JP2002168729A - Optical fiber end face inspection device and optical fiber end face inspection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical fiber end face inspection device and its method capable of making the accuracy of inspection higher than before when the condition of an end face of an optical fiber is inspected by using an optical microscope. SOLUTION: To inspect an end face of the optical fiber, a hold member 130 is provided and used to dispose a light source 110 and the optical microscope 120 so that their respective installation angles 161 and 162 relative to the axial direction 15 of the optical fiber are not smaller than the light receiving angle of the optical fiber and not larger than 45 deg. Accordingly, the light for end- face inspection from the light source is totally reflected by the end face of the optical fiber including a core and a clad, and a part of the light comes into the microscope. Therefore, any flaws or stains on the end face can be recognized with higher accuracy than before and the accuracy of inspection can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber end face inspection apparatus for observing a cut state of end faces of optical fibers to be connected when optical fibers are optically connected to each other using an optical fiber connector. The present invention relates to an optical fiber end face inspection method performed using an optical fiber end face inspection apparatus.

[0002]

2. Description of the Related Art For example, when connecting optical fibers at an installation site of an optical fiber used for a LAN (local area network), the axial directions of the optical fibers in the optical fibers are shifted in parallel or the angle is changed. In some cases, connection loss of transmitted light occurs. Therefore, in order to prevent the occurrence of these inconveniences, an optical fiber connector which has a function of aligning and fixing the end faces and cores of the optical fibers to be connected and capable of attaching and detaching the optical fibers is used. Also, when the end face of each optical fiber to be connected is rough, for example, when there is a flaw, a connection loss of transmitted light occurs. Therefore, when connecting optical fibers, each optical fiber is cut and its cut surface is polished so that a good end face is obtained for each optical fiber. Therefore,
Inspection of whether or not the end face after polishing is good is very important from the viewpoint of reducing the connection loss of light. In addition, since the state of the end face of the optical fiber often depends on a tool for connecting the optical fiber and a skill of the cutting and polishing work of an operator, the inspection of the end face state is important.

[0003] JP-A-8-179219 and JP-A-2
Japanese Patent Application Publication No. 000-221105 discloses an inspection method using an interference microscope as an inspection method of an optical fiber end face. However, these methods observe the interference fringes between the reference plane and the end face of the optical fiber, and the main purpose of the inspection is to measure the optical fiber eccentricity. Further, the optical fiber must be installed in a state where the axial direction of the optical fiber is exactly parallel to the optical axis of the interference microscope.

On the other hand, US Pat. No. 5,813,902, US Pat. No. 6,099,392, and International Publication WO 9
No. 8/47030 discloses an optical microscope for inspecting a cut end face of an optical fiber. In the invention of the publication,
By freely rotating the angle between the axial direction of the optical fiber and the optical axis of the optical microscope between 0 degree and 90 degrees, the end face of the optical fiber can be adjusted to an angle that is easy to inspect. or,
U.S. Pat. No. 5,210,647 discloses that the angle between the axial direction of the optical fiber and the optical axis of the optical microscope is freely changed to adjust the end face of the optical fiber to an easy-to-view angle.

[0005]

As shown in FIG.
The optical fiber 10 has a core 11 which is a portion for transmitting light.
And a clad 12 surrounding the core 11 and reflecting light leaking from the core 11 into the core 11. The light source 20 at one point on the optical axis of the core 11
1, the light receiving angle θ which is the maximum inclination angle with the optical axis.
The light inside is propagated inside the core 11.

Therefore, when the angle between the axial direction of the optical fiber and the optical axis of the optical microscope is within the light receiving angle θ of the core of the optical fiber and the light source is within the light receiving angle θ. It is difficult to determine the scratch on the end face of the optical fiber.
Because the light within the light receiving angle θ propagates through the core as described above, the light from the light source enters the optical fiber, and it is difficult to observe the state of the end face of the optical fiber with the optical microscope. Because you do. If the end face cannot be determined as described above, the quality of the optical fiber connector cannot be determined until the optical fiber connection loss measurement performed after assembling the optical fiber connector. If the optical fiber connector is determined to be defective in the measurement of the basic link loss of the optical fiber connector, the assembled optical fiber connector must be disassembled and the optical fiber must be cut again.

As is apparent from the above description, when observing the state of the end face of an optical fiber using an optical microscope, it is understood that the angle between the axial direction of the optical fiber and the optical axis of the optical microscope poses a problem. . However, the above-mentioned US Pat. No. 5,813,902 and the aforementioned US Pat.
No. 2, International Publication WO98 / 47030,
Neither US Pat. No. 5,210,647 nor the above-mentioned US Pat. No. 5,210,647 makes any mention of the angle between the axial direction of the optical fiber and the optical axis of the optical microscope, which is suitable for discriminating the end face of the optical fiber. The present invention has been made in order to solve such a problem, when inspecting the state of the optical fiber end face using an optical microscope, an optical fiber end face inspection apparatus that can improve the inspection accuracy compared to the conventional, And an optical fiber end face inspection method using the optical microscope.

[0008]

To achieve the above object, the present invention is configured as follows. That is, the first of the present invention
The optical fiber end face inspection apparatus according to the aspect, a light source that irradiates the end face of the optical fiber supported by the optical fiber support member with light for end face inspection, and reflected light reflected from the end face of the end face inspection light is incident. An optical microscope for observing the state of the end face based on the reflected light;
When in ⁻¹ NA (NA is the numerical aperture of the optical fiber), under the condition that the incident angle and the reflection angle of the end face inspection light on the end face of the optical fiber are substantially equal,
The angle between the optical axis in the optical microscope and the axial direction of the optical fiber is set to the sin ⁻¹ NA or more and 45 degrees or less,
And a holding member that holds the light source and the optical microscope by setting the angle between the optical axis of the light source and the axial direction of the optical fiber to be not less than sin ^-1 NA and not more than 45 degrees.

When the light receiving angle of the optical fiber is 0 ° or more and 19 ° or less, the holding member makes the angle between the optical axis in the optical microscope and the axial direction of the optical fiber exceed 19 °. 45 degrees or less, and the angle between the optical axis of the light source and the axial direction of the optical fiber is 19 degrees.
The light source and the optical microscope can be held at a temperature exceeding 45 degrees and 45 degrees or less.

[0010] The holding member is attached to the optical fiber supporting member and has a hinge portion.
In a state where the holding member is attached to the optical fiber supporting member, the light source is rotated with respect to the optical microscope in which an angle between the optical fiber and the axial direction is fixed to not less than sin ^-1 NA and not more than 45 degrees. The light source is movably supported, and the light source is supported at an optimal inspection position in which an angle between the optical axis of the light source and the axial direction of the optical fiber is a value of not less than sin ^-1 NA and not more than 45 degrees. Can also.

When the light source is rotated with respect to the optical microscope at the hinge, the angle between the optical axis of the light source and the axial direction of the optical fiber is the sin. The light source may further include a stopper for preventing free rotation of the light source when the value becomes equal to or more than ^-1 NA and equal to or less than 45 degrees.

[0012] Further, when the light source is rotated to a folding position close to the optical microscope at the hinge portion, the holding member prevents rotation of the light source with respect to the optical microscope. It can also have a prevention part.

Further, in the optical fiber end face inspection method according to the second aspect of the present invention, the light receiving angle of the optical fiber is set to sin ^-1 NA.
(Where NA is the numerical aperture of the optical fiber), under the condition that the incident angle and the reflection angle of the end face inspection light at the end face of the optical fiber are substantially equal, the optical axis of the optical microscope and the optical fiber Angle with the axial direction of the
n ^-1 and 45 degrees or less than NA, and the the angle between the axial direction of the optical axis and the optical fiber of the light source sin ^-1 N
As A or more and 45 degrees or less, the optical fiber, the optical microscope, and the light source are installed, and the end surface inspection light of the end surface of the optical fiber from the light source is reflected on the end surface. Is observed.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical fiber end face inspection apparatus according to an embodiment of the present invention and an optical fiber end face inspection method performed using the optical fiber end face inspection apparatus will be described below with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals. As shown in FIG. 1, an optical fiber end face inspection apparatus 101 according to this embodiment
Are the light source 110, the optical microscope 120, and the holding member 13
0.

The optical fiber 10 to be inspected by the optical fiber end face inspection apparatus 101 is supported by an optical fiber supporting member 150 with its outer periphery protected by a ferrule. As shown in FIG. The optical fiber 10 is attached so that the end face 13 of the optical fiber 10 is located on the surface 151 a of the holding member attachment base 151 of the support member 150. When the optical fibers 10 are connected to each other by the connector as described above, the optical fibers 10 are cut and polished. However, since the optical fibers 10 are cut and polished diagonally, for example, as shown in FIG. The mounting table 151 is inclined at an inclination angle 170 from the horizontal plane. The inclination angle 170 is
In the present embodiment, it is 8 degrees. Incidentally, in FIG.
The thickness of 0 is exaggerated. FIG. 4 shows an optical fiber supporting member 150 to which two optical fibers 10 can be attached.
However, the present invention is not limited to this, and the optical fiber supporting member 150 may be a member to which one optical fiber 10 can be attached.

The optical fiber 10 to be inspected by the optical fiber end face inspection apparatus 101 of the present embodiment is an inorganic optical fiber. Preferably, it is a silica glass fiber. When optical fibers are classified by transmission mode, there are single mode fiber (SM type), multimode graded index type (GI type), and multimode step index type (SI type).
(Japanese Industrial Standards) C 6832 (1995), C 6
835 (1991), for example, SGI-5
The optical fibers specified in 0/125, SGI-62.5 / 125, etc. are the main ones of the optical fibers used for communication, so that they are suitable inspection targets.

The light source 110 is an optical fiber supporting member 1
The end surface 13 of the optical fiber 10 supported by 50 is irradiated with end surface inspection light for the end surface inspection, and any type is available as long as it provides illuminance that allows the optical fiber end surface 13 to be observed using the optical microscope 120. Absent. As shown, it is a small light irradiation device such as a penlight. The reflected light of the end face inspection light reflected on the end face 13 including the core 11 and the clad 12 of the optical fiber 10 is incident on the optical microscope 120, and the optical microscope 120 generates the light of the end face 13 based on the reflected light. State, specifically, the end face 13
Is an optical microscope which has an eyepiece and which enables direct observation with the naked eye of an operator. The optical microscope 120
An example of the effective magnification is 50 times or more, and the possible visual field is φ2.
It is not more than 00 mm. The microscope is not limited to the optical microscope for performing the direct observation, but may be an optical microscope that displays the state of the end face 13 on a monitor using an imaging camera. Examples of the configuration include an optical fiber end face inspection apparatus including an objective lens of an optical microscope, a light source, an imaging camera, and an image display monitor.

The holding member 130 has the following functions. That is, the light receiving angle of the optical fiber 10 is set to sin ^-1 N
When A (NA is the numerical aperture of the optical fiber), the holding member 130 is provided under the condition that the incident angle and the reflection angle of the end face inspection light on the end face 13 of the optical fiber 10 are substantially equal. A microscope angle 161 between the optical axis 121 of the optical microscope 120 and the axial direction 15 of the optical fiber 10 is not less than sin ^-1 NA and not more than 45 degrees, and the optical axis 111 of the light source 110 and the axis of the optical fiber 10 are different. The light source angle 162 with the direction 15 is
The light source 110 and the optical microscope 120 are held at n ⁻¹ NA or more and 45 degrees or less.

FIG. 1 shows the light receiving angle and the numerical aperture.
This will be described with reference to FIG. Of the light rays emitted from the light source 20 existing at one point on the optical axis of the core 11 and incident on the core 11,
Assuming that the maximum inclination angle with respect to the optical axis is θ and the refractive index of the medium between the light source 20 and the core 11 is n, a numerical value expressed by n sin θ is called a numerical aperture NA. In this embodiment,
Since the medium is air, the refractive index can be set to 1, and the numerical aperture NA = sin θ. Therefore, the maximum tilt angle, that is, the light receiving angle θ is sin ⁻¹ NA.

Therefore, in order to inspect the end face 13 of the core 11 for scratches and dirt, the end face inspection light from the light source 110 needs to be reflected by the end face 13 without being incident on the core 11. That is, with respect to the axial direction 15 of the core 11, the light source 1
By arranging 10 at an angle equal to or greater than the light receiving angle θ,
The reflection efficiency of the end face inspection light on the end face 13 is improved, and the core 1 is improved.
Thus, it becomes possible to detect a flaw or the like on the end face 13 of FIG. The light source 110
Disposing the optical microscope 120 at an angle equal to or greater than the light receiving angle θ with respect to the axial direction 15 in accordance with Newton's axiom that the incident angle and the reflection angle are equal. Become. Therefore, it is required that the incident angle and the reflection angle of the end face inspection light be substantially equal, but according to Newton's axiom, the difference between the incident angle and the reflection angle is 0 degree. However, in practice, it can be said that the difference is substantially equal if the difference is within 3 degrees.

Here, the selection of the arrangement angle of the light source 110 will be described. In the present embodiment, the optical microscope 120 is designed to be installed at an angle of 30 degrees with respect to the axial direction 15 of the optical fiber 10, that is, the axial direction 15 of the core 11, for example. That is, the microscope angle 161 is set to 30 degrees. The value of 30 degrees is a value determined from the viewpoint of facilitating manufacture. Referring to the optical model shown in FIG. 6, the light emitted from the light source 110 enters the optical microscope 120 as reflected light according to Newton's axiom that the incident angle and the reflection angle are equal. That is, assuming that the angle between the axial direction 15 and the optical axis 111 of the light source 110 is α, the end face 13 is obliquely cut at an inclination angle of 8 degrees as described above. Is (α + 8)
Degree. Therefore, since the above-mentioned optical microscope 120 is installed at an angle of 30 degrees with respect to the axial direction 15, (α + 8) + 8 = 30, and the angle α can be theoretically obtained as 14 degrees.

However, since the object to be inspected is an optical fiber, as described above, the light receiving angle θ from the axial direction 15 of the core 11, ie, sin ^The end face inspection light needs to be incident on the end face 13 at an angle of ^-1 NA or more. That is, the angle α, that is, the light source angle 162 is the light receiving angle θ
It is necessary to be above. The above-mentioned JIS C 6832
(1995), for example, when the core diameter is φ6
For a 2.5 μm quartz optical fiber, the light receiving angle θ
Is 18.1 degrees. Therefore, in practice, the light source angle 162 (the angle α) is an angle exceeding the 18.1 degree.

Therefore, the light receiving angle θ of the optical fiber is
For example, when the angle is 0 degrees or more and 19 degrees or less, the holding member 130 is connected to the optical axis 121 of the optical microscope 120.
161 between the optical fiber and the axial direction 15 of the optical fiber is 1
The light source 11 is set to be more than 9 degrees and not more than 45 degrees, and the angle 162 between the optical axis 111 of the light source 110 and the axial direction 15 of the optical fiber is set to be more than 19 degrees and not more than 45 degrees.
0 and the optical microscope 120 described above.

FIGS. 7 to 9 show the microscope angle 161 shown in FIG.
The state of observation of the end face 13 by the optical microscope 120 when the light source angle 162 was changed from 12 degrees to 21.5 degrees in a state where the angle was 30 degrees was illustrated. The optical fiber 10 is a quartz optical fiber having a core diameter of φ50 μm as an example. FIG. 7 shows a case where the light source angle 162 is set to 12 to 15 degrees, that is, an angle at which the incident angle and the reflection angle of the end face inspection light from the light source 110 on the end face 13 are substantially the same. . In this case, the optical fiber 10
The inspection light is incident on the inside, and only the unevenness of the flaw of the clad 12 can be recognized, and the surface of the end face 13 looks black, and the flaw or the like cannot be recognized. FIG. 8 shows a case where the light source angle 162 is set to 18 to 20 degrees. In this case, the roughness of the surface of the end face 13 is recognized when the light source angle 162 exceeds 18 degrees which is almost equal to the light receiving angle θ. Can be. However, in practice, it is important to make it easier to find scratches or the like on the surface than on the surface. From this point, proper recognition cannot be performed at the above 18 to 20 degrees.

On the other hand, FIG.
In this case, the surface flaw or the like can be stably recognized, which seems to be preferable.
In the conventional optical fiber end face inspection apparatus, the light source angle 162 is set to 21 to 21.5 degrees, whereas the conventional optical fiber cannot be recognized unless the scratch has a depth of several tens of μm or more. At this time, even a scratch having a depth of about 1 μm to 10 μm could be recognized. Based on the above experimental results, in the present embodiment, the light source angle 162 is taken as an example and 21 to 2 is used.
It is set to 1.5 degrees. Also, as described above, the light source 11
The upper limit of the installation angle of 0 and the upper limit of the installation angle of the optical microscope 120 are each set to 45 degrees. This is because when the end face 13 of the optical fiber 10 is observed obliquely, its image looks elliptical. Therefore, when installed at an angle of more than 45 degrees, the ratio of the length of the minor axis to the major axis in the elliptical observation image is less than 1/2, and the image in the minor axis direction of the observation image is crushed, This is because it becomes difficult to recognize the scratches and the like. Therefore, in the present embodiment, the upper limit is set to 45 degrees.

On the basis of the above-described grounds for selecting the arrangement angle of the light source 110, the holding member 130 is configured as follows. That is, the holding member 130 is, for example, as shown in FIG.
As shown in FIG. 5, a light source holding member 131 for detachably holding the light source 110, a microscope holding member 132 for detachably holding the optical microscope 120, a hinge 133, and in the present embodiment, the microscope holding member 132 is integrated with the light source holding member 131. And a mounting plate 136 which is formed. More preferably, the mounting plate 136 has a stopper portion 134 and a rotation preventing portion 135, and the hinge portion 13
At 3, the light source holding member 131 and the microscope holding member 1
32 are rotatably connected to each other.

The mounting plate 136 is a plate for mounting the holding member 130 on the holding member mounting base 151 of the optical fiber supporting member 150.
The microscope holding member 132 is formed on the mounting plate 136 in an inclined state so that the microscope 20 is held at the microscope angle 161. In addition, in order to facilitate the mounting of the holding member 130 on the holding member mounting base 151, one end of the mounting plate 136 is provided with an engaging member provided on the holding member mounting base 151 as shown in FIG. A protrusion 1362 that can be fitted into the groove 152 is formed. Further, the optical fiber supporting member 1 is mounted on the holding member mounting base 151 in a state where the mounting plate 136 is mounted, that is, in a state where the holding member 130 is mounted.
In order to make it possible to inspect the end face 13 of the optical fiber 10 supported by the mounting plate 50, the mounting plate 1
36 is provided.

In the present embodiment, the hinge portion 133 is rotatably fitted to the rotation center shaft 1331 provided on the microscope holding member 132 and the rotation center shaft 1331 provided on the light source holding member 131. And an engagement portion 1332. In a state where the rotation center shaft 1331 and the engaging portion 1332 are fitted, the frictional force causes the light source holding member 131 to freely rotate on the microscope holding member 132 unless an external force acts thereon. Never. Hinge part 13
3 indicates that the holding member 130 is the optical fiber supporting member 1
In the state where the optical microscope 120 is attached to the optical microscope 120, the angle between the optical fiber 10 and the axial direction 15 is fixed to be not less than sin ⁻¹ NA and not more than 45 degrees. At the light source 110
, Which is rotatably supported, and an angle between the optical axis 111 of the light source 110 and the axial direction 15 of the optical fiber 10 is a value of not less than sin ^-1 NA and not more than 45 degrees. At 1343, the light source 110 is supported.
The structure is not limited to the structure of the above-described embodiment as long as the hinge 133 performs such a function.

By providing the hinge portion 133, the light source angle 162 can be adjusted, and the end face 13 can be more appropriately and easily recognized for scratches and dirt. Further, by providing the hinge portion 133, the light source 110 can be disposed at the folding position 1353 and the optimum inspection position 1343 with respect to the optical microscope 120 as described later. In this state, the portability of the holding member 130 can be improved.

In the present embodiment, the stopper portion 134 includes a contact portion 1341 provided on the microscope holding member 132,
A projection 1342 provided on the light source holding member 131,
The hinge portion 13 moves in a direction in which the light source angle 162 increases.
3, the light source holding member 131 is rotated around the fulcrum, and in the present embodiment, the light source angle 162 is 21 to 2 as described above.
When the light source 110 is arranged at the optimum inspection position 1343 which is 1.5 degrees, the protrusion 1342
41. That is, when the light source 110 is rotated with respect to the optical microscope 120 about the hinge 133 as a fulcrum, the stopper portion 134 is connected to the optical axis 111 of the light source 110 and the optical fiber 10.
Is 45 ° or more than the above-mentioned sin ⁻¹ NA.
When the value becomes equal to or less than the degree, the rotation of the light source 110 is prevented. The structure is not limited to the structure of the above-described embodiment as long as the stopper 134 performs such a function.

By providing the above-mentioned stopper portion 134,
As described above, JISC 6832 (1995), C
6835 (1991), for example, SGI
For the main optical fibers used in telecommunications, such as -50/125, SGI-62.5 / 125, etc.
The operator simply touches the light source 110 with respect to the optical microscope 120.
Just open the light source 110 until the light source stops rotating.
10 can be arranged at the optimal inspection position 1343, and the state of the end face 13 can be observed in an optimal state.

In the present embodiment, the rotation preventing portion 135 is provided with a projection 1351 provided on the microscope holding member 132,
An engaging portion 1352 provided on the light source holding member 131 and having a hole for engaging with the protrusion 1351 is provided. Such a rotation preventing unit 135 is in a state shown in FIGS. 2 and 3.
When the light source 110 is rotated to the folding position 1353 close to the optical microscope 120 with the hinge 133 as a fulcrum, the light source 110
To prevent rotation. Note that such a function is provided by the rotation prevention unit 1.
As long as 35 is performed, the structure is not limited to the structure of the above-described embodiment.

By having the above-described rotation preventing section 135,
When the light source 110 is disposed at the folding position 1353, it is possible to prevent the light source 110 from rotating carelessly with respect to the optical microscope 120, and the light source 110 and the optical microscope 12 can be prevented from rotating.
The portability of the holding member 130 to which the “0” is attached can be improved.

In the present embodiment, the rotation preventing portion 135 is provided as described above, but may not be provided. Further, in the present embodiment, the optical microscope 120 is installed at an angle of 30 degrees with respect to the axial direction 15 of the core 11, but is not limited to 30 degrees, and the light receiving angle is set as described above. The angle can be set to be not less than 45 ° and not less than sin ⁻¹ NA. Further, in the above-described embodiment, the optical fiber 10 to be inspected is supported by the support member 150, but is not limited thereto.

An optical fiber end face inspection method performed by using the optical fiber end face inspection apparatus 101 configured as described above will be described below. The optical fiber 10 to be inspected is the SGI-50 / 125, SGI-62.5
/ 125 or the like, which is the main optical fiber used for communication. The optical fiber 10 to be inspected is
As shown in FIG. 5, after being cut using a cutting and polishing jig 180, the optical fiber supporting member 15 is polished.
It is assumed that it is set to 0. Also, the optical fiber 10
Is attached to a cutting and polishing jig 180.

First, in step 1, the engaging groove 152 of the holding member mounting base 151 of the optical fiber supporting member 150 is provided.
The projection 136 of the mounting plate 136 of the holding member 130
2, the mounting plate 136, that is, the holding member 130 is mounted on the holding member mounting base 151.
The light source 110 and the optical microscope 120 are held by the holding member 130, and the light source 110 is located at the folding position 1353. Next, in step 2, the operator rotates the light source 110 from the folding position 1353 to the optimum inspection position 1343, that is, until the protrusion 1342 of the stopper 134 contacts the contact portion 1341. .

In the next step 3, the end face inspection light is emitted from the light source 110. Then, in the next step 4, the operator looks into the optical microscope 120 and observes the state of the end face 13 of the optical fiber 10, that is, the presence or absence of scratches and dirt. After the observation, the inspected optical fiber 10 is removed from the optical fiber supporting member 150, the next optical fiber 10 to be inspected is set, and the above inspection is repeated. Note that, in the above-described inspection method, the holding member 130 is attached to the holding member mounting base 15 with the light source 110 previously arranged at the optimum inspection position 1343.
1 can also be mounted. In this case, the operation in step 2 becomes unnecessary. Alternatively, the end surface inspection light may be emitted from the light source 110 in advance.

As described above, according to the optical fiber end face inspection apparatus 101 of the present embodiment, the angle 161 between the optical axis 121 of the optical microscope 120 and the axial direction 15 of the optical fiber 10 is set to the above sin ^-1 NA or more. 45 degrees or less,
The holding member 130 holds the light source 110 and the optical microscope 120 so that an angle 162 between the optical axis 111 of the light source 110 and the axial direction 15 is not less than sin ^-1 NA and not more than 45 degrees. did. Therefore, using the optical fiber end face inspection apparatus 101, the optical fiber 10
By inspecting the end face 13 of the above, the end face inspection light does not enter the core 11 and is reflected by the end face 13, so that the end face 13 can be easily recognized for scratches and dirt as compared with the related art. Therefore, the inspection accuracy of the end face 13 of the optical fiber 10 can be improved as compared with the related art.

FIG. 10 shows JIS C 6823 (19)
(1989), an inspection apparatus for inspecting the basic link loss of the optical fiber 10 connected by the optical fiber connector 190 according to the inspection method specified in the inspection method. FIG. 11 shows the result of measuring the basic link loss of the optical fiber using the inspection device. By performing the inspection using the optical fiber end face inspection apparatus 101 of the present embodiment, the inspection accuracy of the end face 13 is improved as compared with the related art, as described above. Is less likely to be connected than before. Therefore, as shown in FIG. 11, according to the present embodiment, as a result, the basic link loss can be reduced as compared with the related art. Therefore, assembling productivity of the optical fiber 10 can be improved as compared with the related art. FIG. 11 shows the measurement results of the basic link loss in the conventional and the present embodiments when the length of the cable to be measured is 3 m when the wavelengths of the propagating light are 850 nm and 1300 nm. As is clear from the above, the basic link loss can be reduced by about 30 to 40% in the average value of the basic link loss as compared with the related art.

[0040]

As described in detail above, according to the optical fiber end face inspection apparatus of the first aspect and the optical fiber end face inspection method of the second aspect of the present invention, a holding member is provided, and a light source and a light source are provided by the holding member. For the optical microscope, set the installation angle of each optical fiber with respect to the axial direction at 45 ° or more
The above-mentioned light source and the above-mentioned optical microscope were arranged so that the end face of the optical fiber was inspected. Therefore,
The end face inspection light from the light source is totally reflected by the end face including the core and the clad of the optical fiber and a part of the light is incident on the optical microscope. Can be recognized, and the inspection accuracy can be improved.

Further, by providing the hinge portion, the arrangement angle of the light source and the optical microscope can be adjusted, and the end face can be more appropriately and easily recognized for scratches and dirt. Further, by providing the hinge portion, the light source can be arranged at the folding position and the optimal inspection position with respect to the optical microscope, and the portability of the holding member in the state where the light source is arranged at the folding position. Can be improved.

Further, by providing the stopper portion, the operator can simply open the optical microscope and the light source until the rotation stops, and the optical microscope and the optical microscope can be located at an optimum position for observing the end face. The light source can be arranged.

Further, by providing the rotation preventing portion, it is possible to prevent the light source from being carelessly rotated when the light source is disposed at the folding position, and to improve portability.

[Brief description of the drawings]

FIG. 1 is a side view showing an optical fiber end face inspection apparatus according to an embodiment of the present invention, showing a state where a light source is arranged at an inspection position.

FIG. 2 is a view showing a state in which a light source is folded in the optical fiber end face inspection apparatus shown in FIG.

FIG. 3 is a view showing a holding member provided in the optical fiber end face inspection apparatus shown in FIG. 1;

FIG. 4 is a plan view of a support member provided in the optical fiber end face inspection apparatus shown in FIG.

FIG. 5 is a perspective view showing a state in which the end face inspection of the optical fiber is performed using the optical fiber end face inspection apparatus shown in FIG.

6 is a diagram showing an optical model when considering the setting of the arrangement angle of a light source and an optical microscope in the optical fiber end face inspection apparatus shown in FIG.

FIG. 7 is a diagram showing an observation state of an end face of an optical fiber when an arrangement angle of a light source with respect to an optical microscope is changed.

FIG. 8 is a diagram illustrating an observation state of an end face of an optical fiber when an arrangement angle of a light source with respect to an optical microscope is changed.

FIG. 9 is a diagram showing an observation state of an end face of an optical fiber when an arrangement angle of a light source with respect to an optical microscope is changed.

10 is a diagram showing a configuration of a measuring device for measuring a basic link loss when an optical fiber inspected by the optical fiber end face inspection device shown in FIG. 1 is connected by an optical fiber connector.

FIG. 11 is a graph showing a comparison result of a basic link loss of an optical fiber between the related art and the present embodiment.

FIG. 12 is a diagram for explaining a light receiving angle of an optical fiber.

[Explanation of symbols]

10 optical fiber, 101 optical fiber end face inspection device,
110: light source, 120: optical microscope, 130: holding member, 133: hinge portion, 134: stopper portion, 135: rotation preventing portion.

Claims (6)

[Claims] A light source for irradiating an end face of an optical fiber supported by an optical fiber support member with light for end face inspection, and a reflection reflecting the end face inspection light on the end face. An optical microscope (120) for observing the state of the end face based on the incident light and the reflected light, and when the light receiving angle of the optical fiber is sin ^-1 NA (NA is the numerical aperture of the optical fiber), Under the condition that the incident angle and the reflection angle of the end face inspection light on the end face of the optical fiber are substantially equal, the optical axis (121) in the optical microscope and the axial direction (15) of the optical fiber are different. the angle Nasu not more than 45 degrees above sin ^-1 NA, and the light source and the light angle between the axial direction of the optical fiber and the optical axis (111) in the light source as 45 degrees or less above sin ^-1 NA or more Optical fiber end surface inspection apparatus characterized by comprising a holding member (130) for holding a microscope. 2. When the light receiving angle of the optical fiber is not less than 0 degrees and not more than 19 degrees, the holding member makes an angle between an optical axis in the optical microscope and an axial direction of the optical fiber exceed 19 degrees. 2. The optical fiber end face inspection according to claim 1, wherein the light source and the optical microscope are held at 45 degrees or less, and the angle between the optical axis of the light source and the axial direction of the optical fiber is set to more than 19 degrees and 45 degrees or less. apparatus. 3. The holding member is attached to the optical fiber supporting member, and has a hinge portion (133). The hinge portion is configured to be attached to the optical fiber supporting member when the holding member is attached to the optical fiber supporting member. The light source is rotatably supported with respect to the optical microscope in which an angle between the optical fiber and the axial direction is fixed to be not less than sin ^-1 NA and not more than 45 degrees, and the optical axis of the light source and the light are supported. 3. The optical fiber end face inspection apparatus according to claim 1, wherein the light source is supported at an optimal inspection position (1343) in which an angle between the fiber and the axial direction is a value equal to or greater than sin ⁻¹ NA and equal to or less than 45 degrees. 4. The holding member, when rotating the light source with respect to the optical microscope at the hinge, sets an angle between the optical axis of the light source and the axial direction of the optical fiber to the sin. A stopper portion (13) for preventing free rotation of the light source when the value becomes not less than ^-1 NA and not more than 45 degrees.
The optical fiber end face inspection apparatus according to claim 3, further comprising (4). 5. The holding member prevents the light source from rotating with respect to the optical microscope when the light source is rotated to a folding position (1353) close to the optical microscope at the hinge portion. The optical fiber end face inspection apparatus according to claim 4, further comprising a rotation preventing portion (135) that performs rotation. 6. The light receiving angle of the optical fiber is defined as sin ^-1 NA.
When (NA is the numerical aperture of the optical fiber), the incident angle and the reflection angle of the end face inspection light on the end face (13) of the optical fiber are substantially equal to each other in the optical microscope (120). The angle between the optical axis (121) and the axial direction (15) of the optical fiber is not less than sin ^-1 NA and 4
5 degrees or less, and the optical axis (11
1) and the angle between the axial direction of the optical fiber and the si
n ^-1 NA or more and 45 degrees or less, the optical fiber, the optical microscope, and the light source are installed, and the end face inspection light of the end face of the optical fiber from the light source is reflected on the end face based on the reflected light. A method for inspecting an end face of an optical fiber, comprising observing a state of the end face.