JP2000162567A - Optical switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize the switching having a uniform wavelength characteristic. SOLUTION: This optical switch is provided with an acoustooptical element 24 by which light beams 11 introduced by a light introduction member 6 are entered from a first surface and an ultrasonic wave 12 is applied from the outside, then the entered light beams are diffracted and emitted from a second surface as first diffracted light beams and the first diffracted light beams entered from the second surface are diffracted so that a wavelength dispersion direction becomes an opposite direction and emitted from the first surface as second diffracted light beams, spectrooptical members 25, 26 by which the emitted first diffracted light beams are divided so that the wavelength dispersion direction becomes the opposite direction, returned by a mirror, divided again and entered again to the acoustooptical element 24, and a light outgoing member 7 by which the second diffracted light beams emitted from the first surface of the acoustooptical element 24 are fetched and outgone to the outside. By turning on/off the ultrasonic wave applied to the acoustooptical element, the light beams passing toward the light outgoing member 7 from the light introduction member 6 is turned on/off.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an optical switch for turning on / off light using an acousto-optic device.

[0002]

2. Description of the Related Art When light flowing through an optical communication circuit is mechanically turned on / off by using a shielding plate or the like, there is a certain limit in the on / off speed. Therefore, as an optical switch for turning on / off light at a high speed of, for example, one hundred and several tens KHz, FIG.
An optical switch using an acousto-optic element as shown in FIG.

In FIG. 7, through-holes 2 and 3 are formed in mutually adjacent surfaces 1a and 1b of a substantially box-shaped light-shielding container 1. A fiber collimator 6 supported by a mounting plate 4 is mounted in one through hole 2. The other through hole 3 has a fiber collimator 7 supported by a mounting plate 5.
Is installed. An acousto-optic device 8 and a reflection mirror 9 are incorporated in the light shielding container 1.

[0004] Light 11 input from the outside via an optical fiber 10 is converted into, for example, parallel light by a fiber collimator 6 and is incident on the acousto-optic element 8 from an incident surface 8 a of the acousto-optic element 8. The acousto-optic element 8 is configured to emit light 11 incident on the incident surface 8a when the ultrasonic wave 12 is not applied to the surface 8b orthogonal to the incident surface 8a.
Are emitted as transmitted light 13 from the exit surface 8c facing the entrance surface 8a.

When the ultrasonic wave 12 is applied to a surface 8b orthogonal to the incident surface 8a, the light 11 incident on the incident surface 8a is diffracted and becomes a diffracted light 14 from the exit surface 8c. Is emitted. Therefore, the diffracted light 14
Passes through different optical paths for the transmitted light 13.

The diffracted light 14 emitted from the emission surface 8c of the acousto-optic device 8 is reflected by the reflection mirror 9 and enters the fiber collimator 7. The fiber collimator 7 condenses the incident diffracted light 14 and guides the diffracted light 14 to an external optical fiber 15.

FIG. 8 is a diagram for explaining the operation principle of the acousto-optic device 8. A vibrator 12 a is attached to a surface 8 b of the acousto-optic element 8 orthogonal to the incident surface 8 a. When the vibrator 12 a is energized, the ultrasonic wave 12 is applied to the acousto-optic element 8. The refractive index of the acousto-optic element 8 is n, the wavelength of the ultrasonic wave 12 is A, the incident angle of the light 11 is α, and the light 1 is
Assuming that the wavelength of 1 is λ and the diffraction order is M, the outgoing angle (diffraction angle) β at each principal length λ is expressed by Expression (1) from the expression of the diffraction grating. β (λ) = Sin ⁻¹ {(Mλ / nA) −sinα} (1) As is apparent from the equation (1), when the ultrasonic wave 12 is not applied, the diffraction order M becomes 0, and Since the wavelength A of the sound wave 12 becomes infinite, the emission angle β (λ) becomes −α,
The transmitted light 13 is not diffracted.

In the optical switch configured as described above, when the ultrasonic wave 12 is applied to the acousto-optic element 8, the light 11 guided from the optical fiber 10 to the fiber collimator 6 is diffracted by the acousto-optic element 8. , Diffracted light 14
Through the reflection mirror 9, the fiber collimator 7
To the external optical fiber 15.

The ultrasonic wave 1 applied to the acousto-optic element 8
In a state where 2 is cut off, the light 11 guided from the optical fiber 10 to the fiber collimator 6 is emitted as it is as transmitted light 13 without being diffracted by the acousto-optic element 8.
Since this transmitted light 13 does not enter the reflection mirror 9, it does not enter the fiber collimator 7.

Therefore, by turning on / off the ultrasonic wave 12 applied to the acousto-optic element 8, it is possible to turn on / off light traveling from the fiber collimator 6 as the light introducing member to the fiber collimator 7 as the light guiding member. It becomes possible.

In the optical switch having such a configuration, the output light 1 guided to the optical fiber 15 from the fiber collimator 7 when the ultrasonic wave 12 is turned on / off at a high speed.
In order to improve the on / off characteristics in 6, an optical switch device shown in FIG. 9 in which two optical switches shown in FIG. 7 are connected in series has been proposed.

In FIG. 9, an input light 16 input from the outside is diffracted by a first optical switch 20a. The output light 17 from the first optical switch 20a enters the second optical switch 20b via an optical fiber, and is output as the output light 19 from the second optical switch 20b.

The first optical switch 20a and the second optical switch 20a
Each ultrasonic wave 12 applied to each acousto-optical element 8 incorporated in the optical switch 20a is controlled on / off at the same time.

The ON / OFF waveform of the ultrasonic wave 12, the ON / OFF waveform of the output light 17 of the first optical switch 20a corresponding to the ON / OFF waveform, and the second light in the optical switch device thus configured. FIG. 10 shows the relationship with the on / off waveform of the output light 19 of the switch 20b.

As described above, the two optical switches 20a, 20a
0b in series, the residual light generated in the output light 17 of the first optical switch 20a during the off period of the ultrasonic wave 12 is output to the output light 19 of the second optical switch 20b.
Can be greatly reduced. That is, the ON / OFF extinction ratio of the output light 19 can be greatly improved.

The output light 1 of the second optical switch 20b
In 9, in comparison with the output light 17 of the first optical switch 20a, the follow-up property when the ultrasonic wave 12 is turned on / off, that is, the frequency characteristic can be improved.

[0017]

However, in an optical switch using an acousto-optic device shown in FIG. 7 and an optical switch device in which two optical switches shown in FIG. 9 are connected in series,
There were the following issues that still need to be improved.

That is, in recent years, in order to improve communication efficiency in optical communication, light transmitted and received by one optical fiber is not a single wavelength light but a light obtained by multiplexing a plurality of lights having different wavelengths. Has been adopted.

The input light 16 incident on the optical switch or the optical switch device for turning on / off such light includes the light shown in FIG.
Each wavelength lambda ₁ as shown in 1, λ _2, ..., a plurality of peaks 21 corresponding to lambda ₅ occurs.

When the light 11 having a plurality of wavelength components is incident on the acousto-optic element 8, as shown in FIGS. 8 and (1), the output angle β (λ) of the diffracted light 14 output from the output surface 8b is obtained.
Has a different value for each wavelength λ ₁ , λ ₂ ,..., Λ ₅ .

Therefore, when the optical path length of the diffracted light 14 becomes longer, the diffracted light 14 spreads in the wavelength dispersion direction. as a result,
The diffracted light 14 is incident over a wide range on the incident surface (incident lens) of the fiber collimator 7. The incidence surface (incident lens) of the fiber collimator 7 does not have uniform incidence efficiency over the entire surface, but the incidence efficiency decreases toward the periphery.

Further, the incident angle with respect to the pair on the incident surface becomes farther away from the vertical direction as it goes to the peripheral portion. Therefore, the incidence efficiency is further reduced toward the periphery. Therefore, the light guided from the fiber collimator 7 to the optical fiber 15 or the output light 17 from the first optical switch 20a has the frequency characteristics shown in FIG. As shown in FIG. 11B, there is a problem that the value of each peak 21a differs depending on each wavelength λ ₁ , λ ₂ ,..., Λ ₅ .

Thus, each wavelength λ ₁ , λ ₂ ,..., Λ ₅
This tendency is further enhanced when the output light 17 from the first optical switch 20a having a plurality of peaks 21a that are different each time is incident on the second optical switch 20b.

As shown in FIG. 11C, the output light 19 from the second optical switch 20b is incident on the center of the incident surface of the fiber collimator 7 and the value of the peak 21b of the wavelength λ ₃ and the incident light. the difference between the value of the wavelength lambda ₁ of the peak 21b incident on the peripheral portion of the face problems to further expand.

Further, two optical switches 20 shown in FIG.
In an optical switch device in which a and 20b are connected in series,
Compared to the optical switch shown in FIG. 7, two extra fiber collimators are interposed in the optical path between the input light and the finally output light, and as shown in FIG. There is a problem that the light intensity of the output light 19 from the second optical switch 20b is greatly reduced as compared with the light intensity of the first input light 16.

The present invention has been made in view of such circumstances. For example, by providing a spectral optical member that separates the diffracted light diffracted by the acousto-optic element so that the wavelength dispersion direction is reversed. Even if a plurality of wavelength components are included in the input light, the light intensity at each wavelength included in the output light can be maintained substantially uniform and the light loss / minimization is maintained while maintaining the light loss to a minimum. An object of the present invention is to provide an optical switch capable of increasing a fire extinguishing ratio.

[0027]

In order to solve the above-mentioned problems, an optical switch according to the present invention comprises a light introducing member for introducing light from the outside and a light introduced by the light introducing member on a first surface. Is incident from the outside and an ultrasonic wave is applied from the outside, so that the incident light is diffracted and emitted as the first diffracted light from the second surface, and the first diffracted light is incident from the second surface. Is diffracted so that the wavelength dispersion direction becomes the opposite direction, and is emitted from the first surface as a second diffracted light, and the first diffracted light emitted from the second surface of the acousto-optic device Is split so that the wavelength dispersion direction is in the opposite direction, is turned back by a mirror, is split again, and is again incident on the acousto-optic element from the second surface, and the first surface of the acousto-optic element Takes in the second diffracted light emitted from the It is composed of a light leading member to be. Then, by turning on / off the ultrasonic wave applied to the acousto-optic element, the light traveling from the light introducing member to the light guiding member is turned on / off.

In the optical switch configured as described above, light input from the outside via the light introducing member is incident on the first surface of the acousto-optic element, and is diffracted by the acousto-optic element to form the first light. Are emitted from the second surface as diffracted light.
This first diffracted light is wavelength-dispersed.

The first diffracted light emitted from the second surface is dispersed in the spectral optical member in the direction opposite to the wavelength dispersion direction, is then turned back by a mirror, is again dispersed, and is separated from the second surface by the same light. Incident on the acousto-optic device. The first diffracted light that has entered the same acousto-optic element from the second surface is diffracted again so that the chromatic dispersion direction is reversed in the process of traveling in the direction opposite to the outward path.

In this case, the first diffracted light emitted from the second surface of the acousto-optic element is diffracted by the spectral optical member in the direction in which the wavelength dispersion direction is reversed. That is, a first differential dispersion diffraction mechanism is formed. As a result, the spectral directions at the respective wavelengths cancel each other, and the first diffracted light emitted from the second surface of the spectral optical member may have the same emission angle regardless of the wavelength.

Further, the first diffracted light, which is split again, is output from the spectral optical member, and is incident from the second surface of the acousto-optic element, is converted into the second diffracted light from the first surface of the acousto-optic element. In the process of being emitted, the wavelength dispersion direction is diffracted in the opposite direction. That is, a second differential dispersion diffraction mechanism is formed. As a result, the spectral directions at the respective wavelengths cancel each other, and the dispersion of the second diffracted light emitted from the first surface of the acousto-optic element may become zero.

As a result, the second diffracted light emitted from the first surface of the acousto-optic element can be made into a spot light in which light of each wavelength contained in the second diffracted light is concentrated at one point. .

Therefore, the second light incident on the light guide member
Even if the optical path length is long, the diffracted light is not spread in the wavelength dispersion direction and is incident on the incident surface of the light guiding member as a narrow spot. As a result, the light intensity of each wavelength included in the light led out from the light lead-out member can be made uniform. Further, since the light passes through the acousto-optic element twice, the extinction ratio in ON / OFF of the light can be increased.

Further, since no other light introducing member or light guiding member is interposed between the light introducing member and the light guiding member, light loss between the light introducing member and the light guiding member is minimized. Can be suppressed.

Further, an optical switch according to another aspect of the present invention includes a light introducing member for introducing light from the outside, a light introduced by the light introducing member being incident thereon, and an ultrasonic wave being applied from the outside. The first acousto-optic element that diffracts the incident light and emits it as first diffracted light, and the first diffracted light emitted from the first acousto-optic element are arranged such that the wavelength dispersion directions are opposite. The spectroscopic optical member that splits the light and folds the light with a mirror, splits the light again, and emits the light, and the first diffracted light emitted from the light separating optical member are incident, and the ultrasonic wave is applied from the outside, so A second acousto-optic element that diffracts the first diffracted light so that the wavelength dispersion direction is in the opposite direction and emits the diffracted light as second diffracted light; and a second acousto-optic element that emits the second diffracted light. Light extraction members that take in and lead out It is configured. And the first and second
By turning on / off each ultrasonic wave applied to the acousto-optic element at the same time, light traveling from the light introducing member to the light guiding member is turned on / off.

In the optical switch configured as above, the light input through the light introducing member undergoes the first diffraction by the first acousto-optic element, and the second diffraction by the second acousto-optic element.
The second diffraction is performed. Then, the first diffraction in the first acousto-optic element and the first diffraction in the spectral optical member
Is formed. Further, a second difference dispersion analysis diffraction mechanism is formed by the spectral light in the spectral optical member and the second diffraction in the second acousto-optical element.

Therefore, in the present invention, one acousto-optical element in the above-mentioned invention is divided into two acousto-optical elements, and the optical operation is almost the same as that of the above-mentioned invention.
Therefore, it is possible to obtain substantially the same operation and effect as the above invention.

In still another invention, a polarization scrambler for randomly changing the polarization direction of the light introduced by the light introducing member is provided.

The diffraction efficiency of the acousto-optic device may vary slightly depending on the polarization direction of the incident light. Further, the polarization direction of the incident light is not always constant. Therefore, in the present invention, the polarization direction of the incident light is randomly changed by the polarization scrambler, thereby eliminating the fluctuation factor of the light intensity due to the polarization direction of the output light.

In another aspect of the present invention, a prism for splitting the first diffracted light emitted from the second surface of the acousto-optic element so as to be in the wavelength dispersion direction, And a corner mirror for causing the first diffracted light emitted from the second surface to be incident on the second surface of the acousto-optic element at a position different from the emission position of the first diffracted light.

In the optical switch configured as described above, since the spectral optical member is composed of an extremely simple optical member including a prism and a corner mirror, the optical switch can be configured at low cost.

[0042]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 is a perspective view showing a schematic configuration of an optical switch according to a first embodiment of the present invention. The same parts as those of the conventional optical switch shown in FIG. Therefore, the detailed description of the overlapping part is omitted.

A fiber collimator 6 as a light introducing member and a fiber collimator 7 as a light guiding member are mounted on the same surface 1a of the light shielding container 1 formed in a substantially box shape. In the light shielding container 1, a polarization scrambler 23, an acousto-optic device 24, a prism 25 and a corner mirror 26 are incorporated. The prism 25 and the corner mirror 26 constitute a spectral optical member. Acoustooptic device 24
Is applied with an ultrasonic wave 12 whose on / off is controlled by an external signal.

FIG. 2 is a sectional view showing the structure of the fiber collimator 6. A connector 6b for connecting the optical fiber 10 is attached to one end of a through hole 6a penetrating the fiber collimator 6 in the axial direction, and an emission surface (incident surface) of the light 11 is provided at the other end located in the light shielding container 1. 6c is formed. The collimator lens 6 is inserted into the through hole 6a.
d is stored. In the fiber collimator 6 having such a configuration, the light input from the optical fiber 10 is converted into parallel light by the collimator lens 6d and emitted from the emission surface 6c.

The other fiber collimator 7 has the same configuration as the fiber collimator 6, except that the traveling direction of light is reversed.

FIG. 3A is a schematic plan view when the optical switch of FIG. 1 is cut horizontally at the position of the fiber collimator 6, and FIG. 3B is a schematic diagram of the optical switch of FIG. It is a plane schematic diagram at the time of cutting horizontally at 7 positions.

In FIGS. 1, 3 (a) and 3 (b),
The light 11 having a plurality of light components having different wavelengths λ, which are input from the outside via the optical fiber 10, are converted into, for example, parallel rays by the fiber collimator 6, and the polarization direction is changed by the polarization scrambler 23. It is converted into light that changes randomly.

The light 11 passing through the polarization scrambler 23
Is incident on the acousto-optic element 24 from an incident surface (first surface) 24a of the acousto-optic element 24. In the acousto-optic element 24, when the ultrasonic wave 12 is applied, the light 11 incident on the incident surface (first surface) 24a is diffracted, and the light 11 is transmitted from the emission surface (second surface) 24b to the first surface. Is emitted as the diffracted light 27. The first diffracted light 27 emitted from the exit surface (second surface) 24b of the acousto-optic element 24 enters the entrance surface 25a of the prism 25.

In the prism 25, the first diffracted light 27 incident on the incident surface 25a is split in the direction opposite to the diffraction direction of the acousto-optic device 24, and is emitted from the emission surface 25b.

The first diffracted light 27 emitted from the exit surface 25b of the prism 25 is reflected downward by a corner mirror 26 composed of two mirrors 26a and 26b, and
As shown in (b), the emission surface (second surface) 24b is again
Is incident on the acousto-optic element 24 via the.

In the acousto-optic element 24, when the ultrasonic wave 12 is applied, the emission (second surface) 24
The first diffracted light 27 incident from b is diffracted and emitted as a second diffracted light 28 from an incident surface (first surface) 24a.

The entrance surface 24a of the first acousto-optic element 24 (first
The second diffracted light 28 emitted from the surface 24a) enters the fiber collimator 7. The fiber collimator 7 condenses the incident second diffracted light,
Derived to 5.

When the ultrasonic wave 12 is not applied to the acousto-optic element 24, the incident surface 24a
The light 11 incident on the acousto-optic element 24 from the light source is emitted from the emission surface 24b as transmitted light 29 without being diffracted. The transmitted light 29 is split by the prism 25, and the transmitted light 29 split by the prism 25 is incident on the corner mirror 26, but is reflected by the first diffracted light 27.
Is significantly different from the direction of (1) and is not incident on the fiber collimator 7.

Accordingly, by turning on / off each ultrasonic wave 12 applied to the acousto-optic element 24, the light 11 traveling from the fiber collimator 6 to the fiber collimator 7 is changed.
Can be turned on / off.

Next, the details of the path on which the light 11 input from the fiber collimator 6 enters the fiber collimator 7 as the second diffracted light 28 will be described with reference to FIGS. 3 (a) and 3 (b).

The incident surface (first surface) 2 of the acousto-optic device 24
The light 11 having a plurality of wavelength components incident on the light 4a is diffracted in a state where the ultrasonic wave 12 is applied to the first diffracted light 2
The light 7 is emitted from the emission surface (second surface) 24b. The first diffracted light 27 is light that is split in a wavelength dispersion direction determined by the direction of the elastic wave generated by the applied ultrasonic wave 12 and the incident direction.

Outgoing surface (second surface) 2 of acousto-optical element 24
The first diffracted light 27 emitted from 4b is
The direction (posture) of the prism 25 is set in the illustrated direction in consideration of the refraction of light and the like, so that the chromatic dispersion direction is opposite to the chromatic dispersion direction in the acousto-optic element 24. Can be set to That is, the prism 25 splits the light in a direction in which the wavelength dispersion direction converges. Therefore, as shown in FIG. 3A, the attitude angle of the prism 25 is set so that the light of each wavelength of the first diffracted light 27 split by the prism 25 has the same emission angle regardless of the wavelength. It is possible to

The first diffracted light 27 converted into light having the same emission angle irrespective of the wavelength is again converted into a parallel light state through the prism 25 as shown in FIG. The light enters the emission surface (second surface) 25b of the optical element 24.

In this process, the first diffracted light 27 travels in the opposite direction through the prism 25, so that light having the same emission angle is converged by the prism 25 regardless of the wavelength.

The first diffracted light 27 further converged from the light having the same emission angle irrespective of the wavelength enters the emission surface (second surface) 25b of the acousto-optic element 24. Therefore, the first diffracted light 27 is diffracted again in the acousto-optic element 24.

However, the wavelength dispersion direction determined by the elastic wave generated by the applied ultrasonic wave 12 and the incident direction when diffracted in the acousto-optic element 24 is opposite to the incident first diffracted light 27. Direction, the first diffracted light 27 is split in the opposite direction.

As a result, the light of each wavelength of the second diffracted light 28 emitted from the incident surface (first surface) 24a of the acousto-optic element 24 is focused at one point as shown in FIG. The light is concentrated and becomes a spot light similarly to the light 11 input from the fiber collimator 6.

Therefore, the spot diameter d of the second diffracted light 28
Is incident on the incident surface of the fiber collimator 7 with a narrow spot diameter without spreading even if the optical path length is long. As a result, the light intensity of each wavelength contained in the light 30 led out from the fiber collimator 7 can be made uniform.

Since the light travels back and forth through the acousto-optic element 24, the extinction ratio at the time of light on / off can be increased.
Further, since another fiber collimator is not interposed between the fiber collimators 6 and 7, light loss between the fiber collimators 6 and 7 can be suppressed to a minimum.

Further, since only one acousto-optic element 24 is accommodated in one light-shielding container 1, the conventional optical switch device shown in FIG. 9 in which two optical switches 20a and 20b are connected in series is provided. As a result, the entire apparatus can be made smaller and lighter.

(Second Embodiment) FIG. 4 is a perspective view showing a schematic configuration of an optical switch according to a second embodiment of the present invention. The same parts as those of the optical switch according to the first embodiment shown in FIG. Therefore, the detailed description of the overlapping part is omitted.

In the optical switch according to the second embodiment, one of the optical switches according to the first embodiment shown in FIG.
Pieces of acousto-optical elements 24
And a second acousto-optic element 31b. Also, the first and second acousto-optical elements 31
Each ultrasonic wave 12 applied to a and 31b is simultaneously controlled on / off by an external signal.

In the optical switch of the second embodiment configured as described above, the light 11 input from the fiber collimator 6 enters the first acousto-optic element 31a via the polarization scrambler 23, After being diffracted, the light is split by the prism 25 as the first diffracted light 27. The first diffracted light 27 split by the prism 25 is again
5, the second acousto-optical element 31b
Is incident from the opposite direction. Then, the first diffracted light 2
7 is diffracted in the opposite direction by the second acousto-optic element 31b and becomes a second diffracted light 28 as a second acousto-optic element 31b.
And is incident on the fiber collimator 7.

Therefore, the first diffraction in the first acousto-optic element 31a and the first spectral analysis of the first diffracted light 27 in the prism 25 constitute a first differential dispersion analysis mechanism. The first diffracted light 2 in the prism 25
7 for the second time and 2 acousto-optic elements 3
The second diffraction of the first diffracted light 27 in 1b constitutes a second differential diffraction mechanism.

Therefore, the spot diameter of the second diffracted light 28 finally incident on the fiber collimator 7 can be maintained in the minimum state. Therefore, substantially the same technical effects as those of the optical switch of the first embodiment shown in FIG. 1 can be obtained.

(Third Embodiment) FIG. 5 is a perspective view showing a schematic configuration of an optical switch according to a third embodiment of the present invention. The same parts as those of the optical switch according to the first embodiment shown in FIG. Therefore, the detailed description of the overlapping part is omitted.

In the optical switch according to the third embodiment, a flat total reflection mirror 32 is used instead of the corner mirror 27 in the optical switch according to the first embodiment shown in FIG.
Is adopted. Further, a fiber collimator 6 for guiding the light 11 from the outside and a fiber collimator 7 for leading the light 30 to the outside are attached to the surface 1a of the light shielding container 1 so as to be vertically inclined.

In the optical switch of the third embodiment configured as described above, the light 11 from the fiber collimator 6
Is incident on the acousto-optic element 24 while being inclined vertically.
Therefore, the first diffracted light 27 diffracted by the acousto-optic element 24 is split by the prism 25 and is reflected by the total reflection mirror 3.
The light 2 is incident obliquely from above and is reflected obliquely downward. Further, the first diffracted light 27 is split again by the prism 25, diffracted in the opposite direction by the acousto-optic element 24, and finally enters the fiber collimator 7 as second diffracted light 28.

Therefore, substantially the same effects as those of the optical switch according to the first embodiment shown in FIG. 1 can be obtained.

(Fourth Embodiment) FIG. 6 is a schematic plan view showing a schematic configuration of an optical switch according to a fourth embodiment of the present invention. The same parts as those of the optical switch according to the first embodiment shown in FIG. Therefore, the detailed description of the overlapping part is omitted.

In the optical switch according to the fourth embodiment, one acousto-optical element 24 and one
One prism 25, one total reflection mirror 27, and one polarization scrambler 23 are incorporated. On one surface 1a of the light-shielding container 1, one fiber collimator 33 that is used for both input and output of light is attached.

Further, an optical coupler 34 for separating input and output of light is connected to the fiber collimator 33 via the optical fiber 10.

In the optical switch of the fourth embodiment configured as described above, the input light 35 is input to the fiber collimator 33 via the optical coupler 34 and the optical fiber 10. The light 11 guided from the fiber collimator 33 into the light shielding container 1 is diffracted by the acousto-optic element 24, converted into parallel light by the prism 25 as the first diffracted light 27, and is incident on the total reflection mirror 37.

The total reflection mirror 37 is disposed perpendicularly to the optical path of the first diffracted light 27 having the same emission angle regardless of the wavelength. Therefore, the traveling direction of the first diffracted light 27 is reversed by 180 ° by the total reflection mirror 37, and travels in the original optical path in the opposite direction. And prism 2
5, the wavelength dispersion direction is reduced, the light is diffracted in the opposite direction by the acousto-optic element 24, emitted as the second diffracted light 28 from the incident surface 24a of the acousto-optic element 2, and passed through the polarization scrambler 23 to be the same. The light enters the fiber collimator 33.

The second light incident on the fiber collimator 33
The diffracted light 28 is transmitted through the optical fiber 10 to the optical coupler 34.
Are separated from the input light 35 and extracted as output light 36.

Therefore, in the optical switch according to the fourth embodiment, the light passes through the acousto-optic element 24 and the prism 25.
Therefore, the same effects as those of the optical switches of the first and third embodiments can be obtained.

Further, in the optical switch according to the fourth embodiment, since the light reciprocates along the same path in the light shielding container 1, the fiber collimator 33 can be limited to only one. Optical components can be miniaturized. As a result, the size of the optical switch itself can be reduced.

Note that the present invention is not limited to the optical switches of the above embodiments. In each embodiment, fiber collimators 6 and 7 are used as the light introducing member and the light introducing member. However, it is also possible to employ a fiber condenser incorporating a condensing lens as the light introducing member and the light introducing member.

[0084]

As described above, in the optical switch according to the present invention, the wavelength dispersion direction of diffracted light between one acousto-optic element that reciprocates light or two acousto-optic elements that light passes therethrough. Are arranged so that they face in opposite directions (difference dispersion).

Therefore, even if a plurality of wavelength components are included in the input light, the light intensity at each wavelength included in the output light can be maintained substantially uniform, and the optical loss can be maintained at a minimum. In addition, the extinction ratio in turning on / off light can be increased.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a schematic configuration of an optical switch according to a first embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of a fiber collimator incorporated in the optical switch according to the first embodiment.

FIG. 3 is a view showing a state of diffraction of light in the optical switch according to the first embodiment.

FIG. 4 is a perspective view showing a schematic configuration of an optical switch according to a second embodiment of the present invention.

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

FIG. 6 is a plan view showing a schematic configuration of an optical switch according to a fourth embodiment of the present invention.

FIG. 7 is a schematic sectional view showing a schematic configuration of a conventional optical switch.

FIG. 8 is a view showing diffraction characteristics of an acousto-optic element incorporated in the optical switch.

FIG. 9 is a schematic diagram showing a schematic configuration of an optical switch device in which two conventional optical switches are incorporated.

FIG. 10 is a waveform chart showing the operation characteristics of the optical switch device in which two conventional optical switches are incorporated.

FIG. 11 is a wavelength characteristic diagram of light showing operation characteristics of the optical switch device in which two conventional optical switches are incorporated.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Shielding housing 6,7,33 ... Fiber collimator 10,15 ... Optical fiber 11 ... Light 12 ... Ultrasonic wave 23 ... Polarization scrambler 24 ... Acoustic optical element 25 ... Prism 26 ... Corner mirror 37 ... First diffraction Light 28 second diffracted light 29 transmitted light 31a first acousto-optical element 31b second acousto-optical element 32, 37 total reflection mirror 29 transmitted light 32, 37 total reflection mirror 34 optical coupler

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yukio Tsuda 5- 10-27 Minamiazabu, Minato-ku, Tokyo Anritsu Corporation (72) Inventor Hiroshi Komazawa 5- 10-27 Minamiazabu, Minato-ku, Tokyo Anritsu F term (reference) in the company 2H079 AA04 AA13 BA01 CA05 DA02 EA11 HA14 HA15 KA09 KA14

Claims (4)

[Claims] 1. A light introducing member (6) for introducing light from the outside, and light introduced by the light introducing member is incident from a first surface, and an ultrasonic wave (12) is applied from the outside. As a result, the incident light is diffracted and emitted as first diffracted light (27) from the second surface, and the wavelength dispersion direction of the first diffracted light incident from the second surface is reversed. And diffracted as described above to form the second diffracted light (28).
An acousto-optic device (24) emitted from the surface of the acousto-optic device, and the first diffracted light emitted from the second surface of the acousto-optic device are split so that the wavelength dispersion directions are opposite to each other, and are returned by a mirror. A spectral optical member (2) for re-spectralizing and re-entering the acousto-optic element from the second surface.
5, 26) and a light deriving member (7) for taking in the second diffracted light emitted from the first surface of the acousto-optic element and leading it out to the outside, An optical switch, characterized by turning on / off a sound wave to turn on / off light traveling from the light introducing member to the light guiding member. 2. A light introducing member (6) for introducing light from the outside, and light introduced by the light introducing member is made incident, and the ultrasonic wave (12) is applied from the outside to make the incident light. A first acousto-optic element (31a) that diffracts light and emits it as first diffracted light, and the first diffracted light emitted from the first acousto-optic element has a wavelength dispersion direction opposite to that of the first acousto-optic element. Optical member (25, 26) that splits the light and turns it back by a mirror, splits the light again, and emits the light, and receives the first diffracted light emitted from the spectral optical member, and receives an ultrasonic wave (12) from the outside. Is applied, the incident first diffracted light is diffracted so that the wavelength dispersion direction becomes the opposite direction, and the second acousto-optic element (31b) that emits the second diffracted light as second diffracted light; 2nd time emitted from the acousto-optic device of No. 2 A light deriving member (7) for taking in light and deriving the light to the outside; by simultaneously turning on / off each ultrasonic wave applied to the first and second acousto-optic elements, An optical switch for turning on / off light directed to a light guide member. 3. The optical switch according to claim 1, further comprising a polarization scrambler for randomly changing a polarization direction of the light introduced by the light introducing member. 4. The spectral optical member disperses the first diffracted light emitted from the second surface of the acousto-optic element so that the wavelength dispersion direction is opposite, and disperses the incident light again. A first diffracted light emitted from the second surface of the acousto-optic element is different from an emission position of the first diffracted light on the second surface of the acousto-optic element 2. The optical switch according to claim 1, further comprising a corner mirror for making the light incident on the position.