JP2004325982A - Optical switch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent occurrence of a light loss based on a magnetic hysteresis and to realize a stable operation of an optical switch which performs switching of optical paths by using variation in the bend of a magnetic strain element piece. <P>SOLUTION: The element piece of the optical switch is almost or absolutely not bent when a magnetic field is not applied on the element piece. In this case, the light from a light incident part is not shielded by the element piece but irradiated toward a first light emitting part. Meanwhile, the magnetic strain thin film composing the element piece is extended or contracted when the magnetic field is applied on the element piece, a deviation strain is generated between the thin film and the base body constituting the element piece, thus, the element piece is bent to either side of the base body or the magnetic strain thin film. In this case, the light is shielded by the element piece, a mirror provided on the element piece on the optical path of the light from the light incident part is displaced and the mirror reflects and guides the light to a second light emission part. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical switch using a piece having a magnetostrictive film formed on a substrate.
[0002]
[Prior art]
In an optical communication system, an optical switch is required to switch an optical communication line. As one of the optical switch systems, for example, an optical switch of a system in which a reflection mirror is arranged on an optical path and the angle of change of the reflection mirror is changed to change the light reflection direction is known. 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, and the like are known.
[0003]
2. Description of the Related Art An optical switch using an attractive force of a magnet and an electromagnet is known as a conventional magnetic force type optical switch (for example, see Patent Document 1). This optical switch is configured such that a mirror on which a magnetic body is mounted is mounted on a substrate via a support that can move three-dimensionally, and an electromagnet is provided near the mirror. In such an optical switch, an electromagnet is operated to generate a magnetic field from the electromagnet, a 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]
Further, as an optical switch of a magnetic force system different from this, an optical switch using a piece (magnetostrictive element) in which a film made of a magnetostrictive material is formed on a substrate having bending elasticity and flexibility is known. (For example, see Non-Patent Document 1). In this optical switch, light from an incident optical fiber is reflected by a mirror formed on the surface of the magnetostrictive element. When no magnetic field is applied to the magnetostrictive element, light is incident on the mirror at a predetermined angle, and light reflected on the mirror surface is guided to the first output optical fiber. In contrast, when a magnetic field is applied to the magnetostrictive element, the magnetostrictive element bends. Accordingly, light is incident on the mirror surface at an incident angle different from that when no magnetic field is applied, and light reflected on the mirror surface is reflected by the second output optical fiber located at a different position from the first output optical fiber. To the exit optical fiber. As described above, by switching the value of the applied magnetic field and controlling the amount of bending of the magnetostrictive element, light can be switched.
[0005]
[Patent Document 1]
JP-A-2000-162520 (pages 1 to 5)
[Non-patent document 1]
S. Moon, S.M. H. Lim et al., "Optical Switch Driven by Giant Magnetostrictive Thin Film Systems, Part of the Digital System, D.E., Optical Switch Driven by Giant Magnetostrictive Thin Films." Paris, France) (March to April 1999) (pp. 854-862)
[0006]
[Problems to be solved by the invention]
However, in an optical switch using the attractive force of a magnet and an electromagnet, it is necessary to attach a magnetic body to the mirror and attach the mirror to the substrate via a deformable support, so that the number of parts increases. There has been a problem that the structure is complicated and the manufacturing process is also complicated.
[0007]
In an optical switch using a magnetostrictive element, if the applied magnetic field is reduced to zero after applying a magnetic field to the magnetostrictive element, the residual magnetization due to the influence of magnetic hysteresis disappears after a certain period of time. When the magnetostrictive film has a magnetic hysteresis, as shown in FIG. 8A, after a magnetic field is applied from the demagnetized state to saturate the magnetization, and even when the magnetic field is again reduced to zero, the original demagnetized state is strictly restored. It does not return and becomes a residual magnetization state. In this state, when the magnetic field applied to the magnetostrictive film is repeatedly turned ON / OFF, the state reciprocates between the saturated magnetization state and the residual magnetization state, and these states are repeatedly reproduced in a short time. Thereby, the magnetostrictive film also expands and contracts according to the change in these states. On the other hand, when the magnetostrictive film is left for several hours without applying a magnetic field in the residual magnetization state, the magnetostrictive film gradually changes from the residual magnetization state to the demagnetized state (arrow AR8 in FIG. 8A). The magnetostrictive state also returns to the original state when no magnetic field is applied. As a result, although slightly, the amount of deflection (deflection angle) of the magnetostrictive element changes, the optical path of the light reflected on the mirror surface is slightly shifted, and a loss occurs when the light enters the output optical fiber. .
[0008]
Another cause of the change in the magnetization state of the magnetostrictive film in the demagnetized state is that, as shown in FIG. 8B, there is a case where the bending of the magnetostrictive film remains even when the applied magnetic field is zero. . For example, the direction of each magnetization in the magnetostrictive film may be in a random direction as shown in the lower left diagram of FIG. 8B, or may be reversed in a predetermined direction as shown in the lower right diagram of FIG. 8B. It may be aligned in the direction. When the magnetization direction is random as shown in the lower left part of FIG. 8B, the magnetostrictive film does not expand or contract because the magnetization as a whole is canceled. On the other hand, when the directions (vectors) of adjacent magnetizations are opposite to each other as shown in the lower right diagram of FIG. 8B, the directions of the adjacent magnetizations are opposite but along a certain direction. Since they are arranged vertically, they expand or contract in that direction in accordance with the sign of the magnetostriction constant of the magnetostrictive film. As described above, even when the applied magnetic field is set to zero, the magnetization is distributed so that the direction of the magnetization of the magnetostrictive film is oriented along the predetermined direction, so that the magnetostrictive film is in a stretched state. That is, even when the applied magnetic field is zero, the bending of the magnetostrictive element may remain. As described above, the residual bending of the magnetostrictive element affects the optical path of the reflected light.
[0009]
The magnetic hysteresis in the magnetostrictive film can be reduced to a negligible level by improving the soft magnetic characteristics of the magnetostrictive film.However, when a magnetostrictive material having a large magnetostriction constant is selected as the magnetostrictive film, Magnetic hysteresis tends to increase. Therefore, in an optical switch using a magnetostrictive film having magnetic hysteresis, it is important to suppress or eliminate optical loss.
[0010]
Therefore, an object of the present invention is to provide an optical switch that switches the optical path by using a change in the amount of bending of a magnetostrictive element, thereby preventing the occurrence of optical loss based on magnetic hysteresis and achieving stable operation. It is to provide a switch.
[0011]
[Means for Solving the Problems]
According to an aspect of the present invention, a light incident portion for entering light into the optical switch;
A first light emitting unit and a second light emitting unit that selectively emit light from the light incident unit from the optical switch;
A substrate comprising a base, a thin film formed of a magnetostrictive material on one side of the base, and a mirror;
Magnetic field applying means for applying a magnetic field to the element;
When a magnetic field is applied to the element, light from the light incident portion is guided to the second light emitting portion via the mirror, and when no magnetic field is applied, light from the light incident portion is emitted. Is guided to the first light emitting unit.
[0012]
In the optical switch of the present invention, the element is hardly or not bent at all while no magnetic field is applied to the element. At this time, the light from the light incident part is irradiated toward the first light emitting part without being blocked by the element. On the other hand, when a magnetic field is applied to the element, the magnetostrictive thin film constituting the element expands or contracts, thereby causing a shear stress between the element and the substrate constituting the element, and the element is placed on the substrate side or the magnetostrictive thin film. Flex to either side. At this time, the light is blocked by the element, the mirror provided on the element is displaced in the optical path of the light from the light incident part, and the mirror reflects the light and guides it to the second light emitting part. In the optical switch of the present invention, since the light from the light incident portion does not irradiate the mirror when the applied magnetic field is set to zero as described above, the light is transmitted to the first light emitting portion regardless of the bending amount of the element. Always guided. Thus, switching of the 1 × 2 channel optical switch can be performed without causing optical loss.
[0013]
In the optical switch according to the aspect of the invention, it is preferable that the reflection surface of the mirror be substantially parallel to one surface of the base. Preferably, a thin film is formed only on a part of one surface of the base, and the mirror is arranged in a region on one surface of the base where the thin film is not formed. As a result, the element portion in the region where the mirror is arranged does not bend, and therefore, the reflection surface of the mirror can be kept horizontal.
[0014]
In the optical switch of the present invention, it is preferable that the magnetization of the thin film is a saturation magnetization when a magnetic field is applied. Further, it is preferable that the magnetic field applied using the magnetic field applying means is a magnetic field larger than the saturation magnetic field of the thin film. Thus, the amount of deflection of the element when a magnetic field is applied becomes maximum and constant. Further, it is preferable that at least one of the light incident portion and the light emitting portion is an optical fiber with a lens.
[0015]
In the optical switch according to the aspect of the invention, it is preferable that the magnetic field applying unit includes a core partially including a hard magnetic material, a coil provided around the core, and a power supply. Further, the hard magnetic material may be made of a hard magnetic material having a different coercive force. Thus, even when the application of the magnetic field is stopped immediately after the application of the magnetic field to the core by using the magnetic field applying means, the magnetic field continues to be generated in the core, so that the bent state of the element piece is maintained as it is.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited thereto.
[0017]
Embodiment 1
A first embodiment of the optical switch according to the present invention will be described with reference to FIGS. FIGS. 1A and 1B are schematic diagrams of an optical switch 200 of the present invention. FIG. 1A shows that the magnetostrictive element 10 constituting the optical switch 200 is not bent, and the light incident portion The light emitted from the optical fiber with lens 12 is directly incident on the optical fiber with lens 14 serving as a first light emitting portion disposed at a position facing the optical fiber 12. On the other hand, FIG. 1B shows a state in which the magnetostrictive element 10 is bent, and light emitted from the optical fiber 12 is transmitted to the optical fiber 14 via the mirror 5 formed on the magnetostrictive element 10. Shows a state in which the light enters the optical fiber with lens 16 serving as a second light emitting unit disposed at a different position. Details regarding the operation of the optical switch 200 of this embodiment will be described later.
[0018]
[Method of manufacturing magnetostrictive element]
Next, a method for manufacturing a magnetostrictive element used for the optical switch of the present invention will be described with reference to FIG. As shown in FIG. 2, the magnetostrictive element 10 includes a base 1, a magnetostrictive material layer 3, and a mirror 5. The base 1 is a flat quartz glass having a length of 10 mm, a width of 0.8 mm, and a thickness of 20 μm. Next, a magnetostrictive material layer 3 was formed on one surface of the base 1 by sputtering. At this time, as the magnetostrictive material layer 3, a samarium-iron alloy having a negative magnetostriction constant was formed so as to have a thickness of 6 μm. In addition, the region was masked in advance so that the magnetostrictive material layer 3 was not formed in the region 1a 1 mm from one end in the longitudinal direction of the base 1, and sputtering was performed. Next, sputtering was performed by masking such that the mirror 5 was formed only on the surface 1b of the substrate 1 opposite to the surface on which the magnetostrictive material layer 3 was formed and only on the region 1b behind the region 1a. At this time, gold was formed as the mirror 5 to have a thickness of 100 nm. The mirror 5 had a square shape of 0.5 mm × 0.5 mm, and the surface of the mirror 5 was substantially parallel to the surface of the base 1. In this embodiment, quartz glass is used as the base 1, but silicon, metal foil, or the like may be used.
[0019]
[Manufacturing method of optical switch]
Next, an optical switch manufactured using the magnetostrictive element 10 thus obtained will be described with reference to FIGS. As shown in FIG. 1A, the optical switch 200 mainly includes a magnetic core 100, a coil 13, a magnetostrictive element 10, an optical fiber 12 with a lens for incidence, optical fibers 14 and 16 with a lens for emission, and It is composed of a power supply (not shown). As shown in FIGS. 3A and 3B, the magnetic core 100 has a width (length in the Y direction in the figure) d ₁ = 15 mm, length (length in X direction in the figure) d ₂ = 10 mm and height (length in the Z direction in the figure) d ₃ = 10 mm, and a through hole 101 penetrating in the X direction is formed inside the magnetic core 100. As shown in FIG. 3B, the magnetic core 100 is divided into a top surface 100a and a bottom surface 100b in the Z direction by the through holes 101. Further, a gap 18 extending in the X direction is formed at the center of the upper surface 100a of the magnetic core 100 in the Y direction, and the gap 18 divides the upper surface 100a into a right upper surface 100ar and a left upper surface 100al. . The gap 18 communicates with the through hole 101. The width of the through hole 101 and the width of the gap 18 (gap width) are 10 mm and 1.2 mm, respectively. The magnetic core 100 is made of a soft magnetic material made of ferrite. The soft magnetic material of the magnetic core 100 has a coercive force of 0.2 [Oe]. The magnetic core 100 was produced by pressing a soft magnetic material made of ferrite into a desired shape.
[0020]
As shown in FIG. 1A, a coil 13 made of an enameled wire having a diameter of 0.3 mm is provided on the bottom portion (100b) of the magnetic core 100 so as to rotate about 200 times in the X and Z directions. I have. A power supply (not shown) is connected to both ends of the coil 13 and supplies power to the coil 13. The magnetostrictive element 10 extends in the X direction in the gap (18), and is arranged such that the surface of the magnetostrictive element 10 is parallel to the surface of the upper surface (100 a) of the magnetic core 100. Here, as shown in FIG. 1A, an adhesive is attached to the support piece 15 sandwiched between the ends of the gap (18), with one end of the magnetostrictive element 10 on the side where the mirror 5 is not formed as a fixed end. The other end of the magnetostrictive element 10 was left free without being supported. Note that the magnetostrictive element 10 is arranged in the gap such that the magnetostrictive material layer of the magnetostrictive element 10 faces the coil 13 side.
[0021]
Next, the arrangement of the optical fiber 12 with a lens for incidence and the optical fibers 14 and 16 with a lens for emission will be described with reference to FIG. The optical fiber with a lens for incidence 12 and the optical fibers with a lens for emission 14 and 16 are optical fibers each having a condensing lens at the tip, and use an optical fiber for a single mode with a wavelength of 1.5 μm. Was. As shown in FIG. 4A, at a position facing the optical fiber 12 (on the optical axis of the optical fiber 12), the light emitted from the optical fiber with a lens for incidence 12 is directly incident. An optical fiber with a lens for emission is arranged. On the other hand, as shown in FIG. 4B, when the amount of deflection of the magnetostrictive element 10 becomes saturated as described later, the optical fiber with a lens for emission 16 is separated from the optical fiber for incidence 12. It is arranged at a position where the light irradiated and reflected on the surface of the mirror 5 formed on the magnetostrictive element 10 is incident.
[0022]
[Driving method of optical switch]
Next, a driving method of the optical switch 200 will be described with reference to FIG. As shown in FIG. 1B, a magnetic field is generated in the magnetic core 100 by supplying power to the coil 13 by a power supply (not shown). At this time, a magnetic field is generated in the gap of the magnetic core 100 in the width direction (Y direction) of the magnetostrictive element 10. Thereby, the magnetostrictive material layer made of the samarium-iron alloy of the magnetostrictive element 10 disposed in the gap shrinks in the direction of the generated magnetic field, and as a result, the longitudinal direction of the element is orthogonal to the generated magnetic field. (X direction). The extension of the magnetostrictive material layer causes a shear stress between the magnetostrictive material layer of the magnetostrictive element piece 10 and the base, and the magnetostrictive element piece 10 is indicated by an arrow AR1 with the fixed end fixed by the support piece 15 as a fulcrum. Thus, it bends on the opposite side to the coil 13 side, that is, upward. As a result, the displacement required for switching the optical switch is obtained.
[0023]
Here, the amount of deflection of the magnetostrictive element 10 will be described with reference to FIG. FIG. 5 is a graph showing the relationship between the current flowing through the coil and the angular displacement of the surface of the mirror provided on the magnetostrictive element 10. The angular displacement of the mirror surface is saturated at a current value of 90 mA, and the angular displacement is constant even when a current of 90 mA or more flows. In this magnetostrictive element 10, it was found that when the current was made zero after repeating ON / OFF of the current of 120 mA, the angle of the mirror surface gradually changed, and after several hours, changed by about 0.1 °. . This is because, as described above, the magnetostrictive material layer of the magnetostrictive element gradually changes from the remanent magnetization state to the demagnetization magnetization state. On the other hand, when a current of 120 mA was applied, no angular displacement of the mirror surface was observed even after a long time had passed.
[0024]
Next, a specific method of switching an optical switch in the present embodiment will be described with reference to FIGS. As shown in FIG. 1A and FIG. 4A, in the state where no current flows through the coil 13, that is, when no magnetic field is applied to the magnetic core 100, the magnetostrictive element 10 of the optical switch 200 The light emitted from the incident optical fiber 12 does not bend, and directly enters the output optical fiber 14. On the other hand, a current of 120 mA is applied to the coil 13 so that the magnetic field H is applied to the gap of the magnetic core 100. ₁ = 450 [Oe], the magnetostrictive element 10 bends in the direction of arrow AR1 as shown in FIGS. 1 (b) and 4 (b). As described above, the bending amount of the magnetostrictive element 10 is saturated. Also, when the magnetostrictive element 10 bends, the light emitted from the incident optical fiber is incident on the surface of the mirror 5 on the magnetostrictive element 10 and, after being reflected by the mirror 5, is different from the optical fiber 14. The light is incident on the optical fiber 16 installed at a position and a position where the reflected light can be incident. In this way, by turning ON / OFF the power supply to the coil 13, the optical path can be switched. Thereby, optical switching is realized.
[0025]
In the optical switch according to the present embodiment, when the magnetostrictive element is returned to the original state in which the magnetostrictive element does not bend, a sufficient space is provided between the magnetostrictive elements so that the optical path of light emitted from the optical fiber for incidence is not interrupted. Elements are arranged. As a result, even if the bending state of the magnetostrictive element changes slightly due to the influence of the residual magnetic field or the random change in the magnetization state after the applied magnetic field is reduced to zero as described above, the incident optical fiber is Does not affect the emitted light. Therefore, there is no loss of light incident on the output optical fiber. In addition, when a magnetic field that causes saturation magnetization is applied, the bending change of the magnetostrictive element is constant, and light reflected on the mirror surface of the magnetostrictive element is always reflected in a predetermined direction. Therefore, no light is lost in this case.
[0026]
Further, as shown in FIG. 2, the mirror 5 of the magnetostrictive element 10 in this embodiment is formed in the area 1b on the back side of the area 1a of the base 1 where the magnetostrictive material layer 3 is not formed. Even when the piece 10 is bent, the flatness of the substrate surface in the region 1b is maintained. That is, the flatness of the reflection surface of the mirror 5 is also maintained. Thus, the reflection surface of the mirror 5 can be prevented from functioning as a convex mirror, and the spread of the light flux of the reflected light and the change in the cross-sectional shape of the reflected light can be suppressed. Therefore, it is also possible to suppress the occurrence of light loss due to these.
[0027]
Embodiment 2
A second embodiment of the present invention will be described with reference to FIGS. FIG. 6 shows an optical switch 600 according to the present embodiment, and FIG. 7 shows a magnetic core 500 used for the optical switch 600. In this embodiment, two types of hard magnetic materials (ferrites) having different coercive forces are arranged so that the magnetic core is divided at the center of the bottom surface of the magnetic core in the Y direction, that is, arranged at a position facing the gap. ), Except that a hard magnetic material portion was formed. As shown in FIG. 7A, the hard magnetic body portion of the magnetic core includes a first hard magnetic body portion 55 and a second hard magnetic body portion 57, and the first hard magnetic body portion 55 is a second hard magnetic body portion. The first hard magnetic part 55 is disposed so as to overlap the hard magnetic part 57, that is, on the gap 58 side of the magnetic core 500. The thickness (height) of each of the first hard magnetic body 55 and the second hard magnetic body 57 was 2.5 mm. The coercive force of the first hard magnetic part 55 has 80 [Oe], and the coercive force of the second hard magnetic part 57 has 2500 [Oe]. The magnetic core 500 was manufactured as follows. The soft magnetic body 51, the first hard magnetic body 55, and the second hard magnetic body 57 were each press-molded in a desired shape. Next, the first hard magnetic member 55 and the second hard magnetic member 57 are fixed to each other with an adhesive, and the fixed first hard magnetic member 55 and the second hard magnetic member 57 are bonded to the soft magnetic member 51. It was fixed with the agent.
[0028]
Next, the magnetic characteristics of the magnetic core 500 will be described with reference to FIGS. When a current of 150 mA flows through the coil, an external magnetic field H, which is a magnetic field between the coercive force of the first hard magnetic body portion 55 and the coercive force of the second hard magnetic body portion 57, ₁ '= 90 [Oe] is generated. External magnetic field H ₁ ′ Exceeds the coercive force of the first hard magnetic body 55, the first hard magnetic body 55 ₁ Magnetize in the direction aligned with '. It should be noted that the second hard magnetic body portion 57 has an external magnetic field H in advance. ₁ It is assumed that it is magnetized in the direction of '. Here, the external magnetic field H ₁ 7C, the first and second hard magnetic portions 55 and 57 have magnetic hysteresis, as shown in FIG. 7C, so that the residual magnetizations AR55a and AR57 remain (FIG. 7B). (See the residual magnetic field Ms' in the hysteresis curve of the first hard magnetic body portion shown in FIG. 3). The resultant magnetization AR7a of these residual magnetizations maintains a state in which a magnetic field is generated in the gap 58 of the magnetic core 500.
[0029]
On the other hand, a current of 150 mA flows in the opposite direction to the above, and the magnetic field H ₂ '= −90 [Oe] (that is, H ₂ '= -H ₁ '). Magnetic field H ₂ Since 'is larger than the coercive force of the first hard magnetic body 55, the magnetization of the first hard magnetic body 55 is reversed as shown in FIG. On the other hand, the coercive force of the second hard magnetic body portion 57 is ₂ The magnetization direction of the second hard magnetic body portion 57 does not change as shown in FIG. Here, the external magnetic field H ₂ Is removed, the residual magnetizations AR 55b and 57 remain in the first and second hard magnetic portions 55 and 57, respectively. In the first and second hard magnetic body portions 55 and 57, if the magnitudes of the remanent magnetizations AR55b and AR57 are previously adjusted to be substantially equal, they are opposite to each other. The overall magnetization is almost zero. Thereby, the magnetic field generated in the magnetic core 500 by the hard magnetic material disappears.
[0030]
Using this magnetic core 500, an optical switch 600 as shown in FIG. 6 can be manufactured in the same manner as in the first embodiment. In the optical switch 600 according to the present embodiment, even if the power supply to the coil 53 is stopped after the current is supplied to the coil 53 for a predetermined time (for example, for 10 ms), the magnetic field continues to be applied to the gap (58) of the magnetic core 500. Is maintained. Thereby, as shown in FIG. 6, the bending state of the magnetostrictive element 50 disposed in the gap (58) of the magnetic core 500 is also maintained. On the other hand, the magnetic field generated in the magnetic core 500 disappears by flowing the current in the opposite direction to the coil 53 for a predetermined time (for example, for 10 ms). Thereby, the magnetostrictive element 50 returns to a state where it does not bend. As described above, in the optical switch according to the present embodiment, the power needs to be supplied only when the bending state of the magnetostrictive element 50 is switched, that is, only when the light is switched. The bent state of the piece is maintained in each state and can be said to be a state of self-holding. Further, the optical switch of this embodiment has the same polarity (± H ₁ By simply switching '), the state of the optical switch can be switched.
[0031]
In this embodiment, the first hard magnetic body portion and the second hard magnetic body portion are fixed using an adhesive, but the first hard magnetic body portion is mounted on the second hard magnetic body portion using an adhesive. Instead, the soft magnetic body 51 may be fixed to the side surface of the soft magnetic body 51 with an adhesive. Further, in the present embodiment, two types of hard magnetic materials having different coercive forces were formed with the same thickness, but the thickness of the hard magnetic material having a high coercive force was changed to the thickness of the hard magnetic material having a low coercive force. The first and second hard magnetic body portions may be formed so as not to be smaller. Thereby, the applied magnetic field for canceling the magnetization of the hard magnetic body can be reduced. Further, the hard magnetic portion is formed of one kind of hard magnetic material, and the magnetic field generated in the gap of the magnetic core becomes zero by canceling the magnetization of the soft magnetic material of the magnetic core by the magnetization of the hard magnetic material. By applying, the same effect as in this embodiment can be obtained.
[0032]
In the above embodiment, the magnetostrictive material layer is formed using a samarium-iron amorphous alloy having a negative magnetostriction constant. However, an erbium-iron alloy, a thulium-iron alloy, a samarium-iron-cobalt alloy, and a samarium-erbium- It may be formed using an iron alloy, a samarium-thulium-iron alloy, or the like. Further, a terbium-iron alloy, a holmium-iron alloy, a terbium-nickel alloy, a terbium-cobalt alloy, a terbium-iron alloy (for example, Tb-Co-Fe, Tb-Ni-Fe) having a positive magnetostriction constant, terbium -The magnetostrictive material layer can also be formed using a nickel-based alloy (for example, Tb-Co-Ni), a dysprosium-iron alloy, a gadolinium-iron alloy, a terbium-dysprosium-iron alloy, or the like. When a magnetostrictive material having a positive magnetostriction constant is used for the magnetostrictive material layer, the magnetostrictive material layer is arranged outside the magnetic core, that is, on the mirror forming surface side, in order to keep the bending direction of the magnetostrictive element piece constant. Formed on a substrate.
[0033]
In the above embodiment, the soft magnetic material portion and the hard magnetic material portion used for the magnetic core were manufactured using ferrites having different coercive forces. However, an iron-boron-silicon amorphous alloy, a samarium-cobalt hard magnetic material, or the like was used. May be used. Further, in the above-described embodiment, the case where light is directly incident on the optical fiber 54 from the optical fiber 52 has been described. Alternatively, light may be incident on the optical fiber 54. The position of the optical fiber 56 may be changed in the same manner, and light may be incident on the optical fiber 56 with an appropriate reflecting member interposed therebetween.
[0034]
【The invention's effect】
The optical switch of the present invention accurately guides the light emitted from the light incident portion to the first or second light emitting portion regardless of a small difference in the amount of deflection of the element when the applied magnetic field is set to zero. Therefore, the switching of the 1 × 2 channel optical switch can be performed without causing optical loss.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an optical switch according to a first embodiment of the present invention.
FIG. 2 is a schematic configuration diagram of a magnetostrictive element according to the first embodiment.
FIG. 3 is a schematic diagram of a magnetic core used in the optical switch according to the first embodiment.
FIG. 4 is a diagram for explaining a state of switching to an optical switch according to the first embodiment.
FIG. 5 is a graph showing the relationship between the angular displacement of the mirror surface formed on the magnetostrictive element of the optical switch of Example 1 and the current flowing through the coil.
FIG. 6 is a schematic configuration diagram of an optical switch according to a second embodiment of the present invention.
FIG. 7 is a diagram for explaining a self-holding function in the optical switch according to the second embodiment.
FIG. 8 is a diagram for explaining a problem in an optical switch using a conventional magnetostrictive element.
[Explanation of symbols]
1 Substrate
3 Magnetostrictive material layer
5,5 'mirror
10,50 magnetostrictive element
12,52 Optical fiber with incident lens
14, 16, 54, 56 Optical fiber with exit lens
13,53 coils
15,55 support
18,58 gap
51 Soft magnetic body
55 1st hard magnetic part
57 2nd hard magnetic part
100,500 magnetic core
200,600 Optical switch

Claims (8)

A light incident part for entering light into the optical switch;
A first light emitting unit and a second light emitting unit that selectively emit light from the light incident unit from the optical switch;
A substrate comprising a base, a thin film formed of a magnetostrictive material on one side of the base, and a mirror;
Magnetic field applying means for applying a magnetic field to the element;
When a magnetic field is applied to the element, light from the light incident portion is guided to the second light emitting portion via the mirror. When no magnetic field is applied, light from the light incident portion is emitted. Is guided to the first light emitting unit. The optical switch according to claim 1, wherein a reflection surface of the mirror is substantially parallel to one surface of the base. 3. The light according to claim 2, wherein a thin film is formed only on a part of one surface of the base, and the mirror is arranged in an area on one surface of the base where the thin film is not formed. switch. The optical switch according to any one of claims 1 to 3, wherein the magnetization of the thin film is a saturation magnetization when a magnetic field is applied. The optical switch according to claim 4, wherein the magnetic field applied using the magnetic field applying means is a magnetic field larger than the saturation magnetization of the thin film. The optical switch according to any one of claims 1 to 5, wherein at least one of the light incident part and the light emission part is an optical fiber with a lens. 7. The magnetic field applying means according to claim 1, wherein the magnetic field applying means comprises a core partially including a hard magnetic material, a coil provided around the core, and a power supply. Light switch. The optical switch according to claim 7, wherein the hard magnetic material is made of a hard magnetic material having a different coercive force.

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