JP2004317886A - Optical switch and magnetooptical circuit using same, and method for manufacturing magnetooptical circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical switch whose switching speed is fast and which has superior durability, a magnetooptical circuit, and a method for manufacturing the magnetooptical circuit. <P>SOLUTION: This optical switch includes an optical transmission path (2) made of a dielectric, a magnetic body (3), and a magnetic field application part (4) which changes the magnetized state of the magnetic body (3) by applying a magnetic field to the magnetic body (3), which is arranged nearby the optical transmission path (2) so that light traveling through the optical transmission path (2) is reflected by a surface of the magnetic body (3). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical switch, a magneto-optical circuit using the same, and a method for manufacturing a magneto-optical circuit.
[0002]
[Prior art]
An optical signal has features such as a larger information capacity and an excellent low-loss property than an electric signal. For this reason, information transmission using optical signals has been mainly used for long-distance backbone network communication and the like. However, at present, it has been considered to use the above-mentioned features to replace transmission that has been performed by electric signals in an integrated circuit until now with transmission by optical signals. At this time, in order to form an optical circuit that makes full use of the characteristics of the optical signal such as large capacity and low loss, an optical switch that does not need to perform optical-electrical conversion is required.
[0003]
At present, instead of a conventionally used electric switch, a reflector switch, which is a kind of MEMS (Micro Electro Mechanical Systems) formed by microelectronics technology, has been attracting attention as a next-generation optical switch (for example, , Patent Document 1,).
[0004]
[Patent Document 1]
JP 2001-296486 A
[0005]
[Problems to be solved by the invention]
However, an optical switch based on MEMS is an optical switch that operates mechanically, and it is considered that there is a limit to the switching speed due to its operation principle. For example, the response speed of a general optical switch using MEMS is on the order of several msec. In addition, the response speed may be further reduced during long-term use due to, for example, wear of the operating portion. Therefore, there is a demand for an optical switch having a higher switching speed and excellent durability.
[0006]
[Means for Solving the Problems]
The optical switch of the present invention includes a light transmission path made of a dielectric, a magnetic body, and a magnetic field applying unit that changes a magnetization state of the magnetic body by applying a magnetic field to the magnetic body, wherein the magnetic body is The light transmission path is disposed near the light transmission path such that light traveling through the light transmission path is reflected on the surface of the magnetic body.
[0007]
Next, the magneto-optical circuit of the present invention includes the optical switch and an optical connection unit that performs at least one selected from input of light to an optical transmission path of the optical switch and output of light from the optical transmission path. Contains.
[0008]
Further, the magneto-optical circuit of the present invention includes a light transmission path made of a dielectric, and an optical connection unit that performs at least one selected from input of light to the light transmission path and output of light from the light transmission path. Including an optical circuit,
A magnetic circuit including a magnetic body and a magnetic field applying unit that changes a magnetization state of the magnetic body by applying a magnetic field to the magnetic body,
The optical circuit and the magnetic circuit may be arranged such that light traveling in the light transmission path is reflected on a surface of the magnetic body.
[0009]
Next, the method for manufacturing a magneto-optical circuit according to the present invention includes: (i) at least one selected from a light transmission path made of a dielectric, and light input to the light transmission path and light output from the light transmission path. Forming an optical circuit including an optical connection portion,
(Ii) forming a magnetic circuit including a magnetic body and a magnetic field applying unit that changes a magnetization state of the magnetic body by applying a magnetic field to the magnetic body;
(Iii) arranging the optical circuit and the magnetic circuit such that light traveling in the light transmission path is reflected on the surface of the magnetic body.
[0010]
Also, the method for manufacturing a magneto-optical circuit according to the present invention includes: (I) a step of forming a laminate including a dielectric and a magnetic material;
(II) forming a light transmission path made of the dielectric by processing the laminate into a predetermined shape, and forming a magneto-optical circuit in which the light transmission path and the magnetic substance are laminated. May be included.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same portions are denoted by the same reference numerals, and redundant description may be omitted.
[0012]
(Embodiment 1)
In this embodiment, an optical switch and a magneto-optical circuit according to the present invention will be described.
[0013]
FIG. 1 is a sectional view showing an example of the optical switch of the present invention. The optical switch 1 shown in FIG. 1 includes a light transmission path 2 made of a dielectric, a magnetic body 3, and a magnetic field that changes a magnetization state (for example, a magnetization direction) of the magnetic body 3 by applying a magnetic field to the magnetic body 3. And an application unit 4. Further, the magnetic body 3 is arranged near the light transmission path 2 so that the light 11 traveling in the light transmission path 2 is reflected on the surface 12 of the magnetic body 3. In such an optical switch, the state of polarization of the light 11 traveling in the light transmission path 2 can be controlled by changing the magnetization state of the magnetic body 3 by the magnetic field applying unit 4.
[0014]
When light is incident on the surface of a magnetic body, the state of polarization of the light reflected on the surface differs depending on the magnetization state of the magnetic body. Such a phenomenon is called a Kerr effect (Kerr Effect: a kind of magneto-optical effect). When light is input to the optical switch 1 shown in FIG. 1 (for example, when laser light is incident on the light transmission path 2), the input light (input light) travels along the light transmission path 2. At that time, part or all of the input light is reflected on the surface of the magnetic body 3. The state of polarization of the reflected light differs depending on the magnetization state of the magnetic body 3 due to the Kerr effect. Therefore, by changing the magnetization state of the magnetic body 3, the polarization state of the light (output light) output from the optical switch 1 can be controlled. When the input light travels along the light transmission path 2 under the condition of total reflection (that is, light traveling on the light transmission path enters the interface between the magnetic body and the light transmission path at an angle equal to or greater than the critical angle. In the case, it is considered that part of the input light is seeping out to the magnetic body 3 side as evanescent light at the interface between the magnetic body 3 and the dielectric substance serving as the light transmission path. Therefore, even under such conditions, the polarization state of the light output from the optical switch 1 can be controlled.
[0015]
Further, in the optical switch 1 shown in FIG. 1, the speed at which the state of polarization of the output light changes is considered to depend on the speed at which the magnetization state of the magnetic body 3 changes. The speed at which the magnetization state of the magnetic body 3 changes can be on the order of several hundred psec to several nsec. For this reason, the optical switch 1 can be an optical switch having a higher switching speed than a conventional optical switch using MEMS or the like. The optical switch 1 is different from the optical switch using MEMS in that it does not include a mechanically operated part. For this reason, an optical switch having more excellent durability can be obtained.
[0016]
In the optical switch of the present invention, the position where the magnetic body 3 is disposed is not particularly limited as long as a part or all of the light traveling along the light transmission path 2 can be reflected on the surface of the magnetic body 3. For example, a gap may be provided between the magnetic body 3 and the light transmission path 2. In this case, the size of the gap is, for example, 0.01 μm or less. If the size of the gap is too large, there is a possibility that light traveling in the light transmission path 2 cannot be reflected on the surface of the magnetic body 3. Further, as in the example shown in FIG. 1, the magnetic body 3 may be arranged in contact with the light transmission path 2. In this case, among the light traveling along the light transmission path 2, more light can be reflected on the surface of the magnetic body 3, so that an optical switch with less loss can be provided.
[0017]
The shape of the magnetic body 3 is not particularly limited as long as part or all of the light traveling in the light transmission path 2 can be reflected on the surface of the magnetic body 3. More specifically, the length of a region of the magnetic body 3 where light traveling in the light transmission path 2 is reflected (for example, when the magnetic body is in contact with the light transmission path, for example, ) And the area are not particularly limited. It may be set arbitrarily according to the cross-sectional area of the light transmission path 2, the wavelength of light traveling in the light transmission path 2, the characteristics required as an optical switch, and the like. For example, the cross-sectional area of the light transmission path 2 in a plane perpendicular to the optical path direction is 0.01 μm.²~ 100 μm²In the case where the wavelength of the light input to the light transmission path 2 is in the range of 200 nm to 2000 nm, the length of the region may be set in the range of 0.05 μm to 2 μm, for example. Further, for example, the area of the above region is 0.0025 μm²~ 4μm²Range. Note that the length of the region is the length of the light transmission path 2 in the optical path direction. The light path direction is a direction in which light travels along the light transmission path 2 as a whole, and is a direction corresponding to the arrow A in FIG. Also in the following figures, the optical path direction in the optical switch may be indicated by an arrow A.
[0018]
Further, the number of magnetic bodies 3 arranged near the light transmission path 2 is not particularly limited. It may be one or plural. When a plurality of magnetic bodies 3 are arranged, their relative positions are not particularly limited. What is necessary is just to set arbitrarily according to the characteristic required as an optical switch.
[0019]
The material used for the magnetic body 3 is not particularly limited, and for example, a ferromagnetic material may be used. When a ferromagnetic material is used, it is possible to more easily change the magnetization state of the magnetic material by the magnetic field application unit.
[0020]
The ferromagnetic material used for the magnetic material is not particularly limited. Above all, Heusler alloys such as PtMnSb and NiMnSb, amorphous alloys such as Tb-Co-Fe-based, Ho-Co-Fe-based, irregular alloys such as Fe-Co-Pt-based, and ordered alloys such as Mn-Pt-based If a material or the like is used, the polar Kerr effect, which will be described later, can be further enhanced, and the state of polarization of light traveling in the light transmission path can be changed more greatly.
[0021]
In the optical switch of the present invention, the magnetization direction of the magnetic body 3 may be a direction perpendicular to the surface (the surface 12 in the example of FIG. 1) on which light traveling along the light transmission path 2 is reflected. That is, the magnetization direction of the magnetic body 3 may be a direction perpendicular to the optical path direction of the light transmission path 2 (hereinafter, such a magnetic body 3 is also referred to as a magnetic body having perpendicular magnetization). In this case, the light reflected on the surface of the magnetic body 3 receives a magneto-optical effect called a polar Kerr effect. For this reason, the polarization state of the light traveling in the light transmission path 2 can be changed more greatly, and an optical switch with less loss can be obtained.
[0022]
The dielectric used for the light transmission path 2 is not particularly limited as long as it can transmit input light. For example, an optically transparent material, lithium niobate (LiNbO)₃) And lithium tantalate (LiTaO)₃) May be used. In this case, an optical crystal that has been subjected to proton exchange by diffusing Ti or the like into the optical crystal may be used. Further, since the light confinement effect is large, ferroelectric materials having a large refractive index, for example, lead titanate (PT), lead lanthanum titanate (PLT), lead zirconate titanate (PZT), and lead lanthanum zirconate titanate PLZT-based material containing (PLZT) (more specifically, for example, the formula Pb_1-pLa_p(Zr_qTi_1-q)_{1-p / 4}O₃Any material having a composition represented by As p and q, for example, 0 <p <0.28, 0 <q <1.0) or the like may be used. The optical crystal and the ferroelectric material can be formed into an arbitrary shape and size by an existing semiconductor manufacturing process or the like. When the optical transmission path 2 is formed using the above-mentioned optical crystal and ferroelectric material, the mode can be set using the optical transmission path 2 as a waveguide.
[0023]
The light input to the light transmission path 2 is not particularly limited. Light of a single wavelength may be used, or light of a plurality of wavelengths may be mixed. As a light source of such light, for example, a long wavelength semiconductor laser such as GaInAsP / InP, a vacuum ultraviolet short wavelength laser having a wavelength of about 200 nm, or the like may be used.
[0024]
The structure and the position of the magnetic field application unit are not particularly limited as long as the magnetization state of the magnetic body 3 can be changed. What is necessary is just to set arbitrarily according to the characteristic required as an optical switch. For example, a gap may be provided between the magnetic field applying unit 4 and the magnetic body 3, or both may be in contact with each other. If necessary, an insulator or the like may be arranged between the magnetic field applying unit 4 and the magnetic body 3.
[0025]
FIG. 2 shows another example of the optical switch of the present invention. In the optical switch 1 shown in FIG. 2, the magnetic field applying unit 4 includes a wiring 41 for inducing a magnetic field. The wiring 41 is arranged so as to sandwich the magnetic body 3 between the wiring 41 and the light transmission path 2. In such an optical switch, a magnetic field can be generated by flowing a current through the wiring 41 to change the magnetization state of the magnetic body 3. At this time, if the direction of the current flowing through the wiring 41 is reversed, the magnetization direction of the magnetic body 3 can be easily reversed. Further, since the current flowing through the wiring 41 can be changed on the order of several hundred psec, an optical switch having a higher switching speed can be provided.
[0026]
The material used for the wiring 41 is not particularly limited as long as it is a conductive material. For example, a material containing Al, Cu, Au, Ag, Pt, or the like may be used. SrRuO₃Alternatively, a conductive oxide such as Further, the thickness, shape, and the like of the wiring 41 are not particularly limited. What is necessary is just to set arbitrarily according to the characteristic required as an optical switch.
[0027]
The distance between the wiring 41 and the magnetic body 3 is not particularly limited as long as the magnetization state of the magnetic body 3 can be changed. What is necessary is just to set arbitrarily according to the characteristic required as an optical switch. For example, a gap may be provided between the wiring 41 and the magnetic body 3. In this case, the size of the gap is, for example, 0.01 μm or less. Further, the wiring 41 and the magnetic body 3 may be in contact with each other. In this case, the magnetic field generated in the wiring 41 can be applied to the magnetic body 3 more efficiently. Therefore, an optical switch having a higher switching speed can be provided. When a problem such as an electrical short circuit occurs due to direct contact between the wiring 41 and the magnetic body 3, another material such as an insulator is arranged between the wiring 41 and the magnetic body 3. Is also good.
[0028]
FIG. 3 shows another example of the optical switch of the present invention. The optical switch 1 shown in FIG. 3 includes a wiring 41 in which the magnetic field applying unit 4 induces a magnetic field, as in the example shown in FIG. The wiring 41 is disposed on the side of the magnetic body 3 and above the light transmission path 2. As described above, the relative position of the wiring 41 with respect to the magnetic body 3 is not particularly limited as long as the magnetization state of the magnetic body 3 can be changed. For example, in FIG. 3, the wiring 41 is arranged facing one side surface of the magnetic body 3, but may be arranged facing another side surface of the magnetic body 3. At this time, the number of the side surfaces of the magnetic body 3 facing the wiring 41 is not limited to one.
[0029]
In addition, as shown in FIG. 3, when the wiring 41 is arranged on the side of the magnetic body 3, the size of the optical switch 1 can be further reduced. Further, when the magnetic body 3 is a magnetic body having perpendicular magnetization, the magnetic field generated in the wiring 41 can be more efficiently applied to the magnetic body 3.
[0030]
FIG. 4 shows another example of the optical switch of the present invention. The optical switch 1 illustrated in FIG. 4 includes a wiring 41 in which the magnetic field applying unit 4 induces a magnetic field, as in the example illustrated in FIG. The wiring 41 is arranged at a position facing the magnetic body 3 as a center. In this case, if currents of opposite phases are applied to the pair of wirings 41, the magnetic field applied to the magnetic body 3 can be further increased, and the magnetic field generated in the wirings 41 can be applied to the magnetic body 3 more efficiently. Can be. Further, as in the example shown in FIG. 3, the wiring 41 is arranged on the side of the magnetic body 3, so that the optical switch 1 can be further downsized.
[0031]
Further, the example shown in FIG. 4 can be formed by one wiring 41 as shown in FIG. When a current 42 is applied to the wiring 41 shown in FIG. 5, currents of opposite phases are applied to the pair of wirings 41 shown in FIG. 4, and the magnetic field applied to the magnetic body 3 can be further increased. it can. FIG. 5 is a schematic view of the optical switch 1 shown in FIG. 4 as viewed from above (in the direction of arrow B).
[0032]
FIG. 6 shows another example of the optical switch of the present invention. The optical switch 1 shown in FIG. 6 includes a wiring 41 in which the magnetic field applying unit 4 induces a magnetic field, as in the example shown in FIG. By passing a current 42 through the wiring 41, a magnetic field 43 is generated, and the magnetization state of the magnetic body 3 can be changed. That is, the state of polarized light traveling in the light transmission path 2 can be controlled. In the example shown in FIG. 6, the light transmission path 2 and the magnetic body 3 made of a dielectric are formed on the substrate 13. In addition, FIG. 6 is a schematic diagram, and the scale is changed according to a part in order to make the structure easy to understand. For example, the distance between the wiring 41 and the magnetic body 3 is drawn larger than other portions. Further, the direction of the current 42 is not particularly limited.
[0033]
The material of the substrate 13 is, for example, lithium niobate (LiNbO₃) And lithium tantalate (LiTaO)₃) Or SrTiO doped with a transition metal (for example, Nb or Cr).₃May be used. A compound semiconductor (for example, a GaAs system) may be used. When a compound semiconductor is used, a semiconductor laser serving as a light source can be provided on-chip. Further, Si may be used for the substrate 13. SrTiO_{3- δ}By using such as a buffer on a Si substrate, a GaAs-based, SiGe-based, InP-based, etc. semiconductor (laser) can be formed by epitaxial growth or the like. In addition, when an optical transmission path is formed on the substrate 13, CeO is used as a buffer layer on the substrate 13._{2- δ}And Pt may be arranged. Here, δ is a value reflecting the oxygen deficiency in the material.
[0034]
In the optical switch according to the present invention, the magnetic field applying unit 4 may further include a magnetic flux guide that focuses the magnetic field induced by the wiring 41. An example of such an optical switch is shown in FIGS. 7A and 7B.
[0035]
The optical switch 1 shown in FIGS. 7A and 7B includes, as the magnetic field applying unit 4, a wiring 41 and a magnetic flux guide 44 that focuses a magnetic field induced by the wiring 41. In this case, the magnetic field generated in the wiring 41 can be applied to the magnetic body 3 more efficiently. Therefore, an optical switch having a higher switching speed can be provided.
[0036]
The shape of the magnetic flux guide 44 is not particularly limited as long as the magnetic field generated in the wiring 41 can be focused. It may be set arbitrarily according to the characteristics required for the optical switch, the requirements in the manufacturing process, and the like. For example, the cross section when combined with the wiring 41 may be rectangular as shown in FIG. 7A or trapezoidal as shown in FIG. 7B. In the case of a trapezoidal shape as in the example shown in FIG. 7B, more current can flow at a position closer to the magnetic body to which the magnetic field is applied, so that the magnetic field can be more efficiently applied to the magnetic body. can do. In the example shown in FIGS. 7A and 7B, the wiring 41 and the magnetic flux guide 44 have a shape in which the wiring 41 and the magnetic flux guide 44 are in close contact with each other. However, when both are in close contact, a magnetic field can be more efficiently applied to the magnetic body.
[0037]
The material used for the magnetic flux guide 44 is not particularly limited as long as the magnetic field generated in the wiring 41 can be focused. For example, a ferromagnetic material may be used.
[0038]
The ferromagnetic material used for the magnetic flux guide 44 is not particularly limited, and for example, a soft magnetic alloy film containing at least one element selected from Ni, Co, and Fe may be used. Above all, the formula Ni which indicates the atomic composition ratio_xCo_yFe_zIn the above, a Ni-rich soft magnetic alloy film represented by 0.6 ≦ x ≦ 0.9, 0 ≦ y ≦ 0.4 and 0 ≦ z ≦ 0.3, or 0 ≦ x ≦ 0.4, 0. It is preferable to use a Co-rich soft magnetic alloy film represented by 2 ≦ y ≦ 0.95 and 0 ≦ z ≦ 0.5. Such a soft magnetic material has a small coercive force and can be easily formed.
[0039]
Further, the ferromagnetic material used for the magnetic flux guide 44 preferably does not have an excessively large coercive force. When a ferromagnetic material having an excessively large coercive force is used as the magnetic flux guide, controllability of the magnetization state of the magnetic body 3 is reduced by maintaining the magnetization of the magnetic flux guide 44 itself, or the magnetization direction of the magnetic flux guide 44 itself is changed. For this reason, extra energy is required, and the efficiency as an optical switch may be reduced. In addition, as the value of the saturation magnetic field of the ferromagnetic material used for the magnetic flux guide 44 is larger and / or the magnetic permeability of the ferromagnetic material used for the magnetic flux guide 44 is larger, the thickness of the magnetic flux guide 44 should be reduced. Can be.
[0040]
FIGS. 8A and 8B show another example of the optical switch of the present invention. FIGS. 8A and 8B are schematic diagrams of the optical switch 1 as viewed from above, as in FIG. The optical switch 1 shown in FIGS. 8A and 8B includes, as the magnetic field applying unit 4, a wiring 41 and a magnetic flux guide 44 that focuses a magnetic field induced by the wiring 41. The magnetic flux guide 44 is disposed only near the magnetic body 3 to which a magnetic field is applied. In this case, the magnetic field can be more efficiently applied to the magnetic body 3 without unnecessarily increasing the coercive force of the magnetic flux guide 44. FIG. 8B is a cross-sectional view of the optical switch 1 shown in FIG.
[0041]
When arranging the magnetic flux guide 44 near the magnetic body 3, the magnetic flux guide 44 may be divided and arranged as shown in FIG. In this case, an increase in the coercive force of the magnetic flux guide 44 can be further suppressed, and a magnetic field can be applied to the magnetic body 3 more efficiently. The example shown in FIG. 9 is the same as the example shown in FIG.
[0042]
Next, the magneto-optical circuit of the present invention will be described.
[0043]
The magneto-optical circuit according to the present invention includes the above-described optical switch according to the present invention and an optical connection unit that performs at least one selected from input of light to the optical transmission path of the optical switch and output of light from the optical transmission path of the optical switch. And
[0044]
In other words, the magneto-optical circuit of the present invention performs at least one selected from a light transmission path made of a dielectric material and light input to the light transmission path of the optical switch and light output from the light transmission path of the optical switch. The optical circuit includes an optical circuit including an optical connection unit, and includes a magnetic circuit including a magnetic body and a magnetic field application unit that changes a magnetization state of the magnetic body by applying a magnetic field to the magnetic body. Further, the optical circuit and the magnetic circuit are arranged so that light traveling in the light transmission path is reflected on the surface of the magnetic body.
[0045]
In such a magneto-optical circuit, the state of polarization of light input to the light transmission path can be controlled by the Kerr effect, which is a type of magneto-optical effect, by changing the magnetization state of the magnetic material by the magnetic field application unit. it can. Therefore, a magneto-optical circuit having a high switching speed and excellent durability can be obtained.
[0046]
An example of the magneto-optical circuit of the present invention is shown in FIGS. FIG. 11 is a cross-sectional view showing a part of a cross section of the magneto-optical circuit 6 shown in FIG.
[0047]
The magneto-optical circuit 6 shown in FIGS. 10 and 11 includes a light transmission path 2 made of a dielectric material, and an optical connection unit 5 that inputs light to the light transmission path 2 and outputs light from the light transmission path 2 (ie, , The optical connection unit 5 can also be called an optical input / output unit). In addition, the magneto-optical circuit 6 includes a magnetic circuit 62 including the magnetic body 3 and a magnetic field applying unit that changes a magnetization state of the magnetic body 3 by applying a magnetic field to the magnetic body 3. At this time, the optical circuit 61 and the magnetic circuit 62 are stacked on the substrate 13 so that the light 17 traveling in the light transmission path 2 is reflected on the surface of the magnetic body 3. In the examples shown in FIGS. 10 and 11, the wiring 41 is arranged as a magnetic field applying unit.
[0048]
The optical connection unit 5 includes a polarization filter 51. On the optical connection unit 5, a light emitting / receiving element 15 which is a type of photoelectric conversion element that converts an electric signal and an optical signal into and out of each other is arranged. I have. The light receiving / emitting element 15 is a light source for light input to the optical connection unit 5 (that is, for light input to the light transmission path 2), and is output from the optical connection unit 5 (that is, output from the light transmission path 2). Also, it is a light receiving element that receives light. The plurality of light receiving / emitting elements 15 arranged on the optical connection unit 5 are connected to an LSI 16 that controls the light receiving / emitting element 15. In the magnetic circuit 62, portions other than the magnetic body 3 and the wiring 41 are filled with the insulator 18, and the wirings 41 or the wiring 41 and the magnetic body 3 are electrically insulated. In addition, portions of the optical connection portion 5 other than the polarization filter 51 are filled with an insulator 19 that does not transmit light.
[0049]
The insulator 18 filled in the magnetic circuit 62 is not particularly limited as long as it is an insulating material or a semiconductor material. For example, elements of Group IIa to VIa (Mg, Ti, Zr, Hf, V, Nb, Ta, Cr, etc.), lanthanoids (La, Ce, etc.) and elements of Groups IIb to IVb (Zn, B, Al, A compound of at least one element selected from Ga, Si and the like and at least one element selected from F, O, C, N and B may be used. The insulator 18 may be filled in a portion of the optical circuit 61 other than the light transmission path 2. Further, the insulator 19 filled in the optical connection part 5 is not particularly limited as long as it is an insulating material or a semiconductor material. For example, elements of Group IIa to VIa (Mg, Ti, Zr, Hf, V, Nb, Ta, Cr, etc.), lanthanoids (La, Ce, etc.) and elements of Groups IIb to IVb (Zn, B, Al, A compound of at least one element selected from Ga, Si, and the like and at least one element selected from F, O, C, N, and B may be used. The insulators may be filled in the entire optical circuit 61, the magnetic circuit 62, and the optical connection portion 5, or may be filled only in necessary portions. If not necessary, each part does not have to be filled with the above-mentioned insulator.
[0050]
In such a magneto-optical circuit, by inputting an electric signal to the light receiving and emitting element 15, light generated in the light receiving and emitting element 15 can be input to the light transmission path 2 as an optical signal composed of linearly polarized light. The optical signal input to the light transmission path 2 is reflected on the surface of the magnetic body 3 while traveling along the light transmission path 2 to control the state of polarization. That is, if the magnetization state of each magnetic body 3 on the path of the optical signal input to the light transmission path 2 is controlled, an optical signal can be output from a specific polarizing filter 51 on the path. The output optical signal can be converted into an electric signal again by the light receiving / emitting element 15, for example.
[0051]
In the magneto-optical circuit of the present invention, the structure and material of the optical connection unit 5 are not particularly limited as long as light can be input to the light transmission path 2 and / or light can be output from the light transmission path 2. In addition to the structure shown in the examples of FIGS. 10 and 11, for example, an optical connection unit 5 (light input unit) for inputting light to the light transmission path 2 is arranged at one end of the light transmission path 2, At the other end of the transmission path 2, an optical connection section 5 (light output section) for outputting light from the light transmission path 2 may be arranged. At this time, only one of the light input unit and the light output unit may be arranged.
[0052]
Further, the magneto-optical circuit of the present invention may further include a light source. In this case, a smaller magneto-optical circuit can be obtained. As the light source, for example, a light emitting / receiving element or a semiconductor laser shown in the examples of FIGS. 10 and 11 may be used. When a semiconductor laser is used, it may be integrated with a magneto-optical circuit.
[0053]
In the magneto-optical circuit of the present invention, the light transmission path may be in contact with the magnetic body. As described above in the description of the optical switch, a magneto-optical circuit with less loss can be provided.
[0054]
The magneto-optical circuit as described above can be obtained, for example, by the method for manufacturing a magneto-optical circuit described in the second embodiment. Further, the magneto-optical circuit of the present invention can be used, for example, as a basic element for controlling an optical carrier, such as a communication optical switch.
[0055]
(Embodiment 2)
In the present embodiment, a method for manufacturing a magneto-optical circuit according to the present invention will be described.
[0056]
FIG. 12 shows an example of a method for manufacturing a magneto-optical circuit according to the present invention. First, as shown in FIG. 12A, a light transmission path 2 made of a dielectric and an optical connection unit for inputting light to the light transmission path 2 and / or outputting light from the light transmission path 2 are formed. An optical circuit 61 is formed. In the example shown in FIG. 12A, the optical connection unit includes an optical input unit 52 that inputs light to the optical transmission path 2 and an optical output unit 53 that outputs light from the optical transmission path 2 (step). (I)).
[0057]
Next, as shown in FIG. 12B, a magnetic circuit 62 including the magnetic body 3 and the wiring 41 is formed (step (ii)). The wiring 41 functions as a magnetic field applying unit that changes the magnetization state of the magnetic body 3 by applying a magnetic field to the magnetic body 3. In addition, the order of performing the step (i) and the step (ii) is not particularly limited. For example, step (ii) may be performed first, or step (i) and step (ii) may be performed simultaneously.
[0058]
Next, as shown in FIG. 12C, the optical circuit 61 and the magnetic circuit 62 are laminated so that light traveling in the light transmission path 2 is reflected on the surface of the magnetic body 3 (step (iii)). , A magneto-optical circuit 6 is obtained.
[0059]
With this manufacturing method, a magneto-optical circuit having a high switching speed and excellent durability can be manufactured. Further, when an optical circuit and a magnetic circuit are separately manufactured in advance, the two can be stacked in an optimum positional relationship, or the optical circuit and the magnetic circuit can be freely combined. Note that the optical connection unit may be only one of the light input unit and the light output unit, or as shown in the examples of FIGS. 10 and 11, both the light input and the light output. It may be an optical connection part.
[0060]
In the step (i), a method for forming the optical circuit 61 is not particularly limited. For example, after the light transmission path 2 is formed on the substrate, a part of the light transmission path 2 may be implanted with protons or the like, and the injected area may be used as the light input unit 52 and / or the light output unit 53 to form the optical circuit 61. . Alternatively, the optical circuit 61 may be formed by using a substrate made of a compound semiconductor and forming an embedded transmitting / receiving system (Light Emitting and Deducing Diode: LEAD) on the substrate. In this case, the optical input unit 52 may be, for example, a DFB device realized as an InGaAsP optical IC, a Fabry-Perot device, or the like (Reference: H. Inoue et al .: Applied Physics Letters vol. 51). pp. 1577 (1987)). The light output unit 53 may be, for example, an avalanche device or a Franz-Keldysh device.
[0061]
An example of such an optical circuit 61 is shown in FIG. An optical circuit 61 shown in FIG. 13 has a light transmission path 2 formed on a substrate 13 and a laser 52 formed at one end as a light input section. A light detector 55 is formed at the other end of the light transmission path 2 as a light output unit. Such an optical circuit 61 can perform current driving. Note that the laser 52 and / or the photodetector 55 may be mounted on the substrate 13. If necessary, an optical system such as a lens may be arranged between the laser 54 and the light transmission path 2 and / or between the light transmission path 2 and the light detector 55.
[0062]
In the step (ii), a method for forming the magnetic circuit 62 is not particularly limited. For example, pulsed laser deposition (PLD), ion beam deposition (IBD), cluster ion beam, RF, DC, ECR, helicon, ICP, sputtering method of facing target, molecular beam epitaxy (MBE), ion plating, etc. The magnetic material 3 and the wiring 41 may be laminated on the substrate by using a method such as the PVD method, the CVD method, the plating method, or the sol-gel method. At that time, if necessary, fine processing is performed by combining physical or chemical etching methods such as ion milling, RIE, FIB and the like used in semiconductor processes, and photolithography techniques using a stepper, EB method and the like. Is also good. The surface may be flattened by CMP, cluster ion beam etching, or the like. A specific example will be described later in the embodiment. The magnetic field application unit is not limited to the wiring 41 shown in the example of FIG. 12, and its structure is not particularly limited as long as a magnetic field can be applied to the magnetic body 3.
[0063]
Further, in the above step (iii), the optical circuit 61 and the magnetic circuit 62 may be laminated by bonding the two circuits with, for example, a resist or an ultraviolet curing epoxy resin material. In addition, when laminating, positioning may be performed by placing markers or the like in advance in both circuits. When the two circuits are stacked, their relative positions are not particularly limited. What is necessary is just to set arbitrarily according to the characteristic required as the magneto-optical circuit 6. The relative position between the light transmission path 2 and the magnetic body 3 may be the same as in the case of the above-described optical switch. In particular, when the optical circuit 61 and the magnetic circuit 62 are stacked so that the light transmission path 2 and the magnetic body 3 are in contact with each other, the magneto-optical circuit 6 with less loss can be obtained.
[0064]
When the optical circuit 61 and the magnetic circuit 62 are stacked in the above step (iii), a marker may be set in advance on at least one of the circuits, and both circuits may be stacked together with the marker. . According to such a manufacturing method, a magneto-optical circuit can be manufactured with higher accuracy.
[0065]
FIG. 14 shows another example of the method for manufacturing a magneto-optical circuit according to the present invention. First, as shown in FIG. 14A, a stacked body 7 including a dielectric 71 and a magnetic body 72 is formed (step (I)). The laminate 7 shown in FIG. 14A includes a conductor 74 and an insulator 73 for electrically insulating the conductor 74 and the magnetic body 72 in addition to the dielectric 71 and the magnetic body 72. Contains.
[0066]
Next, as shown in FIG. 14B, a light transmission path made of a dielectric is formed by processing the laminate 7 into a predetermined shape, and the light transmission path 2 and the magnetic body 3 are laminated. The magneto-optical circuit 6 is formed (step (II)). In the magneto-optical circuit 6 shown in FIG. 14B, the light transmission path 2 from the dielectric 71 shown in FIG. 14A, the magnetic substance 3 from the magnetic substance 72 shown in FIG. A conductor 41 shown in FIG. 14A is formed of a wiring 41 serving as a magnetic field applying part, and an insulator 18 for maintaining insulation between the wiring 41 and the magnetic body 3 is formed of an insulator 73 shown in FIG. I have. In addition, at both ends of the light transmission path 2, an optical input unit 52 and an optical output unit 53, which are optical connection units, are arranged. The arrangement of both is based on the steps (I) and (II). And may be performed after the above step (II). When the conductor 74 is not included in the stacked body 7, the wiring 41 serving as the magnetic field applying unit may be arranged between the step (I) and the step (II). It may be performed after II).
[0067]
With this manufacturing method, a magneto-optical circuit having a high switching speed and excellent durability can be manufactured.
[0068]
Further, in the manufacturing method shown in FIG. 14, the step (II) includes a step (a) of removing a part of the magnetic body from the laminate. With such a manufacturing method, the arrangement of the optical switches in the magneto-optical circuit can be finely adjusted. Further, the size of the magneto-optical circuit itself can be reduced more easily.
[0069]
In the step (I), the method for forming the laminate 7 is not particularly limited. For example, pulsed laser deposition (PLD), ion beam deposition (IBD), cluster ion beam, RF, DC, ECR, helicon, ICP, sputtering method of facing target, molecular beam epitaxy (MBE), ion plating, etc. And the other methods such as the PVD method, the CVD method, the plating method, and the sol-gel method. When forming the laminate 7, the dielectric 71 is formed so that when the dielectric 71 becomes a light transmission path, light traveling on the light transmission path can be reflected on the surface of the magnetic substance. And the magnetic body 72 may be laminated. As will be described later in the embodiments, the dielectric 71 may be processed in advance into the shape of a light transmission path (for example, a rib shape).
[0070]
In the step (II), the method of processing the laminate into a predetermined shape is not particularly limited. In the step (a), the method of removing a part of the magnetic material from the laminate is not particularly limited. For example, a physical or chemical etching method such as ion milling, RIE, or FIB used in a semiconductor process or the like, or a photolithography technique using a stepper, an EB method, or the like may be used. Further, these may be combined, or the surface may be planarized by using CMP, cluster ion beam etching, or the like. When the laminate is processed into a predetermined shape, for example, it may be processed into a shape required for a magneto-optical circuit.
[0071]
In the example shown in FIG. 14, the conductor 74 serving as a magnetic field application unit is formed as a part of the laminated body 7 when forming a magneto-optical circuit, but the magnetic field application unit (or the conductor serving as a magnetic field application unit) is provided. Is not particularly limited. For example, it may be performed between the above steps (I) and (II), or may be performed after the above step (II).
[0072]
Note that the light transmission path, the magnetic body, the wiring, the optical connection section, and the like in this embodiment may be the same as the light transmission path, the magnetic body, the wiring, the optical connection section, and the like described in the first embodiment.
[0073]
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples. Note that the present invention is not limited to the following embodiments.
[0074]
(Example 1)
In this example, an optical switch as shown in FIG. 6 was manufactured, and a magnetic field was applied to a magnetic body to check the actual operation.
[0075]
First, a method for manufacturing an optical switch according to the present embodiment will be described.
[0076]
First, LiNbO is placed on a substrate made of MgO.₃Was formed by magnetron sputtering. The length of the light transmission path in the direction perpendicular to the optical path direction and perpendicular to the substrate was 1 μm, and the length of the light transmission path in the direction perpendicular to the optical path direction and parallel to the substrate was 10 μm (ie, perpendicular to the optical path direction). The cross-sectional area of the light transmission path in the direction is 10 μm²). The length of the light transmission path in the light path direction was 10 mm.
[0077]
Next, a magnetic material was laminated on the light transmission path by a lift-off process using a positive resist. As the magnetic material, a TbCoFe amorphous alloy magnetic film was used. The thickness of the magnetic body was 400 nm, and the length of the magnetic body with respect to the optical path direction was 10 μm. The lamination of the magnetic material was performed so that the magnetic material had perpendicular magnetization.
[0078]
Next, the magnetic material and the Al₂O₃An insulator (thickness: 0.5 μm) made of Cu is laminated, and a wiring containing Cu as a main component (cross-sectional area: 2.5 μm)²(0.5 μm × 5 μm)) to produce an optical switch as shown in FIG. Note that a magnetron sputtering method was used for laminating the insulating film and the wiring.
[0079]
In such an optical switch, the distance between the magnetic body and the wiring for applying a magnetic field to the magnetic body is about 0.5 μm, and it is considered that the magnetization state of the magnetic body can be changed by applying a current to the wiring. Can be
[0080]
Linear polarized light was incident on the optical switch prepared as described above from one end of the light transmission path using a laser (wavelength 488 nm) and a polarizing optical system. At that time, the response as an optical switch was evaluated by changing the magnetization state of the magnetic material and measuring the output intensity of light emitted from the other end of the light transmission path. The evaluation method is described below.
[0081]
First, a current of 30 mA is applied to the wiring, and the output intensity of light (P_out ⁺³⁰) Was measured. The output intensity was measured by arranging a polarizing filter having a relationship of linear Nicols with the linearly polarized light incident on the light transmission path at the output end of the light transmission path, and measuring the intensity of light transmitted through the polarization filter. A photodiode was used for measuring the light intensity. Next, the current applied to the wiring is changed in a pulse shape and applied in a direction opposite to the previous direction (the magnitude of the current is 30 mA), and the light output intensity (P_out ^-30) Was measured. Finally, the measured output intensity of light and the intensity of linearly polarized light (P_in) And the ratio M_pAnd the response as an optical switch was evaluated. Note that M_pIs a value given by the following equation.
[0082]
M_p= (| P_out ⁺³⁰-P_out ^-30| / P_in) × 100 (%)
As a result of the evaluation, M_pThe value was about 30% to 60%, and it was found that the optical switch of the present example can switch an optical signal. In the case of a magneto-optical circuit, for example, an optical connection section including a polarizing filter or the like may be arranged at both ends of the light transmission path. Then, the M_pBy setting a threshold of about a value, for example, setting ON when the output intensity is equal to or higher than the threshold, and setting OFF when the output intensity is equal to or lower than the threshold, the optical signal can be switched.
[0083]
In the optical switch of the present embodiment, M_pThe change in the value is due to the change in the polarization state of the light incident on the light transmission path depending on the magnetization state of the magnetic material. Further, since the magnetic material has perpendicular magnetization, it is considered that the polar Kerr effect works when light is reflected on the surface of the magnetic material.
[0084]
When the response speed of the output light with respect to the current pulse applied to the wiring was simultaneously evaluated, the change in the output light in the order of several hundred ps to several ns with respect to the current pulse having a rise / fall time of several hundred ps width. Was observed. Therefore, it is understood that the optical switch of the present invention can realize a switching speed three orders of magnitude or more faster than that of the conventional MEMS switch.
[0085]
(Example 2)
In this example, an optical switch as shown in FIG. 9 was manufactured, and a magnetic field was applied to a magnetic body to check the actual operation. The evaluation of the optical switch was performed using the same method as in the first embodiment. However, the magnitude of the current applied to the wiring was 18 mA.
[0086]
First, LiNbO is placed on a substrate made of MgO.₃Was formed by magnetron sputtering. The length of the light transmission path in the direction perpendicular to the optical path direction and perpendicular to the substrate was 1 μm, and the length in the direction perpendicular to the optical path direction and parallel to the substrate was 10 μm. The length of the light transmission path in the light path direction was 10 mm.
[0087]
Next, a magnetic material was laminated on the light transmission path by a lift-off process using a positive resist. As the magnetic material, a TbCoFe amorphous alloy magnetic film was used. The thickness of the magnetic body was 400 nm, and the length of the magnetic body with respect to the optical path direction was 10 μm. The lamination of the magnetic material was performed so that the magnetic material had perpendicular magnetization.
[0088]
Next, the magnetic material and the Al₂O₃An insulator (thickness: 0.5 μm) made of Cu is arranged, and a wiring mainly composed of Cu (cross-sectional area: 2.5 μm)²(0.5 μm × 5 μm)). Note that a magnetron sputtering method was used for the arrangement of the insulating film and the wiring. In such an optical switch, the distance between the magnetic body and the wiring for applying a magnetic field to the magnetic body is about 0.5 μm, and it is considered that the magnetization state of the magnetic body can be changed by applying a current to the wiring. Can be
[0089]
Next, a magnetic flux guide made of NiFe (permalloy) was arranged on the wiring, and an optical switch as shown in FIG. 9 was manufactured. The individual magnetic flux guides were arranged so as to cover the wiring, and the interval (pitch) between adjacent magnetic flux guides was 1 μm. The thickness of the magnetic flux guide was 100 nm. The magnetic flux guide was arranged by a lift-off process using a positive resist. An optical switch without a magnetic flux guide was also manufactured at the same time (the other configuration is exactly the same as the optical switch with the magnetic flux guide).
[0090]
When the optical switch prepared as described above was evaluated, when the magnetic flux guide was not provided, 50% to 60% of M_pThe value was obtained, and it was found that the optical switch of the present example can switch an optical signal. In addition, the same M at a lower current value than that of the first embodiment._pThe value was obtained, presumably because the shape of the wiring for applying the magnetic field to the magnetic material was different. That is, it was found that the optical switch according to the present embodiment can more efficiently apply a magnetic field to a magnetic body than the optical switch according to the first embodiment.
[0091]
In addition, when a magnetic flux guide is provided, the equivalent M_pValue was obtained. That is, it was found that the optical switch provided with the magnetic flux guide can more efficiently apply the magnetic field to the magnetic body.
[0092]
(Example 3)
In this example, an optical switch as shown in FIG. 6 was manufactured, and a magnetic field was applied to a magnetic body to check the actual operation. The evaluation of the optical switch was performed using the same method as in the first embodiment.
[0093]
First, LiNbO is placed on a substrate made of MgO.₃Was formed by magnetron sputtering. The length of the light transmission path in the direction perpendicular to the optical path direction and perpendicular to the substrate was 1 μm, and the length in the direction perpendicular to the optical path direction and parallel to the substrate was 10 μm. The length of the light transmission path in the light path direction was 10 mm.
[0094]
Next, a magnetic material was laminated on the light transmission path by a lift-off process using a positive resist. The magnetic material used was a PtMnSb magnetic film. The thickness of the magnetic body was 400 μm, and the length of the magnetic body with respect to the optical path direction was 10 μm. The lamination of the magnetic material was performed so that the magnetic material had perpendicular magnetization.
[0095]
Next, the magnetic material and the Al₂O₃An insulator (thickness: 0.5 μm) made of Cu is arranged, and a wiring mainly composed of Cu (cross-sectional area: 2.5 μm)²(0.5 μm × 5 μm), and an optical switch as shown in FIG. 6 was manufactured. Note that a magnetron sputtering method was used for the arrangement of the insulating film and the wiring. In such an optical switch, the distance between the magnetic body and the wiring for applying a magnetic field to the magnetic body is about 0.5 μm, and it is considered that the magnetization state of the magnetic body can be changed by applying a current to the wiring. Can be
[0096]
When the optical switch prepared in this way was evaluated, the M of 40% to 70% was evaluated._pThe value was obtained, and it was found that the optical switch of the present example can switch an optical signal.
[0097]
Further, when a magnetic flux guide made of NiFe (permalloy) is arranged on the wiring to form an optical switch as shown in FIG. 7A, when a current of about ± 20 mA is applied to the wiring, the equivalent M is obtained._pValue was obtained. That is, it was found that the magnetic field can be more efficiently applied to the magnetic body by the arrangement of the magnetic flux guide. When the shape of the wiring and the magnetic flux guide is trapezoidal as shown in FIG._pValue was obtained.
[0098]
In addition, when the wiring is shaped as shown in FIG. 5 and a magnetic flux guide is provided, the current applied to the wiring is reduced by 10% to 40% as compared with the case without the magnetic flux guide, but is reduced by 40% to 70% % M_pValue was obtained.
[0099]
(Example 4)
In this example, an optical switch was manufactured using the method shown in FIG. 15 and its evaluation was performed. First, a method for manufacturing an optical switch will be described with reference to FIGS.
[0100]
First, a laminate in which the substrate 13, the dielectric 71, the magnetic substance 72, the insulator 73, and the conductor 74 are sequentially laminated is formed (FIG. 15A). Next, a resist 20 is arranged on the conductor 74 in a shape of a light transmission path required as an optical switch, and irradiated with Ar ions (FIG. 15B). By irradiation with Ar ions, portions other than those on which the resist 20 is disposed are removed while leaving the substrate 13, and the light transmission path 2 is formed on the substrate 13 (FIG. 15C). Next, a resist 20 is arranged on the conductor 74 in a shape of a magnetic material required as an optical switch, and irradiated with Ar ions (FIG. 15D). By irradiation with Ar ions, portions other than those where the resist 20 is disposed are removed leaving the substrate 13, and the magnetic body 3 is formed on the light transmission path 2 (FIG. 15E). Next, the insulator 18 is laminated on the whole (FIG. 15F). Next, lift-off is performed to expose the conductor 74 (FIG. 15G). Next, a conductor 74 is further laminated on the entire surface of the insulator 18 (FIG. 15H). Next, a resist 20 is arranged on the conductor 74 in a shape of a wiring required as an optical switch, and irradiated with Ar ions (FIG. 15 (i)). The conductor 74 other than the portion where the resist 20 is disposed is removed by the Ar ion irradiation, and the wiring 41 is formed (FIG. 15 (j)). Thus, an optical switch can be obtained.
[0101]
In this embodiment, an MgO substrate was used as the substrate 13. The dielectric 71 is made of LiNbO doped with Ti by diffusion.₃And a TbCoFe magnetic film for the magnetic body 72, and Al for the insulator 73 and the insulator 18.₂O₃For the conductor 74, a multilayer film made of Ta / Cu / Pt / Ta was used. Further, when the dielectric 71 was laminated on the substrate 13, an LPE (Liquid Phase Epitaxy) method was used, and for laminating other materials, a magnetron sputtering method was used. The size of each part was the same as that of the first embodiment.
[0102]
When the same evaluation as in Example 1 was performed on the optical switch prepared in this way, the M of 30% to 60% was obtained._pThe value was obtained, and it was found that the optical switch of the present example can switch an optical signal.
[0103]
Also, as shown in FIGS. 16 to 19, substantially the same M_pAn optical switch showing a value was obtained. In FIGS. 16 to 19, the same reference numerals are given to portions using the same material as in FIG. 15, and detailed description is omitted. A conductor 75 laminated on the conductor 74 in the step shown in FIG. 19I (the conductor 75 becomes the magnetic flux guide 44 in the step shown in FIG. 19J) includes Ni—Fe (permalloy). ) Was used. The size of each part and the like were the same as in Example 1, and the lamination of each layer was performed using a magnetron sputtering method or the like. Also, in the steps from FIG. 16D to FIG. 16E, the steps from FIG. 18G to FIG. 18H, and the steps from FIG. 19I to FIG. Has been done.
[0104]
When the method shown in FIG. 18 is used, an optical switch having a structure as shown in FIGS. 4B and 5 can be easily obtained. When the method shown in FIG. 19 is used, an optical switch having a structure as shown in FIG. 8 can be easily obtained.
[0105]
In addition, in the example shown in FIGS. 16 to 19, instead of using the light transmission path 2 formed by processing a dielectric into a rib shape in advance, LiNbO₃In the case where a film-shaped dielectric made of is prepared and an optical transmission path is formed by selectively diffusing and doping Ti with the above-described dielectric, an optical switch showing almost the same result can be obtained. Was.
[0106]
Further, proton-exchanged LiNbO is used as a dielectric material serving as an optical transmission path.₃Or SrTiO doped with Nb₃, PZT film (PZT: (Pb, Zr) TiO₃The optical switch showing almost the same result can be obtained even when (1) is used.
[0107]
In each of the methods shown in FIGS. 15 to 19, the ions to be irradiated are not limited to Ar ions. For example, Kr ions, Xe ions, or the like may be used.
[0108]
(Example 5)
In the present example, an optical switch as shown in FIG. 6 was manufactured by the process shown in FIG. 12, and a magnetic field was applied to the magnetic material to check the actual operation. The evaluation of the optical switch was performed using the same method as in the first embodiment.
[0109]
In this embodiment, an MgO substrate is used as a substrate, and a dielectric (1 μm thick) is SrTiO doped with Nb by diffusion.₃(To ensure transparency, the Nb content was set to about 0.05 at.% To 0.5 at.%), And a PtMnSb magnetic film was used for the magnetic material (0.4 μm in thickness). The lamination of the magnetic material was performed so that the magnetic material had perpendicular magnetization, and the temperature of the substrate was set to 500 ° C. In addition, the insulator (thickness 0.5 μm) is made of Al₂O₃A multilayer film made of Ta / Cu / Pt / Ta was used for the conductor (thickness: 0.5 μm). Note that a magnetron sputtering method was used for laminating each layer. In such an optical switch, the distance between the magnetic body and the wiring for applying a magnetic field to the magnetic body is about 0.5 μm, and it is considered that the magnetization state of the magnetic body can be changed by applying a current to the wiring. Can be
[0110]
When the optical switch prepared as described above was evaluated, the M of 30% to 60% was measured._pThe value was obtained, and it was found that the optical switch of the present example can switch an optical signal.
[0111]
(Example 6)
In this example, an optical switch as shown in FIG. 6 was manufactured using an optical circuit and a magnetic circuit as shown in FIG. 20, and an actual operation was confirmed by applying a magnetic field to a magnetic body. The evaluation of the optical switch was performed using the same method as in the first embodiment.
[0112]
An optical circuit 61 shown in FIG. 20 (a) has a substrate 13 made of MgO on which LiNbO₃Are laminated. In addition, a marker 21 is disposed on the substrate 13.
[0113]
In the magnetic circuit 62 shown in FIG. 20B, the magnetic body 3 made of TbCoFe and the wiring 41 made of Cu are laminated on the substrate 13 made of MgO. In addition, a concave portion corresponding to the marker 21 provided in the optical circuit 61 shown in FIG.
[0114]
Such an optical circuit 61 and a magnetic circuit 62 were laminated while aligning the marker 21 and the concave portion, thereby producing a magneto-optical circuit as shown in FIG. The size of each part was the same as in Example 1.
[0115]
Also, a resist or polyimide is used as the marker 21, and the lamination of the optical circuit 61 and the magnetic circuit 62 is performed by bonding the two circuits using a resist used during lithography or an ultraviolet-curable epoxy resin material. Was.
[0116]
When the optical switch prepared as described above was evaluated, the M of 30% to 60% was measured._pThe value was obtained, and it was found that the optical switch of the present example can switch an optical signal.
[0117]
【The invention's effect】
As described above, according to the present invention, an optical switch and a magneto-optical circuit having a high switching speed and excellent durability can be obtained. Further, it is possible to provide a method for manufacturing the magneto-optical circuit.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view showing an example of an optical switch according to the present invention.
FIG. 2 is a schematic sectional view showing an example of the optical switch of the present invention.
FIG. 3 is a schematic sectional view showing an example of the optical switch of the present invention.
FIG. 4 is a schematic sectional view showing an example of the optical switch of the present invention.
FIG. 5 is a schematic view showing an example of the optical switch according to the present invention.
FIG. 6 is a schematic diagram showing an example of the optical switch of the present invention.
FIGS. 7A and 7B are schematic cross-sectional views showing an example of the optical switch of the present invention.
FIG. 8A is a schematic diagram showing an example of the optical switch of the present invention. FIG. 8B is a schematic cross-sectional view showing a cross section of the optical switch shown in FIG.
FIG. 9 is a schematic diagram showing an example of the optical switch of the present invention.
FIG. 10 is a schematic diagram illustrating an example of a magneto-optical circuit according to the present invention.
11 is a schematic sectional view showing a part of a section of the magneto-optical circuit shown in FIG. 10;
FIG. 12 is a schematic cross-sectional view illustrating an example of a method for manufacturing a magneto-optical circuit according to the present invention.
FIG. 13 is a schematic sectional view showing an example of an optical circuit used for the magneto-optical circuit of the present invention.
FIG. 14 is a schematic cross-sectional view illustrating an example of a method for manufacturing a magneto-optical circuit according to the present invention.
FIG. 15 is a schematic view illustrating an example of a method for manufacturing a magneto-optical circuit according to the present invention.
FIG. 16 is a schematic view illustrating an example of a method for manufacturing a magneto-optical circuit according to the present invention.
FIG. 17 is a schematic view illustrating an example of a method for manufacturing a magneto-optical circuit according to the present invention.
FIG. 18 is a schematic view illustrating an example of a method for manufacturing a magneto-optical circuit according to the present invention.
FIG. 19 is a schematic view illustrating an example of a method for manufacturing a magneto-optical circuit according to the present invention.
FIG. 20A is a schematic diagram illustrating an example of an optical circuit used in the magneto-optical circuit according to the present invention. FIG. 20B is a schematic diagram illustrating an example of a magnetic circuit used in the magneto-optical circuit of the present invention.
[Explanation of symbols]
1 Optical switch
2 Light transmission path
3 Magnetic material
4 Magnetization applying part
5 Optical connection
6. Magneto-optical circuit
7 laminate
11, 17 light
12 Surface
13 Substrate
14, 18, 19, 73 Insulator
15 Light receiving and emitting element
16 LSI
20 Resist
21 Marker
41 Wiring
42 current
43 Magnetic field
44 Magnetic flux guide
51 Polarizing filter
52 Optical input section
53 Light output section
54 laser
55 Photodetector
61 Optical Circuit
62 magnetic circuit
71 Dielectric
72 Magnetic material
74, 75 conductor

Claims (21)

A light transmission path made of a dielectric, a magnetic body, and a magnetic field applying unit that changes a magnetization state of the magnetic body by applying a magnetic field to the magnetic body,
An optical switch, wherein the magnetic body is disposed near the light transmission path such that light traveling in the light transmission path is reflected by a surface of the magnetic body. The optical switch according to claim 1, wherein the magnetic body is disposed in contact with the light transmission path. The optical switch according to claim 1, wherein the magnetization direction of the magnetic body is a direction perpendicular to the surface of the magnetic body. The optical switch according to claim 1, wherein the magnetic field applying unit includes a wiring that induces a magnetic field. The optical switch according to claim 4, wherein the magnetic field application unit further includes a magnetic flux guide that focuses the magnetic field induced by the wiring. The optical switch according to claim 5, wherein the magnetic flux guide is made of a soft magnetic alloy film containing at least one element selected from Ni, Co and Fe. The optical switch according to claim 4, wherein the wiring is arranged so as to sandwich the magnetic body between the wiring and the light transmission path. The optical switch according to claim 4, wherein the magnetic field application unit includes a pair of wires arranged at positions facing each other with the magnetic body as a center. The optical switch according to claim 1, wherein the magnetic body is made of a ferromagnetic material. The optical switch according to claim 9, wherein the ferromagnetic material is at least one selected from a Heusler alloy and an amorphous magnetic material. The optical switch according to claim 1, wherein the light transmission path is made of lithium niobate or lithium tantalate. An optical switch according to any one of claims 1 to 11, further comprising: an optical connection unit that performs at least one of input of light to an optical transmission path of the optical switch and output of light from the optical transmission path. Magneto-optical circuit. 13. The magneto-optical circuit according to claim 12, wherein the optical connection includes a polarizing filter. 13. The magneto-optical circuit according to claim 12, further comprising a light source for inputting the light into the light transmission path. 13. The magneto-optical circuit according to claim 12, further comprising a light receiving element that receives the light output from the light transmission path. A light transmission path made of a dielectric, and an optical circuit including an optical connection unit that performs at least one selected from input of light to the light transmission path and output of light from the light transmission path,
A magnetic circuit including a magnetic body and a magnetic field applying unit that changes a magnetization state of the magnetic body by applying a magnetic field to the magnetic body,
A magneto-optical circuit, wherein the optical circuit and the magnetic circuit are arranged such that light traveling in the light transmission path is reflected on a surface of the magnetic body. 17. The magneto-optical circuit according to claim 16, wherein the optical circuit and the magnetic circuit are arranged such that the light transmission path is in contact with the magnetic body. The magneto-optical circuit according to claim 17, wherein the magnetic body is disposed in contact with a part of the light transmission path. (I) A step of forming an optical circuit including a light transmission path made of a dielectric and an optical connection portion that performs at least one of light input to the light transmission path and light output from the light transmission path When,
(Ii) forming a magnetic circuit including a magnetic body and a magnetic field applying unit that changes a magnetization state of the magnetic body by applying a magnetic field to the magnetic body;
(Iii) arranging the optical circuit and the magnetic circuit so that light traveling in the light transmission path is reflected on the surface of the magnetic body. (I) forming a laminate including a dielectric and a magnetic material;
(II) forming a light transmission path made of the dielectric by processing the laminate into a predetermined shape, and forming a magneto-optical circuit in which the light transmission path and the magnetic substance are laminated. A method for manufacturing a magneto-optical circuit including: The step (II) includes:
(A) A method for manufacturing a magneto-optical circuit, comprising a step of removing a part of the magnetic material from the laminate.

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