JP2003015060A - Optical switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical switch which has a small and simple structure and can be manufactured at a low cost. SOLUTION: This optical switch 100 is provided with an element piece 10 and a magnetic field applying part 200. The element piece 10 is provided with a magnetostriction material thin film 3 and a reflection film 4 on a base body 1 having flexibility, and the element piece 10 reflects light from an incident part 31. The magnetostriction material thin film 3 has quality that extends and contracts in a magnetizing direction, and in the element piece 10, the amount of deflection changes in accordance with the extension/contraction of the magnetostriction material thin film 3. A magnetic field applying part 200 applies a magnetic field in a different direction to the element piece 10 to change the amount of deflection of the element device 10. Since the direction of light reflected at the element device 10 changes in this way, the optical path of light from the light incident part 31 can be changed to an optical fiber 14 or 15 of an emitting part 32.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical switch for switching an optical transmission path, and more particularly to an optical switch for switching an optical transmission path by changing a light reflection direction.

[0002]

2. Description of the Related Art In an optical communication system, an optical switch is required to switch optical communication lines. As one of optical switch systems, for example, an optical switch is known in which a reflection mirror is arranged on the optical path and the angle of the reflection mirror is changed to change the light reflection direction. In such an optical switch, as a method of changing the angle of the reflection mirror, for example, an electrostatic method, a piezoelectric method, a magnetic force method, etc. are known, and an optical switch using the magnetic force method continuously supplies electric power. It is excellent in that the angle of the reflection mirror can be kept constant even if the supply is not continued.

As an example of a conventional magnetic force type optical switch, for example, Japanese Patent Application Laid-Open No. 2000-162520 discloses an optical switch utilizing the attractive force between a magnet and an electromagnet. The optical switch described in this document is configured such that a mirror to which a magnetic material is attached is attached to a substrate through a support that can move three-dimensionally, and an electromagnet is provided near the mirror. In such an optical switch, the electromagnet is operated to generate a magnetic field from the electromagnet,
The magnetic substance attached to the mirror is attracted to the electromagnet by magnetic interaction, and the laser incident on the mirror is switched in a predetermined direction.

[0004]

However, in the above-mentioned magnetic force type optical switch, since it is necessary to attach a magnetic body to the mirror and attach the mirror to the substrate via a deformable support, There is a problem that the number of points increases, the structure becomes complicated, and the manufacturing process also becomes complicated.

The present invention has been made to solve the above-mentioned problems of the prior art, and an object thereof is to provide a novel optical switch which has a small size and a simple structure and can be easily manufactured. .

[0006]

According to a first aspect of the present invention, in an optical switch for switching a light transmission path, a light incident portion, a light emitting portion, a substrate, a thin film made of a magnetostrictive material, and An element including a reflective film; and a magnetic field applying means for applying a magnetic field to the element, and utilizing the difference in bending of the element due to the magnetic field application of the magnetic field applying means, There is provided an optical switch characterized by switching light to a light emitting unit.

The optical switch according to the first aspect of the present invention includes an element in which a thin film made of a magnetostrictive material is formed on a base, and the element functions as an element for switching an optical path. The element piece is configured, for example, by forming a magnetic material thin film and a reflective film on a thin plate-shaped substrate, one end of the element piece is supported by a supporting portion, and the other end portion is bent at a predetermined angle. I'm out. The light incident from the light incident portion of the optical switch is reflected by the reflecting film of the elemental piece, and the reflected light is guided to the light emitting portion. Here, the magnetostrictive material forming the element has the property of expanding or contracting in a predetermined direction when magnetized. Whether it expands or contracts in the magnetized direction depends on the type of magnetostrictive material. When the element is composed of a magnetostrictive material having a property of extending in the magnetized direction, when a magnetic field is applied to the element by the magnetic field applying means, for example, in the element longitudinal direction (the longitudinal direction of the element). Since the magnetostrictive material thin film extends in the vertical direction of the element, a shear stress is generated between the substrate and the magnetostrictive material thin film, and the element is bent back so that the side on which the magnetostrictive material thin film is formed is the outer side. That is,
The amount of deflection of the element increases. On the other hand, a magnetic field is applied by the magnetic field applying means to the element in a direction perpendicular to the element longitudinal direction, for example, in a direction parallel to the surface of the element and perpendicular to the longitudinal direction (horizontal direction of the element). When applied, the magnetostrictive material thin film does not extend in the longitudinal direction of the element and extends in the lateral direction of the element, so that the amount of bending of the element decreases compared to the case where a magnetic field is applied in the longitudinal direction of the element. In this way, the amount of deflection of the element changes depending on the direction of the magnetic field applied to the element, so that the light incident on the element surface from the light incident portion is reflected at different angles. Therefore, by positioning the light emitting part in the optical switch so that the reflected light reflected at different angles depending on the bending amount of the element is received,
Optical switching is possible that switches the light transmission path.

The dimensional change of the magnetostrictive material (the length of expansion or contraction with respect to the original length) is several tens × 10 ⁻⁶ to several thousand hundreds × 1.
Although it is extremely small at about 0 ⁻⁶ , it is possible to control the bending amount of the element piece to be large by appropriately adjusting the thicknesses and materials of the substrate and the magnetostrictive material thin film.

In the present invention, the substrate forming the element is
It may be formed of a material that is flexible and has a predetermined bending elasticity. As a material for forming the base, for example,
Silicon, silicon oxide, glass, copper-nickel alloy, or the like can be used.

In the present invention, the magnetostrictive material is preferably composed of an alloy of a rare earth element and an iron group element. Such a magnetostrictive material is optimal because it has a large magnetostriction. As rare earth elements, terbium (Tb), samarium (S
m) and at least one selected from the group consisting of dysprosium (Dy) can be used, and as the iron group element, at least one selected from the group consisting of iron, cobalt, and nickel can be used.

The reflection film forming the element may be formed on at least one surface of the substrate. Even if it is formed on the magnetostrictive material thin film, it is formed on the side opposite to the side on which the magnetostrictive material thin film is formed. May be. The reflective film may be formed on the entire surface of the substrate or may be partially formed only in the region where light enters and exits.

In the optical switch of the present invention, the magnetic field applying means may be configured to be able to apply a magnetic field to the element in two directions, for example, the longitudinal direction (vertical direction) of the element and a direction perpendicular to the longitudinal direction. The magnetic field can be applied in the direction (lateral direction) or in the longitudinal direction of the element and the thickness direction of the element. The magnetic field applying unit can be configured using, for example, a permanent magnet or a coil. When a coil is used as the magnetic field applying means, it is preferable to provide a magnetic core formed of a soft magnetic material such as iron or permalloy for the purpose of increasing the strength of the generated magnetic field.

The optical switch of the present invention may include a stopper for supporting the other end of the element piece, one end of which is supported by the supporting portion. Such a stopper can limit the bending or warping of the element piece caused by the application of the magnetic field applying means.

In the optical switch of the present invention, the light incident portion and the light emitting portion can be formed by using, for example, an optical fiber, and an optical element such as a lens is provided on the light emitting side or the light emitting side of the optical fiber. Can be prepared.

According to a second aspect of the present invention, in an optical switch for switching a light transmission path, a magnetostrictive material having a reflecting surface; a light incident portion and a light emitting portion; and applying a magnetic field to the magnetostrictive material. An optical switch is provided, which comprises:

The optical switch according to the second aspect of the present invention can reflect the light from the light incident portion on the reflection surface of the magnetostrictive material and guide it to the light emitting portion. For example, a rod-shaped magnetostrictive material is used as the magnetostrictive material, and when a magnetic field is applied to the rod-shaped magnetostrictive material by the magnetic field applying means, the rod-shaped magnetostrictive material expands and contracts in the length direction. For example, if a reflecting surface is formed at the tip of the rod-shaped magnetostrictive material, the reflecting surface is displaced according to expansion and contraction of the rod-shaped magnetostrictive material due to application of a magnetic field, so that the direction of light reflected by the reflecting surface can be switched. Therefore, optical switching can be realized. As the magnetostrictive material having a reflective surface, a magnetostrictive material having an arbitrary shape and size such as a flat plate or a column can be used as long as it has a reflective surface as a part thereof.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The optical switch according to the present invention will be specifically described below, but the present invention is not limited thereto.

FIG. 1 shows a schematic plan view of an optical switch according to the present invention. Further, FIG. 2 shows a cross-sectional view of the optical switch shown in FIG. 1 in the AA direction. As shown in FIGS. 1 and 2,
The optical switch 100 includes an element piece 10, a support portion 19 that supports one end of the element piece 10, stoppers 11 and 12 that supports the other end of the element piece 10 to limit the operation, and a magnetic field to the element piece 10. A magnetic field applying unit 200 for applying, a light incident unit 31 to which an optical signal from the outside is input, and a light emitting unit 32 to output the optical signal to the outside are provided. The light incident part 31 includes the optical fiber 13 and the lens 18 provided on the light emitting side of the optical fiber 13. The light emitting portion 32 is provided with the optical fiber 14
And a lens 17 provided on the light incident side, and an optical fiber 15 and a lens 16 provided on the light incident side.

FIG. 3 shows a schematic sectional view of the element 10. As shown in FIG. 3, the element 10 includes a base film 2, a base film 2,
It has a structure including a magnetostrictive material thin film 3 and a reflective film 4. The substrate 1 is required to be sufficiently thin because it is necessary to increase the bending of the magnetostrictive material thin film 3 depending on the magnetization direction. Therefore, the surface of the silicon substrate was thermally oxidized to form an oxide layer having a desired thickness, and the back surface was etched with a potassium hydroxide solution to form a thin substrate. Vertical 1.0
A flat SiO ₂ substrate having a size of 0.5 cm, a width of 0.5 cm, and a thickness of 2 μm was produced. Although SiO ₂ is used as the substrate 1 here, a metal foil having elasticity can also be used.

Next, a base film 2, a magnetostrictive material thin film 3 and a reflective film 4 were sequentially formed on the substrate 1 by a sputtering method. First, titanium was formed as a base film 2 on the substrate 1 to a film thickness of 10 nm. Then, a terbium-iron amorphous alloy as a magnetostrictive material thin film 3 having a film thickness of 2 μm is formed on the base film 2.
The film was formed at m. Although a terbium-iron amorphous alloy is used as the magnetostrictive material here, a crystalline terbium-iron alloy, a terbium-dysprosium-iron alloy, or the like can also be used. Next, aluminum was formed into a film having a thickness of 50 nm as the reflective film 4 on the magnetostrictive material thin film 3. Although aluminum is used as the material for forming the reflective film 4 here, a metal material such as gold or platinum can be used, and a dielectric multilayer film can be used as the reflective film 4.

The magnetic field applying section 200 includes X coils 22 and 2
3, Y coils 24 and 25, and the magnetic core 21. The magnetic core 21 is a rectangular (frame-shaped) metal frame that surrounds the four sides of the element 10 and is made of Mn-Zn ferrite. Here, an oxide material is used as the material for forming the magnetic core 21, but a soft magnetic material such as iron, permalloy, or an iron-cobalt alloy can be used.
The horizontal axis portions 21c and 21d of the magnetic core 21 function as the magnetic cores of the X coils 22 and 23, respectively, and the vertical axis portions 21a and 21b of the magnetic core 21 respectively correspond to the Y coils 24 and 2.
5 functions as a magnetic core. In order for the left and right portions of the horizontal axis portions 21c and 21d of the magnetic core 21 to have the same polarity,
A current is supplied to each of the X coils 22 and 23. As a result, the magnetic field Hx in the X direction in FIG. 2 is applied to the element piece 10 sandwiched by the X coils 22 and 23. Further, the Y coils 24 and 25 are arranged so that the upper portions and the lower portions of the vertical axis portions 21c and 21d of the magnetic core 21 have the same polarity.
By applying current to each of the Y coils 24 and 2
A magnetic field Hy in the Y direction in FIG. 2 can be applied to the element 10 sandwiched by the elements 5.

Next, the operation of the optical switch 100 will be described. First, a current is applied to the X coils 22 and 23 of the magnetic field applying unit 200 to apply a longitudinal magnetic field Hx to the element 10. The magnetic field strength of the magnetic field Hx is, for example, 100 [O
e] to 500 [Oe]. As a result, the magnetostrictive material thin film 3 of the element 10 expands in the longitudinal direction, so that the element 10 bends downward in FIG. At this time,
The other end of the element piece 10 is supported in contact with the stopper 12, and the bending of the element piece 10 is limited. At this time, the light emitted from the optical fiber 13 of the light incident part 31 enters the element 10 through the lens 18, is reflected by the reflection film 4 of the element 10 at a predetermined angle, and then the light emission part 32. It is incident on the optical fiber 15 through the lens 16. Here, the X coils 22 and 2
Even if the magnetic field Hx generated from the magnetic field applying unit 200 is stopped by stopping the supply of the current to the magnetostrictive material thin film 3, the magnetostrictive material thin film 3 remains magnetized due to the coercive force of the magnetostrictive material thin film 3 of the element 10. The bending amount of the piece 10 is kept constant. Therefore, the light emitted from the optical fiber 13 is always
It is incident on 5.

Next, the X coil 22 of the magnetic field applying section 200.
Y coil 2 in a state where the supply of the electric current to and 23 is stopped.
An electric current is applied to each of 4 and 25, and a magnetic field H is applied to the element 10.
Apply y. By applying such a magnetic field Hy, the element 10
In the magnetostrictive material thin film 3 of No., extension in the longitudinal direction (direction of Hx) is eliminated, so that the bending amount of the element piece 10 in FIG. 1 is reduced, and the element piece 10 is displaced to the position shown by the broken line in FIG. At this time, the other end of the piece 10 comes into contact with and is supported by the stopper 11. At this time, the optical fiber 13 of the light incident part 31
The light emitted from passes through the lens 18 and enters the element 10 and is reflected by the reflection film 4 of the element 10 at a predetermined angle.
The light enters the optical fiber 14 through the lens 17 of the light emitting portion 32 through the optical path indicated by the broken line. Here, Y coil 2
The magnetic field applying section 200 is stopped by stopping the current supplied to 4 and 25.
Since the magnetostrictive material thin film 3 remains magnetized by the coercive force of the magnetostrictive material thin film 3 of the element 10 even if the magnetic field Hy generated from the element 10 is zero, the amount of bending of the element 10 is kept constant. Therefore, the light emitted from the optical fiber 13 of the light incident portion 31 is always incident on the optical fiber 14 of the light emitting portion 32.

As described above, the optical switch 100 switches the electric currents supplied to the X coils 22 and 23 and the Y coils 24 and 25 of the magnetic field applying section 200, whereby the element 10
Of the optical fiber 13 of the light incident part 31 by changing the bending amount of the
Since the light from can be reflected in the direction in which the optical fiber 14 or the optical fiber 15 of the light emitting portion 32 exists, switching of the optical transmission path can be realized. Further, the currents to be passed through the X coils 22 and 23 and the Y coils 24 and 25 of the optical switch 100 are required only when switching the state of the element 10, that is, when switching the optical transmission path, and retain the state of the element 10. For X coil 22, 2
It is not necessary to keep the current flowing through the 3 or Y coils 24, 25.

Although the optical switch of the present invention has been specifically described above with reference to the embodiments, the present invention is not limited to this and may include various modifications and improvements. For example, in the above embodiment, as shown in FIG.
The deflection amount of the element is controlled by switching the direction of the applied magnetic field with respect to the X direction and the Y direction. For example, the direction of the applied magnetic field is in the X direction and the thickness direction of the element 10 (direction perpendicular to the paper surface). Can also be switched to control the state of the element. In order to apply a magnetic field in the thickness direction of the element piece, for example, in FIG. 1, electromagnetic coils and permanent magnets may be arranged above and below the element piece 10. Alternatively, a metal frame as a magnetic core may be arranged so that the plane including the frame and the surface of the element are perpendicular to each other. In addition, the magnetic field applying unit 200
Used two coils, the X coil 22 and the X coil 23, in order to generate the magnetic field Hx in the X direction with respect to the element 10, but using either one of the X coils 22 and 23, It is also possible to apply a magnetic field in the X direction to the piece 10. In this case, a gap may be formed in the intermediate portion of each of the vertical axis portions 21a and 21b of the magnetic core 21. As a result, a magnetic field is generated from the gap portion of the vertical axis portion 21a of the magnetic core 21 toward the gap portion of the vertical axis portion 21b, so that the magnetic field is located between the gap portion of the vertical axis portion 21a and the gap portion of the vertical axis portion 21b. A magnetic field in the X direction can be applied to the element 10 that operates. Similarly, when the magnetic field Hy in the Y direction is generated with respect to the element 10, the Y coil 24 and the X
It is also possible to apply a magnetic field in the Y direction to the element piece 10 by using either one of the coils of the coils 25 instead of using the two coils. In this case, the horizontal axis portions 21c and 21 of the magnetic core 21 are
A gap may be formed in each intermediate portion of d.
As a result, a magnetic field is generated from the gap portion of the horizontal shaft portion 21c of the magnetic core 21 toward the gap portion of the horizontal shaft portion 21d, so that the magnetic field in the Y direction can be applied to the element 10 located between them.

Further, in the optical switch shown in FIG. 1, the element piece 10 is constructed by forming the magnetostrictive material thin film 3 on the light input / output side with respect to the substrate 1. The element 10 can be formed by forming the magnetostrictive material thin film 3 on the opposite side. In addition, in the optical switch 100 shown in FIG.
Although the light incident portion 31 and the light emitting portion 32 are positioned on the upper side, they may be positioned on the lower side. In this case, the reflection film 4 of the element 10 may be formed on the back surface of the substrate 1 so that the back surface of the element 10 reflects light.

Further, as the optical switch according to the present invention, instead of the optical switch shown in FIG. 1, for example, a cylindrical magnetostrictive material 4 having a reflective film 49 on the upper surface as shown in FIG. 4 is used.
3, the coil 47 wound around it, and the light incident part 4
It is also possible to fabricate the optical switch 300 including the light emitting section 42 and the light emitting section 42. By passing a current through the coil 47 of the optical switch 300 shown in FIG.
3 is applied with a magnetic field in the length direction, and the columnar magnetostrictive material 43
Extends in the longitudinal direction as indicated by the broken line. As a result, the light from the light incident portion 41 is reflected by the reflection film 49 on the upper surface of the cylindrical magnetostrictive material 43 and enters the optical fiber 45. By demagnetizing the cylindrical magnetostrictive material 43, the magnetization of the cylindrical magnetostrictive material 43 disappears, and the cylindrical magnetostrictive material 43 contracts to the position shown by the solid line. At this time, the light from the light incident portion 41 is reflected by the reflection film 49 on the upper surface of the cylindrical magnetostrictive material 43 to be reflected by the light emitting portion 4.
It is incident on the second optical fiber 46. As described above, the optical switch 300 shown in FIG. 4 can also switch the light from the light incident portion 41 to the optical fiber 45 and the optical fiber 46 of the light emitting portion 42, similarly to the optical switch shown in FIG. Therefore, the light transmission path can be switched. Although a cylindrical magnetostrictive material is used here as the magnetostrictive material, a prismatic magnetostrictive material can also be used.

[0028]

The optical switch of the present invention can realize switching of an optical transmission path with an extremely simple structure. Further, since the manufacturing process when manufacturing the optical switch can be simplified, an inexpensive optical switch can be provided.

[Brief description of drawings]

FIG. 1 is a schematic plan view of an optical switch according to the present invention.

FIG. 2 is a sectional view taken along line AA of the optical switch shown in FIG.

FIG. 3 is a schematic cross-sectional view of a piece used in the optical switch according to the present invention.

FIG. 4 is a conceptual diagram of an optical switch utilizing expansion and contraction of a cylindrical magnetostrictive material according to the present invention.

[Explanation of symbols]

1 substrate 2 Underlayer film 3 Magnetostrictive material thin film 4 Reflective film 10 pieces 11, 12 stopper 13, 14, 15 optical fiber 16, 17, 18 lens 19 Support 21 magnetic core 22, 23 X coil 24, 25 Y coil 31 Light incident part 32 Light emitting part 200 Magnetic field application section

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Koichiro Wakabayashi             Hitachima, 1-88, Torora, Ibaraki City, Osaka Prefecture             Within Kucsel Co., Ltd. (72) Inventor Norio Ota             Hitachima, 1-88, Torora, Ibaraki City, Osaka Prefecture             Within Kucsel Co., Ltd. F term (reference) 2H041 AA12 AB14 AC05 AZ02 AZ06                       AZ08

Claims (14)

[Claims] 1. An optical switch for switching a light transmission path; a light incident part; a light emitting part; a base, an element including a thin film made of a magnetostrictive material and a reflection film; and a magnetic field applied to the element. An optical switch for switching the light from the light incident part to the light emitting part by utilizing the difference in the bending of the element piece due to the magnetic field applied by the magnetic field applying means. 2. The optical switch according to claim 1, wherein the reflective film is formed on at least one surface of the base. 3. The optical switch according to claim 1, further comprising a support member for supporting one end of the element piece, and a stopper for locking the other end of the element piece. 4. The optical switch according to claim 1, wherein the magnetostrictive thin film is formed by using an alloy composed of a rare earth element and an iron group element. 5. The rare earth metal element is at least one element selected from the group consisting of terbium, dysprosium, and samarium, and the iron group element is at least selected from the group consisting of iron, cobalt, and nickel. The optical switch according to claim 4, wherein the optical switch is one kind of element. 6. The optical switch according to claim 1, wherein the magnetic field applying unit generates a magnetic field in a longitudinal direction of the element and a direction perpendicular to the surface of the element. . 7. The magnetic field applying means generates a magnetic field in the longitudinal direction and in a direction perpendicular to the longitudinal direction within the plane of the elemental piece, according to claim 1. Optical switch. 8. The optical switch according to claim 1, wherein the magnetic field applying unit is a coil. 9. The optical switch according to claim 8, wherein the coil has a soft magnetic core. 10. The element is a flat plate having a quadrangular planar structure, and the magnetic core is a quadrangular frame member arranged so as to surround four sides of the element, and each side of the frame member. The optical switch according to claim 9, wherein a coil is wound around each. 11. The optical switch according to claim 1, wherein the light incident portion and the light emitting portion have optical fibers. 12. An optical switch for switching a light transmission path; a magnetostrictive material having a reflecting surface; a light incident portion and a light emitting portion;
A magnetic field applying means for applying a magnetic field to the magnetostrictive material; 13. The optical switch according to claim 12, wherein the magnetostrictive material is an alloy composed of a rare earth element and an iron group element. 14. The rare earth metal element is terbium,
At least one element selected from the group consisting of dysprosium and samarium, wherein the iron group element is iron,
The optical switch according to claim 13, wherein the optical switch is at least one element selected from the group consisting of cobalt and nickel.