JPS619609A - Connecting method of optical fiber - Google Patents

Abstract

PURPOSE:To keep optical fibers free from undue stress and to connect two pieces of the optical fibers with high reliability in the stage of welding and connecting the two fibers by connecting said fibers while controlling the axial force between the two fibers. CONSTITUTION:The two optical fibers 3, 4 are respectivey gripped by holders 1, 2. The holder 1 is fixed onto a base 7 supported by two pieces of parallel springs 8, 9 and strain gages 16, 17 are adhered to the surfaces of the parallel springs 8, 9. The springs 8, 9 deflect when the axial force acts at the top end of the fiber 3. The force is detected from the magnitude of the strain in this stage. The two optical fibers are so spaced and heated that the force acting axially on the fibers 3, 4 is first made zero, then the top ends of the fibers 3, 4 are butted to each other until the specified force is attained and while such force is maintained, the top ends are heated and thereafter the force acting axially on the fibers is decreased to the prescribed force. Since the fibers are welded and connecting under heating in such a state, the fibers are kept free from the undue stress.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a connection method for heating and fusing optical fibers.

[Prior art]

A conventional heating fusion splicing method for original fibers will be explained with reference to FIG.

(1) First, align the axes of the two original fibers 3.4 across the connector held by the holder 1.2Vc. There are several ways to achieve this, such as setting the VC in advance with high precision, placing it in the V-groove, and adjusting the position by operating the fine movement table while confirming the position with a microscope, etc., but they are not shown in Figure 1.
ing. At this stage, it is assumed that the outer sheaths of the connecting portions of the original fibers 3 and 4 have been removed, and that the outer periphery of the core wires has also been cleaned of dust and the like that would impede the connection.

(11) Next, move in the axial direction and bring the two optical fibers together. This operation involves weakening the gripping force of holder 1 or 2 in advance, bringing holders 1 and 2 closer together, and
This is achieved by releasing in the axial direction when the end faces abut.

(ii) Next, using this position as a reference, the original fiber is moved back in the axial direction so that the end faces of the original fiber face each other at a certain distance, and a discharge is caused between the electrodes 5.fl, and the original fiber 3. Melt the surface of the end face of step 4.

(lv) In this state, move the original fibers 3 and 4 a certain distance in the axial direction again by 5 VC to bring the two original fibers together by 3.4 t and fuse them together, then stop the release 1E and let them cool and solidify. The connection is complete.

As mentioned above, in the fusion process of the employee's original fiber,
It controls only the distance between the tips of the two original fibers 3.4, and does not control the force acting in the axial direction of the two original fibers 3.4. , 4 will buckle, the force will be close to 0 because the connection part will melt during heating, etc. The pressing force will change greatly between the initial stage and the final stage of the fusion described above (iV). However, since the distance is controlled, a high-precision positioning mechanism is required to make accurate and precise connections. [Summary of the Invention] In order to solve these drawbacks, the present invention has the following drawbacks: The objective is to realize a highly reliable fiber-optic connection system.

[Embodiments of the invention]

The second factor is an embodiment of this invention, and in this case, 2
Since the axes of the original fibers are aligned using the same method as in the prior art, the mechanism for this purpose is omitted. The two original fibers 3 and 4 are held by holders 1 and 2, respectively. The holder 1 is supported by two parallel springs 8 and 9 and is fixed on one holder 7. Parallel springs 8,9
is fixed on a movable table 10, and the movable table 10 is movable in the direction of arrow 14 by means of a screw 12 directly connected to a motor 11 and a guide 13. The holder 2 is fixed on a support base 15, and electrodes 5 and 6 for discharge heating are installed in the middle part of the holders 1 and 2.

Strain gauges 16 and 17 are pasted on the surfaces of the parallel springs 8 and 9.
When an axial force is applied to the tip of the original fiber 3, the parallel spring 8.9 is deflected, and the deflection can be detected from the magnitude of the strain at that time. The motor 11 is (
In this case 1) C servo motor is preferable) Power amplifier 1
The drive is controlled by the arithmetic circuit 19 via B'&. The motor 11 is generally equipped with a detector 23 such as a speed detector or a position detector.
is installed coaxially, and its output is fed back to the arithmetic circuit 19. Further, the outputs of the strain gauges 16 and 17 are fed back to the strain gauge amplifier 20 intermediary calculation circuit 19, and the difference from the pressure command value 21 corresponding to a predetermined heating time is fed back to the motor 11vc. Therefore, if the force acting on the tip of the original fiber 3 is too large, the moving table ICY is moved backward, and if it is too small than the command value, the moving table 10'F! :The entire control circuit is configured to move the robot forward and maintain a predetermined force.

′! ! In addition, a discharge drive circuit 2 for discharging between the electrodes 5 and 6
The pressing pressure and heating temperature between the original fibers 3.4 can also be controlled in relation to each other by the control Z calculation circuit 19 of No.2.

The operation of this device is different from the conventional operation shown in FIG. , once the tips of both optical fibers 3°4 are separated, the axial direction between them is heated to zero, and the unevenness of the end face is heated to make it smooth. The applied force is controlled to be approximately constant during discharge heating, and thereafter the applied force is gradually reduced until it reaches a predetermined value. Note that the force at this time only needs to be approximately constant. Since this will vary depending on the n+1 discharge time, discharge strength, etc., the optimal combination of discharge time and pressing force is determined experimentally in advance, and the pressure command value 21 is generated as f'! 1 bye (S.

In addition, as a method for detecting cans, we will use parallel springs 8.
Although the method explained above is based on the method of attaching a strain gauge to 9, it is obvious that the method is not limited to this method, and that a method of supporting the strain gauge with a coil spring, detecting the displacement with a displacement detector such as a differential transformer, and converting it into force is also possible. be.

〔Effect of the invention〕

As explained above, this invention controls the force between two source fibers in addition to fusion splicing the source fibers, thereby preventing excessive force from acting on the source fibers (thus, ensuring reliability). It has the advantage of being able to provide fiber connections with high quality (1.) and stable quality.

Also, since it does not control distance like the conventional method, it does not require a precise positioning mechanism, but it also has the advantage of being able to implement inexpensive equipment.

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating a conventional heat fusion method, and FIG. 2 is a perspective view and a block diagram of an electric circuit showing an example of an apparatus for realizing the present invention. In the figure, 1 and 2 are Holters, 3 and 4 are original fibers, 5.6 are electrodes, 7 is a stand, 8 and 9 are parallel springs, 10 is a moving stand, and 11
is a motor, 12 is a screw, 13 is a guide, 14 is an arrow indicating the direction of movement, 15 is a support base 16, 17 is a strain gauge, 18
19 is a power amplifier, 19 is an arithmetic circuit, 20 is a strain gauge amplifier, 21 is a pressure command value, 22 is a discharge drive circuit, and 23 is a detector. 'Ih1 diagram

Claims (1)

[Claims] In a method of permanently connecting two optical fibers by heating and fusing them, both optical fibers are separated and heated so that the force acting in the axial direction of both optical fibers becomes zero at first, and then a constant force is applied to the optical fibers. 1. An optical fiber characterized in that the tips of both optical fibers are brought into contact with each other and heated while maintaining that force, and then heated while gradually reducing the force acting in the axial direction until a predetermined force is reached. How to connect.