JP2938317B2 - How to align optical fiber with V-groove - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for adjusting the position of an optical fiber to a V-groove in a fully automatic fusion splicer for a multi-core optical fiber ribbon. However, this method can also be used for manual alignment. It can also be used for single-core optical fibers.

[0002]

2. Description of the Related Art Conventionally, when performing batch fusion splicing of optical fiber tape cores, the axes have been aligned by inserting each core into a V-groove which has been precision machined. FIG.
Is an embodiment of the V-groove base 10, but is an integral type in which V-grooves 12 are formed in a straight line on the left and right so as to face each other across a concave portion serving as a discharge region. Each of the tape cores arranged in the V-grooves on both sides is pushed in the butt direction,
By monitoring the pushing amount and the axis deviation on a television, a connection with low loss has been realized.

By the way, in the fully automatic fusion of the tape core starting from the automatic cutting of the tape end, simple control of the pushing amount and confirmation of the axis deviation as described above are not enough. Alignment between the tape core and the V-groove is required. Therefore, a case of fully automatic fusion of the optical fiber ribbon will be described (FIG. 5). The V-groove base 10 is configured such that all the V-grooves 12 face the z direction (the direction in which the optical fibers are joined) (see the arrow for the xyz direction), and the V-groove pitch is almost equal to the tape core wire pitch. As shown in FIG.
Is advanced in the z direction, and each optical fiber 22 in the tape is
It is brought above the groove 12 (b). At this time, the optical fiber 22 is in a state of floating away from the V-groove 12. Next, as shown in (c), the illumination light 30 is applied from below the V-groove base 10, the transmitted light of the optical fiber 22 is observed by the imaging device 32, and the position of the optical fiber 22 with respect to the V-groove 12 is detected. 34 is an objective lens. Imaging device 3
If the positional relationship between 2 and V groove base 10 is fixed, the position of V groove 12 can be marked on the monitor screen. V
When the position of the optical fiber 22 with respect to the groove 12 is shifted by Δs, the entire optical fiber 22 is translated in the x direction by Δs, and the position of the V groove 12 (that is, the V groove 12
(The position where the center of the optical fiber coincides with the optical fiber) (d). Next, the V-groove base 10 is raised in the y direction, and the V-groove 12
Is brought into contact with the optical fiber 22. Thereby, the optical fiber 22 is set in the V-groove 12. Alternatively, the optical fiber 22 can be lowered and housed in the V-groove 12.

[0004]

Since the above-mentioned method is a one-way observation, the axial deviation in the x direction (in the direction perpendicular to the illumination light 30) can be detected quite well, but the y direction (in the illumination light 30).
There is a problem that a detection error is large with respect to the axial deviation (in the same direction as the direction). Note that if there is an axis shift in the same direction as the illumination light 30, an axis shift in the y direction will occur with the optical fiber to be connected.

[0005]

2. Description of the Related Art Conventionally, two-directional observation using a mirror has been used for alignment of optical fibers. It can be considered that this is used for axis alignment between the optical fiber 22 and the V groove 12. FIG. 6 shows the situation. A mirror 36 having a reflecting surface in the yz direction is placed beside the V-groove 10. The illumination light 30 is applied to the mirror 36 from an oblique direction. The light 300 reflected by the mirror 36 and transmitted through the optical fiber 22 is observed by the imaging device 32 to obtain a real image of the optical fiber 22. Further, the mirror 3 is moved after moving the imaging device 32 and passing through the optical fiber 22.
6, the virtual image 2 of the optical fiber 22
2 ". From the image processing of both images,
The axis deviation of the optical fiber 22 on the x and y axes is obtained.
Next, the V-groove 12 (the V-groove 12 into which the optical fiber 22 enters)
If the normal positions on the x and y axes are determined in advance on the monitor screen, it can be determined whether or not the positions of the optical fibers are matched. The fiber 22 can be accurately placed in the V-groove 12.

[0006]

However, in order to move the imaging device 32 and observe a real virtual image, the V-groove 10
Is different from the movement of the imaging device 32 (x direction), the position of the V groove 12 cannot be accurately detected on the screen. Therefore, since the direction and amount of movement for correcting the position of the optical fiber 22 are not known, the method of monitoring the real virtual image at another position and another screen as described above is used.
In the direction observation method, it is extremely difficult to precisely align the V-groove 12 with the optical fiber 22.

[0007]

The present invention is based on the above-described two-direction observation method. In the prior art, however, the imaging apparatus was moved to observe real and virtual images at different positions. There is a difference in that the real virtual image is captured in the same visual field and the same monitor screen by arranging the imaging device at a position where the real virtual image can be observed at the same time and adjusting the focus.

FIG. 1 is a schematic explanatory view of the two-direction observation method. The V-groove base 10 is disposed on the right side of the mirror 36, and the distance between the mirror 36 and the V-groove base 10 is fixed, but the V-groove base 10 moves in the vertical (y) direction parallel to the reflection surface of the mirror 36. The optical fiber 22 is freely movable, and by moving it upward, each core of the multi-core optical fiber 22 can be housed and arranged in each V-groove 12 of the V-groove base 10.

On the left side of the mirror 36, the light 3 from the illumination light 30
A virtual image 22 ′ of the optical fiber 22 observed by 02 is drawn, and is captured in the same field of view of the imaging device 32 together with the real image 22 by the light 300. The image pickup device 32 can be moved at least in the X direction at least for the purpose of focusing, and in order to average the clarity of the real virtual images projected on the same screen, a mirror point which is an intermediate point between these real virtual images is used. The initial setting is made so that point D is in focus.

Now, the present invention is implemented as follows using the above configuration. As shown in FIG. 1 and FIG.
From the table 10, for example, select the second V-groove 12 from the left
(See below for selection) and place the bottom A at a specific position
To decide. Then, on the screen of the imaging device,
The real image at the fixed position A and the corresponding specific position on the virtual image side
A "is determined in advance, and is set as a reference interval T2.
You. After the reference interval T2 has been determined, the original of the same conditions, on the screen of the imaging device, the V
The distance T between the real image and the virtual image B ″ (shown by a broken line on the left side of the mirror) of the optical fiber core wire B accommodated in the bottom A of the groove 12
Ask 2 '. Since Δs, which is determined by the difference between the interval T2 ′ and the reference interval T2, is the amount of displacement between the core wire B and the V-groove 12, the optical fiber 22 is appropriately moved in the +/− direction in the x direction. On the screen of the imaging device, T2 '
= T2, Δs is eliminated, and the center of the optical fiber 22 coincides with the center of the V-groove. When the movement of the optical fiber 22 is completed and the center of each optical fiber coincides with the center of each V groove 12, the V groove base 10 is raised in the Y direction, and the optical fiber is stored in each V groove.

[ Supplementary Explanation of Reference Interval] The bottom A of the V-groove 12 is selected as a reference point for determining the reference interval. As an example, in the case of FIG. 1, the bottom of the second V groove 12 from the left (on the drawing) is selected, but this is an example,
A may choose anywhere. For example, the leftmost V-groove 12 or the center or the end of the V-groove base 10 may be used.
When the specific position A of the V groove 12 is the second V groove 12 from the left, the corresponding specific position B of the optical fiber is the second optical fiber 22 from the left (the second V groove 1 from the left).
2 is the second optical fiber 22 from the left). When A is the leftmost V groove 12, B is the leftmost optical fiber 2
It becomes 2. When A is at the center of the V-groove 10, B is the center position of all the optical fibers 22 in the x direction. A plurality of specific positions may be selected and their average may be determined.

[0012]

[0014]

[ Supplementary explanation on the interval T2 'between the real image and the virtual image at the specific position B of the optical fiber] As described above, the specific position A of the V-groove 12 is 2 from the left.
When the reference interval T2 is obtained by selecting the first optical fiber, the specific position B of the optical fiber is also the second optical fiber 222 from the left as shown in FIG. 221 is the leftmost optical fiber. As shown in FIG. 3A, the mirror 36 is irradiated with the illumination light 30 at an angle θ (the same angle as when T2 is obtained). Light 3 reflected by mirror 36 and transmitted through optical fiber 222
00 is observed by the imaging device 32 and its real image 222 ′
Get. FIG. 2B shows a screen 320 of the imaging device 32. Also, by slightly moving the imaging device 32 in the x direction,
The virtual image 222 ″ is obtained by the light 302 reflected by the mirror 36 after passing through the optical fiber 222. This real image 22 is obtained.
The interval between 2 ′ and the virtual image 222 ″ is T2 ′. Since the real image and the virtual image are extremely close to each other and the moving amount of the imaging device 32 is small, all or all of the real image and the virtual image can be displayed on one screen 320. Almost everything can be stored.

[Positioning of Optical Fiber 22 and V-groove 12] T2 'and T2 are compared. When T2 '> T2,
The optical fiber 22 is moved to the left (in a direction approaching the mirror 36). Then, when T2 '= T2, the optical fiber 222 is on the AE in FIG. V groove stand 10
Is raised in the y direction by a required amount, the optical fiber 222
Fits in the V-groove 12 exactly. The scale on the screen is determined so as to correspond to the actual position of the optical fiber.

There are the following methods for moving the optical fiber 22. Move it little by little, and screen 32
Stop when T2 '= T2 on 0. FIG.
When the deviation between the V-groove 12 and the optical fiber 22 is Δs, Δs = (T2′−T2) / 2 × cos θ, so Δs is determined by calculating backward from T2 and T2 ′ . It may be moved by that amount . The optical fiber 2
2 instead of moving the V-groove 10
good.

[0018]

The distance between the mirror real image and the virtual image of the tip of the optical fiber arranged at a specific position of the V-groove is obtained.
Since the reference interval is used as the reference interval, the value of the reference interval does not change even if the V groove 12 moves up and down as described above. Then, since the position of the optical fiber 22 is corrected based on this reference interval, when the V-groove 12 is lifted, the optical fiber 22 is accurately accommodated therein. Further, since the optical fiber is observed from two directions, unlike the one-direction observation, the detection accuracy of the axis deviation with respect to the optical fiber of the connection partner is high.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of how to obtain a reference interval T2 in the present invention.

FIG. 3 is an explanatory diagram of a method of obtaining an interval T2 ′ between a real image and a virtual image of an optical fiber according to the present invention.

FIG. 4 is an explanatory diagram of a V-groove.

FIG. 5 is an explanatory view of a conventional method of aligning an optical fiber with a V-groove.

FIG. 6 is an explanatory diagram of a case where a two-way observation method using a mirror is used for axial alignment of a V-groove and an optical fiber.

[Explanation of symbols]

 Reference Signs List 10 V groove base 12 V groove 20 Optical fiber tape 22, 222 Optical fiber 222 ′ Real image of optical fiber 222 ”Virtual image of optical fiber 30 Illumination light 300, 302 Light 32 Imaging device 320 Screen 34 Objective lens 36 Mirror

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G02B 6/255

Claims (1)

(57) [Claims] 1. A method of positioning an optical fiber and a V-groove base, wherein a mirror is provided beside the V-groove base, and each of the optical fiber and the V-groove is a real image by an imaging device.
And mirror virtual images can be observed on the same screen
; Then, on the screen of the image pickup device, the specific position location of the V-groove
Of previously obtained a distance between the virtual image by real and the mirror, and it with the reference interval T2, on the screen of the image pickup apparatus, the optical fiber corresponding to a specific position of the V-groove, by the real image and the mirror Between the virtual image
How to align septum T2 'a, determined by the same conditions as those of the reference interval T2, the interval T2' in the so as to coincide with the reference interval T2, the position of the optical fiber in the V groove.