JPS6115402B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device used to align two optical fibers axially when joining them together. When joining two optical fibers, it is necessary to make their axes perfectly coincide, and conventionally the following means have been adopted.

(a) While observing the contact state of two optical fibers using a microscope, one fiber is moved slightly using an X-Y-Z fine movement stage to align the axes.

(b) Guide the fiber using a jig with a groove such as a V-groove.

C. Dividing a jig with mutually parallel planes in the axial direction and sandwiching the fibers aligned on one plane with the other plane.

D. Inserting the fiber into a pre-adjusted tube.

In all of these cases, it is assumed that the outer dimensions of the fiber are at predetermined values, and the core and cladding are treated as being concentric, so any errors that occur in the dimensions and position during fiber manufacturing will be accounted for after the fiber is joined. It was inevitable that this would lead to errors in the characteristics and large variations would occur.

SUMMARY OF THE INVENTION An object of the present invention is to improve the above-mentioned drawbacks and to provide a device that can adjust the axial position of the optical fibers while measuring their axial positions so that the cores of the optical fibers can align with each other in the axial direction.

Embodiments of the present invention shown in the drawings will be described below.

FIG. 1 is a perspective view showing the positional relationship of two optical fibers to be joined. 1 is a first optical fiber movable in X and Y2 directions perpendicular to each other, and 2 is a second optical fiber. 1 is shown in a fixed position for joining with the optical fiber 1 of No. 1. CL indicates the clad part of the fiber, and CO indicates the core part. 1st
The optical fiber 1 moves in the Z direction and in the X-Y direction in Figure 1.
After making rough adjustments in the directions simply and visually, fine adjustments are made in the X and Y directions. FIG. 2 is a block diagram showing this adjusting device.

3 is a helium-neon laser light source, 4 is a lens that allows the laser light to enter the second optical fiber 2, and 5 is a photovoltaic meter that measures the amount of light that has passed through the first optical fiber 1 and its output. For example, obtain and store it as a BCD code. 6a and 6b are storage devices, 7 is a comparator, 8 is a moving stage for minutely moving the first optical fiber, 9 ₁ and ₉₂ are electric motors that drive the moving stages, and 10 is a motor control device.

First, when adjusting in the X-axis direction, the measurement is performed at the initial position of the first optical fiber 1 using the photovoltaic meter 5 which passes from the light source 3 through the optical fibers 2 and 1, and is stored in the storage device 6a. Control device selection line 1 from control device 10
1 outputs, for example, "0" so that the storage device 6a is selected and the storage device 6b is not selected. After the memory is finished,
The moving stage 8 moves the first optical fiber 1 by Δx in the X direction, and stores the output at that time in the storage device 6b. Control device 10 selects line 1
1 is set as "1". Next, the comparison arithmetic unit 7 compares the outputs A and B of both the storage devices 6a and 6b. That is, data A in the storage device 6a and data B in the storage device 6b are compared in size, and if A>B, k.(A-B)/Δx (1) is calculated. Let k be a constant of proportionality.

In this case, the amount of transmitted light of the first optical fiber decreases after the movement than before movement, indicating that the positional deviation of the core CO becomes large, so the value of △x is reversed, that is, on the The fiber position is moved in the opposite direction from the previous time by the calculated value of equation (1). New data is stored in the storage devices 6a and 6b before and after the movement. Compare the sizes of new data A and B, and if A<B (including the case of the original movement mentioned above), calculate K・|A−B|/Δx (2), and only the calculated value Move the fiber to the next position.

In Figure 3, if the horizontal axis is the x direction and the vertical axis is the photovoltaic meter output, then the moving distance Δx ₁ in the x direction is
The outputs of A ₁ and B ₁ show the case of equation (1) described above, and the outputs of A ₂ and B ₂ show the case of equation (2) for Δx ₂ . It is clear from the curve in FIG. 3 that when Δx is held constant, the value of equation (1) or (2) approaches zero. The point where equation (1) becomes zero, that is, the position Xm on the x-axis where the photovoltaic meter output shows the maximum value is the position where the axes of both optical fibers best match in the X-axis direction.

Next, by repeating the above-mentioned procedure in the same manner in the Y-axis direction, Ym is obtained. In this case, it is natural that the denominator of equations (1) and (2) is ΔY.The positions of Xm and Ym are the positions where the axes of both optical fibers 1 and 2 perfectly match.

In the arithmetic expression, Δx and ΔY can be collectively expressed as Δr. Setting Δr to a constant, small value means that the best position can be reached without repeating zigzag movements before and after the best position, which is significant because it can be processed in an extremely short time when automating the embodiment shown in Fig. 2. be.

In this way, according to the present invention, by measuring the amount of light that passes through the core of the optical fiber, it is possible to position the optical fibers so that their axial directions coincide, so that it is possible to join the cores together in the best possible condition. be. The fact that the adjustment can be made without depending on the uniformity of the outer shape of the optical fiber or the concentricity of the core and the cladding, as in the prior art, means that there are no variations due to these factors, and the properties after bonding are extremely good. Since the operation of the device is logical, the axial directions can be matched in a short time, and automation is easy.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the positional relationship of two optical fibers to be joined, FIG. 2 is a block diagram of an embodiment of the present invention, and FIG. 3 is a diagram showing a change curve of the output of a photovoltaic meter. DESCRIPTION OF SYMBOLS 1... First optical fiber, 2... Second optical fiber, 3... Laser light source, 4... Lens, 5...
Photovoltaic meter, 6a, 6b...Storage device, 7...Comparison calculation device, 8...Movement stage, 9 ₁ , 9 ₂ ...
Electric motor, 10... electric motor control device.

Claims (1)

[Scope of Claims] 1. A first optical fiber that is movable by a mechanism that can be moved slightly in two directions orthogonal to each other, a second fiber that is fixed at a position to be joined to the fiber, and a second optical fiber that is fixed in position to be joined to the first optical fiber. a light emitting source that inputs light from the side opposite to the surface to be welded; a light meter that measures the amount of light output from the side opposite to the surface to be joined of the first optical fiber; An optical fiber comprising two storage devices that store data before and after fine movement of the fiber, and a device that compares and calculates the outputs of the storage devices, and finely moves the first optical fiber based on the output of the comparison calculation. axial mating device. 2 The two storage devices that store the light meter outputs store the light meter outputs before and after moving the second optical fiber by a certain minute amount Δr, and each memory device output A and B
2. The optical fiber axial direction matching device according to claim 1, wherein k.|A−B|/Δr is calculated for . (However, k is a proportionality constant)