JPH06148448A - Inspecting method for aligning state of optical waveguide and optical waveguide - Google Patents

Abstract

PURPOSE:To realize an inspection for aligning state of optical fiber on a multifiber optical connector. CONSTITUTION:An optical connector 4 having plural (n) side optical fibers 41 fixed and arranged in a state where each end face on one side is aligned in a row and a column on nearly the same flat surface, and constituting an optical switch by combining with a master side optical fiber selectively and optically coupling to the each end face is prepared. Illuminating light is made incident from the other end face side of the (n) side optical fiber 41, and the image of outgoing light is picked up on one end face side where the (n) side optical fiber is aligned and arranged on nearly the same flat surface, so that each central position of the aligned and arranged (n) side optical fiber 41 is found. The average position of the central position of each (n) side optical fiber 41 arranged in the row direction and that of each (n) side optical fiber 41 arranged in the column direction are found by each row and column among the found central positions. Based on the average position, the (n) side optical fiber 41 whose deviation exceeds the range of standard deviation is decided to be faulty.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting the alignment state of optical waveguides in a multi-fiber optical connector.

[0002]

2. Description of the Related Art One optical fiber (master-side optical fiber) and n optical fibers (n-side optical fiber) are opposed to each other at their end faces, and the master-side optical fiber is moved to move the n-side to be optically coupled. There is a 1: n optical switching device for switching the optical fibers. The n-side optical fiber is fixedly arranged in the multi-core optical connector, and the optical communication signal transmission path is switched by selectively optically coupling with the master-side optical fiber held in the single-core optical connector.

Conventionally, for measuring the eccentricity of a multi-fiber optical connector, for example, the "High-precision dimensional measurement technology of multi-fiber connector" of B-343, National Conference of the Institute of Electronics, Information and Communication Engineers, 1988, is known. . FIG. 13 is a perspective view schematically showing this. The optical connector 101 is a stage (X
Direction, the movable stage in the Y direction) and is illuminated by the illumination light source 102 from the rear end face. Optical connector 101
An image pickup device 104 such as a CCD is disposed on the front end face side of the image pickup device while sandwiching the objective lens 103, and an image of the front end face of the optical connector 101 is formed on the image pickup device 104.

Here, the optical connector 101 is provided with two guide pin holes 105 on both sides, and a large number of fiber holes 106 are formed between them. Therefore, the illumination light from the illumination light source 102 is guided by the guide pin hole 105.
Then, it passes through the fiber hole 106 and becomes transmitted illumination light, which is incident on the imaging device 104. The image processing device 107 is provided with image data of transmitted illumination light from the front end face of the optical connector 101.

Therefore, since the image processing apparatus 107 can obtain the contours of the edges of the front end faces of the guide pin hole 105 and the fiber hole 106, the center positions of the guide pin hole 105 and the fiber hole 106 can be obtained from the results. Therefore, by comparing this measured center position with the designed center position, the so-called eccentricity amount and eccentric direction can be obtained,
Enables product evaluation. The CRT 108 visually displays the imaging data and the measurement result.

[0006]

However, in the above-mentioned conventional technique, the actual measurement position of the fiber hole 106 determined with the guide pin hole 105 as a reference is compared with the designed center position determined with the guide pin hole 105 as a reference. However, the amount of eccentricity and the direction of eccentricity of the fiber hole 106 are required. Therefore, the two guide pin holes 105 that sandwich the fiber hole 106
Fiber holes 10 in multiple rows instead of one row
The conventional high-accuracy dimension measuring technique cannot be directly applied to the multi-fiber optical connector in which 6 are arranged. In the above-described multi-fiber optical connector in which the n-side optical fibers in the 1: n optical switching device are arranged in alignment, the guide pin holes 105 are not used, and the optical fibers are arranged in multiple rows in the row and column directions. Has been done. For this reason, it is difficult to grasp the eccentricity state, that is, the alignment state of each optical fiber in the n-side optical connector arranged in this way, and the alignment state of the optical fiber may be inspected by the above-mentioned conventional measurement technique. could not.

It is an object of the present invention to provide an optical waveguide alignment state inspection method capable of accurately inspecting the alignment state of each optical waveguide even with such an n-side optical connector.

[0008]

A method for inspecting an alignment state of an optical waveguide according to the present invention comprises a plurality of n-side optical waveguides or optical waveguides in which one end face is fixedly arranged in rows and columns in substantially the same plane. First, an optical connector having a fiber and comprising an optical switch that is combined with a master side optical waveguide or an optical fiber that selectively optically couples to each of the end faces is prepared.
In step, the illumination light is incident from the other end face side of the n-side optical waveguide or the optical fiber, and the outgoing light is imaged at the one end face side that is aligned and arranged on substantially the same plane. A second step of obtaining the center position of each end face of the waveguide or the optical fiber, and an average position of the center positions of the end faces of the n-side optical waveguides or optical fibers arranged in the row direction among the center positions obtained in the second step and From the third step of obtaining the average position of the center position of each end face of the n-side optical waveguide or optical fiber arranged in the column direction for each row and each column, and the average position of the center position of the end face obtained in this third step A fourth step of determining that the n-side optical waveguide or the optical fiber whose center of the end face is located at a position exceeding a predetermined range is defective, and the aligned state of the optical waveguide is inspected.

[0009]

According to the present invention, the eccentric state of the optical waveguide or the optical fiber center position is based on the relative position between the optical waveguides or the optical fibers without using the absolute position of the guide pin hole as a reference as in the prior art. It will be possible to evaluate.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a case where the present invention is applied to an optical fiber alignment state inspection method for an n-side optical connector used in a 1: n optical switch device will be described.

First, before the description of the present embodiment, a 1: n optical switch device using the n-side optical connector will be described.

In this type of conventional device, light switching involving mechanical contact was performed. For example, the master side optical fiber was inserted in the ferrule and this was inserted in the split sleeve. Here, an n-side optical fiber is set for each sleeve in the split sleeve, and the light can be switched by changing the insertion target.

However, with such physical contact, the outer shape of the ferrule changes due to abrasion, and the positioning accuracy decreases with use. In particular, in the optical coupling of single mode optical fibers, the core diameter is about 10 μm, so if there is an axis deviation of, for example, about 1 μm, an optical coupling loss of about 0.3 to 0.5 dB will generally occur. Therefore, a non-contact type optical switch device and a method of aligning the same are desired, but the optical axis alignment is extremely difficult in the non-contact type.

Therefore, the applicant of the present application has proposed the following non-contact type 1: n optical switch device and its centering method in a separate patent application.

That is, this optical switch device has a master side optical connector having a master side optical fiber for transmitting an optical communication signal, and a plurality of n side optical connectors each having a coupling end face arranged in an array. is doing. The parallel driving means translates the master side optical fiber in parallel along the coupling end face,
The rotation drive means rotates the master-side optical fiber around its optical axis along with this parallel movement. The master side optical fiber is coupled to the sensing optical fiber by the coupling means, and the sensing light is incident on the sensing optical fiber from the sensing light source. The monitor light that is reflected from the master side optical fiber after being incident on the n side optical fiber and returns via the master side optical fiber is detected by the monitor light detecting means. The calculation means is based on the phase of the rotational movement by the rotation drive means and the phase of the fluctuation of the detected light quantity by the monitor light detection means, and the rotation center position of the master side optical fiber and the center position of the n side optical fiber to be optically coupled to this. The deviation direction between and is calculated. The control means controls the parallel driving means so that the master side optical fiber moves in the direction opposite to this deviation direction.

FIGS. 10 and 11 show the vicinity of the optical switching portion of the 1: n optical switching device, FIG. 10 is a sectional view thereof, and FIG. 11 is a partially broken perspective view.

As shown in FIG. 10, the Y-axis coarse movement stage 22 is attached to the upper base plate 42, and the lower base plate 4 is attached.
An n-side optical connector 4 is attached to 3. Then, as shown in FIGS. 10 and 11, the fine movement tube 1
The upper end portion of is fixed to the fixed stage 20 by the tube support arm 23, and the master side optical fiber 31 is fixed to the fixed stage 20 by the fiber support arm 24 above it.

The X-axis coarse movement stage 21 coarsely moves in the X-axis direction when a pulse signal is given from an X-axis coarse drive circuit (not shown), and the Y-axis coarse movement stage 22 also receives a pulse from a Y-axis coarse drive circuit (not shown). Coarse movement in the Y-axis direction is given by a signal. As a result, the n-side optical fiber 41 of the n-side optical connector 4 optically coupled to the master-side optical fiber 31 is switched according to the optical coupling switching command from the CPU. The X-axis coarse movement stage 21 and the Y-axis coarse movement stage 22 are constituted by stepping motors and move in steps by an amount corresponding to the number of pulses of a given pulse signal.

The fine movement tube 1 is composed of a tube type piezoelectric element, and when a voltage is applied to this element, the piezoelectric material layer is stretched or compressively strained. Therefore, the tip end portion of the fine movement tube 1 horizontally finely or rotationally moves by controlling the voltage application to the piezoelectric element, and the tip end of the master side optical fiber 31 also moves according to this movement.

Next, the deviation direction between the center of rotation of the master-side optical fiber 31 and the center of the n-side optical fiber 41 opposed thereto and the principle of calculating the deviation amount will be described. 12
In (a), the solid line circle shows the core of the master side optical fiber 31, and the dotted line circle shows the core of the n side optical fiber 41. Now, it is assumed that the center of rotation of the master-side optical fiber 31 (marked by a white circle in the figure) is deviated from the center of the n-side optical fiber 41 (marked by a cross in the figure) by a certain amount in the minus x direction. Then, the position of the core of the rotating master-side optical fiber 31 changes from the circle 1 to the circle 5 in the figure, so that the optical coupling rate between the master-side optical fiber 31 and the n-side optical fiber 41 is increased. Changes according to the rotation phase.

Here, sensing light is emitted from the master-side optical fiber 31, and this sensing light is incident on the n-side optical fiber 41 at a rate according to the above-mentioned optical coupling rate, and is internally reflected and returned. Come on. The returned monitor light is re-incident on the master side optical fiber 31 and detected by the photodetector. The fluctuation of the detected light amount is caused by the optical coupling rate of the master side optical fiber 31 and the n side optical fiber 41. It corresponds to the fluctuation of. Therefore, the deviation direction of the rotation center of the master side optical fiber 31 can be obtained from the phase of the rotational movement of the master side optical fiber 31 and the phase of the fluctuation of the light amount detected by the photodetector. On the other hand, the deviation amount between the rotation center position of the master side optical fiber 31 and the center position of the n side optical fiber 41 can be judged by the magnitude (amplitude) of the fluctuation of the light amount detected by the photodetector. The CPU finely moves the tip of the fine movement tube 1 in the correction direction of the deviation direction by the obtained deviation amount, and aligns the master side optical fiber 31 and the n side optical fiber 41.

Each n in such an n-side optical connector 4
The alignment state of the side optical fiber 41 is inspected by the present embodiment described below.

FIG. 1 is a perspective view showing the overall construction of an optical fiber alignment state inspection apparatus to which the method of this embodiment is applied.
FIG. 2 is a block diagram showing the functional configuration.

As shown in FIG. 1, the optical connector 4 is set on a rotary stage 51 which is rotatable on a horizontal plane, and the rotary stage 51 is mounted on a Y-axis stage 52 which is linearly driven in the Y direction. The axis stage 52 is an X-axis stage 53 that is linearly driven in the X direction orthogonal to the Y direction.
Is mounted on. A microscope 62 having an objective lens 61 attached thereto is set above the optical connector 4, and a CCD camera 63 is mounted on the microscope 62. Further, a reflective AF (autofocus) device 64 is attached to the side of the microscope 62, and these are attached to a Z-axis stage 54 that is movable in the vertical direction (Z direction).

On the other hand, the rotary stage 51 and the Y-axis stage 5
2, the side surfaces of the X-axis stage 53 and the Z-axis stage 54 that move in parallel are equipped with a length measuring device typified by a linear scale, and the movements are detected by the sensors 71 to 74 to generate a pulse corresponding to the movement amount. It is designed to output. Also,
A light source 40 is separately provided, and illumination light from the light source 40 is sent to the optical connector 4 via an optical fiber 41.

As shown in FIG. 2, the rotary stage 51 is a rotary drive mechanism 81, the Y-axis stage 52 is a Y-axis drive mechanism 82, the X-axis stage 53 is an X-axis drive mechanism 83, and the Z-axis stage 54 is a Z-axis. It is movable by an axis drive mechanism 84, and these drive mechanisms 81 to 84 are composed of stepping motors, etc.
Controlled by 5. In addition, the sensors 71 to 74
Output pulses are counted by the counter 75 and the movement amount is monitored. The rotary stage 51 is usually used in a fixed state in this embodiment. However, if the optical connector 4 is largely tilted with respect to the X and Y axes, it can be driven and used if necessary.

The output (image data) of the CCD camera 63 is sent to the image processing device 91 for contour detection and center position calculation, and is also sent to the image AF device 92 for focusing. The image processing device 91 and the image AF
The output of the device 92 is sent to the CPU 93 and appropriately displayed on the CRT 94. The CPU 93 is a reflection type AF device 64.
In addition to controlling the stage driver 85, the light source 40 for illuminating the optical fiber 41 is controlled via the light source driver 44.

FIG. 3 shows the state of the optical connector 4 in this embodiment. A large number of fiber holes 5 are formed in an array, an optical fiber 41 is inserted into each fiber hole 5, and each optical fiber 41 is fixedly arranged in a state aligned in the X direction and the Y direction. One end surface of each of the optical fibers 41 is exposed from the opening of the fiber hole 5 on the same plane of the front end portion of the optical connector 4. Illumination light from the light source 40 enters from the other end face of the optical fiber 41 via a lens (not shown).

FIG. 4 shows the detailed structure of the reflection type AF device 64. This is a focus detection device based on the critical angle method, and light is incident on the surface to be measured (front end surface of the optical connector 4) from the vertical direction (coaxial direction to the optical fiber 41). The measurement light from the light source 641 is collimated by the collimator lens 642, is incident on the polarization beam splitter 643, and is reflected in the orthogonal direction. The reflected light is a quarter wave plate 64
By passing through 4, the plane of polarization is rotated by 45 ° and focused by the condenser (or objective) lens 645.

Here, when the surface to be measured is at the focal position of the condenser lens 645 (state of the solid line), the reflected light passes through the same optical path and is collimated again by the condenser lens 645, and 1 /
The plane of polarization is further rotated through 45 ° through the four-wave plate 644. Thereby, the reflected light is reflected by the polarization beam splitter 643.
Since the planes of polarization are orthogonal to each other, the light beam passes through the polarization beam splitter 643 as it is and the critical angle prism 6
It is incident on 46. Here, since the critical angle prism 646 has an angle θ in the drawing as a critical angle, the incident light is totally reflected, and the reflected light is incident on the two-divided sensor 647. Therefore, it can be seen that light is equally incident on both light receiving surfaces of the two-divided sensor 647, and the surface to be measured is at the in-focus position.

On the other hand, when the surface to be measured is separated from the reflective AF device 64 as shown by the dotted line in the figure, the reflected light after passing through the condenser lens 645 becomes focused light, and in this state, the critical angle prism. It is incident on 646. Then, the incident angle of the incident light on the reflecting surface of the critical angle prism 646 is equal to or greater than the critical angle θ on one side and equal to or less than θ on the opposite side.
Only the light with the critical angle θ or less is reflected and the two-division sensor 647
Detected by. Therefore, by comparing the detection levels on both the light receiving surfaces of the two-divided sensor 647, it is found that the measured surface is separated. On the contrary, when the surface to be measured is closer than the focus position, the output ratio of the two-divided sensor 647 is reversed, so it can be seen that the surface is approached. This enables focus detection.

In the critical angle method, as shown by the solid line in FIG. 5, the measuring light for focusing operation is directed to the front end face of the optical connector 4 from the direction coaxial with the incidence of the light from the light source 40 on the optical fiber 41. It irradiates the end face of a certain optical fiber 41,
In order to adopt this configuration, a wavelength-selective beam splitter 640 is provided on the optical path. That is, the beam splitter 640 transmits the white light (solid line) from the light source 40, and the light source 641 of the reflective AF device 64.
Infrared light (wavelength 830 nm, for example) is configured to be reflected. Thereby, the image pickup by the CCD camera 63 and the focusing operation by the reflection type AF device 64 can be simultaneously executed.

Further, as shown by the alternate long and short dash line in FIG. 5, the light from the light source 648 is incident in the oblique axis direction, and the reflected light is reflected by the camera 64.
Focusing may be detected by imaging at 9. That is, in the present invention, not only the critical angle method as shown in FIG. 4 but also focus detection by another method, for example, the knife edge method or the astigmatism method can be used.

The wavelength of the incident light on the optical fiber 41, that is, the emission wavelength of the light source 40 is not particularly limited, but it is desirable that the wavelength is longer than the cutoff wavelength of the optical fiber 41. That is, as shown in FIG. 6, when the wavelength is longer than the cutoff wavelength, a single mode is set, and the intensity distribution of the light emitted from the optical fiber 41 becomes a Gaussian distribution ((a) in the figure). Can be accurately determined. On the other hand, when the wavelength is shorter than the cutoff wavelength, the multimode type light intensity distribution shown in FIG. However, even in this case, by accurately focusing using the reflective AF device 64, it is possible to accurately measure the center of the core.

To detect the edge of the end face image for determining the center of the core of the optical fiber 41, as shown in FIG. 7A, the change in luminance of the end face pattern is examined in the X and Y directions to find the change point, that is, the edge. A circle pattern may be detected from this combination of edges, but it may also be performed by a memory batch method as shown in FIGS. 7B and 7C. That is, the emitted light from the optical fiber 41 is divided into a plurality of image pickup ranges, and is picked up by the CCD camera 63, and stored in the frame memory built in the image processing apparatus 91. And FIG.
From the address corresponding to the edge as shown in (c), the circle equation is calculated by the least square method. As a result, the coordinates of the center of the circle, that is, the center position of the core of the optical fiber 41 can be obtained.

Next, a method of inspecting the alignment state of optical fibers, which is executed by using the above apparatus, will be described. FIG. 8 is a flowchart thereof. First, as shown in FIG. 1, the optical connector 4 is set on the upper surface of the rotary stage 51 (step 100
1), the Y-axis stage 52 and the X-axis stage 53 are driven to align the microscope 62 with the optical fiber 41, and the reflective AF device 64 and the Z-axis stage 54 perform a focusing operation (step 1002). Next, the light source 40 is turned on to project the illumination light onto the optical fiber 41, and the CCD camera 63 images the emitted light (step 1003). When the image pickup data is obtained, it is stored in the frame memory of the image processing apparatus 91. The above operation is for all optical fibers 4
1 (step 1004), and when completed, the core center position of each optical fiber 41 is calculated (step 1005). The contour pattern detection in this case is
The method shown in FIGS. 7B and 7C is used.

As described above, when the actually measured position of the core center of the optical fiber 41 is obtained by the operations up to step 1005, the center of each optical fiber 41 arranged in the X direction (row direction) among the obtained center positions. Average position, and Y
The average position of the center positions of the optical fibers 41 arranged in the direction (column direction) is obtained for each row and each column (step 1006). Next, the variation of the center position of each optical fiber 41 with respect to the average position of each center position for each row and each column is obtained as a standard deviation (step 1007). That is, it is obtained as follows.

FIG. 9A is a front view of the optical connector 4 as seen from the front end face, and FIG. 9B is a partially enlarged view of the actual measurement position of the center position of each optical fiber 41 in this front view. It is a thing. Each average position of the center positions in the X direction and the Y direction is obtained by dividing the sum of the actually measured values for each direction by the number of positions, and is indicated by a chain line. Next, the differences Δx and Δy between these average positions and the measured positions are obtained, and the standard deviation σ of the central position is obtained for each row and column from this difference.

Next, the measured value of the center position of each optical fiber 41 and this standard deviation σ are compared for each row and each column (step 1008). As a result of this comparison, if the measured value is within the standard deviation centered on the average position, it is determined that the optical fiber 41 is in a good alignment (step 1009). On the other hand, if the measured value deviates from the standard deviation centered on the average position, it is determined that the alignment state of the optical fiber is not good (step 1010).

The alignment state of each optical fiber 41 fixedly arranged in the optical connector 4 is inspected as described above, so that the alignment operation at the time of optical switching in the 1: n optical switch can be accurately performed without error. .

[0041]

According to the present invention, the eccentricity of the center position of the optical waveguide or the optical fiber is based on the relative position of the optical waveguide or the optical fiber without using the absolute position of the guide pin hole as a reference as in the prior art. It becomes possible to evaluate the condition. Therefore, according to the present invention, it becomes possible to inspect the optical waveguide alignment state even with a multi-fiber optical connector that cannot be inspected by conventional techniques.

[Brief description of drawings]

FIG. 1 is a perspective view of an apparatus to which an optical fiber alignment state inspection method according to an embodiment is applied.

FIG. 2 is a block diagram of an apparatus to which the optical fiber alignment state inspection method according to the embodiment is applied.

FIG. 3 is a perspective view of the connector according to the embodiment.

FIG. 4 is an explanatory diagram of focus detection by the critical angle method.

FIG. 5 is an explanatory diagram of focus detection.

FIG. 6 is an intensity distribution chart of light emitted from an optical fiber.

FIG. 7 is an explanatory diagram of center position detection.

FIG. 8 is a flowchart showing an optical fiber alignment state inspection method according to an embodiment.

FIG. 9 is a diagram of an optical connector showing an optical fiber alignment state inspection method according to an embodiment.

FIG. 10 is a cross-sectional view showing a configuration of a main part of a 1: n optical switch device to which an embodiment is applied.

FIG. 11 is a perspective view showing a main part configuration of a 1: n optical switch device to which the embodiment is applied.

FIG. 12 is an explanatory diagram of rotational movement of a master-side optical fiber.

FIG. 13 is a perspective view showing a conventional example.

[Explanation of symbols]

4 ... Optical connector, 40 ... Light source, 41 ... Optical fiber, 51
... rotary stage, 52 ... Y-axis stage, 53 ... X-axis stage, 54 ... Z-axis stage, 61 ... objective lens, 62 ...
Microscope, 63 ... CCD camera, 64 ... Reflective AF device,
81 ... Rotational drive mechanism, 82 ... Y-axis drive mechanism, 83 ... X-axis drive mechanism, 84 ... Z-axis drive mechanism, 85 ... Stage driver, 91 ... Image processing device, 92 ... Image AF device, 93 ...
CPU, 94 ... CRT, 641 ... Light source, 642 ... Condensing lens, 643 ... Polarizing beam splitter, 644 ... 1/4
Wave plate, 645 ... Condensing lens, 646 ... Critical angle prism, 647 ... 2-division sensor, 640 ... Beam splitter.

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[Procedure amendment]

[Submission date] September 17, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Title of invention

[Correction method] Change

[Correction content]

Title: Optical waveguide alignment state inspection method and optical waveguide

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0001

[Correction method] Change

[Correction content]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting the alignment state of an optical waveguide in a multi-fiber optical connector and an optical waveguide inspected by this method.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

The present invention provides an optical waveguide alignment state inspection method capable of accurately inspecting the alignment state of each optical waveguide even with such an n-side optical connector, and an optical waveguide inspected by this method. The purpose is to provide.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

[0009]

According to the present invention, the eccentric state of the optical waveguide or the optical fiber center position is based on the relative position between the optical waveguides or the optical fibers without using the absolute position of the guide pin hole as a reference as in the prior art. It will be possible to evaluate. Further, an optical waveguide in which the eccentricity of these center positions is grasped can be obtained.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0041

[Correction method] Change

[Correction content]

[0041]

According to the present invention, the eccentricity of the center position of the optical waveguide or the optical fiber is based on the relative position of the optical waveguide or the optical fiber without using the absolute position of the guide pin hole as a reference as in the prior art. It becomes possible to evaluate the condition. Therefore, according to the present invention, it becomes possible to inspect the optical waveguide alignment state even with a multi-fiber optical connector that cannot be inspected by conventional techniques. Further, since the eccentric state of the center position of the optical waveguide inspected according to the present invention is known, a stable product with low loss is always supplied to the market.

Front page continuation (72) Inventor Shinji Nagasawa 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation

Claims (5)

[Claims] 1. A master side that has a plurality of n-side optical waveguides or optical fibers, one end face of which is fixedly arranged in rows and columns in substantially the same plane, and selectively optically couples to each of the end faces. A first step of preparing an optical connector that is combined with an optical waveguide or an optical fiber to form an optical switch; and illuminating light is incident from the other end face side of the n-side optical waveguide or optical fiber, and arranged in a substantially same plane. The second step of obtaining the center position of each end face of the n-side optical waveguide or the optical fiber arranged in line by imaging the emitted light on the side of the one end face that has been formed, and the center position obtained in the second step. Of these, an average position of the center positions of the respective end faces of the n-side optical waveguides or optical fibers arranged in the row direction and a center position of the n-side optical waveguides or the respective end faces of optical fibers arranged in the column direction. n that a third step, the third end face center of a position exceeding a predetermined range from the average position of the center position of the end surface obtained in step positioned obtaining average position of the each row and each column
A method for inspecting the alignment state of an optical waveguide, which comprises a fourth step of determining that the side optical waveguide or the optical fiber is defective. 2. The fourth step is characterized in that the n-side optical waveguide or the optical fiber whose center of the end face is located at a position exceeding the range of standard deviation from the average position of the center position of the end face is judged to be defective. Item 2. An optical waveguide alignment state inspection method according to Item 1. 3. In the second step, the wavelength of the illumination light incident on the n-side optical waveguide or the optical fiber is set to a wavelength longer than the cutoff wavelength of the n-side optical waveguide or the optical fiber. The optical waveguide alignment state inspection method according to claim 1 or 2. 4. In the second step, focusing for imaging the light emitted from the n-side optical waveguide or the optical fiber is performed by projecting light onto the end face of the n-side optical waveguide or the optical fiber from the coaxial or oblique axis direction. 3. The method for inspecting the alignment state of an optical waveguide according to claim 1, wherein the inspection is performed by detecting reflected light. 5. In the second step, the center position of each end face of the n-side optical waveguide or the optical fiber is stored in a memory by collectively storing the imaging data of the light emitted from the n-side optical waveguide or the optical fiber. The optical waveguide alignment state inspection method according to claim 1 or 2, wherein the determination is made by later detecting a boundary between bright and dark of the image pickup screen.