JP2006184032A - Method and instrument for measuring center displacement of wedge-shaped fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an instrument for measuring the curvature radius of an end part of a wedge-shaped fiber and the amount of its center displacement in three dimensions by a simple method. <P>SOLUTION: This method for size measurement with the end part of the wedge-shaped fiber placed on a specimen table while forming an image of the end part of the wedge-shaped fiber by means of a lens, is characterized in that, in observing the end part of the wedge-shaped fiber through the lens, the curvature radius of the end part of the wedge-shaped fiber is measured from a relation between the width of a light-source reflection image of the wedge-shaped fiber projected onto the end part and the known curvature radius of the end part corresponding to the width while measuring a distance from a light-source reflection image of an outer diameter to the center of the end part when making an image-forming point coincide with the outer diameter of an optical fiber from its end part, and the distance is compared with a distance from the outer diameter of a known optical fiber to the center of the end part, thereby calculating the amount of its center displacement. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for measuring the tip shape of a wedge-shaped fiber used for optical communication, industrial use, and the like.

In recent years, the output of the LD module 124 has been increased, and it has been used not only for optical communication but also for medical and industrial purposes. The light patterns emitted from these high-power LDs 122 are not circular Gaussian distributions but are elliptical shapes that are different in the vertical and horizontal directions.
The ellipticity of the light emitted from the LD 122 is defined as the aspect ratio. For example, in an excitation LD of 980 nm used for optical communication, the light having an aspect ratio between 2.5: 1 and 4: 1 is used. Pattern. In order to efficiently couple the emitted light having such a shape, various tip shapes 121 have been proposed, and a typical example is a wedge-shaped fiber 11. The wedge-shaped fiber 11 is an optical fiber as shown in FIG. There are two inclined surfaces 61 formed symmetrically with respect to the central axis of the core 63 at the end of the lens, and a tip end portion 62 is provided with a semi-cylindrical curved surface continuously with respect to these inclined surfaces 61. Is forming. In general, the optical fiber 126 formed with the tip shape 121 is metallized 127 and is assembled with the LD 122 inside the optical package 123 to form an LD module 124. When assembled in the optical package 123, the optical axis is aligned with the tip shape 121 so that the coupling efficiency is maximized, and then fixed to the optical package 123 with solder 125.

  In assembling these optical packages 123, it is important to efficiently couple the light emitted from the LD 122 to the optical fiber.

  As described above, high coupling efficiency can be achieved by adjusting the radius of curvature LF of the distal end portion 62 of the wedge-shaped fiber 11 in accordance with the aspect ratio of the LD 122 so that the coupling with the light emitted from the LD 122 is optimal. .

In order to obtain a high coupling efficiency, it is important that not only the radius of curvature LF of the distal end portion 62 of the wedge-shaped fiber 11 but also the distal end portion 62 exists symmetrically with the core 63. When the tip 62 is displaced from the center of the core 63 of the optical fiber, part of the incident light leaks into the clad 64 without satisfying the propagation condition of the core 62, and the coupling efficiency is increased. descend. The radius of curvature LF and the center position shift amount LB of the distal end portion 62 of the wedge-shaped fiber 11 have a great influence on the coupling efficiency, and the coupling efficiency is greatly reduced only when the accuracy differs by several μm.
Therefore, in manufacturing the wedge-shaped fiber 11, it is necessary to measure and evaluate the curvature radius LF and the center position deviation amount LB of the tip 62 in a short time with high accuracy.

  As shown in FIG. 8, the tip end fiber 72 is observed from the side surface of the optical fiber with a CCD camera 81 or the like as shown in FIG. There is a method of measuring the curvature radius LF. The front spherical fiber 71 is formed by forming a spherical surface at the distal end portion 72 symmetrically with the core 63. The wedge-shaped fiber 11 is used for the LD 122 having a large aspect ratio, whereas the front spherical fiber 71 is an LD 122 having a small aspect ratio. Used for. This method has been used as a method for measuring the tip shape of the tip spherical fiber 71. By observing the wedge-shaped fiber 11 from the direction AB as shown in FIG. 9, the curvature radius LF and the center position are measured. The deviation amount LB can be measured.

Further, as a conventional measuring method for the other tip-spherical fiber 71, the method shown in FIG. 10 has also been used. In this method, the tip portion 72 of the tip sphere is observed from the axial direction with a coaxial epi-illumination front-view microscope, and the shape of the light source 106 is passed through the condenser lens 105, the half mirror 102, and the objective lens 101 and copied to the tip portion 72. A generated light source image is formed on the observation surface 104 through the objective lens 101 and the eyepiece lens 103, and the curvature radius LF of the object to be measured is measured using the fact that the size of the light source image is proportional to the radius of the tip 72. Is the method. It was also possible to measure the radius of curvature LF of the wedge-shaped fiber 11 using this measuring method for the tip-end fiber 71 (see Patent Document 1).
JP-A-2-95206

  However, in the conventional method of measuring from the side surface of the optical fiber, since the object to be measured is observed only from the side surface, only one-sided information is obtained, and the radius of curvature LF and the center of the distal end portion 62 of the wedge-shaped fiber 11 are obtained. There has been a problem that the three-dimensional information of the positional deviation amount LB cannot be obtained.

  In the information from the side surface, when the curvature radius LF of the tip end portion 62 is different at both ends of the tip end portion 62, only the maximum value can be measured. For example, when the radius of curvature LF of the tip 62 is small in the core 63 of the optical fiber, the core radius of curvature LF cannot be evaluated.

  Further, the center position shift amount LB of the tip 62 is only information on the optical fiber outer diameter 12, and the center position shift amount LB near the core 63 of the optical fiber could not be evaluated. Therefore, although the required curvature radius LF and center position deviation LB are satisfied from the measurement result, there is a problem that when the LD module 124 is actually manufactured, the required coupling efficiency cannot be obtained. It was.

  In the conventional method disclosed in Patent Document 1, since the evaluation is performed from the axial direction of the optical fiber, the curvature radius LF of the distal end portion 62 that cannot be confirmed by the method of measuring from the side surface of the conventional optical fiber is three-dimensional. Although it can be obtained as information, the center position deviation amount LB needs to be measured by a conventional method of measuring from the side surface of the optical fiber. There was a problem that it was not possible to evaluate.

  Furthermore, since it is necessary to measure the curvature radius LF of the tip 62 from the optical fiber axis method and then to measure the center displacement LB from the side surface of the optical fiber, the wedge-shaped fiber 11 is set on each measuring machine. Therefore, there is a problem that it takes time for measurement.

  In view of the above problems, the present invention provides a center of a wedge-shaped fiber in which the tip of the wedge-shaped fiber is placed on a sample stage and the center position of the wedge-shaped fiber is measured by forming an image on the tip of the wedge-shaped fiber with a lens. In the positional deviation measurement method, when the tip of the wedge-shaped fiber is observed through the lens, the relationship between the width of the reflected light source image of the wedge-shaped fiber and the known radius of curvature of the tip corresponding to the width is determined. Measure the radius of curvature of the tip of the fiber and measure the distance from the reflected light source image of the outer diameter to the center of the tip when the imaging point is matched to the outer diameter of the optical fiber. Compared with the distance from the outer diameter of the fiber to the center of the tip, the center position shift amount is calculated.

  Further, the width of the light source reflected image of the tip portion and the magnitude of the radius of curvature of the tip portion have a proportional relationship.

  In addition, the present invention provides a wedge-shaped fiber dimension measuring apparatus using the wedge-shaped fiber shape measuring method.

  According to the present invention, it is possible to measure the radius of curvature of the tip of the wedge-shaped fiber and the amount of center position deviation by a three-dimensionally simple method.

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

  FIG. 1 is a conceptual diagram of a method for measuring the size of the tip of a wedge-shaped fiber 11 according to the first embodiment of the present invention.

A wedge-shaped fiber 11, which is an object to be measured according to the present invention, is installed on the stage 1. The light emitted from the light source 9 is condensed by the condenser lens 7, reflected by the half mirror 3, further condensed by the objective lens 2, and condensed on the tip 62 that is a measurement object. The condensed light is reflected by the tip 62, passes through the objective lens 2 and the half mirror 3, passes through the eyepiece lens 4, and forms a light source reflected image 23 on the observation surface 5. The formed light source reflection image dimension LA has a proportional relationship that increases as the curvature radius LF of the tip 62 increases and decreases as it decreases. Specifically, the relationship is expressed by the following formula 1. Here, α is a proportional coefficient, and β is a constant. By obtaining the proportionality coefficient α and the constant β, the radius of curvature LF can be obtained from the light source reflection image size LA of the observation surface 5. As for the proportionality coefficient α and the constant β, the wedge-shaped fiber 11 having a known curvature radius LF is measured, and the light source reflection image size LA at that time is obtained. This is repeated 10 times or more, and the proportionality coefficient α and constant β may be obtained by the least square method from the light source reflection image dimensions LA obtained for the curvature radius LF.

  As the light source reflected image 23, the light source reflected image 23 is defined with a contrast ratio of 30 to 80% as a threshold value. When the contrast ratio is defined to be less than 30%, the reflected light from the inclined surface 61 other than the tip 62 is also read, so the light source reflected image 23 cannot be defined correctly, and the contrast ratio is defined to be greater than 80%. In this case, since the size of the light source reflected image 23 is very small, it is difficult to determine the size. For this reason, a threshold value of 30 to 80% may be used as the contrast ratio. More desirably, the size of the light source reflected image is most easily determined when the contrast ratio is about 50%. When the contrast ratio is changed, the size of the light source reflection image 23 changes. Therefore, in the measurement, the light source reflection image 23 must be defined with a constant contrast ratio, and the proportionality coefficient α with the curvature radius LF must be obtained. There is. When the definition of the contrast ratio is changed, the proportionality coefficient α must be obtained again. The light source reflection image dimension LF can be obtained by measuring the size of the light source reflection image 23 in the CD direction.

  Next, a method for measuring the center shift LB of the tip 23 will be described. The center line 24 of the light source reflection image is measured from the light source reflection image 23, and then the optical fiber outer diameter image 21 is set in a state where the focus of the measuring device is adjusted to the optical fiber outer diameter 12 and the optical fiber outer diameter 12 is in focus. Keep measuring. Since the position of the light source reflected image center line 24 measured previously is already known, the optical fiber center line 22 is calculated from the position of the optical fiber outer diameter image 21. The optical fiber center line 22 is a line that passes through the center of the optical fiber and is parallel to the light source reflected image center line 24 on the same plane that is perpendicular to the optical axis of the optical fiber and passes through the light source image. Since the distance to the light source reflected image center line 24 indicates the center position shift amount LB of the tip 62, the center position shift amount LB can be measured by obtaining this distance. Thus, the center position deviation amount LB of the distal end portion 62 of the wedge-shaped fiber 11 can be grasped three-dimensionally.

  In this measurement method, the wedge-shaped fiber 11 that can be measured may be any type of optical fiber such as a single mode fiber, a multimode fiber, or a polarization maintaining fiber, and any of the cladding diameter D2 and the core diameter D1. Such a size may be sufficient. Any wedge-shaped fiber 11 can be measured as long as the inclined surface 61 is formed symmetrically on the core 63 of the optical fiber and the curved surface is formed at the tip 62 thereof.

Next, a measuring apparatus using the measuring method of the present invention will be described. In the measuring apparatus of the present invention, the optical system 8 includes a light source 9 and a condensing lens 7 for introducing light from the light source and the half mirror 3, and an objective lens 2 for enlarging the tip 62, the eyepiece 4 and the eyepiece. For example, a coaxial epi-illumination microscope may be used.
The magnification of the microscope is preferably about 200 to 400 times. If the magnification is low, it is difficult to measure the light source reflection image dimension LA. Conversely, if the magnification is high, the optical fiber outer diameter 12 of the optical fiber is out of the field of view, and the optical fiber outer diameter image 21 of the optical fiber is measured. Because it becomes difficult to do. The light source of the measuring apparatus of the present invention may be any light source that is generally used, such as a halogen bulb.

  In order to observe the light source reflected image 23, a scale may be provided in the microscope and visually observed. However, in order to quantitatively grasp the positional relationship, a CCD camera 6 is installed and this CCD camera is used. It is better to project the video from 6 on the monitor 13 or the like. More preferably, it is better to obtain the curvature radius LF and the center position deviation amount LB of the tip 62 by taking the CCD camera 6 into the image processing apparatus 10 and performing calculations, and it is possible to reduce the scale reading error and the measurement effort. It can be omitted greatly. In particular, the light source reflection image dimension LA has a different value depending on the defined contrast ratio, and is difficult to discriminate visually. By processing the video captured by the CCD camera 6, the contrast ratio can be read as a numerical value, so that the range of the light source reflection image 23 is clear and the correct light source reflection image dimension LA can be obtained.

  A measurement procedure using this apparatus will be described with reference to FIG. First, the proportional relationship between the light source reflected image 23 and the curvature radius LF is confirmed with the wedge-shaped fiber 11 having the known curvature radius LF of the tip 62. Next, the wedge-shaped fiber 11 as the object to be measured is set in the measuring apparatus. The wedge-shaped fiber 11 is preferably set so that the optical axis direction of the wedge-shaped fiber 11 is ± 5 ° or less with respect to the optical axis direction of the measuring apparatus. The reason for this is that when the set angle is shifted by 5 ° or more, there is a difference in the distance between the both ends of the distal end portion 62 of the wedge-shaped fiber 11 and the objective lens of the measuring device, and the both sides of the wedge-shaped fiber 11 are not in focus. This is because an error in obtaining the optical fiber center line 22 increases.

  When the wedge-shaped fiber 11 is set and then focused, a light source reflected image 23 shown in FIG. 3C is formed on the monitor 13, and this image is read by the image processing apparatus 10. Next, the focal point is adjusted to the optical fiber outer diameter 12 of the optical fiber. As shown in FIG. 3B, an optical fiber outer diameter image 21 of the optical fiber is formed on the monitor 13, and this image is read by the image processing apparatus 10, and the light source reflection image 23 and the light previously read are read. The fiber outer diameter images 21 are superimposed.

  As a result, an image in which both are overlaid is formed as shown in FIG. After the superposition, the optical fiber center line 22 and the light source reflected image center line 24 are produced.

  FIG. 4B shows an example of superimposed images. In FIG. 4B, the light source reflected image size LA and the center position deviation amount LB of the tip 62 of the wedge-shaped fiber 11 are measured from the A side at the measurement point 41, the measurement point 42, the measurement point 43 and the sampling size LC in order. , Measure until reaching the B side.

  Thereafter, the curvature radius LF is calculated from the light source reflection image dimension LA according to Equation 1. FIG. 4A shows the curvature radius LF and the center position shift amount LB of the tip obtained in this way. As can be seen from this figure, it can be measured three-dimensionally along the tip 62 of the wedge-shaped fiber 11.

  The sampling dimension LC is preferably set so that the number of measurement points is three or more, although it depends on the type of the wedge-shaped fiber 11 to be measured. When the sampling dimension LC is increased, the number of measurement points is reduced and the accuracy of the measurement result is lowered. Conversely, when the sampling dimension LC is reduced, the number of measurement points increases, so that the measurement accuracy is improved. However, since the time required for the measurement time increases, it may be set so that necessary information can be obtained. .

  Further, the sampling dimension LC does not need to be set at a constant interval, and may be set at an arbitrary interval for each measurement point. Since the optical fiber has a structure in which light propagates through the core 63, the sampling dimension LC is set so that the number of measurement points in the vicinity of the core 63 that affects the coupling efficiency of the wedge-shaped fiber 11 is increased to shorten the measurement time. it can.

  In the wedge-shaped fiber 11 using a single-mode optical fiber, the core diameter D1 is often as small as 10 μm or less. Therefore, the radius of curvature near the core 63 of the tip 62 of the wedge-shaped fiber 11 contributes to the coupling with the LD. LF and center position shift amount LB. Therefore, it is only necessary to determine whether or not it is good based on the measurement data of the radius of curvature LF of the core 63 portion of the wedge-shaped fiber 11 and the center position deviation amount LB.

  The wedge-shaped fiber 11 using a multimode optical fiber has a cladding diameter D2 as large as 125 μm and a core diameter D1 as large as 105 μm, and is used for coupling with an LD 122 whose active layer width is approximately 100 μm. There are many. Since the LD 122 emits a beam extending in a direction perpendicular to the active layer over a width of 100 μm, the wedge-shaped fiber 11 has a center position shift amount LB in order to combine the emitted light from the LD 122 over the entire core 63. It is desirable that the curvature radius LF of the tip end portion 62 be constant as much as possible. For the evaluation of the wedge-shaped fiber 11, by measuring with the measuring method of the present invention, the tip shape can be correctly grasped according to the type of optical fiber used, and the coupling efficiency with the LD 122 is improved. It becomes possible to evaluate correctly.

  The wedge-shaped fiber 11 is used when coupled to the LD 122 as described above. However, the LD 122 is weak against reflected return light, and when there is reflected return light, the operation of the LD 122 becomes unstable. In order to prevent this, an AR coat may be applied to the distal end portion 62 of the wedge-shaped fiber 11. In the measurement method of the present invention, a coaxial episcopic microscope is used, so that not only the shape of the tip portion 11 but also an appearance evaluation such as defects in the AR coating film and adhesion of dust can be performed. It is also possible to check for defects such as cracks and chipping at the tip 62 and abnormalities such as cracks.

  FIGS. 5A and 5B show an example of the light source reflection image 23 and the optical fiber outer diameter image 21 observed with this measuring apparatus. From the observed image of FIG. 5A, the light source reflected image 23 on the A and B sides is large, and the light source reflected image center 24 is displaced from the optical fiber center line 22, so that the tip portions on the A and B sides It can be seen that the curvature radius LF of 62 is large and the center position shift amount LB is also large.

  5B, the light source reflected image 23 at the center of the fiber is small and the light source reflected image center 24 is displaced from the optical fiber center line 22. It can be seen that the curvature radius LF is small and the center deviation LB is also large. These observation results are the same in the conventional measurement method, but by using the measurement method of the present invention, the shape of the tip 11 can be correctly confirmed.

  As described above, since the evaluation is performed from the axial direction of the wedge-shaped fiber 11 by using this measurement method, it is possible to obtain three-dimensional information on the curvature radius LF and the center position deviation amount LB of the distal end portion 62. Therefore, the vicinity of the core 63 other than the optical fiber outer diameter 12 of the wedge-shaped fiber 11 can be evaluated.

  In addition, since the setting of the wedge-shaped fiber 11 to the measuring machine is only required once, the measurement can be easily performed in a short time.

  Here, the experiment was conducted by the following method.

  In the measurement apparatus of the present invention shown in FIG. 1, the light source reflection image dimension LA of the wedge-shaped fiber 11 whose known radius of curvature LF is known is 35%, 50%, 75% as an example, and 25%, 90 as a comparative example. % Contrast ratio was determined as a threshold value.

  Using the eyepiece 4 with a magnification of 40 and the objective lens 2 with a magnification of 20 times, the light source reflected image 23 is observed with the CCD camera 6, and the result is used for the optical fiber core 63. The light source reflection image dimension LA was determined.

  As an object to be measured, fifteen wedge-shaped fibers 11 having a radius of curvature LF of 5.80 to 20.00 μm at the tip of an optical fiber core 63 using a single mode optical fiber are prepared, and light sources at respective contrast ratios. The reflection image dimension LA was determined, and from the measurement results, the proportionality coefficient α and the constant β in Formula 1 were determined using the least square method.

  Further, a square error I was obtained for evaluation of the measurement result. The square error I is a value expressed by Equation 2 when the curvature radius of the i-th wedge-shaped fiber is LFi and the light source reflection image LAi. The smaller this value, the smaller the curvature radius LF and the light source reflection image LA. It is shown that the error of Formula 1 between is small.

Table 1 shows the measurement results of LA and the calculation results of the proportional count α, constant β, and square error I.

  From Table 1, as an example of the present invention, when the contrast ratio is 35% to 75% as a threshold value, the square error I is 0.789 to 0.996, but as a comparative example, the contrast ratio is 25% and In 90%, it became large with 5.589 and 2.445%.

  From this result, in the light source reflected image 23, it was possible to measure the measurement error small by defining the light source reflected image 23 with the contrast ratio of 30 to 80% as a threshold value.

  Next, as Example 1, the measurement method shown in FIG. 1 of the present invention and the measurement methods shown in FIGS. The shift amounts LB were measured, and the measurement results were compared.

  As the measurement sample, five wedge-shaped fibers 11 using a single mode optical fiber with a known radius of curvature LF and center position deviation LB at the center of the core 63 were used.

  As a measuring method of Example 1 of the present invention, a light source reflected image 23 is observed with a CCD camera 6 using an eyepiece 4 with a magnification of 40 and an objective lens 2 with a magnification of 20 times, and the result is subjected to image processing. Using the apparatus 10, the light source reflection image size LA and the center position deviation amount LB at the center of the core 63 were obtained, and the light source reflection image 23 used a contrast ratio of 50% as a threshold value.

  The proportionality constant α and constant β were calculated from the value of the light source reflection image dimension LA using the value obtained in the example of Table 1 and using the numerical value 1.

  As Comparative Example 1, the measurement method of FIG. 9 was used to observe from the side surface at a magnification of 400 times, and was observed with the CCD camera 81 to obtain the curvature radius LF and the center position shift amount LB.

  As Comparative Example 2, the curvature radius LF at the center of the core was measured using the eyepiece 103 with a magnification of 40 and the objective lens 101 with a magnification of 20 by the measurement method of FIG. In the conventional measurement method shown in FIG. 10 of Comparative Example 2, the center deviation amount LB cannot be measured, and the measurement was performed using the conventional measurement method shown in FIG.

Table 2 shows the measurement results of each measurement method.

  From Table 2, in Example 1 of the present invention, the maximum values of the measurement errors of the curvature radius LF and the center position deviation amount LB were 0.25 μm and 0.5 μm, respectively.

  On the other hand, in the measurement result of Comparative Example 1, a maximum measurement error of curvature radius LF of 1.03 μm and center position deviation LB of 1.71 μm occurred.

  Further, in the measurement result of Comparative Example 2, the measurement error of the curvature radius LF was 0.28 μm or less, which was the same measurement accuracy as the present invention, but the measurement error of 1.71 μm occurred in the center position deviation amount LB. It was.

  From this result, in the conventional method of observing from the side of the optical fiber, the measurement error was large in both the curvature radius LF and the center position deviation amount LB.

  Further, in the conventional method of measuring from the axial direction of the optical fiber, the radius of curvature LF can be measured accurately, but the center position deviation amount LB cannot be measured, and therefore, it is observed from the side of the conventional optical fiber. It is necessary to measure by the method, and as a result of the measurement, the center position shift amount LB is large.

  On the other hand, in Example 1 of the present invention, the tip shape could be accurately measured by the method of measuring the center position shift amount of the tip.

It is the schematic of the wedge-shaped fiber tip shape measuring apparatus of this invention. It is a measurement screen of the wedge-shaped fiber tip shape measuring device of the present invention. (A)-(c) is a measurement screen of the wedge-shaped fiber tip shape measuring apparatus of this invention. (A) is an example of the measurement result of the wedge-shaped fiber tip measuring device of this surface, (b) is a measurement screen of the tip shape measuring device of the present invention. (A), (b) is a measurement screen of the wedge-shaped fiber tip shape measuring apparatus of this invention. (A) is a side view of the wedge-shaped fiber, (b) is a top view from the optical axis direction of the wedge-shaped fiber, and (c) is a front view of the wedge-shaped fiber. (A) is a front view of a tip spherical fiber, (b) is a top view from the optical axis direction of a tip spherical fiber. It is a schematic diagram for demonstrating the tip shape measuring method of the conventional tip spherical fiber. It is a schematic diagram for demonstrating the conventional wedge shape fiber tip shape measuring method. It is a schematic diagram for demonstrating the conventional wedge shape fiber tip shape measuring method. It is a schematic diagram for demonstrating the mounting method of a wedge-shaped fiber. It is a schematic diagram which shows the optical module using a wedge-shaped fiber.

Explanation of symbols

1: Stage 2: Objective lens 3: Half mirror 4: Eyepiece 5: Observation surface 6: CCD camera 7: Condensing lens 8: Optical system 9: Light source 10: Image processing device 11: Wedge-shaped fiber 12: Optical fiber outer diameter 13: Monitor 21: Optical fiber outer diameter image 22: Optical fiber center line 23: Light source reflection image 24: Light source reflection image center line 41: Measurement point 42: Measurement point 43: Measurement point 61: Inclined surface 62: Tip 63: Core 64: Clad 71: Tip sphere fiber 72: Tip portion 81: CCD camera 82: Monitor 101: Objective lens 102: Half mirror 103: Eyepiece lens 104: Observation surface 105: Condensing lens 106: Light source 121: Tip shape 122: LD
123: Package 124: LD module 125: Solder 126: Optical fiber 127: Metallization A: Direction indication code B: Direction indication code C: Direction indication code D: Direction indication code LA: Light source reflected image size LB: Center position shift amount LC : Sampling dimension LF: Curvature radius D1: Core diameter D2: Cladding diameter

Claims (3)

In the wedge-shaped fiber center position deviation measuring method in which the wedge-shaped fiber is placed on the sample stage and the wedge-shaped fiber is imaged on the tip of the wedge-shaped fiber by a lens to measure the center-position deviation of the wedge-shaped fiber. When the tip of the fiber is observed, the radius of curvature of the tip of the wedge-shaped fiber is measured from the relationship between the width of the reflected light source reflected image of the wedge-shaped fiber and the known radius of curvature of the tip corresponding to the width. In addition, measure the distance from the reflected light source image of the outer diameter to the center of the tip when the imaging point is matched with the outer diameter of the optical fiber, and the distance from the known outer diameter of the optical fiber to the center of the tip A method for measuring the displacement of the center position of a wedge-shaped fiber, characterized in that a center position shift amount is calculated as compared with the above. 2. The method for measuring the deviation of the center position of a wedge-shaped fiber according to claim 1, wherein the width of the light source reflected image of the tip portion and the radius of curvature of the tip portion have a proportional relationship. A wedge-shaped fiber center position deviation measuring apparatus using the wedge-shaped fiber center position deviation measuring method according to claim 1.

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