Ring resonator and manufacturing method therefor

Abstract

To provide a ring resonator that suppresses generation of a thermal interference while maintaining the length of a ring waveguide which is heated by a heater, and a manufacturing method therefor.SOLUTION: The ring resonator comprises an input waveguide, a first ring waveguide, a second ring waveguide, an output waveguide, and a heater. The first ring waveguide includes a first waveguide section optically connected to the input waveguide, and a third waveguide section which is longer of two waveguide sections that connect a second waveguide section optically connected to the second ring waveguide. The second ring waveguide includes a fourth waveguide section optically connected to the second waveguide section, and a sixth waveguide section which is longer of two waveguide sections that connect a fifth waveguide section optically connected to the output waveguide. The heater runs along the third waveguide section and the sixth waveguide section.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to ring resonators and methods for manufacturing the same. [Background technology]

[0002] Patent Document 1 discloses a technique for realizing a tunable optical filter by arranging a heater on a double microring waveguide. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6434864 Summary of the Invention [Problem to be solved by the invention]

[0004] When a heater is placed near the coupling region of two ring waveguides, the two ring waveguides will thermally interfere with each other. Although the thermal interference can be suppressed by shortening the length of the heater placed along the ring waveguide, this approach results in a problem in that the length of the waveguide to be heated becomes shorter.

[0005] The present disclosure has been made to solve these problems, and aims to provide a ring resonator and a manufacturing method thereof that suppresses the occurrence of thermal interference while ensuring the length of the waveguide to be heated. [Means for solving the problem]

[0006] The ring resonator according to the present disclosure comprises: an input waveguide; a first ring waveguide; a second ring waveguide; and an output waveguide; and Heater and Equipped with the first ring waveguide comprises a first waveguide portion optically connected to the input waveguide, a second waveguide portion optically connected to the second ring waveguide, and two curved waveguide portions each connecting the first waveguide portion and the second waveguide portion; the lengths of the two waveguide portions of the first ring waveguide are different from each other; the second ring waveguide comprises a fourth waveguide portion optically connected to the second waveguide portion, a fifth waveguide portion optically connected to the output waveguide, and two curved waveguide portions each connecting the fourth waveguide portion and the fifth waveguide portion; the lengths of the two waveguide portions of the second ring waveguide are different from each other; the first waveguide portion and the fifth waveguide portion are disposed on opposite sides of a center line passing through the first ring waveguide and the second ring waveguide; a first orientation along the first waveguide portion and the fifth waveguide portion and a second orientation along the second waveguide portion and the fourth waveguide portion are not parallel to each other; The heaters are disposed along a third waveguide portion, which is the longer of the two waveguide portions of the first ring waveguide, and a sixth waveguide portion, which is the longer of the two waveguide portions of the second ring waveguide.

[0007] A method for manufacturing a ring resonator according to the present disclosure includes: forming an input waveguide, a first ring waveguide, a second ring waveguide, and an output waveguide; forming a heater; Including, the first ring waveguide comprises a first waveguide portion optically connected to the input waveguide, a second waveguide portion optically connected to the second ring waveguide, and two curved waveguide portions each connecting the first waveguide portion and the second waveguide portion; the lengths of the two waveguide portions of the first ring waveguide are different from each other; the second ring waveguide comprises a fourth waveguide portion optically connected to the second waveguide portion, a fifth waveguide portion optically connected to the output waveguide, and two curved waveguide portions each connecting the fourth waveguide portion and the fifth waveguide portion; the lengths of the two waveguide portions of the second ring waveguide are different from each other; the first waveguide portion and the fifth waveguide portion are disposed on opposite sides of a center line passing through the first ring waveguide and the second ring waveguide; a first orientation along the first waveguide portion and the fifth waveguide portion and a second orientation along the second waveguide portion and the fourth waveguide portion are not parallel to each other; The heaters are disposed along a third waveguide portion, which is the longer of the two waveguide portions of the first ring waveguide, and a sixth waveguide portion, which is the longer of the two waveguide portions of the second ring waveguide. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to provide a ring resonator that suppresses the occurrence of thermal interference while ensuring the length of the waveguide that is heated, and a method for manufacturing the same. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic plan view of a ring resonator according to a reference example. [Figure 2] FIG. 1 is a schematic plan view of a ring resonator according to the present disclosure. [Figure 3] FIG. 1 is a schematic cross-sectional view of a ring resonator according to the present disclosure. [Figure 4] 1 is a schematic cross-sectional view of a ring resonator according to the present disclosure; [Figure 5] FIG. 1 is a schematic plan view of a ring resonator according to the present disclosure. [Figure 6] 1 is a flowchart illustrating a method for manufacturing a ring resonator according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0010] Consideration leading to the embodiment The configuration of a ring resonator 20 according to a reference example will be described below with reference to Fig. 1. Fig. 1 is a schematic plan view of the ring resonator 20. The ring resonator 20 includes an input waveguide 2, a ring waveguide 3a, a ring waveguide 3b, an output waveguide 4, a heater 5, and a heat insulating structure 6.

[0011] When the ring waveguides 3a and 3b are not distinguished from each other, they may simply be referred to as the ring waveguide 3. The ring waveguides 3a and 3b have a racetrack shape. The racetrack shape is composed of two parallel lines of equal length and two curved lines connecting the two parallel lines. The portion of the ring waveguide 3 that corresponds to the parallel lines is also called the straight section, and the portion that corresponds to the curved lines is also called the semicircular section.

[0012] The input waveguide 2 is optically connected to one straight section of the ring waveguide 3a (e.g., the straight section at the bottom of the figure). Light is input to one end of the input waveguide 2 (e.g., the end on the left side of the figure). Part of the input light propagates to the ring waveguide 3a.

[0013] Light propagated into ring waveguide 3a circulates in one direction (e.g., counterclockwise in the figure). The other straight section of ring waveguide 3a (e.g., the upper straight section in the figure) is optically connected to one straight section of ring waveguide 3b (e.g., the lower straight section in the figure). Light of the resonant wavelength of ring waveguide 3a propagates into ring waveguide 3b.

[0014] The light propagated to the ring waveguide 3b circulates in one direction (for example, clockwise in the figure). The other straight portion of the ring waveguide 3b (for example, the straight portion at the top in the figure) is optically connected to the output waveguide 4. Light with the resonant wavelength of the ring waveguide 3b propagates to the output waveguide 4. The resonant wavelength of the ring waveguide 3a and the resonant wavelength of the ring waveguide 3b may be the same.

[0015] The output waveguide 4 outputs light from one end (for example, the end on the right side in the figure).

[0016] The heater 5 and the heat insulating structure 6 are arranged along the ring waveguide 3a and the ring waveguide 3b. The heater 5 and the heat insulating structure 6 arranged along the ring waveguide 3a are also referred to as the heater 5a and the heat insulating structure 6a, respectively. The heater 5 and the heat insulating structure 6 arranged along the ring waveguide 3b are also referred to as the heater 5b and the heat insulating structure 6b, respectively. As shown in the figure, the heater 5 and the heat insulating structure 6 may be arranged along the semicircular portions of the ring waveguides 3a and 3b.

[0017] The heat insulating structure 6 is, for example, an air layer or a vacuum layer disposed below the ring waveguide 3 and the heater 5. By disposing the heater 5 and the heat insulating structure 6, the power input to the heater 5 is reduced.

[0018] The following describes a case where the heater 5 and the heat insulating structure 6 are arranged along the entire circumference of the ring waveguides 3a and 3b. The heat insulating structures 6a and 6b are close to each other in the region where the ring waveguides 3a and 3b are optically connected to each other (also called the coupling region). This causes a problem of reduced mechanical strength of the ring resonator 20. Similarly, because the heaters 5a and 5b are close to each other in the coupling region, heating one ring waveguide can cause an unintended temperature change in the other ring waveguide. In other words, there is a problem of thermal interference between the ring waveguides 3a and 3b.

[0019] As shown in the figure, shortening the length of the heater 5 can prevent a decrease in mechanical strength and the occurrence of thermal interference. However, this shortens the length of the heated ring waveguides 3a and 3b, which reduces the effect of reducing power consumption.

[0020] When the lengths of the straight portions of the ring waveguides 3a and 3b are increased, the heater 5a and the heat insulating structure 6a can be extended along the straight portions located on the input waveguide 2 side. Similarly, the heater 5b and the heat insulating structure 6b can be extended along the straight portions located on the output waveguide 4 side. This allows the length of the heated ring waveguide 3 to be increased, but the length of one circumference of the ring waveguide 3 increases. Increasing the length of one circumference can result in a decrease in the FSR (Free Spectral Range). Increasing the length of the straight portions of the ring waveguide 3 while reducing the radius of curvature of the semicircular portions can suppress the decrease in FSR, but increases the loss due to bending.

[0021] As described above, it is difficult for the ring resonator 20 according to the comparative example to achieve all of the requirements of low power consumption, ensuring mechanical strength, and suppressing thermal interference. Based on the above considerations, the present inventors have arrived at the invention according to the embodiment.

[0022] Embodiment 1 The configuration of ring resonator 10 will be described below with reference to Figure 2. Figure 2 is a schematic plan view of ring resonator 10. Ring resonator 10 includes an input waveguide 2, ring waveguides 3a and 3b, an output waveguide 4, a heater 5, and a heat insulating structure 6. Ring waveguide 3a corresponds to the first ring waveguide. Ring waveguide 3b corresponds to the second ring waveguide. When ring waveguides 3a and 3b are not distinguished from each other, they may be simply referred to as ring waveguides 3.

[0023] The input waveguide 2, the ring waveguide 3a, the ring waveguide 3b, and the output waveguide 4 each include a core through which light propagates. The core is surrounded by a cladding. The core is made of, for example, Si. The cladding is made of, for example, SiO2. The refractive index of the material forming the core is different from the refractive index of the material forming the cladding. The ring resonator 10 may be formed on an SOI (Silicon on Insulator) substrate having a BOX (Buried Oxide) layer.

[0024] The input waveguide 2 is optically connected to the ring waveguide 3a. Light is input to one end (e.g., the end on the left side in the figure) of the input waveguide 2. A portion of the input light propagates to the ring waveguide 3a.

[0025] The ring waveguide 3a includes a waveguide portion 31a, a waveguide portion 32a, a waveguide portion 33a, and a waveguide portion 34a. The waveguide portion 31a, the waveguide portion 32a, and the waveguide portion 33a correspond to the first waveguide portion, the second waveguide portion, and the third waveguide portion, respectively. The waveguide portion 31a is a portion of the ring waveguide 3a included in a region 91. The input waveguide 2 and the ring waveguide 3a are optically connected to each other in the region 91. The waveguide portion 32a is a portion of the ring waveguide 3a included in a region 92. The ring waveguides 3a and 3b are optically connected to each other in the region 92.

[0026] Waveguide portion 31a is optically connected to input waveguide 2. Waveguide portion 32a is optically connected to waveguide portion 31b of ring waveguide 3b, which will be described later. Two curved waveguide portions each connect waveguide portions 31a and 32a. Curved means, for example, a shape represented by a line including a continuously curved line. The two waveguide portions have different lengths. Waveguide portion 33a is the longer of the two waveguide portions. Waveguide portion 34a is the shorter of the two waveguide portions. Waveguide portions 33a and 34a are physically and optically connected to waveguide portions 31a and 32a, respectively.

[0027] Light input from the waveguide portion 31a circulates in one direction (for example, counterclockwise in the figure) in the ring waveguide 3a, and light of the resonance wavelength of the ring waveguide 3a propagates from the waveguide portion 32a to the ring waveguide 3b.

[0028] The ring waveguide 3b includes a waveguide portion 31b, a waveguide portion 32b, a waveguide portion 33b, and a waveguide portion 34b. The waveguide portions 31b, 32b, and 33b correspond to the fourth, fifth, and sixth waveguide portions, respectively. The waveguide portion 31b is a portion of the ring waveguide 3b that is included in a region 92. The waveguide portion 32b is a portion of the ring waveguide 3b that is included in a region 93. The ring waveguide 3b and the output waveguide 4 are optically connected to each other in the region 93.

[0029] Waveguide portion 31b optically connects to waveguide portion 32a of ring waveguide 3a. Waveguide portion 32b optically connects to output waveguide 4. Two curved waveguide portions each connect waveguide portions 31b and 32b. The lengths of the two waveguide portions are different. Waveguide portion 33b is the longer of the two waveguide portions. Waveguide portion 34b is the shorter of the two waveguide portions. Waveguide portions 33b and 34b are each physically and optically connected to waveguide portions 31b and 32b.

[0030] Light input from the waveguide portion 31b circulates in one direction (for example, clockwise in the figure) in the ring waveguide 3b. Then, light with the resonance wavelength of the ring waveguide 3b propagates from the waveguide portion 32b to the output waveguide 4. The resonance wavelength of the ring waveguide 3a and the resonance wavelength of the ring waveguide 3b may be the same.

[0031] The waveguide portion 31a of the ring waveguide 3a and the waveguide portion 32b of the ring waveguide 3b are provided on opposite sides of a center line passing through the ring waveguides 3a and 3b. The center line may pass through the center of the ring waveguides 3a and 3b.

[0032] Arrow 94 represents the direction along waveguide portion 31a. Arrow 95 represents the direction along waveguide portion 32a and waveguide portion 31b. Arrow 96 represents the direction along waveguide portion 32b. The direction along waveguide portion 31a and waveguide portion 32b (also referred to as the first direction) and the direction along waveguide portion 32a and waveguide portion 31b (also referred to as the second direction) are not parallel to each other. Arrows 94 and 96 represent the first direction. Arrow 95 represents the second direction. The first direction and the second direction may be perpendicular to each other.

[0033] The ring waveguides 3a and 3b may have, for example, a racetrack shape. The racetrack shape is composed of two parallel lines and two curved lines connecting the two parallel lines. The two parallel lines are parallel to a first direction or a second direction. The lengths of the two parallel lines are equal to each other. The illustrated two parallel lines are parallel to the first direction. In this case, the length of the waveguide contributing to the coupling of the ring waveguides 3a and 3b, i.e., the length of the linear waveguide contributing to the coupling of the directional coupler, is relatively short. The ring waveguides 3a and 3b may be circular (e.g., perfect circular). The waveguide portion 31a is included in one of the two parallel lines in the ring waveguide 3a. The waveguide portion 32a is included in one of the two curved lines in the ring waveguide 3a. The waveguide portion 31b is included in one of the two curved lines in the ring waveguide 3b. The waveguide portion 32b is included in one of the two parallel lines in the ring waveguide 3b.

[0034] The output waveguide 4 is optically connected to the waveguide portion 32b of the ring waveguide 3b. The output waveguide 4 outputs light from one end (for example, the end on the right side in the figure).

[0035] The heater 5 and the heat insulating structure 6 are disposed along the waveguide portion 33a of the ring waveguide 3a and the waveguide portion 33b of the ring waveguide 3b, respectively. The heater 5 and the heat insulating structure 6 disposed along the ring waveguide 3a are also referred to as the heater 5a and the heat insulating structure 6a, respectively. The heater 5 and the heat insulating structure 6 disposed along the ring waveguide 3b are also referred to as the heater 5b and the heat insulating structure 6b, respectively. The heater 5 and the heat insulating structure 6 may be disposed along the entirety of each of the waveguide portions 33a and 33b. The length of the waveguide of the ring waveguide 3 where the heater 5 is disposed may be, for example, half or more of the circumferential length of the ring waveguide 3.

[0036] 3 is a schematic diagram illustrating a first example of the AA cross section of FIG. 2. The ring resonator 10 includes a SiO2 layer 7 formed on a substrate (not shown). The SiO2 layer 7 may include a lower SiO2 layer 71 disposed below the ring waveguide 3 and an upper SiO2 layer 72 formed on the lower SiO2 layer 71. The lower SiO2 layer 71 may be, for example, a BOX layer of an SOI substrate. The ring waveguide 3 is formed of, for example, Si.

[0037] The heater 5 is disposed near the ring waveguide 3. Although the heater 5 is shown disposed on the side of the ring waveguide 3, the heater 5 may be disposed above or below the ring waveguide 3.

[0038] The heater 5 is made of, for example, a metal. When power is applied to the heater 5, the resonance wavelength of the ring waveguide 3 shifts.

[0039] The heat insulating structure 6 in the figure is an air layer disposed below the ring waveguide 3. The air layer is formed, for example, by etching the SiO2 layer 7 on both sides of the ring waveguide 3 etc. in the depth direction to form openings O, and then performing isotropic etching using a reactive gas or the like. The heater 5 is located between the openings O and the ring waveguide 3. The heat insulating structure 6 covers the ring waveguide 3 and heater 5 from below.

[0040] 4 is a schematic diagram illustrating a second example of the AA cross section of FIG. 1. The heat insulating structure 6 in the figure is a vacuum layer provided below the ring waveguide 3. The vacuum layer may be formed, for example, by etching the lower SiO2 layer 71 in the depth direction and then performing isotropic etching before forming the upper SiO2 layer 72. After the vacuum layer is formed, the upper SiO2 layer 72 may be formed on the lower SiO2 layer 71.

[0041] Next, the effects of the present disclosure will be described with reference to FIG. 2. The heater 5 and the heat insulating structure 6 are arranged point-symmetrically with respect to the center of the region 92. A sufficient gap is secured between the region where the heater 5a and the heat insulating structure 6a are arranged and the region where the heater 5b and the heat insulating structure 6b are arranged. This prevents a decrease in mechanical strength and the occurrence of thermal interference. Furthermore, since the length of the heater 5a and the heat insulating structure 6a can be secured sufficiently, the power consumption of the heater 5 can be reduced. Since the length of one circumference of the ring waveguides 3a and 3b does not increase, narrow-bandwidth filter characteristics are achieved.

[0042] Embodiment 2 The configuration of ring resonator 1 will be described using Figure 5. Comparing Figure 2 with Figure 5, ring resonator 1 does not need to include heat insulating structure 6. The material forming each waveguide is not limited to Si, and may be any material that can guide light. One or more ring waveguides may be arranged between ring waveguide 3a and ring waveguide 3b.

[0043] The ring resonator 1 can suppress the occurrence of thermal interference while ensuring the length of the ring waveguide 3 heated by the heater 5.

[0044] A method for manufacturing the ring resonator 1 will be described with reference to Figure 6. In step S11, the input waveguide 2, ring waveguide 3a (first ring waveguide), ring waveguide 3b (second ring waveguide), and output waveguide 4 are formed. The input waveguide 2, ring waveguide 3a, ring waveguide 3b, and output waveguide 4 are formed, for example, by forming a resist pattern by lithography and etching an SOI substrate using the resist as a mask. After etching the SOI substrate, an upper SiO2 layer 72 may be formed.

[0045] In step S12, heaters 5 are formed along the waveguide portion 33a (third waveguide portion) of the ring waveguide 3a and the waveguide portion 33b (sixth waveguide portion) of the ring waveguide 3b. The heaters 5 may be formed, for example, by forming a resist pattern using lithography, depositing a metal film, and then peeling off the resist. Alternatively, the heaters 5 may be formed by depositing a metal film and then etching the metal film.

[0046] The order of steps S11 and S12 may be reversed. The method for manufacturing the ring resonator 1 may also include forming a heat insulating structure 6 along the waveguide portion 33a and the waveguide portion 33b. The heat insulating structure 6 may include, for example, forming an opening in the SiO2 layer using a resist or the like as a mask, and performing isotropic etching after the opening is formed.

[0047] The manufacturing method shown in FIG. 6 can manufacture a ring resonator that suppresses the occurrence of thermal interference while ensuring the length of the ring waveguide that is heated by the heater.

[0048] Although the present disclosure has been described above with reference to the embodiments, the present disclosure is not limited to the above-described embodiments. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present disclosure within the scope of the present disclosure. Furthermore, each embodiment can be combined with other embodiments as appropriate.

[0049] Each drawing is merely an example for describing one or more embodiments. Each drawing may relate not only to one particular embodiment, but also to one or more other embodiments. As will be understood by those skilled in the art, various features or steps described with reference to any one drawing can be combined with features or steps shown in one or more other drawings to create, for example, an embodiment not explicitly shown or described. Not all features or steps shown in any one drawing are necessary to describe an exemplary embodiment, and some features or steps may be omitted. The order of steps described in any drawing may be changed as appropriate.

[0050] Some or all of the above-described embodiments can be described as, but are not limited to, the following supplementary notes. (Appendix 1) an input waveguide; a first ring waveguide; a second ring waveguide; and an output waveguide; and Heater and Equipped with the first ring waveguide comprises a first waveguide portion optically connected to the input waveguide, a second waveguide portion optically connected to the second ring waveguide, and two curved waveguide portions each connecting the first waveguide portion and the second waveguide portion; the lengths of the two waveguide portions of the first ring waveguide are different from each other; the second ring waveguide comprises a fourth waveguide portion optically connected to the second waveguide portion, a fifth waveguide portion optically connected to the output waveguide, and two curved waveguide portions each connecting the fourth waveguide portion and the fifth waveguide portion; the lengths of the two waveguide portions of the second ring waveguide are different from each other; the first waveguide portion and the fifth waveguide portion are disposed on opposite sides of a center line passing through the first ring waveguide and the second ring waveguide; a first orientation along the first waveguide portion and the fifth waveguide portion and a second orientation along the second waveguide portion and the fourth waveguide portion are not parallel to each other; The heaters are disposed along a third waveguide portion, which is the longer of the two waveguide portions of the first ring waveguide, and a sixth waveguide portion, which is the longer of the two waveguide portions of the second ring waveguide. Ring resonator. (Appendix 2) The first direction and the second direction are perpendicular to each other. 2. The ring resonator of claim 1. (Appendix 3) a heat insulating structure disposed along each of the third and sixth waveguide portions; 3. The ring resonator of claim 1 or 2. (Appendix 4) The heat insulating structure covers the first ring waveguide, the second ring waveguide, and the heater from below. 4. The ring resonator of claim 3. (Appendix 5) The first ring waveguide and the second ring waveguide each include a core made of Si. 5. The ring resonator of claim 4. (Appendix 6) each of the first ring waveguide and the second ring waveguide is composed of two parallel lines and two curved lines connecting the two parallel lines; The two parallel lines are parallel to the first direction or the second direction. The lengths of the two parallel lines are equal 3. The ring resonator of claim 2. (Appendix 7) the first waveguide portion is included in one of the two parallel lines of the first ring waveguide; the second waveguide portion is included in one of the two curves of the first ring waveguide; the fourth waveguide portion is included in one of the two curves of the second ring waveguide; the fifth waveguide portion is included in one of the two parallel lines in the second ring waveguide; 7. The ring resonator of claim 6. (Appendix 8) The heaters are arranged point-symmetrically with respect to the center of a region where the first ring waveguide and the second ring waveguide are optically connected to each other. 3. The ring resonator of claim 2. (Appendix 9) The heater is disposed along the entirety of each of the third waveguide portion and the sixth waveguide portion. 3. The ring resonator of claim 1 or 2. (Appendix 10) forming an input waveguide, a first ring waveguide, a second ring waveguide, and an output waveguide; forming a heater; Including, the first ring waveguide comprises a first waveguide portion optically connected to the input waveguide, a second waveguide portion optically connected to the second ring waveguide, and two curved waveguide portions each connecting the first waveguide portion and the second waveguide portion; the lengths of the two waveguide portions of the first ring waveguide are different from each other; the second ring waveguide comprises a fourth waveguide portion optically connected to the second waveguide portion, a fifth waveguide portion optically connected to the output waveguide, and two curved waveguide portions each connecting the fourth waveguide portion and the fifth waveguide portion; the lengths of the two waveguide portions of the second ring waveguide are different from each other; the first waveguide portion and the fifth waveguide portion are disposed on opposite sides of a center line passing through the first ring waveguide and the second ring waveguide; a first orientation along the first waveguide portion and the fifth waveguide portion and a second orientation along the second waveguide portion and the fourth waveguide portion are not parallel to each other; The heaters are disposed along a third waveguide portion, which is the longer of the two waveguide portions of the first ring waveguide, and a sixth waveguide portion, which is the longer of the two waveguide portions of the second ring waveguide. Method for manufacturing a ring resonator.

[0051] Some or all of the elements (e.g., configurations and functions) described in Supplementary Notes 2 to 9 that are dependent on Supplementary Note 1 may also be dependent on Supplementary Note 10 in the same dependent relationship as Supplementary Notes 2 to 9. Some or all of the elements described in any Supplementary Note may be applied to various hardware, software, recording means for recording software, systems, and methods. [Explanation of symbols]

[0052] 1, 10, 20 ring resonators 2. Input waveguide 3, 3a, 3b ring waveguide 31a, 32a, 33a, 34a, 31b, 32b, 33b, 34b waveguide section 4 Output waveguide 5, 5a, 5b heater 6, 6a, 6b Insulated structure 7 SiO2 layer 71 Lower SiO2 layer 72 Upper SiO2 layer 91, 92, 93 areas 94, 95, 96 Arrows

Claims

1. an input waveguide; a first ring waveguide; a second ring waveguide; and an output waveguide; and Heater and Equipped with the first ring waveguide comprises a first waveguide portion optically connected to the input waveguide, a second waveguide portion optically connected to the second ring waveguide, and two curved waveguide portions each connecting the first waveguide portion and the second waveguide portion; the two waveguide portions of the first ring waveguide have different lengths; the second ring waveguide comprises a fourth waveguide portion optically connecting to the second waveguide portion, a fifth waveguide portion optically connecting to the output waveguide, and two curved waveguide portions each connecting the fourth waveguide portion and the fifth waveguide portion; the two waveguide portions of the second ring waveguide have different lengths; the first waveguide portion and the fifth waveguide portion are disposed on opposite sides of a center line passing through the first ring waveguide and the second ring waveguide; a first orientation along the first waveguide portion and the fifth waveguide portion and a second orientation along the second waveguide portion and the fourth waveguide portion are not parallel to each other; The heaters are disposed along a third waveguide portion, which is the longer of the two waveguide portions of the first ring waveguide, and a sixth waveguide portion, which is the longer of the two waveguide portions of the second ring waveguide. Ring resonator.

2. The first orientation and the second orientation are perpendicular to each other. The ring resonator of claim 1 .

3. a heat insulating structure disposed along the third waveguide portion and the sixth waveguide portion; 3. The ring resonator according to claim 1.

4. The heat insulating structure covers the first ring waveguide, the second ring waveguide, and the heater from below. The ring resonator of claim 3 .

5. The first ring waveguide and the second ring waveguide each include a core made of Si. The ring resonator of claim 4 .

6. each of the first ring waveguide and the second ring waveguide is composed of two parallel lines and two curved lines connecting the two parallel lines; The two parallel lines are parallel to the first direction or the second direction. The lengths of the two parallel lines are equal to each other The ring resonator of claim 2 .

7. the first waveguide portion is included in one of the two parallel lines in the first ring waveguide; the second waveguide portion is included in one of the two curves of the first ring waveguide; the fourth waveguide portion is included in one of the two curves of the second ring waveguide; the fifth waveguide portion is included in one of the two parallel lines in the second ring waveguide; The ring resonator of claim 6 .

8. The heaters are arranged point-symmetrically with respect to the center of a region where the first ring waveguide and the second ring waveguide are optically connected to each other. The ring resonator of claim 2 .

9. The heater is disposed along the entirety of each of the third waveguide portion and the sixth waveguide portion.

3. The ring resonator according to claim 1.

10. forming an input waveguide, a first ring waveguide, a second ring waveguide, and an output waveguide; forming a heater; Including, the first ring waveguide comprises a first waveguide portion optically connected to the input waveguide, a second waveguide portion optically connected to the second ring waveguide, and two curved waveguide portions each connecting the first waveguide portion and the second waveguide portion; the two waveguide portions of the first ring waveguide have different lengths; the second ring waveguide comprises a fourth waveguide portion optically connecting to the second waveguide portion, a fifth waveguide portion optically connecting to the output waveguide, and two curved waveguide portions each connecting the fourth waveguide portion and the fifth waveguide portion; the two waveguide portions of the second ring waveguide have different lengths; the first waveguide portion and the fifth waveguide portion are disposed on opposite sides of a center line passing through the first ring waveguide and the second ring waveguide; a first orientation along the first waveguide portion and the fifth waveguide portion and a second orientation along the second waveguide portion and the fourth waveguide portion are not parallel to each other; The heaters are disposed along a third waveguide portion, which is the longer of the two waveguide portions of the first ring waveguide, and a sixth waveguide portion, which is the longer of the two waveguide portions of the second ring waveguide. Method for manufacturing a ring resonator.

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