JPH0961666A - Method and device for alignment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To align the optical axes of a two-dimensional optical fiber array and a two-dimensional lens array with high precision by easily and precisely arranging the both. SOLUTION: For the aligning method which aligns the optical axes of the optical fiber array 10 formed by arraying many optical fibers 11 in two dimensions and the collimation lens array 20 formed by arraying many collimation lenses 21 in two dimensions, a mask 40 having linear patterns (mesh type pattern) arrayed horizontally (vertically at the same array pitch as the array pitch of both the arrays 10 and 20 is placed in front of a detector 60 which detects the shape of a light beam 100, the light beam projected by each optical fiber 11 is converged by a collimation lens 20 to irradiate the mask 40, and the shape of the light beam cut off by the mask 40 is detected to adjust the relative positions of the optical fiber array 10 and collimation lens array 20 so that the beam shapes of beams which are passed without being cut off by the mask 20 as to some or all of the light beams from the optical fiber array 10 become uniform, thereby aligning the optical axes of the optical fibers 11 and collimation lenses 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber array in which a large number of optical fibers are arranged in a two-dimensional matrix in an input / output system of a free space type optical switch and a large number of collimation lenses are arranged in a two-dimensional matrix. In the collimation lens array described above, the present invention relates to an alignment technique for aligning the optical axes of the corresponding optical fibers of both arrays and the collimation lens.

[0002]

2. Description of the Related Art Conventional optical communication networks require various optical switches. The free space type optical switch is one of them, and it is an optical switch of the type that spatially connects or switches between optical fiber arrays.

In particular, an optical switch for connecting two-dimensionally arranged optical fiber arrays is important in realizing a large capacity optical switching technique. In this free space type optical switch, it is necessary to connect the optical fiber arrays with high coupling efficiency. For that purpose, a highly accurate beam propagation technique using an optical fiber array and a lens array optical system for propagating the beam is desired.

[0004]

SUMMARY OF THE INVENTION The present inventor has found the following problems as a result of studying the above conventional technology.

In the above-mentioned prior art, various methods for optical axis alignment have been studied for the combination of a single optical fiber and a lens, or the combination of a one-dimensional optical fiber array and a one-dimensional lens array. However, in the case of a combination of a two-dimensional optical fiber array and a lens array, the manufacturing precision of each, for example, the variation in the array becomes more difficult than in the case of one-dimensional, so it is extremely difficult to optimally adjust the optical axes of both. It was a difficult problem.

Therefore, in an optical input / output system composed of an optical fiber array in which a large number of optical fibers are arranged in a two-dimensional matrix and a collimation lens array in which a large number of collimation lenses are arranged in a two-dimensional matrix, No superior method has been proposed for aligning the optical axis of each optical fiber of the array with the collimation lens.

An object of the present invention is to provide a technique capable of accurately and easily aligning a two-dimensional optical fiber array and a two-dimensional lens array with each other and accurately aligning both optical axes. Especially.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[0009]

The outline of a typical invention among the inventions disclosed in the present application will be briefly described as follows.

(1) In an alignment method for aligning the optical axes of an optical fiber array in which a large number of optical fibers are two-dimensionally arranged and a collimation lens array in which a large number of collimation lenses are two-dimensionally arranged, the arrangement pitch of both arrays is A mask having a line-shaped pattern or a mesh-shaped pattern arranged horizontally or vertically at the same array pitch is placed in front of the detector for detecting the beam shape,
The light beam emitted from each optical fiber is collected by a collimation lens, applied to the mask, and the shape of the beam intercepted at the intersection of the line pattern or mesh pattern is detected by the beam shape detector. , The relative position of the optical fiber array and the collimation lens array is adjusted so that the beam shapes of all the beams of the optical fiber array or the remaining beam that has passed without being blocked by the pattern are uniform, Align the optical axes of the optical fiber and the collimation lens.

(2) In the alignment method of (1), a part of the line-shaped pattern or the mesh-shaped pattern formed on the mask is deleted to provide a portion that does not block the beam, and the light passing through the mask is Is split into two orthogonal beams with a half mirror, and among the split beams, a beam that does not go straight is made incident on a beam shape detector, and the beam shape blocked by a line-shaped or mesh-shaped pattern is detected, The optical axes of the optical fiber array and the collimation lens array are aligned, and at the same time, the light beam that has passed through the portion of the mask that does not block the light beam of the straight light beam is made incident on the prism, and the prism is masked by the mask. When moving in the direction perpendicular to the surface, the position of the returning light whose direction is changed by 180 ° by the prism does not move. Adjusting the optical axis of the array.

(3) A two-dimensional optical fiber array having the same array pitch and a two-dimensional collimation lens array are arranged so that the optical axis directions thereof coincide with each other, and a fine movement mechanism for independently adjusting the positions of the two and the collimation. A mask having a line-shaped or mesh-shaped pattern installed on the light emitting side of the lens array, a light beam shape detector that measures the shape of the light beam that has passed through the mask, and the line-shaped or mesh-shaped pattern The alignment apparatus is provided with means for adjusting the fine movement mechanism so that the shape of the remaining portion of the light beam that has been blocked and passed is uniform for all the light beams or the desired light beam.

(4) In the alignment apparatus of (3), a mask having a line-shaped or mesh-shaped pattern is partially removed to provide an area which does not block the light beam. A half mirror that splits the light beam into a straight light beam and a light beam that is orthogonal to the straight light beam, a light beam shape detector that detects the shape of the straight light beam that is split by the half mirror, and a straight light beam A prism for changing the traveling direction of the light beam passing through the area of the mask that does not block the light beam by 180 °, a light receiving element for detecting the position of the light beam whose traveling direction is changed by the prism, and a position detecting device are provided. It was done.

(5) In the alignment apparatus described in (3) or (4) above, the light beam shape detector comprises a video camera and an image processing device.

According to the above-mentioned means, the optical axes of the optical fibers of the optical fiber array and the collimation lens array and the collimation lens can be aligned accurately and easily. Moreover, each optical axis can be made parallel. It can also be parallel to the optical axis of the optical system of the device in which both arrays are incorporated.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail together with embodiments with reference to the drawings.

In all the drawings for explaining the embodiments, parts having identical functions are given same symbols and their repeated explanation is omitted.

(Embodiment 1) FIG. 1 is a block configuration diagram showing a schematic configuration of an apparatus of an embodiment (Embodiment 1) for realizing an alignment method of the present invention. 10 is a fiber array, 11 is an optical fiber, 20 is a collimation lens array, 21 is a collimation lens, 30 is an alignment device, 40 is a mask, 41 is a glass substrate, 42 is a horizontal line pattern of the mask 40, 43 is a vertical line pattern of the mask 40, 60 is a detector, and 61 is a detector. Monitor, 10
0 is a beam.

In the alignment of the first embodiment, as shown in FIG. 1, an optical fiber array 10 in which a large number of optical fibers 11 are arranged in a two-dimensional matrix and a beam 100 which enters and exits the optical fiber array 10 are arranged. The collimation lens array 20 for collimation is targeted, and in the collimation lens array 20, the collimation lenses 21 are arranged in a two-dimensional matrix like the optical fiber array 10. The collimation lens 21 is composed of a flat plate microlens array, a microball lens array, or the like by the ion diffusion method.

The alignment device 30 is used for aligning the optical axes of the optical fibers 11 of the optical fiber array 10 and the collimation lens 21 of the collimation lens array 20, and at least moves in the X and Y directions and rotates about the Z axis. It is equipped with a mechanism for adjusting the tilt angle of both. Here, the direction of the optical axis is the Z direction (the horizontal direction of the paper surface), the vertical direction of the paper surface is the X direction, and the vertical direction above the paper surface is the Y direction. Optical fiber 11 and collimation lens 21
Is set and arranged at or near the focal length of the collimation lens 21.

A horizontal line pattern 42 or a vertical line pattern 43 is provided after the collimation lens array 20.
A mask 40 having line patterns of both or both
Is installed. The installation position is selected immediately after the lens array 20 so that the light beam after passing through the collimation lens 21 spreads and does not overlap the adjacent light beams.

As shown in FIGS. 2 and 3, the mask 40 is provided with a metal thin film line pattern in which horizontal line patterns 42 or vertical line patterns 43 are arranged in parallel on a transparent substrate 41 such as glass. Composed. Alternatively, as shown in FIG. 3, the horizontal line pattern 4
2 and the vertical line pattern 43 intersect at right angles to form a mesh pattern. The formation of the metal thin film pattern is performed by photolithography which enables highly precise arrangement.

As the mask 40, in addition to the metal thin film line patterns 42 and 43 or the mesh pattern, lines or meshes formed by fine metal wires (FIG. 4), or Si anisotropy is used. A mesh formed by etching (FIG. 5) may be used.

The mask 40 using thin metal wires is a line-shaped one in which several ten to several tens of thin metal wires are arranged horizontally or vertically, or as shown in FIG. The metal thin wires 49 are vertically or horizontally stacked on the horizontally or vertically arranged metal thin wires 49 to form a mesh. The thin metal wire is a gold wire, a piano wire, or the like having a small wire diameter. The thin metal wire is the base 4
The positioning pins 48, which have the same diameter and are arranged at equal intervals on the wiring 7, are wound and wired to be arranged horizontally or vertically. The thin metal wire is fixed by adhesion or the like in a state of being wound around the positioning pin 48.

The mask obtained by anisotropic etching of Si shown in FIG. 5 has a (100) plane of a Si single crystal, for example, KO.
It is manufactured by utilizing the fact that a rectangular through hole can be formed by etching with an H solution. Matrix-shaped rectangular through holes 46 are formed in the Si wafer substrate 45 to form a mesh. The rectangular holes 46 in the matrix arrangement are formed in the Si wafer substrate 45 by using the photolithography technique.

The arrangement pitch of the horizontal line patterns 42 and the vertical line patterns 43 of the mask 40 is the same as the arrangement pitch of the optical fibers 11 of the optical fiber array 10 and the collimation lens array 20 and the collimation lens 21. The width of the horizontal line pattern 42 and the vertical line pattern 43, or the diameter of the fine line is selected so as to be smaller than the diameter of the light beam to be aligned.

The alignment method in such an apparatus configuration will be described below. Regarding alignment of the optical axes of the individual optical fibers 11 of the optical fiber array 10 and the collimation lens array 20 and the collimation lens 21, first, the beam 100 is emitted from the optical fiber 11. The collimation lens 21 is set at or near the focal length, and the optical fiber 11 and the collimation lens 21 are moved by the XY movement of the alignment device 30 and the rotation around the Z axis.
The light beam 100 is collimated by roughly aligning the relative positions of the above, and the mask 40 is irradiated with the light beam 100. The light beam 100 is partially masked by the horizontal line pattern 42 or the vertical line pattern 43 of the mask 40 so that the mask 40
Pass through.

The passed light beam 100 is incident on a light beam shape detector 60 for detecting the light beam shape. As the light beam shape detector 60, a video camera capable of detecting a large number of beams at one time is useful. The light beam shape detector 60 images the light beam shape and displays it on the monitor 61 or the like. The shape of the light beam 100 that has passed through the mask 40 is compared for all of the optical fiber 11 and the collimation lens 21, or for the desired optical fiber 11 and the collimation lens 21.

In this case, the shapes can be compared more easily by extracting the contours of the beam shape using an image processing device based on the image signal to the monitor 61.

FIGS. 6A and 6B show beam shapes before and after passing through the linear pattern. FIG.
The positional relationship between the light beam and the line of the mask 40 is shown in (a), (b), and (c). FIG. 6A shows the beam shape blocked by the linear pattern, and FIG. 6B shows the beam shape before being incident on the linear pattern.

The light beam 100 passing through the mask 40
Is a horizontal line pattern 42 as shown in FIG.
Alternatively, if the vertical line pattern 43 is located at the center of the beam 100, the center of the light beam 100 is blocked, and the arc-shaped portions at the left and right (or the top and bottom) ends of the round light beam are detected. In the case of the cross pattern, as shown in FIG. 7C, fan-shaped portions at the four corners of the round light beam are detected.

Regarding the shape of each light beam 100 on the monitor 61, as shown in FIGS. 6 (a) and 7 (a), the arc-shaped portions at both ends of the detected round light beam 100 become uniform. Using the alignment device 30, the optical fiber 11 and the collimation lens 2 are moved by performing the movement in the X and Y directions, the rotation around the Z axis, and the adjustment of the tilt angle.
Finely adjust the relative position of 1. FIG. 7B shows a state where the adjustment is insufficient. In this way, the optical fiber array 1
The optical axes of both the optical fiber array 10 and the collimation lens array 20 can be adjusted to an optimum state by adjusting all the light beams from 0 or a desired light beam so as to have a uniform shape.

(Embodiment 2) FIG. 8 is a block diagram showing the schematic construction of an apparatus of another embodiment (Embodiment 2) for realizing the alignment method of the present invention. Reference numeral 70 denotes a prism, 8
Reference numeral 0 is a light receiving element for position detection, 90 is a light beam position detecting device, 100 is a light beam, 110 is a light beam that travels in a direction orthogonal to the light beam that travels straight in the optical axis direction, and 120 is light that travels straight in the optical axis direction. The beam.

In the first embodiment, since the mask is installed immediately after the lens array 20, there is a point that it is difficult to detect a slight tilt of the light beam as a change in the beam shape after passing through the mask. The second embodiment improves on this point.

The alignment apparatus 30 of the second embodiment is
As shown in FIG. 8, it is used for aligning the optical axes of the optical fiber array 10 and the collimation lens array 20, and rotation in the X-axis, Y-axis and X-axis-Y-axis plane and adjustment of the tilt angle with respect to the optical axis. It has a mechanism. The mask 40 is installed immediately after the lens array 20, and the light beam 100 emitted from the optical fiber array 10 is collimated by the collimation lens 21 and is applied to the mask 40. The light beam that has passed through the mask 40 is split by the half mirror 50 into a light beam 120 that travels straight in the optical axis direction and a light beam 110 that travels in a direction orthogonal thereto.

The structure of the mask 40 used here is such that a part of the line pattern is cut so that the light beam 100 is not blocked, as shown in FIG.

As described in the first embodiment, the branched light beam 110 is detected by the light beam shape detector 60 for the shape of the light beam blocked by the mask 40, and the divided shape is all the light beams. Alternatively, the alignment device 30 is adjusted so as to be even with respect to the desired light beam.

On the other hand, of the straight-ahead light beam 120, the light beam that has passed without being blocked by the line pattern of the mask 40 is used, and the traveling direction of the light beam is changed by 180 ° by the prism 70 to detect the position of the light beam. The light is received by the light receiving element 80. When the prism 70 is installed so as to be parallel to the mask 40, the moving direction of the prism 70 is set to the direction perpendicular to the surface of the mask 40, and the prism 70 is moved, the position of the light beam incident on the light receiving element 80 is It moves according to the angle of incidence on the prism 70. By adjusting the alignment device 30 so as to eliminate or extremely reduce the movement amount, the parallelism and the tilt angle of the light beam can be optimized.

Further, by arranging the surface of the mask 40 so as to correspond to the mounting surface of a device such as a free space type optical switch incorporating the optical fiber array 10 and the lens array 20, alignment is performed by the method of the first embodiment. Both the optical fiber array 10 and the lens array 20 can have an optical axis parallel to the optical axis of the device to be incorporated, and can be easily incorporated into the device.

Although the present invention has been specifically described based on the above embodiment, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention. Of course.

[0041]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.

The optical axes of the optical fibers and the collimation lens of the optical fiber array and the collimation lens array can be accurately and easily aligned with each other.

Further, each optical axis can be made parallel.
In addition, both the optical fiber array and the lens array can be made parallel to the optical axis of the optical system of the device.

[Brief description of drawings]

FIG. 1 is a block configuration diagram showing a schematic configuration of an apparatus of an embodiment (Embodiment 1) for realizing an alignment method of the present invention.

FIG. 2 is a diagram for explaining a configuration of an example of a mask according to the first exemplary embodiment.

FIG. 3 is a diagram for explaining the configuration of another example of the mask according to the first embodiment.

FIG. 4 is a diagram for explaining the configuration of another example of the mask according to the first embodiment.

FIG. 5 is a diagram for explaining the configuration of another example of the mask according to the first embodiment.

FIG. 6 is a diagram for explaining a light beam shape for alignment in the first embodiment.

FIG. 7 is a diagram showing a positional relationship between a light beam and a mask line according to the first embodiment.

FIG. 8 is a block configuration diagram showing a schematic configuration of an apparatus of another example (Embodiment 2) for realizing the alignment method of the present invention.

[Explanation of symbols]

10 ... Fiber array, 11 ... Optical fiber, 20 ... Collimation lens array, 21 ... Collimation lens, 30 ... Alignment device, 40 ... Mask, 41 ... Glass substrate, 42 ... Horizontal line pattern, 43 ... Vertical line pattern, 45 ... Si Wafer substrate, 46 ... Rectangular hole, 4
7 ... Mask base, 48 ... Locating pin, 49 ... Metal fine wire, 50 ... Half mirror, 60 ... Light beam shape detector, 61 ... Monitor, 70 ... Prism, 80 ... Position detecting light receiving element, 90 ... Light beam Position detection device, 100 ...
Light beam, 110 ... Light beam traveling in a direction orthogonal to the light beam traveling straight in the optical axis direction, 120 ... Light beam traveling straight in the optical axis direction.

Claims (5)

[Claims] 1. An alignment method for aligning the optical axes of an optical fiber array in which a large number of optical fibers are two-dimensionally arranged and a collimation lens array in which a large number of collimation lenses are two-dimensionally arranged, in which the arrangement pitch of both arrays is the same. A mask having a line pattern or a mesh pattern arranged horizontally or vertically at an array pitch is placed in front of the detector that detects the shape of the beam, and the light beams emitted from each optical fiber are focused by a collimation lens. The beam shape detector irradiates the mask and intercepts the shape of the beam intercepted at the intersections of the line-shaped pattern or the mesh-shaped pattern, and all the beams of the optical fiber array or the desired beam is detected by the pattern. The beam shape of the remaining part that has passed through unobstructed becomes uniform As described above, an alignment method characterized by adjusting the relative positions of the optical fiber array and the collimation lens array to align the optical axes of the optical fiber and the collimation lens. 2. The alignment method according to claim 1, wherein a part of the line-shaped pattern or the mesh-shaped pattern formed on the mask is deleted, a portion that does not block the beam is provided, and the mask passes through the mask. The light is split into two orthogonal beams by a half mirror, and among the split beams, a beam that does not go straight is made incident on a beam shape detector, and the beam shape blocked by a line-shaped or mesh-shaped pattern is detected. At the same time as aligning the optical axes of the optical fiber array and the collimation lens array, the light beam that has passed through the portion of the light beam that has traveled straight and does not block the light beam of the mask is incident on the prism,
When the prism is moved in the direction perpendicular to the mask surface,
An alignment method characterized in that the optical axes of both arrays are adjusted so that the position of the returning light whose direction is changed by 180 ° by a prism does not move. 3. A fine movement mechanism for arranging a two-dimensional optical fiber array having the same array pitch and a two-dimensional collimation lens array such that their optical axis directions coincide with each other, and independently adjusting the position of each, and the collimation lens. A mask having a line-shaped or mesh-shaped pattern installed on the side where the light of the array is emitted, a light-beam shape detector that measures the shape of the light beam that has passed through the mask, and the line-shaped or mesh-shaped pattern An alignment apparatus comprising means for adjusting the fine movement mechanism so that the shape of the remaining portion of the light beam that has been passed through becomes uniform for all the light beams or the desired light beam. 4. The alignment apparatus according to claim 3, wherein a mask having a line-shaped or mesh-shaped pattern is partially removed to provide an area that does not block a light beam, and after passing through the mask. Half-mirror for splitting the light beam of the above into a straight light beam and a light beam orthogonal thereto, a light beam shape detector for detecting the shape of the non-straight light beam split by the half mirror, and a straight light beam Of the light beam passing through the area of the mask that does not block the light beam,
An alignment apparatus comprising: a prism for changing, a light receiving element for detecting a position of a light beam whose traveling direction is changed by the prism, and a position detecting device. 5. The alignment apparatus according to claim 3 or 4, wherein the light beam shape detector comprises a video camera and an image processing apparatus.