JP3045872B2 - Method for aligning optical axis of optical waveguide and optical switch used in this method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of aligning an optical waveguide such that an optical fiber such as an optical fiber and a planar waveguide are displaced relative to each other so that their optical axes coincide with each other. It is about switches.

[0002]

2. Description of the Related Art In such a conventional optical switch,
The following method is known as an optical axis alignment method for optically coupling opposing optical fibers.

[0003] When a movable fiber fixed to a moving stage or the like is optically coupled to a fixed fiber, reference light enters from one end of the fixed fiber or the movable fiber, and the light of the reference light enters the other end. The power is monitored, and while monitoring the strength of the optical power, the movable fiber is finely moved by the moving stage.

More specifically, a computer inputs and instructs approximate coupling position data in the x, y, and z directions, and drives a moving stage via a positioning controller. At this time, if the optical power is small, it can be confirmed that the coupling state is bad, and further, the computer instructs movement in the x-axis, y-axis directions and the like. This operation is repeatedly adjusted until the optical power reaches the maximum value.

[0005]

As described above, in the conventional centering work, it is necessary to input a designated value (input data) to the computer many times stepwise until the optical power reaches the maximum value. In this case, simply from the detection result of the optical power, it is not possible to recognize in which direction the optical axis of the optical fiber to be positioned is deviated, and it is possible to accurately specify the direction to be finely moved. Did not. For this reason, it took an enormous amount of time to perform positioning for all the optical connectors.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to provide an optical waveguide such as an optical fiber in which the optical axes of the optical waveguides coincide with each other. It is an object of the present invention to provide a method of aligning the optical axis of an optical waveguide and a switch used in the method.

[0007]

SUMMARY OF THE INVENTION A method of aligning an optical axis of an optical waveguide according to the present invention has been made in view of the above-mentioned object, and a second optical waveguide to be positioned with respect to a first optical waveguide is provided. An optical axis alignment method for optical waveguides that relatively displaces each other so that optical axes thereof coincide with each other, and irradiates a coupling end face of a first optical waveguide with reference light via a second optical waveguide, A first step of vibrating the second optical waveguide at mutually different frequencies in x and y directions orthogonal to each other in a plane perpendicular to the optical axis of the first optical waveguide, and reflected light at the coupling end face Through the second optical waveguide,
A second step of measuring the variation of the received light level; and a third step of identifying two waveform components that match the frequencies of the respective vibrations of the second optical waveguide in the x and y directions from the measured variation of the received light level. The process and the phase of each of the identified waveform components in the x and y directions and the phase of each of the vibrations in the x and y directions of the second optical waveguide are individually compared in each direction, so that the second position to be positioned is determined. A fourth step of detecting the deflection direction of the optical waveguide, and a fifth step of moving the second optical waveguide based on the detection result, and by repeating the first to fifth steps in order. , The optical axes of which are matched with each other.

The optical axis alignment method of the other optical waveguide is as follows.
An optical axis alignment method for an optical waveguide in which a second optical waveguide to be positioned is relatively moved with respect to a first optical waveguide so that their optical axes coincide with each other, wherein the optical axis of the first optical waveguide is adjusted. In the x, y directions orthogonal to each other in a plane perpendicular to
A first step of oscillating the second optical waveguide at different frequencies and irradiating the coupling end face of the second optical waveguide with reference light via the first optical waveguide;
A second step of receiving the reference light incident on the optical waveguide and measuring the change in the received light level, and calculating the frequency of each vibration in the x and y directions of the second optical waveguide from the measured change in the received light level. The third to identify two waveform components that match
And the phase of each of the identified waveform components in the x and y directions and the phase of each of the vibrations in the x and y directions of the second optical waveguide are individually compared in each direction to determine the position to be positioned. A fourth step of detecting the deflection direction of the second optical waveguide, and a fifth step of moving the second optical waveguide based on the detection result, and the first to fifth steps are sequentially repeated. In this way, the optical axes are matched with each other.

Further, the optical switch according to the present invention comprises:
An optical switch for displacing a second optical waveguide to be positioned relative to the optical waveguide and aligning the optical axes thereof, wherein the second optical waveguide is disposed relative to the first optical waveguide. And holding means for movably holding the second optical waveguide in a plane perpendicular to the optical axis of the first optical waveguide, and different in x and y directions orthogonal to each other in the plane. An x-direction vibrating means and a y-direction vibrating means for vibrating the holding means at a frequency, a light source for irradiating the coupling end face of the first optical waveguide with reference light via the second optical waveguide, Detecting means for receiving the reflected light through the second optical waveguide and outputting a signal corresponding to the intensity of the received reflected light; measuring a signal waveform output from the detecting means; 2 that matches the frequency of each vibration in the y direction
Waveform identification means for identifying two waveform components, the phase of each waveform component in the x and y directions identified by the waveform identification means,
phase control means for individually comparing the phases of the respective vibrations of the x-direction vibration means and the y-direction vibration means in each direction, and drive control for finely moving the holding means in a plane based on the comparison result of the phase comparison means Means.

[0010] The other optical switch is an optical switch for displacing the second optical waveguide to be positioned relative to the first optical waveguide so that their optical axes coincide with each other,
Holding means for arranging the second optical waveguide relative to the first optical waveguide and movably holding the second optical waveguide in a plane perpendicular to the optical axis of the first optical waveguide; When,
In a plane, an x-direction vibrating unit and a y-direction vibrating unit for vibrating the holding unit at different frequencies in x and y directions orthogonal to each other, and a coupling end face of the second optical waveguide,
A light source for irradiating the reference light via the first optical waveguide, and a detecting means for receiving the reference light transmitted through the coupling end face and incident on the second optical waveguide, and outputting a signal corresponding to the intensity of the received transmitted light And the signal waveform output from the detecting means is measured, and the frequency of each vibration in the x and y directions of each vibrating means is matched.
Waveform identification means for identifying two waveform components, the phase of each waveform component in the x and y directions identified by the waveform identification means,
phase control means for individually comparing the phases of the respective vibrations of the x-direction vibration means and the y-direction vibration means in each direction, and drive control for finely moving the holding means in a plane based on the comparison result of the phase comparison means Means.

[0011] The optical waveguide includes an optical fiber and a planar waveguide.

[0012]

According to the optical axis alignment method of one optical waveguide, the second optical waveguide is vibrated while irradiating the reference light from the second optical waveguide. Therefore, when the second optical waveguide moves in a direction coincident with the optical axis of the first optical waveguide with the center axis of the vibration as a boundary, the light transmitted to the first optical waveguide gradually increases, so that the coupling end face has Reflected light decreases, and conversely, as the optical axes move in the direction away from each other, the reflected light at the coupling end face gradually increases. Therefore, by comparing the phase of this oscillation with the phase of the waveform component of the light receiving level, that is, if it is detected whether the phase is the same or the opposite, the second optical waveguide is deviated in either direction of the oscillation direction. Can be recognized.

The method of aligning the optical axis of the other optical waveguide is as follows.
The second optical waveguide is vibrated while irradiating the reference light from the first optical waveguide. Therefore, when the second optical waveguide moves in a direction coincident with the optical axis of the first optical waveguide with respect to the center axis of the vibration, the light transmitted through the second optical waveguide gradually increases, and conversely, As the axes move away from each other, this transmitted light decreases. Therefore, if it is detected whether the phase of the vibration in each direction and the phase of each waveform component of the light receiving level are the same phase or the opposite phase, it is determined in which direction of the vibration direction the second optical waveguide is displaced. Can be recognized.

[0014] In one optical switch, when the second optical waveguide moves in a direction coincident with the optical axis of the first optical waveguide with respect to the center axis of the vibration, the light transmitted to the first optical waveguide is changed. Gradually increases, the reflected light at the coupling end face decreases, and conversely, when the optical axis moves in a direction away from each other, the reflected light at the coupling end face gradually increases. The light receiving level received by the detecting means includes two waveform components due to the vibration in two directions, and each waveform component fluctuates at the same frequency as the vibration frequency in each direction. The oscillating waveform is identified by the waveform identifying means. If the phase of each identified waveform component and the phase of each vibration are compared for each direction, and whether the phases are the same or opposite by phase comparison means, the second optical waveguide can be compared with each vibration direction. It can be recognized in which direction the deflection is.

Further, when the second optical waveguide moves in a direction coincident with the optical axis of the first optical waveguide with respect to the center axis of the vibration, the other optical switch transmits light transmitted to the second optical waveguide. Gradually increases, and conversely, when the optical axes move in the directions away from each other, the transmitted light gradually decreases. Therefore, since each waveform component detected by the detecting means fluctuates at the same frequency as the vibration frequency in each direction, the waveform oscillating at each frequency is identified by the waveform identifying means. If the phase of each of the identified waveform components and the phase of each vibration are compared with each other by the phase comparing means for each direction, the phase of the second optical waveguide is determined with respect to the direction of the vibration. It can be recognized whether it is deviated in the direction of.

[0016]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1A is an explanatory view for explaining an optical axis aligning method according to the present invention. The upper part shows an optical fiber 1 fixed, and the lower part shows light that moves slightly to align the optical axis. 2 shows a fiber 2;

In FIG. 1 (a), in order to make the optical axis of the optical fiber 2 coincide with the optical axis of the optical fiber 1, first, the optical fiber 2 is positioned through the optical fiber 2 toward the coupling end face 1c. Is irradiated with reference light. At the same time, the optical fiber 2 is vibrated about its central axis 2D in the x and y directions orthogonal to each other in a plane perpendicular to the optical axis of the optical fiber 1. The amplitude of this vibration is about 5 to 10% of the core diameter of the optical fiber to be centered. Therefore, if the core diameter is 10 μm, the amplitude is about 0.5 to 1 μm. FIG. 1 shows only a state of vibrating in the x direction for convenience of description, and the y direction is a direction perpendicular to the paper surface.

Here, the operation of vibrating the optical fiber 2 will be described. When the optical fiber 2 relatively moves in the direction of arrow A, the reference light emitted from the core 2a of the optical fiber 2 is reflected by the clad 1b of the optical fiber 1 facing the optical fiber 2, and propagates through the core 2a. The amount of reflected light increases. On the other hand, when the optical fiber 2 relatively moves in the direction of the arrow B, the amount of the reference light emitted from the core 2a of the optical fiber 2 that passes through the core 1a of the optical fiber 1 increases, so that the reflected light The amount of light decreases. As shown in FIG. 1B, if the direction of arrow A is the positive direction of the x-axis, the phase of the vibration of the optical fiber 2 and the phase of the waveform of the light receiving level of the reflected light are the same. .

When the optical fibers 1 and 2 are in the positional relationship shown in FIG. 2A, when the optical fiber 2 relatively moves in the direction of arrow A, light is emitted from the core 2a of the optical fiber 2. Of the reference light, the amount of reflected light decreases because the amount of light passing through the core 1a of the opposing optical fiber 1 increases. On the other hand, when the optical fiber 2 relatively moves in the direction of the arrow B, the amount of reflected light reflected by the clad 1b of the optical fiber 1 out of the reference light emitted from the core 2a of the optical fiber 2 increases. . As shown in FIG. 2B, if the direction of arrow A is the positive direction of the x-axis, the phase of the vibration of the optical fiber 2 is opposite to the phase of the waveform of the light receiving level of the reflected light.

As described above, by comparing the phase of the vibration of the optical fiber 2 with the phase of the waveform of the received light level of the reflected light, and detecting whether the phase is the same phase or the opposite phase, the optical fiber 2 becomes
It is possible to recognize on which side of the vibration direction the deflection is.

The optical fiber 2 is moved based on the result. Thereafter, while the above steps are repeatedly performed, FIG.
As shown in (1), the state where the fluctuation of the light receiving level is reduced and the frequency component of the vibration of the optical fiber 2 does not appear in the fluctuation of the light receiving level is a state where the optical axes coincide with each other. Thus, the optical axes of the optical fibers 1 and 2 can be matched.

Although only the x direction has been described, it is possible to detect the y direction in the same manner. In this case, it is of course possible to individually detect the x direction and the y direction, but it is also possible to detect them simultaneously. For this purpose, the vibration frequency in the x direction and the vibration frequency in the y direction may be set to different frequencies. As a result, the fluctuation of the measured light reception level includes two waveform components that match each frequency. Therefore, if each waveform component is identified based on each frequency, the light reception levels in the x and y directions can be measured simultaneously. It is also possible.

In the above embodiment, the reference light is emitted through the optical fiber 2, but the reference light can be emitted through the optical fiber 1. The operation when the optical fiber 2 is slightly moved in this state will be described with reference to FIGS.

In the positional relationship shown in FIG. 3A, when the optical fiber 2 relatively moves in the direction of arrow A, the core 1 of the optical fiber 1 moves toward the coupling end face 2c of the optical fiber 2.
a, the amount of light reflected by the cladding 2b of the optical fiber 2 increases, and the amount of light transmitted through the core 2a of the optical fiber 2 decreases. When the optical fiber 2 moves relatively in the direction of arrow B, the amount of reference light emitted from the core 1a of the optical fiber 1 that passes through the core 2a increases. As shown in FIG. 3B, if the direction of arrow A is the positive direction of the x-axis, the phase of the vibration of the optical fiber 2 and the phase of the waveform of the received light level of the reflected light are opposite. .

When the optical fibers 1 and 2 are in the positional relationship shown in FIG. 4A, when the optical fiber 2 relatively moves in the direction of arrow A, the reference light emitted from the core 1a is emitted. Of these, the amount of light that passes through the core 2a of the optical fiber 2 that opposes increases. On the other hand, the optical fiber 2 is relatively
In the direction, the amount of reflected light reflected by the cladding 2b of the opposing optical fiber 2 of the reference light emitted from the core 1a increases, and the amount of light transmitted through the core 2a decreases. FIG. 4B shows this relationship.
If the axis is in the positive direction, the phase of the vibration of the optical fiber 2 and the phase of the waveform of the received light level of the reflected light are the same.

Next, FIG. 5 shows the configuration of an optical switch used in the method described above.

The optical switch is a device for finely moving the optical fiber 2 with respect to the fixed optical fiber 1 to perform alignment and optically couple with each other. The optical fiber 2 forms one end of an optical line 3. , And is fixed to a moving stage 4 that moves in three axial directions. The moving stage 4 includes an x-direction vibrator 5 and a y-direction vibrator for slightly vibrating the optical fiber 2 in x and y directions orthogonal to each other in a plane perpendicular to the optical axis of the optical fiber 1. 6 and each of the vibrators 5, 6
Vibrate at different frequencies due to voltage signals of different frequencies applied from the oscillators 7 and 8, respectively. It is preferable that each of the vibrators 5 and 6 is formed of an electrostrictive element or the like that is distorted in a certain direction according to an applied voltage.

The light source 11 comprises an optical fiber 1 and an optical fiber 2
A detector 12 is a light source for irradiating a reference light for positioning to a coupling end face of the optical fiber 2, and a detector 12 receives reflected light of the reference light which propagates through the optical fiber 2 and returns. And is connected to the optical line 3 via.

The detector 12 outputs an electric signal corresponding to the received light level (received light intensity) of the received reflected light. The output signal waveform includes the vibration of each of the vibrators 5 and 6 in each direction. Two waveform components matching the frequency are included, and the two waveform components oscillating at each frequency are identified by the waveform identifier 13.

The identified waveform component in each direction is input to phase comparators 14 and 15 for each direction, and the phase of this waveform component and the waveform of the voltage signal output from oscillators 7 and 8 in each direction are determined. The phase is compared for each direction, and it is detected whether the phase is the same or opposite.

As described above, it is possible to recognize in which direction the optical fiber 2 is deviated with respect to the optical axis of the optical fiber 1 based on the detection result. 16 drives the moving stage 4 in a direction to correct the deviation.

After the movement, the optical fibers 2 are slightly moved in a direction to correct the deviation direction by comparing the respective phases again. By repeatedly performing this operation, as shown in FIG.
When the component of the vibration frequency in each direction of No. 6 does not appear in the fluctuation of the light receiving level, the optical axes are aligned with each other. In this way, the optical axes can be matched with each other.

Although the light source 11 is connected to the optical fiber 2 in the example shown in FIG. 5, the light source 11 may be connected to the opposing optical fiber 1.

In each of the embodiments described above, an optical fiber is exemplified as the optical waveguide, but a planar waveguide may be used.

[0036]

As described above, according to the method of aligning the optical axis of one optical waveguide according to the present invention, the reference light is applied to the coupling end face of the first optical waveguide via the second optical waveguide. And
Since the second optical waveguide is vibrated in the x and y directions in a plane perpendicular to the optical axis, the phase of the vibration waveform of the light receiving level of the reflected light at the coupling end face and the phase of the vibration of the second optical waveguide Is compared in each direction, it is possible to detect in which direction the second optical waveguide to be positioned is deviated with respect to each vibration direction.

In the optical axis alignment method for the other optical waveguide, the coupling end face of the second optical waveguide is irradiated with reference light via the first optical waveguide, and the second optical waveguide is moved with respect to the optical axis. Vibrates in the x and y directions in a vertical plane, and the vibration waveform of the light receiving level of the transmitted light transmitted from the coupling end face;
By comparing the phase with the vibration of the second optical waveguide in each direction, it is possible to detect in which direction the second optical waveguide to be positioned is deviated with respect to each vibration direction. is there.

Further, in one optical switch according to the present invention, the second optical waveguide is vibrated in the x and y directions by the x-direction vibrating means and the y-direction vibrating means, and is coupled via the second optical waveguide. The reflected light from the end face is received by the detecting means, and a waveform component oscillating in each direction is identified by the waveform identifying means from the signal waveform of the detecting means. Furthermore, since the phase of each vibration and the phase of the waveform component are individually compared for each direction by the phase comparing means, if this comparison detects whether the phase is the same or opposite, the second optical waveguide becomes It is possible to detect in which direction the vibration is deviated.

Further, the other optical switch vibrates the second optical waveguide in the x and y directions by the x-direction vibrating means and the y-direction vibrating means, and transmits the reference light emitted from the first optical waveguide. Light is received by the detecting means, and a waveform component oscillating in each direction is identified by the waveform identifying means from the signal waveform of the detecting means. Furthermore, since the phase of each vibration and the phase of the waveform component are individually compared for each direction by the phase comparing means, if this comparison detects whether the phase is the same or opposite, the second optical waveguide becomes It is possible to detect in which direction the vibration is deviated.

[Brief description of the drawings]

FIG. 1A is a partial cross-sectional view showing an enlarged cross section of an opposing optical fiber, and FIG. 1B is a graph showing the relationship between the phase of a vibrating optical fiber and the phase of a vibrating light receiving level. It is.

FIG. 2 (a) is a partial cross-sectional view showing an enlarged cross section of an opposing optical fiber, and FIG. 2 (b) is a graph showing the relationship between the phase of a vibrating optical fiber and the phase of a vibrating light receiving level. It is.

FIG. 3A is a partial cross-sectional view showing an enlarged cross section of an opposing optical fiber, and FIG. 3B is a graph showing the relationship between the phase of a vibrating optical fiber and the phase of a vibrating light receiving level. It is.

FIG. 4A is a partial cross-sectional view showing an enlarged cross section of an optical fiber opposed thereto, and FIG. 4B is a graph showing a relationship between a phase of a vibrating optical fiber and a phase of a vibrating light receiving level; It is.

FIG. 5 is a schematic explanatory view showing a configuration of an optical switch according to the present invention.

FIG. 6A is a partial cross-sectional view showing an enlarged cross section of an optical fiber opposed thereto, and FIG. 6B is a graph showing the relationship between the phase of a vibrating optical fiber and the phase of a vibrating light receiving level. It is.

[Explanation of symbols]

1, 2 ... optical fiber (optical waveguide), 4 ... moving stage (holding means), 5 ... x-direction vibrator, 6 ... y-direction vibrator,
11 light source, 12 detector, 13 waveform discriminator, 14,
15: phase comparator, 16: stage controller (drive control means).

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazuto Saito 1st Tanicho, Sakae-ku, Yokohama-shi, Kanagawa Prefecture Sumitomo Electric Industries, Ltd. Yokohama Works (72) Inventor Tsutomu Watanabe 1st Tayacho, Sakae-ku, Yokohama-shi, Kanagawa Sumitomo Electric (72) Inventor Yasuji Hattori 1st Tayacho, Sakae-ku, Yokohama-shi, Kanagawa Prefecture Sumitomo Electric Industries, Ltd. Yokohama Works (72) Inventor Izumi Mikawa 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Japan (56) References JP-A-1-134404 (JP, A) JP-A-59-26711 (JP, A) JP-A-63-110404 (JP, A) (58) Fields investigated Int.Cl. ⁷ , DB name) G02B 26/00 G01B 11/27 G02B 6/38 G02B 7/00

Claims (4)

(57) [Claims] 1. An optical axis alignment method for an optical waveguide in which a second optical waveguide to be positioned is relatively displaced with respect to a first optical waveguide so that optical axes of the second optical waveguide are aligned with each other. The coupling end face of the optical waveguide is irradiated with the reference light via the second optical waveguide, and the second end in the x and y directions orthogonal to each other in a plane perpendicular to the optical axis of the first optical waveguide. A first step of vibrating the optical waveguides at different frequencies from each other; a second step of receiving reflected light at the coupling end face via a second optical waveguide and measuring a change in the light receiving level; A third step of identifying two waveform components corresponding to the frequencies of the respective vibrations of the second optical waveguide in the x and y directions from the measured fluctuation of the received light level; and the respective waveforms in the identified x and y directions. The phase of the component and the second
A fourth step of detecting the deflection direction of the second optical waveguide to be positioned by individually comparing the phases of the respective vibrations of the optical waveguide in the x and y directions in each direction; Moving the second optical waveguide on the basis of
And an optical axis alignment method for an optical waveguide, wherein the optical axes are aligned with each other by sequentially repeating the first to fifth steps. 2. An optical axis alignment method for an optical waveguide in which a second optical waveguide to be positioned is relatively moved with respect to a first optical waveguide so that optical axes of the second optical waveguide and the first optical waveguide coincide with each other. In a plane perpendicular to the optical axis of the optical waveguide,
A first step of oscillating the second optical waveguide at mutually different frequencies in x and y directions orthogonal to each other and irradiating the coupling end face of the second optical waveguide with reference light via the first optical waveguide; A second step of receiving the reference light incident on the second optical waveguide from the coupling end face, and measuring a change in the received light level; a second optical waveguide based on the measured change in the received light level A third step of identifying two waveform components that match the frequency of each vibration in the x and y directions, a phase of each identified x and y direction waveform component,
A fourth step of detecting the deflection direction of the second optical waveguide to be positioned by individually comparing the phases of the respective vibrations of the optical waveguide in the x and y directions in each direction; Moving the second optical waveguide on the basis of
And an optical axis alignment method for an optical waveguide, wherein the optical axes are aligned with each other by sequentially repeating the first to fifth steps. 3. An optical switch for relatively displacing a second optical waveguide to be positioned with respect to a first optical waveguide so that optical axes of the second optical waveguide and the first optical waveguide coincide with each other. Holding means for arranging the second optical waveguide and movably holding the second optical waveguide in a plane perpendicular to the optical axis of the first optical waveguide; and orthogonal to each other in the plane An x-direction vibrating means and a y-direction vibrating means for vibrating the holding means at different frequencies in the x and y directions, respectively; and a reference light is coupled to the coupling end face of the first optical waveguide via the second optical waveguide. A light source to irradiate, a detecting means for receiving the reflected light from the coupling end face via a second optical waveguide, and outputting a signal corresponding to the intensity of the received reflected light; a signal waveform outputted from the detecting means Are measured, and each of the vibrating means in the x and y directions is measured. 2 to match the frequency of the dynamic
Waveform identification means for identifying two waveform components, the phase of each waveform component in the x and y directions identified by the waveform identification means, and the phase of each vibration of the x direction excitation means and y direction excitation means, An optical switch comprising: phase comparison means for individually comparing in each direction; and drive control means for finely moving the holding means in the plane based on a comparison result of the phase comparison means. 4. An optical switch for relatively displacing a second optical waveguide to be positioned with respect to a first optical waveguide so that optical axes thereof coincide with each other, wherein the optical switch is opposed to the first optical waveguide. Holding means for arranging the second optical waveguide and movably holding the second optical waveguide in a plane perpendicular to the optical axis of the first optical waveguide; and orthogonal to each other in the plane An x-direction vibrating unit and a y-direction vibrating unit for vibrating the holding unit at different frequencies in the x- and y-directions, respectively. A light source for irradiating; a detecting unit for receiving the reference light transmitted through the coupling end face and entering the second optical waveguide; and outputting a signal corresponding to an intensity of the received transmitted light; and an output from the detecting unit. The signal waveform was measured, and x and 2 coincides with the direction of the frequency of the vibration
Waveform identification means for identifying two waveform components, the phase of each waveform component in the x and y directions identified by the waveform identification means, and the phase of each vibration of the x direction excitation means and y direction excitation means, An optical switch comprising: phase comparison means for individually comparing in each direction; and drive control means for finely moving the holding means in the plane based on a comparison result of the phase comparison means.