Optical waveguide device, quantum computing device, and method for manufacturing optical waveguide device

Abstract

An optical waveguide device (1) comprises an optical waveguide substrate (100) having a first surface (100A), and an optical waveguide layer (150) provided on the first surface (100A). The optical waveguide substrate (100) has a first region (101) exposed on the first surface (100A) and linearly extended, and a second region (102) exposed on the first surface (100A) and located on both sides of the first region (101) in plan view. The optical waveguide layer (150) is provided on the first region (101), a second thermal expansion coefficient of the second region (102) is smaller than a first thermal expansion coefficient of the first region (101), and a third thermal expansion coefficient of the optical waveguide layer (150) is smaller than the first thermal expansion coefficient.

Description

[Technical Field]

[0001] The present disclosure relates to an optical waveguide device, a quantum computing device, and a method for manufacturing an optical waveguide device. [Background technology]

[0002] Quantum devices using color centers in a diamond layer are being investigated, as well as optical waveguide devices in which an optical waveguide layer made of diamond is bonded to an optical waveguide substrate made of a material with a lower refractive index than diamond, such as sapphire, in order to propagate the light emitted from the color centers to a detector. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2002-527787 [Patent Document 2] U.S. Patent No. 6,253,009 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional optical waveguide devices, there is a risk of peeling occurring between the optical waveguide substrate and the optical waveguide layer.

[0005] An object of the present disclosure is to provide an optical waveguide device, a quantum computing device, and a method for manufacturing an optical waveguide device that can suppress peeling between an optical waveguide substrate and an optical waveguide layer. [Means for solving the problem]

[0006] According to one aspect of the present disclosure, there is provided an optical waveguide substrate having a first surface and an optical waveguide layer provided on the first surface, wherein the optical waveguide substrate is exposed on the first surface, In the first directionThe optical waveguide layer has a first region extending linearly and a second region exposed on the first surface and positioned on both sides of the first region in a plan view, and the optical waveguide layer has extending in the first direction It is provided, the optical waveguide layer has a first portion having a constant height along the first direction and a second portion having a height decreasing along the first direction, the optical waveguide layer and the first region are in direct contact with each other, the refractive index of the optical waveguide layer is greater than the refractive index of the first region, the optical waveguide layer functions as a core layer of the optical waveguide, a region of the first region that contacts the first portion functions as a clad layer of the optical waveguide, and light propagates from the optical waveguide layer to the optical waveguide substrate in a region of the first region that contacts the second portion, An optical waveguide device is provided in which the second region has a second thermal expansion coefficient smaller than the first thermal expansion coefficient of the first region, and the optical waveguide layer has a third thermal expansion coefficient smaller than the first thermal expansion coefficient. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to suppress peeling between the optical waveguide substrate and the optical waveguide layer. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing an optical waveguide device according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view (part 1) showing the optical waveguide device according to the first embodiment. [Figure 3] FIG. 3 is a cross-sectional view (part 2) showing the optical waveguide device according to the first embodiment. [Figure 4] FIG. 4 is a cross-sectional view showing an optical waveguide device according to a first reference example. [Figure 5] FIG. 5 is a diagram showing deformation of the optical waveguide substrate and the optical waveguide layer in the first reference example. [Figure 6] FIG. 6 is a diagram showing deformation of the optical waveguide substrate and the optical waveguide layer in the first embodiment. [Figure 7] FIG. 7 is a cross-sectional view showing an optical waveguide device according to a second reference example. [Figure 8] FIG. 8 is a cross-sectional view showing an optical waveguide device according to a third reference example. [Figure 9] FIG. 9 is a cross-sectional view (part 1) illustrating a first manufacturing method for the optical waveguide device according to the first embodiment. [Figure 10] FIG. 10 is a cross-sectional view (part 2) illustrating the first manufacturing method of the optical waveguide device according to the first embodiment. [Figure 11]FIG. 11 is a cross-sectional view (part 3) illustrating the first manufacturing method of the optical waveguide device according to the first embodiment. [Figure 12] FIG. 12 is a cross-sectional view (part 4) illustrating the first manufacturing method of the optical waveguide device according to the first embodiment. [Figure 13] FIG. 13 is a cross-sectional view (part 1) illustrating the second manufacturing method for the optical waveguide device according to the first embodiment. [Figure 14] FIG. 14 is a cross-sectional view (part 2) illustrating the second manufacturing method for the optical waveguide device according to the first embodiment. [Figure 15] FIG. 15 is a cross-sectional view (part 3) illustrating the second manufacturing method for the optical waveguide device according to the first embodiment. [Figure 16] FIG. 16 is a cross-sectional view (part 4) illustrating the second manufacturing method of the optical waveguide device according to the first embodiment. [Figure 17] FIG. 17 is a cross-sectional view (part 5) illustrating the second manufacturing method for the optical waveguide device according to the first embodiment. [Figure 18] FIG. 18 is a top view showing an optical waveguide device according to the second embodiment. [Figure 19] FIG. 19 is a cross-sectional view showing an optical waveguide device according to the second embodiment. [Figure 20] FIG. 20 is a top view showing an optical waveguide device according to a modified example of the second embodiment. [Figure 21] FIG. 21 is a cross-sectional view showing an optical waveguide device according to the third embodiment. [Figure 22] FIG. 22 is a cross-sectional view showing an optical waveguide device according to the fourth embodiment. [Figure 23] FIG. 23 is a cross-sectional view showing an optical waveguide device according to the fifth embodiment. [Figure 24] FIG. 24 is a cross-sectional view showing an optical waveguide device according to the sixth embodiment. [Figure 25] FIG. 25 is a cross-sectional view showing an optical waveguide device according to the seventh embodiment. [Figure 26] FIG. 26 is a cross-sectional view showing an optical waveguide device according to the eighth embodiment. [Figure 27]FIG. 27 is a cross-sectional view showing an optical waveguide device according to the ninth embodiment. [Figure 28] FIG. 28 is a diagram illustrating a quantum computer according to the tenth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Note that in this specification and drawings, components having substantially the same functional configurations may be denoted by the same reference numerals to avoid redundant description. In this disclosure, the X1-X2 direction, the Y1-Y2 direction, and the Z1-Z2 direction are defined as mutually orthogonal directions. A plane including the X1-X2 direction and the Y1-Y2 direction will be referred to as the XY plane, a plane including the Y1-Y2 direction and the Z1-Z2 direction will be referred to as the YZ plane, and a plane including the Z1-Z2 direction and the X1-X2 direction will be referred to as the ZX plane. For convenience, the Y1-Y2 direction will be defined as the up-down direction, with the Y1 side referred to as the upper side and the Y2 side referred to as the lower side. Furthermore, a planar view refers to viewing an object from the Y1 side, and a planar shape refers to the shape of an object viewed from the Y1 side.

[0010] (First embodiment) First, a first embodiment will be described. The first embodiment relates to an optical waveguide device. The optical waveguide device according to the first embodiment is used in a quantum computing device such as a quantum computer. FIG. 1 is a perspective view showing the optical waveguide device according to the first embodiment. FIGS. 2 and 3 are cross-sectional views showing the optical waveguide device according to the first embodiment.

[0011] As shown in FIGS. 1 to 3, the optical waveguide device 1 according to the first embodiment includes an optical waveguide substrate 100 and an optical waveguide layer 150. The optical waveguide substrate 100 has a first surface 100A on the Y1 side. The first surface 100A is parallel to the ZX plane. The optical waveguide layer 150 is provided on the first surface 100A.

[0012] The optical waveguide substrate 100 has a first region 101 and a second region 102. The first region 101 and the second region 102 are exposed on the first surface 100A. The first region 101 extends linearly. For example, the first region 101 extends parallel to the Z1-Z2 direction. The second regions 102 are located on both sides of the first region 101 in a plan view, i.e., when viewed from a direction perpendicular to the first surface 100A. In other words, the first region 101 is sandwiched between the two second regions 102 in the X1-X2 direction. The optical waveguide layer 150 is provided on the first region 101.

[0013] The optical waveguide substrate 100 includes a substrate 110 and a stress relief material 120. The thermal expansion coefficient of the substrate 110 is larger than that of the optical waveguide layer 150. The thermal expansion coefficient of the stress relief material 120 is smaller than that of the substrate 110. For example, the optical waveguide layer 150 contains diamond. The optical waveguide layer 150 may be a diamond layer. For example, the substrate 110 contains sapphire (Al2O3). The substrate 110 may be a sapphire substrate. For example, the stress relief material 120 contains diamond. The stress relief material 120 may be a diamond material. The thermal expansion coefficient of diamond is 0.8×10 -6 / K, and the thermal expansion coefficient of sapphire is 8.0×10 -6 / K.

[0014] The substrate 110 includes a first region 101 and a second region 102, with convex portions 111 formed in the first region 101 and concave portions 112 formed in the second region 102. A stress relief material 120 is provided in each concave portion 112. The Y1-side surface of the convex portion 111 and the Y1-side surface of the stress relief material 120 are flush with each other, and these surfaces constitute a first surface 100A. In other words, the first surface 100A includes the Y1-side surface of the convex portion 111 and the Y1-side surface of the stress relief material 120. The depth of the convex portions 111 and the depth of the concave portions 112 are, for example, approximately 100 nm to 1000 nm.

[0015] The first region 101 functions as an optical waveguide in the optical waveguide substrate 100. For example, the refractive index of the portion of the optical waveguide substrate 100 that functions as an optical waveguide is lower than the refractive index of the optical waveguide layer 150.

[0016] The optical waveguide layer 150 includes, for example, a color center 151. The end of the optical waveguide layer 150 closer to the detector (not shown), in this embodiment, closer to the Z1 side, than the color center 151 may have a shape in which the height decreases toward the tip. In this case, good optical propagation efficiency is easily obtained between the optical waveguide layer 150 and the first region 101 of the optical waveguide substrate 100.

[0017] The optical waveguide device 1 according to the first embodiment is cooled to an extremely low temperature, for example, 4 K or less, before use. Therefore, the optical waveguide substrate 100 and the optical waveguide layer 150 thermally contract during use and thermally expand when returned to room temperature after use. In this embodiment, the substrate 110 has protrusions 111 and recesses 112, and a stress relief material 120 is provided in the recesses 112. Therefore, the thermal expansion coefficient of the second region 102 is smaller than that of the first region 101. Furthermore, the thermal expansion coefficient of the optical waveguide layer 150 is smaller than that of the first region 101. This makes it possible to reduce the difference between the thermal expansion coefficient of the second region 102 and that of the optical waveguide layer 150 smaller than the difference between the thermal expansion coefficient of the first region 101 and that of the optical waveguide layer 150, thereby reducing the stress generated between the optical waveguide substrate 100 as a whole and the optical waveguide layer 150. Therefore, peeling between the optical waveguide substrate 100 and the optical waveguide layer 150 can be suppressed.

[0018] Here, the effects of the first embodiment will be further explained in comparison with a reference example. Fig. 4 is a cross-sectional view showing an optical waveguide device according to a first reference example.

[0019] In an optical waveguide device 1X according to a first reference example, an optical waveguide substrate 100 is composed of a substrate 110X, as shown in Fig. 4. The material of the substrate 110X is the same as the material of the substrate 110. The other configurations are the same as those of the first embodiment.

[0020] Fig. 5 is a diagram showing deformation of the optical waveguide substrate and the optical waveguide layer in the first reference example. Fig. 6 is a diagram showing deformation of the optical waveguide substrate and the optical waveguide layer in the first embodiment. The arrows in Fig. 5 and Fig. 6 schematically show the magnitude of deformation, with the longer the arrow, the greater the deformation.

[0021] For example, suppose that the optical waveguide layer 150 and the stress relaxation material 120 are made of diamond, the substrates 110 and 110X are sapphire substrates, the dimension of the optical waveguide layer 150 in the X1-X2 direction is 0.2 μm, the dimension of the optical waveguide substrate 100 in the X1-X2 direction is 5.0 mm, and the optical waveguide layer 150 is disposed at the center of the optical waveguide substrate 100 in the X1-X2 direction.

[0022] In the first reference example, the entire first surface 100A is made up of the substrate 110X. Therefore, when cooled from room temperature to 4 K, the amount of thermal contraction of the optical waveguide layer 150 is only 0.05 nm, while the amount of thermal contraction of the first surface 100A is 12 μm, meaning that the first surface 100A thermally contracts 240,000 times as much as the optical waveguide layer 150. For this reason, as shown in FIG. 5 , a large difference in thermal deformation occurs near the interface between the optical waveguide layer 150 and the optical waveguide substrate 100, and stress is concentrated particularly near the end of the optical waveguide layer 150 in the X1-X2 direction.

[0023] On the other hand, in the first embodiment, of the first surface 100A, the first surface 100A in the first region 101 is made of the substrate 110, but the first surface 100A in the second region 102 is made of the stress relief material 120. Therefore, even when cooled from room temperature to 4 K, only the portion of the first surface 100A in the first region 101 will thermally shrink more than the optical waveguide layer 150. For this reason, as shown in FIG. 6 , the difference in thermal deformation occurring near the interface between the optical waveguide layer 150 and the optical waveguide substrate 100 is small.

[0024] Therefore, according to the first embodiment, it is possible to suppress peeling between the optical waveguide substrate 100 and the optical waveguide layer 150 compared to the first reference example.

[0025] Next, a second and a third reference examples will be described. Fig. 7 is a cross-sectional view showing an optical waveguide device according to the second reference example. Fig. 8 is a cross-sectional view showing an optical waveguide device according to the third reference example.

[0026] 7, in an optical waveguide device 1Y according to a second reference example, an optical waveguide substrate 100 is composed of only a substrate 110, and does not include a stress relaxation material 120. The other configurations are the same as those in the first embodiment.

[0027] According to the second reference example, similarly to the first embodiment, it is possible to suppress peeling between the optical waveguide substrate 100 and the optical waveguide layer 150. However, since the stress relief material 120 is not provided, large stresses are concentrated near the bases 113Y of the protrusions 111 due to temperature changes, which may cause defects such as cracks in the substrate 110.

[0028] In an optical waveguide device 1Z according to the third reference example, as shown in Fig. 8, an optical waveguide substrate 100 has a substrate 110X and a diamond layer 120Z. The diamond layer 120Z is provided on the substrate 110X, and the entire first surface 100A is formed by the diamond layer 120Z. The optical waveguide layer 150 and the diamond layer 120Z are integrally formed. The other configurations are the same as those in the first embodiment.

[0029] According to the third reference example, it is possible to suppress peeling between the integrally formed optical waveguide layer 150 and diamond layer 120Z and the substrate 110X. However, large stress is concentrated near the base 113Z of the optical waveguide layer 150, which may cause defects such as cracks in the diamond layer 120Z. Furthermore, the provision of the diamond layer 120Z reduces the optical confinement effect, resulting in coupling loss in the optical coupling between the optical waveguide layer 150 and the optical waveguide included in the optical waveguide substrate 100.

[0030] Next, two types of manufacturing methods for the optical waveguide device 1 according to the first embodiment will be described. Figures 9 to 12 are cross-sectional views showing a first manufacturing method for the optical waveguide device 1 according to the first embodiment. Figures 13 to 17 are cross-sectional views showing a second manufacturing method for the optical waveguide device 1 according to the first embodiment.

[0031] 9, a substrate having a flat Y1 side is prepared, and this substrate is processed to obtain a substrate 110 having convex portions 111 and concave portions 112. The substrate is processed by, for example, etching.

[0032] 10, a diamond layer 160, which will later become the optical waveguide layer 150 and the stress relaxation material 120, is formed on the substrate 110 to a thickness greater than the height of the protrusions 111. The diamond layer 160 is formed by, for example, chemical vapor deposition (CVD) It can be formed by a method such as the above.

[0033] 11, the diamond layer 160 is polished until the convex portions 111 are exposed. As a result, an optical waveguide substrate 100 having a first surface 100A is obtained. The optical waveguide substrate 100 has a substrate 110 and a stress relief material 120. The Y1-side surface of the substrate 110 and the Y1-side surface of the stress relief material 120 are flush with each other and are included in the first surface 100A.

[0034] 12, an optical waveguide layer 150 including a color center 151 is provided on the protrusion 111, and the optical waveguide layer 150 and the substrate 110 are bonded to each other. For example, the optical waveguide layer 150 and the substrate 110 can be bonded to each other by intermolecular forces.

[0035] In this manner, the optical waveguide device 1 according to the first embodiment can be manufactured.

[0036] In the second manufacturing method, first, similarly to the first manufacturing method, processing up to the formation of the diamond layer 160 is carried out (see Fig. 10). Next, as shown in Fig. 13, a mask 171 is formed on the region of the diamond layer 160 that is to become the optical waveguide layer 150. As the mask 171, for example, a resist pattern is formed.

[0037] 14, the portion of the diamond layer 160 exposed from the mask 171 is dry-etched to form the stress relief material 120 from the diamond layer 160. As a result, an optical waveguide substrate 100 having a first surface 100A is obtained. The optical waveguide substrate 100 has a substrate 110 and a stress relief material 120. The Y1-side surface of the substrate 110 and the Y1-side surface of the stress relief material 120 are flush with each other and are included in the first surface 100A.

[0038] 15, the mask 171 is removed. Next, a mask 172 is formed on the stress relaxation material 120 to cover the Y1 side surface of the stress relaxation material 120 and expose the Y1 side surface of the diamond layer 160. The thickness of the mask 172 is set to be approximately the same as the thickness of the optical waveguide layer 150 to be formed. For example, a resist pattern is formed as the mask 172. A hard mask made of silicon oxide (SiO2), silicon nitride (SiN), or metal may also be formed as the mask 172.

[0039] Thereafter, as shown in FIG. 16, the portion of the diamond layer 160 exposed from the mask 172 is dry-etched to form the optical waveguide layer 150 from the diamond layer 160.

[0040] 17, the mask 172 is removed. Next, the color center 151 is formed in the optical waveguide layer 150 by ion implantation or the like.

[0041] In this manner, the optical waveguide device 1 according to the first embodiment can be manufactured.

[0042] (Second embodiment) Next, a second embodiment will be described. The second embodiment differs from the first embodiment mainly in the configuration of the optical waveguide substrate. Fig. 18 is a top view showing the optical waveguide device according to the second embodiment. Fig. 19 is a cross-sectional view showing the optical waveguide device according to the second embodiment.

[0043] As shown in Figures 18 and 19, the optical waveguide device 2 according to the second embodiment has an optical waveguide substrate 200 instead of the optical waveguide substrate 100. The optical waveguide substrate 200 has a first surface 200A on the Y1 side. The first surface 200A is parallel to the ZX plane. The optical waveguide layer 150 is provided on the first surface 200A. The first region 101 and the second region 102 of the optical waveguide substrate 200 are exposed to the first surface 200A.

[0044] The optical waveguide substrate 200 includes a substrate 210 and a stress relief material 220. The thermal expansion coefficient of the substrate 210 is larger than that of the optical waveguide layer 150. The thermal expansion coefficient of the stress relief material 220 is smaller than that of the substrate 210. For example, the substrate 210 includes sapphire. The substrate 210 may be a sapphire substrate. For example, the stress relief material 220 includes diamond. The stress relief material 220 may be a diamond material.

[0045] The substrate 210 includes a first region 101 and a second region 102. A convex portion 211 is formed in the first region 101, and a plurality of concave portions 212 is formed in the second region 102. In a plan view, the plurality of concave portions 212 are arranged in a square lattice pattern. The concave portions 212 are cylindrical in shape. The cross-sectional shape of the concave portions 212 is rectangular. A stress relief material 220 is provided in each concave portion 212. The Y1-side surface of the convex portion 211 and the Y1-side surface of the stress relief material 220 are flush with each other, and these surfaces constitute a first surface 200A. In other words, the first surface 200A includes the Y1-side surface of the convex portion 211 and the Y1-side surface of the stress relief material 220. The depth of the convex portions 211 and the depth of the concave portions 212 are, for example, approximately 100 nm to 1000 nm.

[0046] The other configurations are the same as those in the first embodiment.

[0047] In the second embodiment, similarly to the first embodiment, peeling between the optical waveguide substrate 200 and the optical waveguide layer 150 can be suppressed.

[0048] Furthermore, in the second embodiment, the second region 102 functions as a photonic crystal depending on the arrangement of the multiple recesses 212 and the stress relaxation material 220. When the second region 102 functions as a photonic crystal, for example, the recesses 212 have a cylindrical shape with a diameter of about 50 nm to 500 nm and a depth of about 100 nm to 1000 nm, and the period of the recesses 212 in the X1-X2 direction and the Z1-Z2 direction is about 100 nm to 500 nm.

[0049] The optical waveguide device 2 according to the second embodiment can be manufactured in the same manner as in the first embodiment.

[0050] 20, a plurality of recesses 212 may be arranged in a triangular lattice pattern in plan view, and a stress relief material 220 may be provided in each recess 212. Fig. 20 is a top view showing an optical waveguide device according to a modified example of the second embodiment.

[0051] Furthermore, among the multiple recesses 212, the stress relaxation material 220 does not need to be provided inside those located on the Z1 side of the optical waveguide layer 150 and those located on the Z2 side of the optical waveguide layer 150.

[0052] (Third embodiment) Next, a third embodiment will be described. The third embodiment differs from the second embodiment mainly in the cross-sectional shape of the recess. Fig. 21 is a cross-sectional view showing an optical waveguide device according to the third embodiment.

[0053] As shown in Figure 21, in the optical waveguide device 3 according to the third embodiment, recesses 312 are formed in the substrate 210 instead of the recesses 212. The recesses 312 are shaped like a cone with a diameter that decreases toward the Y2 side. The cross section of the recesses 312 is triangular. A stress relief material 220 is provided in each recess 312.

[0054] The other configurations are the same as those in the second embodiment.

[0055] The third embodiment can also provide the same effects as the second embodiment.

[0056] The optical waveguide device 3 according to the third embodiment can also be manufactured in the same manner as in the first embodiment.

[0057] (Fourth embodiment) Next, a fourth embodiment will be described. The fourth embodiment differs from the second embodiment mainly in the cross-sectional shape of the recess. Fig. 22 is a cross-sectional view showing an optical waveguide device according to the fourth embodiment.

[0058] As shown in Fig. 22, in the optical waveguide device 4 according to the fourth embodiment, recesses 412 are formed in the substrate 210 instead of the recesses 212. The recesses 412 are shaped like an isosceles truncated cone whose diameter decreases toward the Y2 side. The cross-sectional shape of the recesses 312 is an isosceles trapezoid. A stress relaxation material 220 is provided in each recess 412.

[0059] The other configurations are the same as those in the second embodiment.

[0060] The fourth embodiment can also provide the same effects as the second embodiment.

[0061] The optical waveguide device 4 according to the fourth embodiment can also be manufactured in the same manner as in the first embodiment.

[0062] The width (dimension in the X1-X2 direction) of the protrusions 111, 211 does not need to be equal to the width (dimension in the X1-X2 direction) of the optical waveguide layer 150. For example, the width of the protrusions 111, 211 may be 150% or less of the width of the optical waveguide layer 150. The width of the protrusions 111, 211 is preferably 130% or less, more preferably 120% or less, and even more preferably 110% or less of the width of the optical waveguide layer 150. Furthermore, the width of the protrusions 111, 211 may be 70% or more of the width of the optical waveguide layer 150. The width of the protrusions 111, 211 is preferably 75% or more, more preferably 80% or more, and even more preferably 85% or more of the width of the optical waveguide layer 150.

[0063] In the present disclosure, the materials of the substrate and the stress relaxation material are not particularly limited. For example, when the substrate material is sapphire, the stress relaxation material can be made of diamond, silicon nitride (Si3N4), silicon carbide (SiC), or aluminum nitride (AlN). When the substrate material is silicon carbide, the stress relaxation material can be made of diamond or silicon nitride. The thermal expansion coefficient of silicon nitride is 2.8 × 10 -6 / K, and the thermal expansion coefficient of silicon carbide is 3.7×10 -6 / K, and the thermal expansion coefficient of aluminum nitride is 4.6×10 -6 / K.

[0064] Furthermore, the optical waveguide substrate may have a plurality of first regions, and a plurality of optical waveguide layers may be provided on the optical waveguide substrate.

[0065] (Fifth embodiment) Next, a fifth embodiment will be described. The fifth embodiment differs from the first embodiment etc. mainly in the configuration of the substrate. Fig. 23 is a cross-sectional view showing an optical waveguide device according to the fifth embodiment.

[0066] As shown in FIG. 23 , the optical waveguide device 5 according to the fifth embodiment has an optical waveguide substrate 500 instead of the optical waveguide substrate 100. The optical waveguide substrate 500 has a substrate 510 and a stress relief material 520. The thermal expansion coefficient of the substrate 510 is larger than that of the optical waveguide layer 150. The thermal expansion coefficient of the stress relief material 520 is smaller than that of the substrate 510. For example, the substrate 510 contains sapphire. The substrate 510 may be a sapphire substrate. For example, the stress relief material 520 contains diamond. The stress relief material 520 may be a diamond material.

[0067] The substrate 510 includes a first region 101 and a second region 102, with a convex portion 511 formed in the first region 101 and a concave portion 512 and a concave portion 212 formed in the second region 102. The concave portion 512 is formed on the X1 side and the X2 side of the optical waveguide layer 150. The concave portion 212 is formed on the Z1 side and the Z2 side of the concave portion 512. A stress relief material 520 is provided in each concave portion 512. The stress relief material 520 may also be provided in the concave portion 212, or the stress relief material 520 may not be provided in the concave portion 212.

[0068] The other configurations are the same as those in the first embodiment.

[0069] In the fifth embodiment, as in the first embodiment, peeling between the optical waveguide substrate 500 and the optical waveguide layer 150 can be suppressed.

[0070] (Sixth embodiment) Next, a sixth embodiment will be described. The sixth embodiment differs from the first embodiment etc. mainly in the configuration of the substrate. Fig. 24 is a cross-sectional view showing an optical waveguide device according to the sixth embodiment.

[0071] As shown in FIG. 24, the optical waveguide device 6 according to the sixth embodiment has an optical waveguide substrate 600 instead of the optical waveguide substrate 100. The optical waveguide substrate 600 has a substrate 610 and a stress relief material 620. The thermal expansion coefficient of the substrate 610 is larger than that of the optical waveguide layer 150. The thermal expansion coefficient of the stress relief material 620 is smaller than that of the substrate 610. For example, the substrate 610 contains sapphire. The substrate 610 may be a sapphire substrate. For example, the stress relief material 620 contains diamond. The stress relief material 620 may be a diamond material.

[0072] The substrate 610 includes a first region 101 and a second region 102, with a convex portion 611 formed in the first region 101 and a concave portion 612 and a concave portion 212 formed in the second region 102. The concave portions 612 are formed on the X1 side and the X2 side of the optical waveguide layer 150. The concave portions 612 have a rectangular planar shape extending in the Z1-Z2 direction in a plan view, and a plurality of the concave portions 612 are arranged side by side in the X1-X2 direction. The concave portions 212 are formed on the Z1 side and the Z2 side of the concave portions 612. A stress relief material 620 is provided in each of the concave portions 612. The stress relief material 620 may also be provided in the concave portions 212, or the stress relief material 620 may not be provided in the concave portions 212.

[0073] The other configurations are the same as those in the first embodiment.

[0074] In the sixth embodiment, as in the first embodiment, peeling between the optical waveguide substrate 600 and the optical waveguide layer 150 can be suppressed.

[0075] (Seventh embodiment) Next, a seventh embodiment will be described. The seventh embodiment differs from the second embodiment etc. mainly in the configuration of the substrate. Fig. 25 is a cross-sectional view showing an optical waveguide device according to the seventh embodiment.

[0076] As shown in FIG. 25, the optical waveguide device 7 according to the seventh embodiment has an optical waveguide substrate 700 instead of the optical waveguide substrate 200. The optical waveguide substrate 700 has a substrate 710 and a stress relief material 220. The thermal expansion coefficient of the substrate 710 is larger than that of the optical waveguide layer 150. The thermal expansion coefficient of the stress relief material 220 is smaller than that of the substrate 710. For example, the substrate 710 contains sapphire. The substrate 710 may be a sapphire substrate. For example, the stress relief material 220 contains diamond. The stress relief material 220 may be a diamond material.

[0077] The substrate 710 includes a first region 101 and a second region 102, with convex portions 711 formed in the first region 101 and concave portions 212 formed in the second region 102. The concave portions 212 are formed on the X1 side and the X2 side of the optical waveguide layer 150. A stress relief material 220 is provided in each concave portion 212. Convex portions 711 may also be formed in a region on the Z1 side and a region on the Z2 side of the optical waveguide layer 150 in the second region 102. In this case, for example, by making the refractive index of the convex portions 711 different between the first region 101 and the second region 102, it is possible to confine light within the first region 101.

[0078] The other configurations are the same as those in the second embodiment.

[0079] In the seventh embodiment, similarly to the first embodiment, peeling between the optical waveguide substrate 700 and the optical waveguide layer 150 can be suppressed.

[0080] In the fifth to seventh embodiments, the recess 312 or the recess 412 may be formed instead of the recess 212 .

[0081] (Eighth embodiment) Next, an eighth embodiment will be described. The eighth embodiment differs from the fifth embodiment etc. mainly in the configuration of the substrate. Fig. 26 is a cross-sectional view showing an optical waveguide device according to the eighth embodiment.

[0082] As shown in FIG. 26, the optical waveguide device 8 according to the eighth embodiment has an optical waveguide substrate 800 instead of the optical waveguide substrate 500. The optical waveguide substrate 800 has a substrate 810 and a stress relief material 520. The thermal expansion coefficient of the substrate 810 is larger than that of the optical waveguide layer 150. The thermal expansion coefficient of the stress relief material 520 is smaller than that of the substrate 810. For example, the substrate 810 contains sapphire. The substrate 810 may be a sapphire substrate. For example, the stress relief material 520 contains diamond. The stress relief material 520 may be a diamond material.

[0083] The substrate 810 includes a first region 101 and a second region 102, with convex portions 811 formed in the first region 101 and concave portions 512 formed in the second region 102. The concave portions 512 are formed on the X1 side and the X2 side of the optical waveguide layer 150. A stress relief material 520 is provided in each concave portion 512. Convex portions 811 may also be formed in a region on the Z1 side of the optical waveguide layer 150 and a region on the Z2 side of the second region 102. In this case, for example, by making the refractive index of the convex portions 811 different between the first region 101 and the second region 102, it is possible to confine light within the first region 101.

[0084] The other configurations are the same as those in the fifth embodiment.

[0085] In the eighth embodiment, similarly to the first embodiment, peeling between the optical waveguide substrate 800 and the optical waveguide layer 150 can be suppressed.

[0086] (Ninth embodiment) Next, a ninth embodiment will be described. The ninth embodiment differs from the sixth embodiment etc. mainly in the configuration of the substrate. Fig. 27 is a cross-sectional view showing an optical waveguide device according to the ninth embodiment.

[0087] As shown in FIG. 27, the optical waveguide device 9 according to the ninth embodiment has an optical waveguide substrate 900 instead of the optical waveguide substrate 600. The optical waveguide substrate 900 has a substrate 910 and a stress relief material 620. The thermal expansion coefficient of the substrate 910 is larger than that of the optical waveguide layer 150. The thermal expansion coefficient of the stress relief material 620 is smaller than that of the substrate 910. For example, the substrate 910 contains sapphire. The substrate 910 may be a sapphire substrate. For example, the stress relief material 620 contains diamond. The stress relief material 620 may be a diamond material.

[0088] The substrate 910 includes a first region 101 and a second region 102. Convex portions 911 are formed in the first region 101, and concave portions 612 are formed in the second region 102. The concave portions 612 are formed on the X1 side and the X2 side of the optical waveguide layer 150. The concave portions 612 have a rectangular planar shape extending in the Z1-Z2 direction in a plan view, and a plurality of concave portions 612 are arranged side by side in the X1-X2 direction. A stress relief material 620 is provided in each concave portion 612. Convex portions 911 may also be formed in a region of the second region 102 closer to the Z1 side and a region of the second region 102 closer to the Z2 side than the optical waveguide layer 150. In this case, for example, by making the refractive index of the convex portions 911 different between the first region 101 and the second region 102, it is possible to confine light within the first region 101.

[0089] The other configurations are the same as those in the sixth embodiment.

[0090] In the ninth embodiment, as in the first embodiment, peeling between the optical waveguide substrate 600 and the optical waveguide layer 150 can be suppressed.

[0091] (Tenth embodiment) Next, a tenth embodiment will be described. The tenth embodiment relates to a quantum computer. Fig. 28 is a diagram showing a quantum computer according to the tenth embodiment.

[0092] A quantum computer 10 according to the tenth embodiment includes a general-purpose computer 1001, a control unit 1002, and a quantum device 1003. The control unit 1002 controls the quantum device 1003 based on a control signal from the general-purpose computer 1001. A quantum device including an optical waveguide device according to any of the first to ninth embodiments is used as the quantum device 1003. The control unit 1002 and the quantum device 1003 are housed in a cryostat 1004.

[0093] The quantum computer 10 is capable of performing stable quantum operations.

[0094] Although the preferred embodiments have been described above in detail, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims. [Explanation of symbols]

[0095] 1, 2, 3, 4, 5, 6, 7, 8, 9: Optical waveguide device 10: Quantum Computer 100, 200, 500, 600, 700, 800, 900: Optical waveguide substrate 100A, 200A: 1st page 101:First area 102:Second area 110, 210, 510, 610, 710, 810, 910: PCB 111, 211, 511, 611, 711, 811, 911: Convex 112, 212, 312, 412, 512, 612 recesses 120, 220, 520, 620: Stress relief material 150: Optical waveguide layer 151: Color Center

Claims

1. an optical waveguide substrate having a first surface; an optical waveguide layer provided on the first surface; and The optical waveguide substrate comprises: a first region exposed on the first surface and extending linearly in a first direction; second regions exposed on the first surface and located on both sides of the first region in a plan view; and the optical waveguide layer is provided on the first region so as to extend in the first direction, The optical waveguide layer is a first portion having a constant height along the first direction; a second portion whose height decreases along the first direction; and the optical waveguide layer and the first region are in direct contact with each other; the refractive index of the optical waveguide layer is greater than the refractive index of the first region; the optical waveguide layer functions as a core layer of an optical waveguide; a region of the first region that is in contact with the first portion functions as a clad layer of the optical waveguide; light propagates from the optical waveguide layer to the optical waveguide substrate in a region of the first region that contacts the second portion; a second coefficient of thermal expansion of the second region that is smaller than the first coefficient of thermal expansion of the first region; The optical waveguide device according to claim 1, wherein the third thermal expansion coefficient of the optical waveguide layer is smaller than the first thermal expansion coefficient.

2. The optical waveguide substrate comprises: a first member having a convex portion formed in the first region and a concave portion formed in the second region, the first member having the first thermal expansion coefficient; a second member provided in the recess and having the second thermal expansion coefficient; 2. The optical waveguide device according to claim 1, further comprising:

3. a plurality of the recesses are formed in the second region; 3. The optical waveguide device according to claim 2, wherein the second member is provided in each of the recesses.

4. 4. The optical waveguide device according to claim 3, wherein the second member comprises a photonic crystal.

5. 5. The optical waveguide device according to claim 2, wherein the second member is made of the same material as the optical waveguide layer.

6. 6. The optical waveguide device according to claim 1, wherein the optical waveguide layer contains diamond.

7. The optical waveguide device according to claim 6 , wherein the optical waveguide layer includes a color center.

8. A quantum computing device comprising the optical waveguide device according to any one of claims 1 to 7.

9. A process for obtaining a substrate including a first member having a convex portion in a first region extending linearly in a first direction, having concave portions in second regions located on both sides of the first region in a plan view, and having a first thermal expansion coefficient; forming a second member having a second coefficient of thermal expansion within the recess; providing an optical waveguide layer on the protrusion so as to extend in the first direction; and The optical waveguide layer is a first portion having a constant height along the first direction; a second portion whose height decreases along the first direction; and the optical waveguide layer and the first region are in direct contact with each other; the refractive index of the optical waveguide layer is greater than the refractive index of the first region; the optical waveguide layer functions as a core layer of an optical waveguide; a region of the first region that is in contact with the first portion functions as a clad layer of the optical waveguide; light propagates from the optical waveguide layer to the substrate in a region of the first region that is in contact with the second portion; the second coefficient of thermal expansion is smaller than the first coefficient of thermal expansion; The method for manufacturing an optical waveguide device, wherein the third thermal expansion coefficient of the optical waveguide layer is smaller than the first thermal expansion coefficient.

10. The method for manufacturing an optical waveguide device according to claim 9 , wherein the optical waveguide layer is provided after the second member is formed.

11. The method for manufacturing an optical waveguide device according to claim 9, wherein the second member and the optical waveguide layer are formed simultaneously.

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