiber F. That is, in the present embodiment, the diameter of the outer peripheral surface of the direction changing member 3 or the outer peripheral surface of the tension applying member 4 or the bottom surface of the groove 4a can be larger than φ280 mm.

[0093] In addition, a groove (second groove) 5a for limiting the position of the optical fiber F may be formed on at least one of the plurality of reels 5. In this case, the position of the optical fiber F bent on the reel 5 having the groove 5a can be further stabilized. Therefore, the measurement accuracy can be further stabilized.

[0094] Furthermore, when the direction in which the plurality of reels 5 are opposed to each other while holding the optical fiber F is set as the left-right direction and the direction orthogonal to both the up-down direction and the left-right direction is set as the front-back direction, the positions of the groove 4a and the second groove 5a in the front-back direction may be consistent with each other. Thus, it is suppressed that the portion of the optical fiber F that contacts the reel 5 and the tension applying member 4 is subjected to unnecessary bending in the front-back direction. In addition, the grooves of both the reel 5 and the tension applying member 4 can prevent the trajectory of the optical fiber F from shifting in the front-back direction.

[0095] When the direction in which the plurality of reels 5 are opposed to each other with the optical fiber F sandwiched therebetween is set to the left-right direction when viewed from the top and bottom, at least one of the plurality of reels 5 may be movable obliquely relative to the left-right direction. In this case, the reels 5 can be prevented from contacting each other.

[0096] The measuring device 10B of this embodiment includes a position detection unit 6 that detects the vertical position of the tension applying member 4. This structure can determine whether the optical fiber F is properly wound on the reel 5. Therefore, it is possible to prevent the characteristics of the optical fiber F from being measured under an incorrect bending condition.

[0097] In addition, the plurality of reels 5 may include at least one reel 5 disposed on the left side of the tension applying member 4 in the left-right direction, and at least one reel 5 disposed on the right side of the tension applying member 4 in the left-right direction. Thus, the trajectory of the optical fiber F can be compactly concentrated, and the dimension of the optical fiber along the vertical direction of the measuring device can be shortened.

[0098] In addition, the plurality of reels 5 may include a reel 5 for bending the optical fiber F at an angle of 90° and a reel 5 for bending the optical fiber F at an angle of 180°. By combining the plurality of reels 5 in this way, it is possible to bend the optical fiber F at a desired angle, and thus it is possible to easily adjust the angle of the bend applied to the optical fiber F. In addition, it is easy to design the path (trajectory) of the optical fiber F from the light source 1 to the light receiving unit 2.

[0099] In addition, regarding the method of applying a bend to an optical fiber of the present embodiment, in this method, the optical fiber F having both ends fixed is suspended from the direction changing member 3, a tension is applied to the optical fiber F hanging from the direction changing member 3 using the tension applying member 4, and a bend is applied to the optical fiber F using a plurality of reels 5 arranged between the direction changing member 3 and the tension applying member 4. According to this structure, the position of the portion of the optical fiber F that contacts the direction changing member 3 and the tension applying member 4 and is bent is less likely to deviate in the vertical direction. In addition, by contacting the reel 5 with the optical fiber F to which tension is applied in advance by the tension applying member 4, it is possible to suppress the residual slack and twist in the optical fiber F that contacts the reel 5. Therefore, it is possible to improve the ease of setting the optical fiber F and make the measurement accuracy more stable.

[0100] Example

[0101] The above-mentioned embodiment will be described below using specific examples. In addition, the present invention is not limited to the following examples.

[0102] (Bending loss measurement)

[0103] Prepared as Fig. 6AThe measuring device 10C is as shown. The measuring device 10C includes: a light source 1, a light receiving unit 2, a direction changing component 3, a tension applying component 4, three reels 5, a position detecting unit 6 (not shown), and a balance structure 7. The diameter of the outer peripheral surface of the three reels 5 is set to φ20 mm. The tension applying component 4 has a groove 4a, and the diameter of the bottom surface of the groove 4a is φ280 mm. In the measuring device 10C, the three reels 5 are used to apply a bend to the optical fiber F as a measurement object. As for the bend applied to the optical fiber F by the tension applying component 4, since the radius of curvature is 140 mm, it is not a measurement object. In addition, since the diameter of the direction changing component 3 is also greater than φ280 mm, the bend applied to the optical fiber F by the direction changing component 3 is also not a measurement object.

[0104] like Fig. 6A As shown, after the optical fiber F is set in the measuring device 10C, the reel 5 is moved to become Figure 6B The status shown. Figure 6B As shown, the optical fiber F is bent at an angle of 90° by the upper and lower winding drums 5, respectively. In addition, the optical fiber F is bent at an angle of 180° by the central winding drum 5. Therefore, by using the measuring device 10C, a bend equivalent to a curvature radius of 10 mm × 360° is applied to the optical fiber F. This bending condition is the same as when the optical fiber F is wound around a drum with a diameter of φ20 mm.

[0105] As shown in Table 1, the tension applied to the optical fiber F by the tension applying member 4 is varied within a range of 1 gf to 20 gf. The tension is adjusted by changing the position and weight of the weight 7c. σ shown in Table 1 represents the magnitude of the deviation (standard deviation) of the measurement under each condition. This is described in more detail below.

[0106] [Table 1]

[0107]

[0108] Regarding Comparative Example 1, the optical fiber F in a straight state is connected to the light source 1 and the light receiving unit 2, and the transmission power P1 is measured by the light receiving unit 2. The measurement wavelength is set to 1625nm. Thereafter, the optical fiber F is manually wound around a cylinder with a diameter of φ20mm, and light is emitted from the light source 1 in this state, and the transmission power P2 is measured by the light receiving unit 2. Regarding Comparative Example 1, since the winding is performed by manual operation, there is no tension data, but it can be considered that the tension is about 10gf. The value Δ of the loss caused by winding the optical fiber F around the drum can be calculated by the following formula (1).

[0109] Δ=10Log(P1 / P2)…(1)

[0110] This measurement was performed ten times, and the standard deviation of the Δ value was calculated, σ=1.52 dB.

[0111] In Example 1-1, a tension of 20 gf is applied to the optical fiber F by using the tension applying member 4 and the balance structure 7. The measurement wavelength is the same as that of the comparative example, which is 1625 nm. Fig. 6A After measuring the transmitted power P1 in the state shown in Figure 6B The transmission power P2 is measured in the state shown. When the transmission power P2 is measured, the position detection unit 6 confirms that the tension applying member 4 is in the specified position. In other words, it is confirmed that the optical fiber F is properly wound around the three reels 5. In Comparative Example 1 and Example 1-1, the conditions for bending applied to the optical fiber F are substantially the same.

[0112] Regarding Example 1, Δ was also calculated using equation (1). This measurement was performed ten times, and the standard deviation of the Δ value was calculated. The standard deviation σ=0.56 dB.

[0113] Regarding Examples 1-2 to 1-7, σ was calculated by the same procedure as in Example 1-1. However, the tension was appropriately adjusted as shown in Table 1 by changing the position and weight of the weight 7 c.

[0114] As shown in Table 1, the value of σ for any of Examples 1-1 to 1-7 is significantly smaller than that for Comparative Example 1. The reason is considered. Since the optical fiber F is manually wound around the cylinder in Comparative Example 1, the posture of the optical fiber F wound around the cylinder is prone to deviation. For example, the optical fiber F is easily wound around the cylinder in a twisted state, or the optical fiber F is easily wound with an inclination relative to the axial direction of the cylinder.

[0115] If the posture of winding around the cylinder varies in this way, the radius of curvature of the bend applied to the optical fiber F also varies. Therefore, it is considered that in Comparative Example 1, the variation of Δ is large and the value of σ is also large.

[0116] On the other hand, in Examples 1-1 to 1-7, the measuring device 10C was used, and therefore, a bend could be stably applied to the optical fiber F. Therefore, it is considered that the variation of Δ is small and the value of σ is also small.

[0117] There is no substantial difference in the value of σ in Examples 1-1 to 1-7. Therefore, if the tension applied to the optical fiber F is 20 gf or less, the value of σ can be suppressed to a small value. Although there is no data when the tension is less than 1 gf, it is believed that if the tension is too small, the slack of the optical fiber F cannot be fully eliminated.

[0118] Therefore, the tension is preferably 20 gf or less, and more preferably 1 gf or more and 20 gf or less.

[0119] Next, prepare Figure 7 The measuring device 10D shown in the figure has a light source 1, a light receiving unit 2, a direction changing unit 3, a tension applying unit 4, 22 reels 5, a position detecting unit 6 (not shown), and a balance structure 7. Eleven reels 5 are arranged so as to clamp the optical fiber F on the -X side, and the remaining 11 reels 5 are arranged so as to clamp the optical fiber F on the +X side. The diameter of the outer peripheral surface of each reel 5 is set to φ30 mm. The tension applying unit 4 has a groove 4a, and the diameter of the bottom surface of the groove 4a is φ280 mm.

[0120] Here, the same number of the plurality of reels 5 are arranged in the left-right direction so as to sandwich the tension applying member 4. By arranging the plurality of reels 5 in this way, the trajectory of the optical fiber F can be compactly gathered, thereby performing more stable measurement.

[0121] In the measuring device 10D, the 22 reels 5 apply a bend (equivalent to a curvature radius of 15 mm×3600°) to the optical fiber F as a measurement target. The bend applied to the optical fiber F by the tension applying member 4 is not a measurement target because the curvature radius is 140 mm. In addition, the bend applied to the optical fiber F by the direction changing member 3 is not a measurement target because the diameter of the direction changing member 3 is also φ280 mm or more.

[0122] As shown in Table 2, the tension applied to the optical fiber F by the tension applying member 4 was changed in the range of 1 gf to 20 gf. The tension was adjusted by changing the position and weight of the weight 7c. In addition, in Comparative Example 2 and Examples 2-1 to 2-7 shown in Table 2, the measurement wavelength was set to 1550 nm. Other aspects were the same as those in Table 1.

[0123] [Table 2]

[0124]

[0125] As shown in Table 2, there is no substantial difference in the value of σ in Examples 2-1 to 2-7. As with the results in Examples 1-1 to 1-7, the tension is preferably 20 gf or less, and more preferably 1 gf or more and 20 gf or less.

[0126] In Examples 2-1 to 2-7, the bending diameters were larger and the bending loss values ​​were smaller than those in Examples 1-1 to 1-7. Thus, even when the bending conditions were changed, the effectiveness of setting the tension to 1 gf or more and 20 gf or less was confirmed.

[0127] (Cut-off wavelength measurement based on the bending method)

[0128] In order to measure the cutoff wavelength under the bending condition of the optical fiber F wound around a φ60 mm cylinder, similarly to the above-mentioned bending loss measurement, the following Fig. 6A The measuring device 10C shown in the figure is the same as the measuring device 10C used in the bending loss measurement except that the diameter of the reel 5 is φ60 mm. As shown in Table 3, as Comparative Example 3 and Examples 3-1 to 3-7, the cutoff wavelength of the optical fiber F was measured ten times under each condition. The cutoff wavelength was measured in accordance with IEC 60793-1-44.

[0129] [Table 3]

[0130]

[0131] In Comparative Example 3, the optical fiber F was manually wound around a cylinder having a diameter of 60 mm by one turn, thereby applying a bend to the optical fiber F.

[0132] In Examples 3-1 to 3-7, the measurement device 10C was used to apply a bend to the optical fiber F. In Comparative Example 3 and Examples 3-1 to 3-7, the conditions for applying the bend to the optical fiber F were substantially the same.

[0133] The σ column in Table 2 shows the standard deviation of the cutoff wavelength measured ten times under each condition.

[0134] As shown in Table 3, in Examples 3-1 to 3-7, compared with Comparative Example 3, the value of the standard deviation σ can be significantly reduced.

[0135] As with the results in Table 1, it was confirmed that the measurement accuracy of the cutoff wavelength can be improved by using the measuring device 10C. When measuring the cutoff wavelength, the tension is also preferably 20 gf or less, and more preferably 1 gf or more and 20 gf or less.

[0136] (Cut-off wavelength measurement based on multimode method)

[0137] use Figure 1A The measuring device 10A shown measures the cutoff wavelength based on the multimode method. The measuring device 10A includes: a light source 1, a light receiving unit 2, a direction changing component 3, and a tension applying component 4. A cylinder with a diameter of φ280 mm is used as the direction changing component 3. The tension applying component 4 has a groove 4a, and the diameter of the bottom surface of the groove 4a is φ280 mm.

[0138] As shown in Table 4, as Comparative Example 4 and Examples 4-1 to 4-7, the cutoff wavelength of the optical fiber F was measured ten times by the multimode method under each condition.

[0139] The cutoff wavelength is measured by the multimode method in the following manner.

[0140] In Comparative Example 4, both ends of the optical fiber F were provided at the light source 1 and the light receiving unit 2, and the optical fiber F was manually wound around a φ280 mm reel by one turn to give a bend.

[0141] In Examples 4-1 to 4-7, the bend was applied using the measuring device 10A. The direction changing member 3 and the tension applying member 4 applied a bend of φ280 mm at 360° to the optical fiber F, and no extra bend was applied to other parts. That is, in Comparative Example 4 and Examples 4-1 to 4-7, the conditions for applying the bend to the optical fiber F were substantially the same.

[0142] In Comparative Example 4 and Examples 4-1 to 4-7, light was incident on the optical fiber F from the light source 1 in a state where the optical fiber F was bent, and the transmitted power P1(λ) was measured by the light receiving unit 2. Next, the optical fiber F was removed from the measuring device 10A, a multimode optical fiber was connected to the light source 1 and the light receiving unit 2, and the received light power P2(λ) of the light passing through the multimode optical fiber was measured. The cutoff wavelength based on the multimode method was calculated using P1(λ) and P2(λ) in accordance with IEC-60793-1-44.

[0143] [Table 4]

[0144]

[0145] As shown in Table 4, in Examples 4-1 to 4-7, the value of the standard deviation (σ) can be significantly reduced compared to Comparative Example 4. Thus, it was confirmed that the use of the measuring device 10D can improve the measurement accuracy of the cutoff wavelength based on the multimode method. In addition, when measuring the cutoff wavelength based on the multimode method, the tension is preferably 20 gf or less, and more preferably 1 gf or more and 20 gf or less.

[0146] (Cut-off wavelength measurement based on the bending method)

[0147] Next, change the bending conditions, using Fig. 8A The measuring device 10E shown measures the cutoff wavelength based on the bending method. The measuring device 10E includes: a light source 1, a light receiving unit 2, a direction changing unit 3, a tension applying unit 4, four reels 5, three reels 5A, a position detecting unit 6 (not shown), and a balance structure 7. As the direction changing unit 3, a cylinder with a diameter of φ80 mm is used. The diameter of the outer circumference of the four reels 5 is set to φ80 mm. The diameter of the outer circumference of the three reels 5A is set to φ60 mm. The tension applying unit 4 has a groove 4a, and the diameter of the bottom surface of the groove 4a is φ80 mm.

[0148] Here, the four reels 5 are arranged in the same number in the left-right direction to sandwich the tension applying member 4, and the three reels 5A are arranged only on the left side. In this way, as long as there are at least one reel 5 arranged on the left side of the tension applying member 4 and at least one reel 5 arranged on the right side of the tension applying member 4 in the left-right direction, the dimension of the optical fiber along the vertical direction of the measuring device can be shortened.

[0149] According to the measuring device 10E, the direction changing member 3, the tension applying member 4, and the four winding drums 5 are used to apply a bend to the optical fiber F as a measurement object. The positions of the emission side connecting portion 1a and the incident side connecting portion 2a in the vertical direction coincide with the position of the upper end of the direction changing member 3. Therefore, a curvature radius of 40 mm × 90° (see FIG. 1 ) is applied to the portion of the optical fiber F along the direction changing member 3. Figure 8B The optical fiber F is bent at two locations by the direction changing component 3. Therefore, the bend applied to the optical fiber F by the direction changing component 3 corresponds to a curvature radius of 40 mm×180°.

[0150] The four reels 5 each bend the optical fiber F with a curvature radius of 40 mm×90°. The tension applying member 4 bends the optical fiber F with a curvature radius of 40 mm×180°. The three reels 5A bend the optical fiber F with a curvature radius of 30 mm×(90°+180°+90°).

[0151] Taking the above into account, the measuring device 10E applies a bend corresponding to a curvature radius of 40 mm×720° (two turns) and a bend corresponding to a curvature radius of 30 mm×360° (one turn) to the optical fiber F.

[0152] As shown in Table 5, as Comparative Example 5 and Examples 5-1 to 5-7, the cutoff wavelength of the optical fiber F was calculated ten times under each condition using the bending method. The cutoff wavelength was calculated using the transmission power before and after the bending with a curvature radius of 30 mm × 360° (one turn) applied by the reel 5A in addition to the bending with a curvature radius of 40 mm × 720° applied by the reel 5 of the measuring device 10E under the bending condition.

[0153] [Table 5]

[0154]

[0155] In Comparative Example 5, the optical fiber F was manually wound around a φ80 mm cylinder twice, thereby applying a bend to the optical fiber F. In this state, the transmission power P1 was measured. Next, based on the state in which the optical fiber F was wound around a φ80 mm cylinder twice, the optical fiber F was further wound around a φ60 mm cylinder once, thereby applying a bend. In this state, the transmission power P2 was measured. The cutoff wavelength was measured using P1 and P2 obtained in this way.

[0156] In Examples 5-1 to 5-7, the optical fiber F was bent using the measuring device 10E. Specifically, the transmission power P1 was measured in a state where the optical fiber F was bent with a curvature radius of 40 mm × 720° using the reel 5. Next, the transmission power P2 was measured in a state where the optical fiber F was bent with a curvature radius of 30 mm × 360° using the reel 5A in addition to the reel 5. The cutoff wavelength was measured using P1 and P2 obtained in this way.

[0157] In Comparative Example 5 and Examples 5-1 to 5-7, the conditions for bending applied to the optical fiber F are substantially the same.

[0158] The σ column in Table 5 shows the standard deviation of the cutoff wavelength measured ten times under each condition.

[0159] As shown in Table 5, in Examples 5-1 to 5-7, compared with Comparative Example 5, the value of the standard deviation σ can be significantly reduced.

[0160] Thus, it was confirmed that the measurement accuracy of the cutoff wavelength can be improved by using the measuring device 10E. In addition, when the cutoff wavelength is measured by changing the bending conditions, the tension is preferably 20 gf or less, and more preferably 1 gf or more and 20 gf or less.

[0161] (Mode Field Diameter Measurement)

[0162] In order to measure the mode field diameter under the bending condition of the optical fiber F wound around a φ60 mm cylinder, the following was prepared in the same way as the bending loss measurement described above. Fig. 6A The measuring device 10C shown in the figure is the same as the measuring device 10C used in the bending loss measurement except that the diameter of the roll 5 is φ60 mm. As shown in Table 6, as Comparative Example 6 and Examples 6-1 to 6-7, the mode field diameter was measured ten times under each condition. The measurement of the mode field diameter was performed in accordance with IEC60793-1-45.

[0163] [Table 6]

[0164]

[0165] In Comparative Example 6, the optical fiber F was manually wound around a cylinder having a diameter of 60 mm by one turn, thereby applying a bend to the optical fiber F.

[0166] In Examples 6-1 to 6-7, the measurement device 10C was used to apply a bend to the optical fiber F. In Comparative Example 6 and Examples 6-1 to 6-7, the conditions for applying the bend to the optical fiber F were substantially the same.

[0167] The σ column in Table 6 shows the value of the standard deviation of the mode field diameter measured ten times under each condition.

[0168] As shown in Table 6, in Examples 6-1 to 6-7, compared with Comparative Example 6, the value of the standard deviation σ can be significantly reduced.

[0169] Thus, it was confirmed that the measurement accuracy of the mode field diameter can be improved by using the measuring device 10C. In addition, when measuring the mode field diameter, the tension is preferably 20 gf or less, and more preferably 1 gf or more and 20 gf or less.

[0170] In addition, the technical scope of the present invention is not limited to the above-mentioned embodiment, and various modifications can be added within the scope not departing from the gist of the present invention.

[0171] For example, in the above-mentioned embodiment, the bending loss, cutoff wavelength, and mode field diameter are cited as the characteristics of the optical fiber F to be measured. However, when measuring other characteristics of the optical fiber F, the measuring devices 10A to 10E of this embodiment or the bending applying method of this embodiment can also be used. When measuring the characteristics that require bending of the optical fiber F, the measurement accuracy can be improved by applying this embodiment.

[0172] In addition, the arrangement of the reel 5 is not limited to the example of the measuring devices 10B to 10E, and can be changed as appropriate.

[0173] In addition, the emitting side connection part 1a and the incident side connection part 2a do not necessarily have to face forward (+Y side). For example, the emitting side connection part 1a and the incident side connection part 2a may also face upward or backward. Alternatively, the emitting side connection part 1a may face left, and the incident side connection part 2a may face right. In these cases, the optical paths (optical fiber, optical waveguide, etc.) may be connected to the emitting side connection part 1a and the incident side connection part 2a, respectively, and the ends of these optical paths may be arranged as follows: Figure 1AIn addition, if the two ends of the optical fiber F are connected at the end of the optical path, and the direction in which the optical fiber F extends is changed downward by the direction changing component 3, the same effect as the above-mentioned embodiment can be obtained. In these cases, the direction changing component 3 also changes the direction in which the optical fiber F, whose two ends are optically connected to the light source 1 and the light receiving unit 2, extends downward.

[0174] In addition, the following distance may be adjusted to prevent the optical fiber F from being tilted with respect to the direction changing member 3, the distance being the left-right distance between the emitting side connection portion 1a and the incident side connection portion 2a, or the left-right distance between the ends of the optical paths respectively connected to the emitting side connection portion 1a and the incident side connection portion 2a. Figure 1A In the embodiment, the distance between the emission-side connection portion 1 a and the incident-side connection portion 2 a in the left-right direction may be equal to the diameter of the bottom surface of the groove 4 a of the tension applying member 4 .

[0175] In addition, the positions of the emission-side connection portion 1 a and the incidence-side connection portion 2 a in the vertical direction may be different from each other.

[0176] In addition, components in the above-described embodiment may be appropriately replaced with known components without departing from the spirit of the present invention, and the above-described embodiment and modified examples may be appropriately combined.

[0177] For example, you can also Figure 3A to Figure 3C The reel 5 of the shown shape is used as the reel 5, 5A of the measuring devices 10B to 10E.

[0178] In addition, you can also Figure 1D The spring 4b shown is applied to the measuring devices 10B to 10E.

[0179] In the measuring devices 10B to 10E, the spring 4b may be used instead of the balance structure 7. Alternatively, in the measuring devices 10B to 10E, the spring 4b and the balance structure 7 may not be used, and tension may be applied to the optical fiber F using only the weight of the tension applying member 4.

[0180] Description of Reference Numerals

[0181] 1-light source; 2-light receiving part; 3-direction changing part; 4-tension applying part; 4a-slot; 5, 5A-reel; 5a-slot (second slot); 6-position detecting part; 10A~10E-measuring device; F-optical fiber.

Claims

1. An optical fiber measuring device, comprising: a light source that emits light toward the optical fiber; a light receiving unit for receiving light propagating in the optical fiber; a direction changing component, which suspends the optical fiber so that the direction in which the optical fiber, both ends of which are optically connected to the light source and the light receiving unit, extends is changed downward; a tension applying member for applying tension to the optical fiber hanging from the direction changing member; as well as a plurality of drums that apply a bend to the optical fiber, The plurality of reels are arranged between the direction changing member and the tension applying member. When viewed from the top and bottom directions, the directions in which the optical fibers are clamped by the plurality of reels are set to be the left and right directions. At least one of the plurality of reels is movable obliquely with respect to the left-right direction.

2. An optical fiber measuring device, comprising: a light source that emits light toward the optical fiber; a light receiving unit for receiving light propagating in the optical fiber; a direction changing component, which suspends the optical fiber so that the direction in which the optical fiber, both ends of which are optically connected to the light source and the light receiving unit, extends is changed downward; a tension applying member for applying tension to the optical fiber hanging from the direction changing member; as well as a plurality of drums that apply a bend to the optical fiber, The plurality of reels are arranged between the direction changing member and the tension applying member. When viewed from the top and bottom directions, the directions in which the optical fibers are clamped by the plurality of reels are set to be the left and right directions. The plurality of reels include at least one reel disposed on the left side of the tension applying member in the left-right direction, and at least one reel disposed on the right side of the tension applying member in the left-right direction.

3. The optical fiber measuring device according to claim 1 or 2, characterized in that: The tension applying member is formed with a groove for restricting the position of the optical fiber.

4. The optical fiber measuring device according to claim 1 or 2, characterized in that: A second groove for limiting the position of the optical fiber is formed in at least one of the plurality of reels.

5. The optical fiber measuring device according to claim 4, characterized in that: The tension applying member is formed with a groove for limiting the position of the optical fiber. When a direction orthogonal to both the up-down direction and the left-right direction is set as the front-back direction, The positions of the groove and the second groove in the front-rear direction are consistent.

6. The optical fiber measuring device according to claim 1 or 2, characterized in that: A position detection unit is provided to detect the position of the tension applying member in the up-down direction.

7. The optical fiber measuring device according to claim 1 or 2, characterized in that: The tension applied by the tension applying member to the optical fiber is 20 gf or less.

8. The optical fiber measuring device according to claim 1 or 2, characterized in that: The plurality of reels include a reel for bending the optical fiber at an angle of 90° and a reel for bending the optical fiber at an angle of 180°.

9. A method for applying a bend to an optical fiber, wherein: The optical fiber with both ends fixed is suspended on the direction changing component. Applying tension to the optical fiber hanging from the direction changing component using a tension applying component, applying a bend to the optical fiber using a plurality of reels disposed between the direction changing member and the tension applying member, When viewed from the top and bottom directions, the directions in which the optical fibers are clamped by the plurality of reels are set to be the left and right directions. At least one of the plurality of reels is movable obliquely with respect to the left-right direction.

10. A method for applying a bend to an optical fiber, wherein: The optical fiber with both ends fixed is suspended on the direction changing component. Applying tension to the optical fiber hanging from the direction changing component using a tension applying component, applying a bend to the optical fiber using a plurality of reels disposed between the direction changing member and the tension applying member, When viewed from the top and bottom directions, the directions in which the optical fibers are clamped by the plurality of reels are set to be the left and right directions. The plurality of reels include at least one reel disposed on the left side of the tension applying member in the left-right direction, and at least one reel disposed on the right side of the tension applying member in the left-right direction.

Images