Isolator

Abstract

To install a magnetic body with high accuracy.SOLUTION: An isolator 10 includes a substrate 11, a waveguide 12, a nonreciprocal member 13, a clad 14, and a magnetic body 15. The substrate 11 has a substrate surface sus. The waveguide 12 is located on the substrate surface sus. The nonreciprocal member 13 is located adjacent to at least a part of the waveguide 12 when viewed from a normal direction of the substrate surface sus. The clad 14 is located on the substrate surface sus, covering the waveguide 12 and the nonreciprocal member 13. The magnetic body 15 overlaps the waveguide 12 when viewed from the normal direction. The magnetic body 15 is located closer to the waveguide 12 on the substrate surface sus side and away from the substrate surface sus. Alternatively, the magnetic body 15 is located on the back side of the substrate surface sus. The magnetic body 15 is embedded in at least one of the clad 14 or the first layer on the substrate surface sus side, and the substrate 11 or the second layer on the back side of the substrate surface sus.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an isolator. [Background technology]

[0002] An interference-type optical isolator generates a phase change by applying a magnetic field to a magneto-optical material (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2007 / 083419 Summary of the Invention [Problem to be solved by the invention]

[0004] In an interference-type optical isolator, the magnetic field application means must be installed with high precision to generate a uniform magnetic field around the magneto-optical material, but it is difficult to install a minute magnetic field application means with high precision.

[0005] An object of the present disclosure is to provide an isolator in which a magnetic field application means is installed with high precision. [Means for solving the problem]

[0006] The isolator according to the first aspect is a substrate having a substrate surface; a waveguide located on the substrate surface; a non-reciprocal member positioned adjacent to at least a portion of the waveguide when viewed from a normal direction of the substrate surface; a cladding covering the waveguide and the nonreciprocal member and positioned on the substrate surface; a magnetic body that overlaps the waveguide when viewed from the normal direction and is located on the substrate surface side, away from the substrate surface than the waveguide, or on the back side of the substrate surface; The magnetic material is embedded in at least one of the cladding on the substrate surface side or a first layer located farther from the substrate surface than the cladding, and the substrate on the back side of the substrate surface or a second layer located on the back side of the substrate surface. [Effects of the Invention]

[0007] According to the present disclosure, the magnetic field applying means is installed with high precision. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view showing a configuration of an isolator according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing the configuration of a first modified example of the isolator of FIG. [Figure 3] FIG. 2 is a cross-sectional view showing the configuration of a second modified example of the isolator of FIG. [Figure 4] FIG. 2 is a cross-sectional view showing the configuration of a third modified example of the isolator of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of an isolator to which the present disclosure is applied will be described with reference to the drawings.

[0010] 1, an isolator 10 according to an embodiment of the present disclosure includes a substrate 11, a waveguide 12, a nonreciprocal member 13, a cladding 14, and a magnetic material 15. The isolator 10 may be an isolator that operates for TE waves.

[0011] The substrate 11 may be flat. One of the main surfaces of the substrate 11 is a substrate surface (sus). The main surface refers to the surface with the largest area in a rectangular parallelepiped. The substrate 11 may be made of a conductor such as metal, a semiconductor such as silicon, glass, or resin.

[0012] The waveguide 12 is located on the substrate surface sus. The waveguide 12 may extend along the substrate surface sus. The waveguide 12 may propagate electromagnetic waves along the extension direction. The waveguide 12 may be made of, for example, silicon.

[0013] The nonreciprocal member 13 may be located adjacent to at least a portion of the waveguide 12 when viewed from the normal direction of the substrate surface sus. More specifically, the nonreciprocal member 13 may be located adjacent to a portion extending in the extension direction of the waveguide 12. Furthermore, the nonreciprocal member 13 may be located so as to cover at least the side surface ss of the portion of the waveguide 12. The side surface ss of the waveguide 12 is a surface that is parallel to the normal direction of the substrate surface sus and the extension direction of the waveguide 12.

[0014] The nonreciprocal member 13 may be positioned so as to cover the upper surface us of a part of the waveguide 12, in other words, the surface opposite to the substrate 11. Furthermore, by using a manufacturing method described later, the nonreciprocal member 13 may have a portion that is continuous with the portion covering the side surface ss of the waveguide 12 and extends along the substrate surface sus.

[0015] Furthermore, the nonreciprocal member 13 may include a second nonreciprocal member 17 and a third nonreciprocal member 18 in addition to the first nonreciprocal member 16 adjacent to the waveguide 12. The second nonreciprocal member 17 may be located on the opposite side of the waveguide 12 from the portion of the first nonreciprocal member 13 that covers the side surface ss of the waveguide 12, as viewed from the normal direction of the substrate surface sus. The second nonreciprocal member 17 may have the same length as the first nonreciprocal member 16 in the extension direction of the waveguide 12. The second nonreciprocal member 17 may be located away from the waveguide 12, as viewed from the normal direction of the substrate surface sus. The second nonreciprocal member 17 may be Z-shaped or S-shaped in a cross section perpendicular to the extension direction. The third nonreciprocal member 18 may be located on the same side of the waveguide 12 as the portion of the first nonreciprocal member 13 that covers the side surface ss of the waveguide 12, when viewed from the normal direction of the substrate surface sus. The third nonreciprocal member 18 may have the same length as the first nonreciprocal member 16 in the extension direction of the waveguide 12.

[0016] The nonreciprocity member 13 may be formed of a transparent magnetic material such as YIG (yttrium iron garnet), Ce-substituted YIG, Bi-substituted YIG, or other partially substituted materials thereof, a ferromagnetic material such as FeCo, FeNi, or CoPt, or a material containing a ferromagnetic material. Alternatively, the nonreciprocity member 13 may be formed of a dielectric material composited with magnetic nanoparticles, such as a nanogranular material.

[0017] The cladding 14 is located on the substrate surface sus, covering the waveguide 12 and the nonreciprocal member 13. The refractive index of the cladding 14 may be greater than the refractive index of the waveguide 12.

[0018] When viewed from the normal direction of the substrate surface sus, the magnetic body 15 is positioned so as to overlap the waveguide 12. The magnetic body 15 is positioned on the substrate surface sus side, farther from the substrate surface sus than the waveguide 12, or on the back side of the substrate surface sus as shown in FIG.

[0019] 1, in a configuration in which the magnetic body 15 is provided on the substrate surface sus side, the magnetic body 15 may be embedded in the cladding 14 on the substrate surface sus side. Alternatively, as shown in Fig. 3, at least a portion of the magnetic body 15 may be embedded in a first layer 19. The first layer 19 is located farther from the substrate surface sus than the cladding 14. The first layer 19 may be, for example, a glass substrate.

[0020] A recess having the same shape as the magnetic body 15 when viewed from the normal direction of the substrate surface sus may be formed in advance in the first layer 19. The magnetic body 15 may be partially embedded by being positioned in the recess. The portion of the magnetic body 15 exposed from the first layer 19 may be covered with a sealing material 20.

[0021] The sealing material 20 may be formed by solidifying a sealing agent, which may be an organic material such as an epoxy resin, a silicone resin, a urethane resin, or a phenolic resin.

[0022] The first layer 19 may be provided in only a partial area of ​​the clad 14 when viewed from the normal direction of the substrate surface sus. In other words, the first layer 19 does not have to be provided in the entire area of ​​the clad 14 when viewed from the normal direction. When viewed from the normal direction, electrode pads 21 may be provided outside the area occupied by the glass substrate as the first layer 19. The electrode pads 21 may apply voltages to various elements provided on the substrate 11.

[0023] As shown in Fig. 2, in a configuration in which the magnetic body 15 is provided on the back side of the substrate surface sus, a portion of the magnetic body 15 may be embedded in the substrate 11. Alternatively, as shown in Fig. 4, at least a portion of the magnetic body 15 may be embedded in the second layer 22. The second layer 22 is located on the back side of the substrate surface sus with respect to the cladding 14. The second layer 22 may be, for example, a glass substrate.

[0024] 2, in a configuration in which a portion of the magnetic body 15 is embedded in the substrate 11, a recess having the same shape as the magnetic body 15 when viewed from the normal direction of the substrate surface sus may be formed in the substrate 11 on the back side of the substrate surface sus. The magnetic body 15 may be partially embedded by being positioned in the recess. The portion of the magnetic body 15 exposed from the substrate 11 may be sealed by being covered with a sealing material 23.

[0025] The sealing material 23 may be formed by solidifying a sealing agent, which may be an organic material such as an epoxy resin, a silicone resin, a urethane resin, or a phenolic resin.

[0026] 4, in a configuration in which a portion of the magnetic body 15 is embedded in the second layer 22, a recess having the same shape as the magnetic body 15 when viewed from the normal direction of the substrate surface sus may be formed in the second layer 22 on the side opposite to the surface of the second layer 22 facing the substrate 11. The magnetic body 15 may be partially embedded by being positioned in the recess. The portion of the magnetic body 15 exposed from the second layer 22 may be sealed by being covered with a sealing material 23.

[0027] The magnetic body 15 is preferably made of a material that has a strong magnetic force and does not lose its magnetism even at 260° C. The magnetic body 15 may be made of a substance containing, for example, neodymium, samarium cobalt, or the like.

[0028] Next, a method for manufacturing the isolator 10 will be described below. In the manufacturing method of this embodiment, an example will be described in which SiO2 is used for the substrate 11 and Si is used for the waveguide 12. However, as mentioned above, the materials for the substrate 11 and the waveguide 12 are not limited to these materials.

[0029] First, one of the Si layers of an SOI (Silicon On Insulator) substrate having an SiO2 layer between the surface Si layers may be patterned to form a waveguide 12 having a longitudinal direction along the substrate surface sus on a substrate 11 having an SiO2 layer.

[0030] Next, a first cladding layer may be formed by, for example, CVD (Chemical Vapor Deposition) on the substrate 11 from the substrate surface sus side on which the waveguide 12 is formed. The first cladding layer is made of the same material as the cladding 14 in the isolator 10.

[0031] Next, a first mask layer may be formed on the opposite side of the substrate 11 in the first clad layer, where the nonreciprocal member 13 is embedded in the clad 14. The first mask layer may be formed by depositing a material for the first mask layer on the first clad layer and then forming a mask shape by lithography. The first mask layer may cover the region other than the first trench formation region when viewed from the normal direction of the substrate surface sus. The first trench formation region may include the region in the waveguide 12 where the first nonreciprocal member 16 is formed.

[0032] Next, dry etching using CF4 gas or CHF3 gas may be performed to remove the first cladding layer in the area not covered by the first mask layer, thereby forming a trench in the first trench formation area. After forming the trench, the nonreciprocal member 13 is formed by spraying a film material of the nonreciprocal member 13 from an oblique direction rotated from the normal to the substrate surface sus around the axis of the extension direction of the waveguide 12. After forming the nonreciprocal member 13, the first mask layer may be removed by resist stripping.

[0033] After removing the first mask layer, a second cladding layer may be deposited by CVD to re-form the cladding 14 in the trench. The second cladding layer may be deposited until the entire nonreciprocal member 13 is buried. The second cladding layer may be made of the same material as the first cladding layer. After depositing the second cladding layer, a planarization process may be performed.

[0034] The manufacturing method varies depending on the arrangement of the magnetic material 15. First, a manufacturing method for an isolator 10 having the magnetic material 15 embedded in the cladding 14 as shown in FIG. 1 will be described. A second mask layer may be formed on the opposite side of the substrate 11 in the second cladding layer, where the magnetic material 15 is embedded in the cladding 14. The second mask layer may be formed by depositing a material for the second mask layer on the second cladding layer and then forming a mask shape using lithography. The second mask layer may cover the region other than the second trench formation region when viewed from the normal direction of the substrate surface sus. The second trench formation region may include the region of the waveguide 12 where the magnetic material 15 is formed. Next, a trench may be formed in the second trench formation region by performing dry etching using CF4 gas or CHF3 gas to remove the second cladding layer in the region not covered by the second mask layer. The dry etching for forming the trench may be controlled so as to stop at the top surface of the first nonreciprocal member 16. Wet etching may also be used for forming the trench. After forming the trench, a magnetic material may be deposited by sputtering. After forming the magnetic material 15, the second mask layer may be removed by lift-off. After removing the second mask layer, a third cladding layer may be deposited by CVD to re-form the cladding 14 in the trench. The third cladding layer may be made of the same material as the first cladding layer. After depositing the third cladding layer, a planarization process may be performed.

[0035] Next, a method for manufacturing an isolator 10 will be described, in which a magnetic body 15 is embedded in a first layer 19 on the surface of the cladding 14 opposite the substrate surface sus, as shown in FIG. A recess having the same shape as the magnetic body 15 when viewed from the normal direction may be formed in the main surface of a plate member that will become the first layer 19. The magnetic body 15 may be partially embedded in the recess. After embedding the magnetic body 15 in the recess, a sealant may be applied to cover the exposed magnetic body 15 and cured, thereby covering the magnetic body 15 with a sealant 20. The plate member provided with the magnetic body 15 and sealant 20 may be bonded to a second cladding layer that has been subjected to a planarization process.

[0036] Next, a method for manufacturing an isolator 10 in which a magnetic body 15 is embedded on the back side of the substrate surface sus of a substrate 11, as shown in Figure 2, will be described. A recess having the same shape as the magnetic body 15 when viewed from the normal direction to the substrate surface sus may be formed on the back side of the substrate surface sus of the substrate 11 on which the second cladding layer has been formed. The magnetic body 15 may be partially embedded in the recess. After embedding the magnetic body 15 in the recess, a sealing material may be applied to cover the exposed magnetic body 15 and cured, thereby covering the magnetic body 15 with a sealing material 23.

[0037] Next, a method for manufacturing an isolator 10 will be described, in which a magnetic body 15 is embedded in a second layer 22 on the surface opposite to the substrate surface sus of the substrate 11, as shown in FIG. A recess having the same shape as the magnetic body 15 when viewed from the normal direction may be formed in the main surface of a plate member that will become the second layer 22. The magnetic body 15 may be partially embedded in the recess. After embedding the magnetic body 15 in the recess, a sealant may be applied to cover the exposed magnetic body 15 and cured, thereby covering the magnetic body 15 with a sealant 23. The plate member provided with the magnetic body 15 and sealant 23 may be adhered to the back side of the substrate surface sus of the substrate 11.

[0038] The magnetic body 15 may be magnetized after the isolator 10 is manufactured. Alternatively, in a configuration in which the magnetic body 15 is embedded in any of the first layer 19, the substrate 11, and the second layer 22 as shown in Figures 2 to 4, the magnetic body 15 may be magnetized before being embedded.

[0039] The isolator 10 of this embodiment, configured as described above, comprises a substrate 11 having a substrate surface sus, a waveguide 12 located on the substrate surface sus, a nonreciprocal member 13 located adjacent to at least a portion of the waveguide 12 when viewed from the normal direction of the substrate surface sus, a cladding 14 covering the waveguide 12 and the nonreciprocal member 13 and located on the substrate surface sus, and a magnetic body 15 overlapping the waveguide 12 when viewed from the normal direction and located on the substrate surface sus side, further from the substrate surface sus than the waveguide 12, or on the back side of the substrate surface sus, and the magnetic body 15 is embedded in the cladding 14 on the substrate surface sus side or in a first layer 19 located further from the substrate surface sus than the cladding 14, or in the substrate 11 on the back side of the substrate surface sus or in a second layer 22 located on the back side of the substrate surface sus. With this configuration, the isolator 10 has a configuration in which the magnetic body 15 is embedded, so a recess can be formed in advance at the installation position of the magnetic body 15, and the magnetic body 15 can be aligned with high precision. Furthermore, with this configuration, the isolator 10 can position the magnetic body 15 close to the waveguide 12, so a strong magnetic field can be applied. Therefore, the isolator 10 can reduce the size of the magnetic body 15 that can apply the magnetic field required for the nonreciprocal member 13.

[0040] Furthermore, in the isolator 10, the magnetic body 15 is located in a recess formed in the first layer 19, the substrate 11, or the second layer 22. Generally, an isolator requires a large number of various elements other than the magnetic body to be disposed in the clad. In this situation, the isolator 10 having the above-described configuration allows the size of the magnetic body 15 to be selected arbitrarily without interference from other elements disposed in the clad, compared to a configuration in which the magnetic body 15 is disposed in the clad 14. Furthermore, since the isolator 10 is aligned by fitting it into the recess, the alignment precision of the magnetic body 15 can be maintained even while the magnetic body 15 is pre-magnetized.

[0041] The isolator 10 also includes electrode pads 21, which are located outside the area occupied by the first layer 19 when viewed from the normal direction and which apply voltage to elements provided on the substrate 11. The isolator requires the implementation of electrode pads. However, if the first layer is provided on top of the electrode pads, it becomes impossible to wire electrode cables to the electrode pads. In response to this situation, the isolator 10 having the above-described configuration can be configured to allow the wiring of electrode cables to the electrode pads 21 while still providing the first layer 19 for the implementation of the magnetic material 15.

[0042] The drawings illustrating the embodiments of the present disclosure are schematic, and the dimensional ratios and the like in the drawings do not necessarily correspond to the actual ones.

[0043] Although the embodiments of the present disclosure have been described based on the drawings and examples, it should be noted that those skilled in the art can make various modifications or alterations based on the present disclosure. Therefore, it should be noted that these modifications or alterations are included in the scope of the present disclosure. For example, the functions included in each component can be rearranged so as not to be logically inconsistent, and multiple components can be combined or divided into one.

[0044] Furthermore, embodiments of the present disclosure are not limited to the specific configurations of any of the above-described embodiments, but rather extend to any novel feature or combination thereof described herein, or any novel method or process step or combination thereof described herein.

[0045] In this disclosure, descriptions such as "first" and "second" are identifiers for distinguishing the configuration. In this disclosure, the configurations distinguished by descriptions such as "first" and "second" can have their numbers interchanged. For example, a first non-reciprocal member can have its identifiers "first" and "second" interchanged with a second non-reciprocal member. The identifiers are interchanged simultaneously. The configurations remain distinguished even after the identifiers are interchanged. Identifiers may be deleted. A configuration from which an identifier has been deleted is distinguished by a symbol. The identifiers "first" and "second" in this disclosure should not be used solely to interpret the order of the configurations or to justify the existence of an identifier with a lower number. [Explanation of symbols]

[0046] 10 Isolator 11 Circuit Board 12 Waveguide 13 Non-reciprocal members 14 Clad 15 Magnetic material 16 First non-reciprocal member 17 Second non-reciprocal member 18 Third Non-reciprocal Member 19 First Layer 20 Encapsulating material 21 Electrode pads 22 Second Layer 23 Encapsulating material Side of ss waveguide sus board surface us Top surface of the waveguide

Claims

1. a substrate having a substrate surface; a waveguide located on the substrate surface; a non-reciprocal member positioned adjacent to at least a portion of the waveguide when viewed from a normal direction of the substrate surface; a cladding covering the waveguide and the nonreciprocal member and positioned on the substrate surface; a magnetic body that overlaps the waveguide when viewed from the normal direction and is located on the substrate surface side, away from the substrate surface than the waveguide, or on the back side of the substrate surface; The magnetic material is embedded in at least one of the cladding on the substrate surface side or a first layer located farther from the substrate surface than the cladding, and the substrate on the back side of the substrate surface or a second layer located on the back side of the substrate surface. Isolator.

2. 2. The isolator of claim 1, The magnetic material is located in a recess formed in the first layer, the substrate, or the second layer. Isolator.

3. 3. The isolator according to claim 2, The magnetic body is sealed by being covered with a sealing material. Isolator.

4. 4. The isolator according to claim 1, an electrode pad positioned outside the region occupied by the first layer when viewed from the normal direction, for applying a voltage to an element provided on the substrate; Isolator.

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