JPS60207105A - Automatic aligning device for optical fiber - Google Patents

Abstract

PURPOSE:To align optical fibers speedily by using an actuator which displaces a side block finely at right angles to the optical axis of an optical fiber, and superposing a sine wave, etc., on a DC bias voltage and displacing finely the actuator. CONSTITUTION:The output of a photosensor 14a is passed through a light power meter 14b and a synchronous detector 15 to remove its DC component, and thus only the AC component is extracted and inputted to a polarity decision circuit 16 and a light power comparator 17 separately. The polarity decision circuit 16 is provided wih CO1 which compares a sine wave signal A1 with a reference voltage Vs and outputs a rectangular wave C and CO2 which inputs a signal B and outputs a rectangular wave D, and the AND output E between both signals is obtained. Outputs DX and DY of a microcomputer 18 regarding an X and a Y direction are converted by digital-analog converters 19 and 20 and inputted to one-side input terminals of adding circuits 21 and 22. Amplifiers 26 and 27 amplify those inputs and their outputs are applied to actuators 11 and 12. Thus, the DC bias voltage is superposed upon the AC voltage to drive the actuators, thereby performing speedy aligning operation.

Description

[Detailed Description of the Invention] [Technical Field] This invention relates to a self-aligning device for aligning optical axes of optical fibers when connecting them, and in particular, the invention relates to a self-aligning device for aligning optical axes of optical fibers when connecting them, and in particular, the invention relates to a self-aligning device that is equipped with an actuator that minutely displaces a guide block of an optical fiber using a voltage. This article relates to a self-aligning device for optical fibers.

[Prior art]

2. Description of the Related Art Conventionally, as a self-aligning device for connecting optical fibers, the one shown in FIG. 1 is known. In the figure, l is a base, and 2.3 is a base IK for mounting optical fibers 4 and 4 to be supported and connected facing each other so as to be able to swing in X and Y directions perpendicular to each other at their bases 2a and 8a, respectively. This is a guide block. 5 and 6 are linear motors for swinging the guide blocks 2 and 3, respectively, and 7 and 8 are coil springs interposed between the linear motors 5 and 6 and the guide blocks 2 and 3, respectively.

coil spring? , 8 reduce the movement of the linear motor 5°6 and transmit it to the guide shafts 0.7 and 2 and 3.

The conventional self-aligning device configured as described above feeds optical power passing through the connecting end faces 4a, 4a of the optical fibers 4, 4 to the linear motors 5, 6.
', the guide tabs 0.7 and 2 are slightly displaced via the coil springs 7 and 8, and the optical fibers 4 and 4 are
The optical axes of the two are automatically aligned.

With such a conventional self-aligning device, the beam near motor l'5
．． Since the movement of the kite block 2.3 is transmitted through the coil spring 7.8' (i=) to the kite block 2.3, the responsiveness of the kite block 2.3 to the movement of the linear motors 5, 6 is poor, and therefore the optical fiber There was a drawback that alignment of 4 and 4 required a great deal of time.

[Purpose of the invention]

This invention was made in view of the above-mentioned drawbacks, and is an actuator that slightly displaces a guide lock perpendicular to the optical axis of an optical fiber, and moreover, in directions perpendicular to each other.
Using a voltage displacement driving element such as a piezoelectric element or an electromagnet, this actuator directly drives the guide block, and the actuator is operated by fully superimposing an AC voltage such as a sine wave or triangular wave on a DC bias voltage. The object of the present invention is to obtain an optical fiber centering device that has good responsiveness and can be quickly aligned.

〔Example〕

Hereinafter, an embodiment of the present invention will be described based on FIG.

In FIG. 2, 9. lO is the end face 4a of the optical fibers 4, 4 to be connected, and the movable part 9 has a V-shaped groove 9m and lOm carved on the top surface so that the optical axes of the optical fibers 4a face each other with their optical axes substantially aligned, and lOk is the base 9a.

In 10a, guide blocks 011.12 are supported by the base lTL so as to be swingable in the X direction and the Y direction, respectively. This is an actuator such as a piezoelectric element that vibrates lO' in the X and Y directions that are perpendicular to each other. Here, the actuator 11 is clamped between a movable part 91 (and a fixed part 9e) as shown in FIG. 3, and its length changes in proportion to the applied voltage as shown in the pressure characteristics shown in FIG. The actuator 12 is clamped between the movable part ink and the fixed part 10e at 5 as shown in FIG. This is to swing the movable part 101 of the kite block 10 in the Y direction (vertical direction in the figure).

In FIG. 2, 13 is a reference source generator connected to the outer end surface of one optical fiber 4, and 14 is an optical sensor 14a and an optical power meter 14k connected to the outer end surface of the other optical fiber 4 (FIG. 6). This is an optical power instruction device with a built-in.

Next, the control circuit of the alignment device will be explained with reference to a complete block circuit diagram of FIG.

In the figure, the output of the optical converter 14a is amplified by an optical power meter 14b and input to a synchronous detector 15.The synchronous detector 15 filters the DC component and extracts only the AC component. is divided and input to the optical power comparator 1'7!Here, the polarity judgment circuit 16
is, for example, a circuit as shown in FIG. 7, which includes a comparator CO1 which compares the sine wave signal A with the reference voltage Vs and outputs a rectangular wave pulse C4-, and a rectangular wave pulse by inputting another sine wave signal 13. Conoparator CO2 that outputs D
The respective output rectangular wave pulses C, Df of the comparators C(J, , C(J2) are input to the AND gate A N D, and the AND output E is (U).

In this circuit, the sine wave signals A and 13 are in phase 0)
Tokiha, Figure 8, (1), (IJ), (III
), (IV), (V) VCAs shown, in (1), only the part to the sine wave signal larger than the reference voltage Vs (
11) A rectangular wave output C is output (Il
The sine wave signal 13 shown in ) becomes the rectangular wave signal output shown in (IV). In this case, since the reference voltage is zero, the entire half wave of the sine wave signal B becomes a rectangular wave, and
In the ND, the AND output E, which is the same as the output C, is at a high level j
It can be obtained as -1. When the phase shift of the sine wave signal B to the sine wave signal is 180°, that is, when the phase is reversed, the sine wave signal A indicated by +INK becomes (l) as shown in Fig. 9.
For the output CVc as shown in [), the output of the comparator CO7 for the opposite phase sinusoidal wave 13K is obtained as a rectangular wave No. 1 whose phase is shifted by 180° from the output C as shown in (lv). A, N I) becomes zero as shown in (V), and the low level L becomes loud. Therefore, if 11 of the output E of the AND gate ANIJ is L, it can be determined whether the sine wave signals A and 13 are in phase or out of phase.

The optical power comparator 17 is a circuit as shown in FIG.
A sine wave signal A is input through a diode 1 to the input side of an integrating circuit 1 consisting of be.

FIG. 1 shows the output waveforms of each part of the optical power comparator 17. (1) is the input sine waveform, (formerly diode 1) 1
The waveform of the output F is a half-wave sine wave. (1■)
(IV) is the output G of the operational amplifier OPl, and (IV) is the output of the converter CO3.

The waveform obtained by accumulating the amplitude of the sine wave signal for half waves is the reference voltage ■S, J:! If ll is also large, a rectangular wave is output for the large portion as shown in (IV).

However, Fig. 12 (1), (1), (11),
As shown in (IV), if the waveform integrated over all half-wave amplitudes of the sine wave signal is smaller than the reference voltage Vs, then (IV
) is not output.

Therefore, it is possible to determine whether the power of the input sine wave signal is above or below a certain level.

Returning to FIG. 6, the outputs of the polarity determining circuit 16 and the optical power comparator 17 are each input to the microcomputer 18 as data.

The two types of digital outputs of the microcomputer 18, namely the digital output Dx regarding the vibration in the X direction and the output Dy regarding the vibration in the Y direction, are converted into analogs via digital-to-analog converters 19.20, respectively, and then sent to the adder circuit 21.20.
It is input to one input end of 22.

Here, the adder circuits 21 and 22 include, for example, an operational amplifier (JP2 and resistors H, 2, l (, 3, l) as shown in FIG. 13).

This is a circuit configuration in which voltages eg ``+'' and ``z'' input via resistors ``z'', ``H'', and ``3'', respectively, are obtained.

An alternating current waveform signal (sine wave, triangular wave, rectangular wave, etc.) output from the oscillator 25 is gated and applied to the other input side of each of the adder circuits 21 and 22 via semiconductor switches 28 and 24i according to instructions from the microcomputer 8. It looks like this.

As shown in FIG. 14, the semiconductor switches 28 and 24 are capable of interrupting conduction between the source S and the drain DeO by applying a voltage to the gate q of the field effect transistor '12'L'.

Amplifiers 26 and 27 are connected to amplify the inputs of adder circuits 21 and 22, respectively, and apply the amplified signals to actuators 11 and 12, respectively. The amplifiers 26 and 27 have linear characteristics.

Next, the functions of the microcomputer 80 will be explained with reference to the 70-chart FIG. Note that P1 to P2G in the figure indicate each step of the flowchart.

Start the device with P, and with the initial set of P2
Axis actuator 11 and Y-axis actuator 1
2, a predetermined DC bias voltage VB (see Figure 16 +1)) is added to the bias voltage VB, and then an AC voltage Vc f is added to the bias voltage VB.
The X-axis vibration of the actuator 11 is started at P3, and the guide block 9' is vibrated in the X-axis direction.

Due to this vibration, the indicated value of the optical power meter 14b fluctuates (see FIG. 17), and at P, the optical power comparator 17 detects the fluctuation ΔQ l of the value of the optical power meter 14.
Look at +ΔQ2...

To explain this with reference to FIG. 17, the vertical axis shows the indicated value Q of the optical power meter, and the horizontal axis shows the adjustment position X in the X direction.

In the figure, even if the vibration x, and the vibration x2 have the same amplitude, the vibration x2 is closer to the thickest value of the optical power curve.
The fluctuation ΔQ2 is the fluctuation ΔQ+ for vibration X.
-J Niji is also small.

What we should aim for here is the value of can be considered to be close enough to the top.

Next, at P6, the polarity determination circuit 16 determines whether the vibration of the optical power (J) is in the same phase as the vibration of the actuator 11. Here, the in-phase is something like the vibration x1 in FIG.
If the adjustment position x increases, the optical power (9) also increases. At this time, in order to advance the kite block 9 in the direction in which the adjustment position is increased by △■ (this value is predetermined). However, at the position x3, as the adjustment position X increases, the optical power Q decreases. At this time, the vibration of the optical power Q and the vibration of the actuator 11 are in opposite phase, and in order to move the guide block 9 to the position where the optical power Q becomes extremely thick, the bias voltage Vn is adjusted by decreasing it by Δ■. Move in the direction where position X decreases.

When such a judgment operation is completed, the same operation as above is repeated several times with a wait time of ΔIII, and finally the optical power amplitude Q<Q. I'll do it until I get angry.

This operation is P[1+P7+P8+”Or
This is done at each step of Plo. When the judgment is completed, PII stops superimposing the AC voltage VB0) on the actuator 11 in the X direction to stop the vibration in the X direction, and then similarly applies P12 to the actuator 12 in the Y direction.
~P+o VCJ: ') Do the same as in the case of the X direction above, and when alignment is completed, move the guide block 9. with P2O.
10 is stopped at that position.

Note that as an actuator for vibrating the guide block 9, an actuator based on the attractive force of an electromagnetic coil M as shown in FIG. 18 may be used. The same applies to the guide block IOK.

〔Effect of the invention〕

Since the present invention is configured so that the actuator directly swings the guide block, the response is quick and quick alignment operation is possible, and the structure is small and simple, resulting in low cost.

Furthermore, since the actuator is driven by alternating current, it is easy to amplify the signal, simplifying the circuit configuration, and other advantages.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view showing the main parts of a conventional optical fiber automatic alignment device, and FIGS. 2 to 18 are all related to this invention, and FIG. 2 is a self-aligning 3 and 4 are side views of a kite block that can swing in the X and Y directions, respectively. FIG. 5 is a characteristic diagram of the piezoelectric element, and FIG. is an overall block circuit diagram, FIG. 7 is an electrical circuit diagram showing an example of a synchronous detection circuit, and FIG. 8 is a voltage waveform diagram of the main parts when the sine wave signal type collar A and 15 in FIG. 7 are in phase. Figure 9 is a voltage waveform diagram of the main parts in the case of opposite phase, Figure 10 is a circuit diagram showing an embodiment of the optical power comparator shown in Figure 6, Figures 1 and 12 are Figure 11 shows the voltage waveform of the main part in Figure 10.
The figures are waveform diagrams showing cases where the voltage is constant and below the bell. Fig. 13 is a circuit diagram showing an example of an adder circuit, Fig. 14 is a circuit diagram showing an example of a semiconductor switch, Fig. 15 is a flowchart showing the overall operation process, and Fig. 16 (1) shows the voltage applied to the actuator. Waveform (formerly a diagram showing the waveform of optical power; Figure 17 is a graph showing the relationship between the output voltage of the optical power meter and the adjustment position of the guide book; Figure 18 shows another example of the actuator. It is a side view. 4.4... Optical fiber 9, ■0... Guide block 31.12... Actuator 14a... Optical sensor 141)... Optical power meter 14 - Optical power measuring device 16... Polarity determination circuit] ? ... Optical power comparator 18 ... Microcomputer 21.22 ... Addition circuit 23.24 ... Semiconductor switch 25 ... Oscillator Name of applicant Tokyo Heavy Equipment Industry Co., Ltd. Figure 1 Figure 2

Claims (1)

[Claims] A pair of kite blocks for mounting optical fibers to be connected are swingably supported on a base, a voltage-driven actuator is directly connected to each of these guide blocks, and the actuator is connected to a DC bias voltage and an AC voltage. means for driving in a superimposed manner; means for measuring optical power passing through opposing end surfaces of the plate-connected optical fiber; means for comparing the phase of the vibration of this optical power with the vibration of the 011 actuator; and a comparison of the phases. 1. A self-aligning device for an optical fiber, comprising means for moving an actuator in the forward or reverse direction, and means for stopping the guide block at that position when the amplitude of vibration of the optical power becomes less than a certain value.