JP2973466B2 - Optical fiber fusion splicer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an apparatus for fusion splicing an optical fiber by discharge heating in optical communication or the like.

(Conventional technology and problems to be solved) In a conventional device for fusion splicing an optical fiber having an outer diameter of 125 μm, it is possible to adjust and preset an optimum discharge current value at which connection loss is reduced by using one variable resistor. is there. But,
Optical fibers having an outer diameter of 125 μm also include single-mode optical fibers and multi-mode optical fibers due to their structures, each having a different optimum discharge current value. In recent years, a technique has been established in which a plurality of optical fiber cores are formed into a tape structure and these plural cores are collectively connected. In this case, the optimum discharge current value differs depending on the number of core wires connected collectively. In order to enable such optical fibers having different optimum discharge current values to be realized by one device, the number of VRs for current adjustment is the same as the number of applicable optical fibers.
And select the type of optical fiber to be connected,
A VR reset to match the optical fiber is automatically selected using a relay or the like.

FIG. 3 is a circuit diagram of a current selection circuit of a conventional shared type fusion splicer. In the drawing, (1 ') is a VR for selection, (2')
Is a switching relay, (4) is a CPU, (5) is an optical fiber type selection circuit, (6) is a memory, (7) is a buffer (D
−FF).

In this common-type fusion splicer, the selection of the discharge current setting VR is switched by the relay contact (2 ') as shown in the figure, so when there are two types of applicable optical fibers, two VRs are required. The relay contact configuration 2C, when there are four types of optical fibers, there are four VRs, the relay contacts 6C, and when n types of optical fibers are shared, the number of VRs is n, and the relay contact configuration 2 (n-1) C.
For this reason, when mounting these components on a control board, the mounting area becomes large and it is impossible to reduce the size of the board. In addition, there is a problem that it is difficult to make fine adjustments due to VR during the adjustment, and that the reproducibility of the set values is also poor.

(Means for Solving the Problems) The present invention provides an optical fiber fusion splicing apparatus which has solved the above-mentioned problems. Select and CP
In the case of a current switching circuit in which U has a fixed resistor and an analog switch (multiplexer) connected in series to a circuit for transmitting a signal and switching a value, and requires a discharge current value setting level of eight or more stages, a discharge current selection unit is provided. A first-stage circuit for performing a coarse selection and a second-stage circuit for performing a fine selection are provided, and the number of components of a fixed resistor and an analog switch is reduced.

(Embodiment) FIG. 1 is a circuit diagram of a specific example of a discharge current selection and control circuit in a fusion splicing apparatus according to the present invention.

In FIG. 1, a section A is a discharge current selection section, which comprises a first stage circuit for performing a coarse selection and a second stage circuit for performing a fine selection. In the drawing, (1) is a selection resistor,
A multiplexer (2) selects a selection resistor by the multiplexer (2). (4) is CPU,
(5) is an optical fiber type selection circuit, (6) is a memory,
(7) is a D-FF, which controls the multiplexer (2) by a signal from the CPU (4).

On the other hand, B is a discharge current control unit, (8) is a current control circuit, (9) is a discharge electrode, and (10) is an optical fiber to be connected. This discharge current control unit is an existing circuit, and the potential of the resistor (1) selected in the previous stage of the discharge current is fed back to the control circuit (8) through the point B, and is controlled so as to be a constant discharge current.

In the discharge current selection unit A, a CPU
(4) One multiplexer (2) is controlled by 3 bits of data, and the voltage at both ends of the resistor selected in the first stage circuit is divided into eight levels by eight series resistors (1), and the voltage is divided. Output to point B. Accordingly, eight stages are selected in the first stage circuit and eight stages are selected in the second stage circuit, so that the potential at the point B is finally switched to 64 stages.

That is, a discharge current value of 64 levels can be arbitrarily set by a 6-bit signal.

FIG. 2 is a circuit diagram showing an example of a single-stage discharge current selection unit. In this case, 16 levels of discharge current values can be set by controlling two multiplexers (2) with 4 bits of the CPU (4). For example, in a single-core optical fiber fusion splicing device, etc., the optimum discharge current value differs due to the difference in the structure of the applied optical fiber.
Although a setting is necessary, the difference between the respective current values is at most about 5 mA, so that a 16-level discharge current selection circuit as shown in FIG. 2 is sufficient.

However, in the multi-core batch fusion splicer, for example, when the minimum applicable core number is 1 core and the maximum applicable core number is 12 cores, the setting range of the optimum discharge current value is about 20 mA. In this case, the second
In the 16-level selection circuit shown in the figure, fine adjustment setting of 1 mA or less is impossible, so it is necessary to employ the 64-level selection circuit shown in FIG.

(Effect of the Invention) As described above, according to the fusion splicing device of the present invention, even if the type of optical fiber is different, it is possible to connect with one device, and the size of the device can be reduced. In particular, a fusion splicer having a multi-stage discharge current switching circuit using an analog switch (multiplexer) can set each discharge current value with the same small circuit even if the number of applied optical fibers increases, and can set the current value. The setting reproducibility is also good.

Therefore, when using a so-called shared fusion splicer for a variety of optical fibers having different structures and the number of cores,
Since the circuit is small, the size of the device can be reduced.

FIG. 4 is a diagram showing the relationship between the type of the applied optical fiber and the mounting area of the selection circuit. According to the present invention, the circuit may be constant regardless of the type of optical fiber.
In the case of 16 circuits, the circuit is configured with a mounting area of about 1/4 of the conventional mounting area.

Further, since the fine adjustment of the discharge current value is easy, the adjustment of the current value is effective when used for connection of a dispersion-shifted multi-core optical fiber, which has conventionally been severe. FIG. 5 is a diagram showing the repetition reproducibility when the desired current value is reset, and θ shown in the conventional method is reduced to about 1/3, thereby realizing high reproducibility.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of another specific example of the discharge selection unit control circuit in the fusion splicing apparatus of the present invention. FIG. 2 is a circuit diagram showing an example of a single-stage discharge current selection unit. FIG. 3 is a circuit diagram of a current selection circuit of a conventional shared type fusion splicer. FIG. 4 is a diagram showing the relationship between the type of the applied optical fiber and the mounting area of the selection circuit. FIG. 5 is a diagram showing the reproducibility of the current set value repeatedly. 1 ... selection resistor, 2 ... analog switch (multiplexer), 3 ... current blocking amplifier, 4 ... CPU, 5 ...
... Optical fiber type selection circuit, 6 ... Memory, 7 ... D-
FF (buffer), A: discharge current selection unit, B: discharge current control unit.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yoichi Okamoto 1 Taya-cho, Sakae-ku, Yokohama-shi, Kanagawa Prefecture Sumitomo Electric Industries, Ltd. Yokohama Works (56) References JP-A-2-129606 (JP, A) JP-A Sho 64-91508 (JP, A) JP-A-64-98322 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G02B 6/255

Claims (1)

(57) [Claims] 1. An optical fiber comprising means for setting the structure, type and number of cores of an optical fiber to be connected, a memory for storing a discharge current value corresponding to the type, and a CPU for system control, the optical fiber being heated by discharge. In the fusion splicing device for optical fiber to be fused and connected, when the type of the optical fiber to be connected is selected, the CPU transmits a signal and switches the discharge current value. The circuit includes a fixed resistor and an analog switch (multiplexer) connected in series to the circuit. In the case of a current switching circuit in which the set level of the discharge current value is required to be eight or more, there is no two-stage circuit configuration of a first stage circuit for coarse selection and a second stage circuit for fine selection of the discharge current selection unit. An optical fiber fusion splicing device characterized in that the number of parts of a fixed resistor and an analog switch is reduced.