JPH0154683B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention is a method for collectively welding optical fibers of a multi-core optical fiber core, which is formed into a flat shape by arranging a plurality of optical fibers in parallel at intervals and providing them with a common coating layer. A multi-core optical fiber that allows you to connect even single-core optical fibers by operating a switch on the connecting device. Regarding a single-fiber dual-use connecting device. (Prior art and problems to be solved) Optical fibers include single-core optical fibers and multi-core optical fibers. FIG. 1A is a perspective view of a single-core optical fiber 3, in which a coating portion 2 is provided on the outer periphery of the optical fiber 1 having a diameter of 0.125 mmφ. On the other hand, 2-, 4-, and 5-core multi-core optical fibers have been developed, but the 5-core flat type optical fiber 4 shown in Figure 1 (b) has become the standard, and the optical fibers are arranged in parallel at intervals. Optical fiber 1 with a diameter of 0.125mmφ placed in
A common covering part 2' is provided on the outer circumference of 0.45mm x 1.6mm.
It is formed in a flat shape. When fusion splicing the optical fibers 1 of such a multi-core optical fiber 4 all at once, the coating portion 2' near the end of the optical fiber 4 is removed to expose the optical fiber 1. After trimming the tips of these optical fibers 1, they are mounted on a fusion splicing device, and the optical fibers 1 are welded and connected by electric discharge heating with their connecting end surfaces abutting each other. The connection of the optical fiber 1 of the single-core optical fiber 3 is essentially the same as that of the multi-core optical fiber 4 described above, but as a fusion splicing device, the connection is different from the single-core and the 5-core. Because of the different setting conditions, multi-fiber fusion splicing and single-fiber splicing devices are currently being developed and used separately. On the other hand, as optical fibers become more multi-core, multi-core optical fibers are increasingly used for trunk lines, and single-core optical fibers are now mainly used for connections at the terminal ends. Matatashin. Since there are cases where single-fiber composite optical fiber cables and branch connections are used, there are an increasing number of connections that require both multi-fiber connection equipment and single-fiber connection equipment. There is an urgent need to develop a connecting device that can be used for both single-fiber connections. (Means for Solving the Problems) The present invention solves the above-mentioned problems and makes it possible to connect multi-fiber and single-fiber optical fibers using a fusion splicing device for multi-fiber optical fibers. Its features include a gripping part that arranges a plurality of optical fibers in parallel in a V-groove, and fixes the optical fibers by aligning the axes of the opposing end faces; In the optical fiber fusion splicing apparatus, the optical fiber fusion splicing apparatus includes a moving mechanism for moving the optical fibers to each other and a heating power source for melting and splicing the end faces of the optical fibers together using the heat of the arc discharge of the discharge electrode. It is equipped with a V-groove for fixing the fiber, and the optical fiber movement mechanism has two movements: the amount of movement when connecting a single optical fiber and the amount of movement when connecting a five-fiber optical fiber.
The current value flowing between the electrodes by the heating power source can be set in two stages, one for single-fiber connection and one for five-fiber connection. The present invention is configured to perform fusion splicing by switching the amount of movement of the optical fiber and the discharge current value depending on whether it is a single fiber or a multi-core optical fiber by operating a switch. (Contents of the Invention) The basic configuration of an optical fiber fusion splicing device is shown in FIG. AC/DC switching regulator 41, which normally uses AC100V commercial power as input power,
It is composed of a high frequency discharge power source 42, a mechanical drive section 43, a discharge fusion section 44, and a connection section observation device 45, and connection conditions suitable for the number of optical fibers are set. The connection condition setting value is a condition that is given to the connection device in advance in order to connect the optical fibers with low loss.It is the amount of heat that is melted by the discharge heat when the end faces of the optical fibers are butted together. Set the current to flow. Time to flow the above discharge current. Distance between opposing tips of discharge electrodes. The amount of pushing movement in which the end faces of optical fibers are faced to each other at a fixed interval (usually 20 μm) and the optical fiber is moved in the axial direction until the end faces of the optical fibers come into contact with each other and melt at the same time as discharge occurs. is an essential condition item. The table below shows the differences between fusion splicing devices for single-core optical fibers and for five-core optical fibers.

[Table] Among the differences in the above table, the present inventors found that, as the saying goes, "big is also small," and that the connection setting conditions for multi-fiber also include the connection conditions for single-fiber. We have developed a connecting device that can switch multi-fiber connection conditions to single-fiber connection conditions by electrical operation, and can also connect single-core optical fibers, without replacing or adjusting parts. In other words, the polycore in the table above. Among the single-fiber connection condition settings, the items for which single-fiber connection is not possible unless the multi-fiber connection conditions are changed are: D-(1) Discharge current value D-(4) 2 of the optical fiber push-in movement amount during discharge
It is a point. Regarding the discharge time of D-(2),
From the difference in current density distribution due to the electrode spacing in D-(3), it was found that by adjusting the discharge current value (D-1), there was no problem even in the case of a single core in 6 seconds (discharge current 15 mA with an electrode spacing of 2.5 mm). Confirmed by experiment. Figure 7 shows a positioning diagram of the optical fiber facing the discharge fusion part and aligning the alignment axes.
In the positioning diagram of the optical fiber, a five-core optical fiber is inserted into the V-groove 51 and fixed with a clamp 52, and an arc discharge 54 is generated from the electrode 53 as shown in the figure (b).
The optical fiber is welded by the heat. At this time, the discharge heat is uniformly welded to the five-core optical fiber by setting the current flowing between the electrodes to 19 mA. In addition, Figure C shows the positioning state of a single-core optical fiber using the same device, and Figure D shows the discharge state.The discharge current at this time is set to 15 mA, and the single-core optical fiber is well-positioned. Welded. (Example) A method of electrically setting the above two points of difference using a changeover switch will be described below. D-(1) Discharge current value Figure 3 shows the circuit diagram of the high frequency discharge power supply shown in Table B above. Figure A is a conventional circuit diagram, where 11 is a discharge electrode rod, 12 is a high frequency transformer, 13 is a control unit, and 14 is a conventional circuit diagram.
is a variable resistor for adjusting the discharge current value, and by adjusting this variable resistor 14, the discharge current of 14 to 20 mA between the electrode rods 11 is controlled. Figure B is an improved diagram, variable resistor 1 is the same as variable resistor 4.
4a and 14b were arranged in parallel and connected to the changeover switch 15. The discharge current of variable resistor 14a is 19mA.
The variable resistor 14b is set so that the discharge current is
The discharge current value is set to 15 mA, and by operating the selector switch 15, the discharge current value can be selected for multi-core or single-core. D-(4) Optical fiber push-in movement amount during discharge FIG. 4 is a flowchart showing the movement of the optical fiber 1 during connection. (a) Set the optical fibers 1 on both sides of the abutting plate 9. (b) Move the optical fiber 1 in the direction of the arrow and hit the abutting plate 9 to position the optical fiber 1. (c) Move the optical fiber 1 back a little from the abutting plate 9 in the direction of the arrow. (d) Lower the abutting plate 9 and move the optical fiber 1 forward again. At this time, the optical fiber spacing l is 20 μm in the case of a single fiber, and this position is the origin, and the subsequent movement of the optical fiber 1 is the pushing movement amount. The optical fiber 1 is pre-discharged at the above position to clean the end face of the optical fiber 1. (D') In the case of a multi-core optical fiber, the end faces of the five-core optical fiber are uneven, so the amount of pushing movement must be made larger than that for a single-core optical fiber by the amount of the unevenness. (E) Open the discharge for fusion splicing and push the optical fibers 1 into each other. (f) Indicates the state where the connection has been completed, and (ε) indicates the amount of crossing when fused. In the case of a single fiber, the best splice loss can be obtained when the amount of crossing (ε) during fusion is 20 μm, but in the case of multiple fibers, the length of the end face of each of the five fibers
Since there is a variation of about 20 μm, it is not possible to connect with the same amount of push-in movement as with a single core. Therefore, the setting of the pushing movement amount in case of multiple cores is as follows:
The pre-discharge interval l'20μm + (maximum length variation of the end face of the optical fiber at one end x 2) must be set to 20+
(30×2)=80 μm. In this way, the pushing distance is 40μm when connecting a single core,
The thickness is 80 μm when multiple fibers are connected, and a method for switching between these two setting conditions will be explained with reference to FIG. Figure 5A is an explanatory diagram of the conventional mechanism for setting the pushing movement amount, in which 21 is a drive motor, 22 is a feed screw, 2
3 is an optical fiber fixing base, 24 is a gear, 25 is an origin position indexing plate, 26 is an origin detection sensor, 27 is a pushing movement amount detection indexing plate, and 28 is a pushing movement amount detection sensor. When setting two pushing movement amounts using such a mechanism, it is necessary to adjust the rotation angle position of the pushing movement amount indexing plate 27,
Adjustment requires advanced skill and time. Figure B is an explanatory diagram of an improved mechanism for setting the amount of pushing movement, in which a pair of pushing movement amount detection index plate 29 and sensor 30 are added to the conventional device shown in Figure A, and these are replaced by a changeover switch. 31, and by switching the changeover switch 31, the amount of pushing movement can be set as 27, 28 for single cores or 29, 30 for multiple cores. As mentioned above, by using the improved high-frequency discharge power supply circuit and push-in movement amount setting mechanism, multi-core. Two differences among the connection conditions for single cores:
That is, the discharge current value of D-(1) and the amount of optical fiber push-in movement during discharge of D-(4) can be set by operating a changeover switch. Single-core fusion splicing can be achieved. In the present invention described above, each switching switch 15,
31 into one switch, and by operating this changeover switch, multi-core... You can obtain the connection conditions for each single fiber, and connect multiple fibers with a single touch operation.
Single-core fusion splicing can be achieved. It has been confirmed through experiments that the device of the present invention can also be used to connect four-core and two-core optical fibers, which are currently being developed. The positioning of the discharge welded portion of the optical fiber in this case is shown in FIG. 8A (for the case of 4 fibers) and FIG. 8B (for the case of 2 fibers). In either case, the push-in amount is 80 μm, but the discharge current value for 4-core wires is 19 mA, which is the same as for 5-core wires, and for 2-core wires, it is possible to connect at 16 mA. (Effect of the invention) The above-mentioned multicore of the present invention. According to the single-fiber dual-use connecting device, when connecting multi-fiber optical fibers and single-fiber optical fibers, two devices were conventionally required, but with the device of the present invention, one device can be used for both purposes, and the device The production cost will also be lower.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a single optical fiber (a) and a multi-core optical fiber (b), and FIG. 2 (a) and (b) are illustrations of the discharge electrode spacing. FIG. 3A shows a conventional circuit diagram of a high frequency discharge power supply, and FIG. 3B shows an improved circuit diagram. FIG. 4 is a flowchart showing the movement of the optical fiber during connection, FIG. FIG. 6 is an explanatory diagram of the basic configuration of the fusion splicing device. 7A is a positioning state diagram of a five-core optical fiber, FIG. 7B is a discharge state diagram, FIG. 7C is a positioning state diagram of a single-core optical fiber, and FIG. 7D is a discharge state diagram. Figure 8 A and B are 4-core optical fibers, respectively.
It is a positioning state diagram of a two-core optical fiber. DESCRIPTION OF SYMBOLS 1...Optical fiber, 3...Single-core optical fiber core wire, 4...Multi-core optical fiber core wire, 5...Discharge electrode rod, 9...Abutment plate, 11...Discharge electrode rod, 14,
14a, 14b...Variable resistor, 15...Selector switch, 25...Origin position index plate, 26...Origin detection sensor, 27, 29...Pushing movement amount detection index plate, 28, 29...Pushing movement Amount detection sensor, 31...changeover switch.

Claims (1)

[Claims] 1. A gripping part for arranging a plurality of optical fibers in parallel in a V-groove and fixing the optical fibers by aligning the axes of opposing end surfaces, a moving mechanism for moving the optical fibers in the axial direction, and the optical fibers. In an optical fiber fusion splicing device equipped with a heating power source that melts and connects the end faces of the fibers to each other by the heat of the arc discharge of the discharge electrode, the optical fiber has a V-groove for fixing the multi-core optical fiber with the largest number of gripping parts. The optical fiber moving mechanism has two driving functions: the amount of movement when connecting a single optical fiber and the amount of movement when connecting multiple optical fibers, and the current value flowing between the electrodes by the heating power source has a two-step current value setting function for single-fiber connection and multi-fiber connection, and the amount of optical fiber movement and discharge current value can be adjusted depending on whether the optical fiber to be connected is a single-core optical fiber or a multi-core optical fiber. 1. An optical fiber multi-fiber and single-fiber splicing device characterized in that the optical fiber is configured to switch between single fiber and multi-fiber fusion splicing by operating a switch.