JP3545183B2 - Optical fiber alignment method - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for aligning an optical fiber, and more particularly, to a method for aligning an optical fiber when an axial deviation is large when setting the optical fiber (such as high-strength fusion splicing using a coated clamp).
[0002]
[Prior art]
In FIG.
10 is an optical fiber core, 12 is a covering portion thereof, and 14 'is a bare fiber.
16 is a V-groove, 18 is a V-groove,
Reference numeral 19 denotes a driving device for slightly moving the V-groove base 16 in the xyz directions.
In the case of high-strength fusion splicing of a submarine optical cable or the like, generally, the coated portion 12 of the optical fiber core wire 10 is housed in a V-groove 18 and pressed by a clamp 20 (see Japanese Patent Application Laid-Open No. Sho 62-210406).
22 is an image sensor (such as a CCD camera),
24 is an image processing device,
26 is a computer,
28 is a monitor and 14 is a fiber image.
[0003]
[Alignment]
The image obtained by the image sensor 22 is processed, and the V-groove 16 is finely moved so that the cores of the left and right optical fibers coincide.
[0004]
[Problems to be solved by the invention]
However, the following problems arise in connection for clamping the covering portion 12.
{Circle around (1)} When the optical fiber core 10 is set, the axial deviation tends to increase.
(2) The center position of the bare fiber 14 'may change depending on the diameter of the covering portion 12 (FIG. 7).
At that time, the fiber image 14 may protrude from the observation range 30 of the image sensor as shown in FIG.
[0005]
Heretofore, in particular, the above-mentioned (2) has been performed as follows.
{Circle around (1)} Manually adjust the position roughly using a micro screw or the like.
{Circle around (2)} The V-groove 16 is changed in accordance with the coating diameter, and roughly aligned.
[0006]
{Circle around (1)} When the fiber image 14 protrudes from the observation range 30 at the time of the above-described manual alignment, it is not known to which direction to move the fiber image 14 unless it is moved.
Even when it does not protrude, manual work is troublesome.
{Circle around (2)} In the case of replacing the V-groove 16, the work is troublesome.
If the V-groove base 16 that does not match the diameter of the covering portion 12 is incorrectly attached, the fiber image 14 disappears from the observation range 30 and connection cannot be made.
For the same reason as above, there is a possibility that the connection of the optical fiber with a special diameter cannot be performed.
[0007]
In addition to the case of the covering clamp, the same problem occurs when the axis shift becomes very large because the huge dust 32 is on the V-groove 18 as shown in FIG.
[0008]
[Means for Solving the Problems]
The invention of claim 1, described with reference to FIGS. 2-3.
・ Observe by image sensor
It should be possible to switch between low magnification and high magnification.
As shown in FIG. 3, a window 44 having a size corresponding to the observation range of the high-magnification observation is set in the observation range 30L of the low-magnification observation.
・ After that, perform the following procedure.
(1) It is examined whether or not the fiber image 14 exists in the window 44 by low magnification observation (FIG. 3A).
(2) In the above investigation, when the fiber image 14 does not exist in the window 44, the fiber image 14 is moved into the window 44 (FIG. 3B).
(3) The fiber image 14 in the window 44 is aligned by high-magnification observation (FIGS. 3C and 3D).
[0009]
In the above description, the low magnification is a magnification such that several optical fibers enter the imaging range as shown in FIG.
Although the core position is not known, the outer diameter can be sufficiently observed.
The high magnification is a magnification at which one optical fiber is inserted, as shown in FIG. The position of the core 140 can be observed.
[0010]
In order to perform observation by the image sensor by switching between low magnification and high magnification, for example, the following is performed.
(1) Two image sensors of a low magnification 22L and a high magnification 22H are used (reference example) (FIG. 1).
(2) One image sensor having a zoom lens is used (the present invention) .
[0011]
The meaning of "the window 44 having a size corresponding to the observation range of the high-magnification observation within the observation range 30L of the low-magnification observation" will be described with reference to FIG.
FIG. 4 is a model diagram of a cross section of the field of view of the image sensor 22.
30L is a low magnification observation range, θL is the angle of view,
30H is a high magnification observation range, θH is the angle of view,
44 is a window.
[0012]
In the above, as the alignment procedure,
{Circle around (1)} Whether or not the fiber image 14 exists in the window 44 is examined by low magnification observation.
(2) The fiber image 14 outside the window 44 is moved into the window 44.
(3) The fiber image 14 in the window 44 is aligned by high-magnification observation.
However, this is not always the case.
Starting from the high magnification observation, if the two fiber images 14 are luckily present in the visual field, the alignment can be immediately started.
In this case, low magnification observation is not performed.
[0013]
According to the invention of claim 2, as schematically shown in FIG.
A window having a size corresponding to the observation range of the high-magnification observation in the focused state (FIG. 2B) within the observation range 30L of the low-magnification observation in the out-of-focus state (FIG. 2A). 44 is set.
Then, a procedure similar to the above is performed.
[0014]
The third aspect of the present invention will be described below with reference to FIG.
That is, observation by the image sensor
A / D conversion of the entire image pickup range of the image sensor (the square portion shown by the solid line in FIG. 3), and low-magnification observation;
A / D conversion of only a predetermined portion of the window 44 within the imaging range of the image sensor and a sampling step width smaller than that of the low magnification observation, high magnification observation,
And so on.
Then, it is characterized in that the same procedure as described above is actually observed.
[0015]
Implementation of each of the above procedures can be easily automated, for example, by using a known robot technology or the like.
[0016]
[Reference example]
In FIG.
22L is a low magnification image sensor,
22H is a high magnification image sensor,
34 is a half mirror and 36 is a mirror.
Reference numeral 38 denotes a camera selector, which includes relay switches 40 as many as the number of camera control lines.
Reference numeral 42 denotes a driving device for slightly moving the V-groove base 16 in the xyz directions.
[0017]
[Alignment]
Automatic control is performed as follows based on a program of the computer 26.
{Circle around (1)} A switching signal 25 is output from the computer 26 to perform low-magnification observation with the low-magnification image sensor 22L (FIG. 3A).
30L is a low magnification observation range.
Then, it is checked whether or not the fiber image 14 exists in the window 44.
(2) If the fiber image 14 does not exist in the window 44, the following is performed.
Based on the image data, the computer 26 issues a control command 27 to the drive unit 42, and moves the V-groove 16 to move the fiber image 14 into the window 44 (FIG. 3B).
{Circle around (3)} Then, switch to a high magnification (FIG. 3 (c)).
30H is a high magnification observation range.
{Circle around (4)} Based on the image data, the computer 26 issues a control command 27 to the drive unit 42 to core-align the fiber image 14 in the window 44 (FIG. 3 (d)).
[0018]
In the above (1), if the fiber image 14 exists in the window 44 luckily, the process (2) is omitted and the process immediately proceeds to (3).
[0019]
Embodiment 1 of the present invention
Referring to FIG.
Only one image sensor 22 is used. 220 is an objective lens, and 222 is an imaging surface.
In this case, the apparent magnification is changed by shifting the focus.
[0020]
FIG. 7A shows a case of low-magnification observation in which focus is not achieved.
(B) is a case of high-magnification observation in focus.
[0021]
The alignment procedure is the same as above.
At that time, in the case of (a), the fiber image 14 is out of focus, and only a rough position is known.
However, fine positioning may be performed after returning to a high magnification, so that defocus may be used.
[0022]
Second Embodiment of the Invention
See FIG.
In this case, only one image sensor can be provided.
Also, as an example, a case where the ratio of [low magnification observation magnification] to [high magnification observation magnification] is 1: 2 will be described.
[0023]
First, A / D conversion is performed on the entire imaging range of the image sensor (the 30-L portion of the solid square) to perform low-magnification observation.
(1) Investigation whether the fiber image 14 exists in the window 44, and
(2) Movement of the fiber image 14 outside the window 44 into the window 44,
The procedure of is performed.
[0024]
Next, A / D conversion is performed on only the window 44 portion, and the sampling step size at the time of A / D conversion is set to の of the case of the above low magnification, and high magnification observation is performed.
(3) The fiber image 14 in the window 44 is aligned.
[0025]
【The invention's effect】
{Circle around (1)} Automatic alignment can be performed even when the axial deviation of the left and right optical fibers is large, such as in the case of a coating clamp or when dust is caught in the V-groove.
{Circle around (2)} When the coating is clamped, there is no need to replace the V-groove according to the coating diameter or manually determine a rough position.
The operator does not need to do anything.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of Reference Example .
FIG. 2 is an explanatory diagram of low-magnification observation and high-magnification observation in the present invention.
FIG. 3 is an explanatory diagram of an alignment procedure in the present invention.
FIG. 4 is an explanatory view showing that a window 44 having a size corresponding to the observation range of the high-magnification observation is set in the observation range 30L of the low-magnification observation in the present invention.
FIG. 5 is an explanatory diagram of Embodiment 1 of the present invention.
FIG. 6 is an explanatory diagram of a conventional technique.
FIG. 7 is an explanatory diagram of a problem of the related art (a state in which the axis deviation is large due to a difference in coating diameter).
FIG. 8 is an explanatory view of a problem of the related art (a state in which the fiber image 14 is out of the observation range 30). FIG.
[Explanation of symbols]
Reference Signs List 10 Optical fiber core wire 12 Coated portion 14 'Bare fiber 14 Fiber image 16 V groove base 18 V groove 19 Drive device 20 Clamp 22 Image sensor 220 Objective lens 222 Image pickup surface 22L Low magnification image sensor 22H High magnification image sensor 24 Image processing device 25 Switching signal 26 Computer 27 Control command 28 Monitor 30 Observation range 30L Low magnification observation range 30H High magnification observation range 32 Dust 34 Half mirror 36 Mirror 38 Camera selector 40 Relay switch 42 Driver 44 Window

Claims (3)

In a method of aligning an optical fiber, a single-core optical fiber is observed with a single image sensor, and a fiber image obtained by the observation is image-processed and aligned.
Observation by the image sensor, low magnification and high magnification, so that it can be switched, and,
An optical fiber centering method, wherein a window having a size corresponding to the observation range of the high-magnification observation is set in the observation range of the low-magnification observation, and the following procedure is performed.
(1) A step of checking whether or not the fiber image exists in the window by the low-magnification observation.
(2) A step of moving the fiber image outside the window into the window.
(3) A step of aligning the fiber image in the window by the high-magnification observation. In a method of aligning an optical fiber, a single-core optical fiber is observed with a single image sensor, and a fiber image obtained by the observation is image-processed and aligned.
A window having a size corresponding to the observation range of the high-magnification observation in a focused state is set within the observation range of the low-magnification observation in a state where the image sensor is in focus and the state is out of focus. , And the following procedure is carried out.
(1) A procedure for checking whether or not the fiber image exists in the window by low-magnification observation in which the focus is not focused.
(2) A step of moving the fiber image outside the window into the window.
(3) A step of aligning the fiber image in the window by the in-focus high-magnification observation. In a method of aligning an optical fiber, a single-core optical fiber is observed with a single image sensor, and a fiber image obtained by the observation is image-processed and aligned.
Observation by the image sensor,
Performs overall imaging range of the image sensor converts A / D, a low-magnification observation,
Only A / D given window portion of the imaging range of the image sensor
Converted,

And, the sampling step width is made smaller than the case of the low-magnification observation, so that it can be switched to high-magnification observation,
A method for aligning an optical fiber, comprising performing the following procedure.
(1) A procedure for checking whether or not the fiber image exists in the window by the low magnification observation.
(2) A step of moving the fiber image outside the window into the window.
(3) A step of aligning the fiber image in the window by the high-magnification observation.

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