Micro-ring resonator

Abstract

The present application relates to a ring resonator comprising: a straight waveguide; and the runway type micro ring comprises an arc-shaped coupling section and a first straight arm connected with the arc-shaped coupling section, and the arc-shaped coupling section is coupled with the straight waveguide. Through the arrangement of the runway type micro-ring coupled with the straight waveguide, the perimeter of the annular waveguide can be increased while the communication performance index of the micro-ring is not affected, namely, the loop loss of the micro-ring is reduced, and the technical problem that the insertion loss is increased due to the increase of a transmission path due to the too large radius of the micro-ring in the related technology is solved.

Description

Technical Field

[0001] The present application relates to the field of optical communication devices, and in particular to a microring resonator. Background Art

[0002] In recent years, silicon photonics has become one of the most promising photonic integration platforms due to its compatibility with CMOS technology (complementary metal oxide semiconductor) and high refractive index difference. Microring resonators are small in size, easy to integrate, and usually have high Q values. They are one of the basic structures of silicon photonics and have attracted much attention in the fields of optical communications and sensing.

[0003] The Q value of an optical resonant cavity indicates the sharpness of the resonance peak relative to the center frequency, and describes the ability of the resonant cavity to store and confine light. In many application scenarios that require a narrow filter window or a strong resonance enhancement effect, the Q value and extinction ratio are of great concern. In related technologies, the coupling between waveguides is enhanced by increasing the radius of the microring, but a microring radius that is too large may increase the insertion loss due to the increase in the transmission path. Summary of the invention

[0004] The present application provides a micro-ring resonator, which can solve the technical problem in the related art that the excessively large radius of the micro-ring may lead to an increase in insertion loss due to the increase in the transmission path.

[0005] In a first aspect, an embodiment of the present application provides a microring resonator, which includes: a straight waveguide; a racetrack-type microring, wherein the racetrack-type microring includes an arc-shaped coupling section and a first straight arm connected to the arc-shaped coupling section, and the arc-shaped coupling section is coupled to the straight waveguide.

[0006] In combination with the first aspect, in one embodiment, the microring resonator further includes: a non-concentric microring, wherein the non-concentric microring is accommodated in the racetrack-type microring, and the non-concentric microring is coupled with the first straight arm, so that the non-concentric microring and the racetrack-type microring are nested and coupled, thereby reducing the overall structural loss and improving the Q value.

[0007] In combination with the first aspect, in one embodiment, the first straight arm is provided with a photonic crystal nanobeam, and the non-concentric microring is coupled with the photonic crystal nanobeam. By providing the photonic crystal nanobeam in the first straight arm and coupling it with the non-concentric microring, a more complex optical signal processing function can be realized in a smaller space, which helps to improve the integration and performance of optoelectronic devices.

[0008] In combination with the first aspect, in one embodiment, the cross-sectional width of the non-concentric microring close to the first straight arm is smaller than the cross-sectional width of the non-concentric microring away from the first straight arm, so that the mode field matching of the optical signal during the coupling process is closer, which helps to reduce the energy loss of the optical signal during the coupling process and improve the coupling efficiency.

[0009] In combination with the first aspect, in one embodiment, the cross-sectional width of the non-concentric microring uniformly widens from the side close to the first straight arm to the side away from the first straight arm. The uniform change in the cross-sectional width helps to reduce the scattering and reflection of the optical signal during the transmission process, thereby reducing the loss of the optical signal, and thus improving the transmission efficiency of the optical signal, ensuring the stable transmission of the optical signal in the microring.

[0010] In combination with the first aspect, in one embodiment, the non-concentric circular microring includes a non-concentric coupling segment and a non-concentric non-coupling segment connected to the non-concentric coupling segment, and the non-concentric non-coupling segment is provided with a first thermocouple. By setting the first thermocouple, it is convenient to adjust the resonance peak position of the non-concentric non-coupling segment to enhance the resonance of the non-concentric circular microring and the racetrack-type microring.

[0011] In combination with the first aspect, in one embodiment, the non-concentric non-coupled section is provided with at least two of the first thermo electrodes, and at least two of the first thermo electrodes are symmetrically arranged along the central axis of the non-concentric microring. The symmetrical arrangement of the two first thermo electrodes along the central axis of the non-concentric microring can more accurately control the temperature distribution of the non-concentric microring.

[0012] In combination with the first aspect, in one embodiment, the arc-shaped coupling section has a first radius; the non-concentric micro-ring includes an inner ring and an outer ring arranged around the outer circumference of the inner ring, the outer ring has a second radius, and the first radius is greater than twice the second radius, so that the racetrack-type micro-ring has a sufficiently large space to accommodate the non-concentric micro-rings, so that the non-concentric micro-rings can be accurately positioned and integrated without interfering with the normal operation of the racetrack-type micro-ring.

[0013] In combination with the first aspect, in one embodiment, the racetrack-type microring also includes a second straight arm, the second straight arm is arranged parallel to the first straight arm, and the second straight arm and the first straight arm are respectively connected to the two ends of the arc-shaped coupling section; the second straight arm is provided with a second thermode.

[0014] In combination with the first aspect, in one implementation, the straight waveguide and the racetrack-shaped microring are both made of silicon nitride or lithium niobate.

[0015] The beneficial effects brought by the technical solution provided in the embodiments of the present application include:

[0016] By setting up a racetrack-type micro-ring coupled with a straight waveguide, the circumference of the ring waveguide can be increased without affecting the micro-ring communication performance indicators, that is, the ring loss of the micro-ring can be reduced, solving the technical problem in the related technology that the excessively large radius of the micro-ring may lead to an increase in insertion loss due to the increase in the transmission path. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 A schematic diagram of the overall structure of a microring resonator provided in an embodiment of the present application.

[0019] In the figure:

[0020] 1. Straight waveguide;

[0021] 2. racetrack-shaped microring; 21. arc-shaped coupling section; 22. first straight arm; 221. photonic crystal nanobeam; 23. second straight arm; 231. second hot electrode;

[0022] 3. Non-concentric micro-ring; 31. First thermode; 32. Inner ring; 33. Outer ring. DETAILED DESCRIPTION

[0023] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0024] The embodiment of the present application provides a micro-ring resonator, which can solve the technical problem in the related art that the excessively large radius of the micro-ring may lead to an increase in insertion loss due to the increase in the transmission path.

[0025] See also Figure 1 As shown, a microring resonator provided in an embodiment of the present application may include: a straight waveguide 1, the straight waveguide 1 having a waveguide input end and a waveguide output end; a racetrack-type microring 2, the racetrack-type microring 2 including an arc-shaped coupling section 21 and a first straight arm 22 connected to the arc-shaped coupling section 21, the arc-shaped coupling section 21 is coupled to the straight waveguide 1, and the arc-shaped coupling section 21 may have the same width as the straight waveguide 1 to achieve coupling.

[0026] The embodiment of the present application sets a racetrack-type microring 2 coupled with a straight waveguide 1. Since the racetrack-type microring 2 includes two straight arms and an arc-shaped coupling section, its circumference is mainly determined by the length of the straight arms and the curvature of the arc-shaped coupling section 21, rather than just relying on the radius. Therefore, compared with the traditional circular microring, the circumference of the annular waveguide can be significantly increased without increasing the overall size or radius of the microring. A longer annular waveguide circumference means that the optical signal propagates longer in the microring, thereby reducing the round trip loss, that is, the energy loss caused by factors such as material absorption and scattering when the optical signal propagates in the microring. Furthermore, the design of the racetrack-type microring 2 also provides greater flexibility. By adjusting the length of the straight arm and the curvature of the arc-shaped coupling section 21, the performance parameters of the microring resonator can be easily adjusted to meet different application requirements, solving the technical problem in the related art that the excessively large radius of the microring may increase the insertion loss due to the growth of the transmission path.

[0027] In some optional embodiments, the microring resonator may further include: a non-concentric microring 3, the non-concentric microring 3 is accommodated in the racetrack-type microring 2, and the non-concentric microring 3 is coupled with the first straight arm 22. The waveguide width of the non-concentric microring 3 has different widths along its circumference. Preferably, at the position where the non-concentric microring 3 is coupled with the first straight arm 22, the waveguide width of the non-concentric microring 3 is equal to the width of the waveguide of the first straight arm 22. In the embodiment of the present application, the non-concentric microring 3 is used, and when the optical signal is transmitted in the annular waveguide, the contact surface between the mode field and the inner wall in the wide waveguide area is reduced, and the scattering loss caused by the side wall can be effectively reduced in this area. Furthermore, the non-concentric microring 3 is arranged in the racetrack-type microring 2, so that the non-concentric microring 3 and the racetrack-type microring 2 are nested and coupled, reducing the loss of the entire structure, thereby improving the Q value.

[0028] In some optional embodiments, the first straight arm 22 is provided with a photonic crystal nanobeam 221, and the non-concentric microring 3 is coupled with the photonic crystal nanobeam 221. The photonic crystal nanobeam 221 can be formed by introducing defects with periodic air holes. The two holes in the first straight arm 22 are used as partial reflection units to form an FP resonant cavity (Fabry-Perot resonant cavity), and its resonant mode is coupled with the resonant mode of the non-concentric microring 3 resonator, and interference produces Fano resonance (Fano resonance). At the same time, Fano resonance can also be generated by nesting the non-concentric microring 3 with the racetrack-type microring 2 to increase the extinction ratio of the resonance peak. In the embodiment of the present application, by arranging the photonic crystal nanobeam 221 in the first straight arm 22 and coupling it with the non-concentric microring 3, more complex optical signal processing functions can be realized in a smaller space, which helps to improve the integration and performance of optoelectronic devices.

[0029] In some optional embodiments, the cross-sectional width of the non-concentric microring 3 close to the first straight arm 22 is smaller than the cross-sectional width of the non-concentric microring 3 away from the first straight arm 22, that is, at the coupling point between the non-concentric microring 3 and the first straight arm 22, it can be set to be the position where the width of the non-concentric microring 3 is the smallest, so that the mode field matching of the optical signal during the coupling process is closer, which helps to reduce the energy loss of the optical signal during the coupling process and improve the coupling efficiency. When the optical signal is transmitted in the non-concentric microring 3, the contact surface between the mode field of the wide waveguide area and the inner wall is reduced, and the scattering loss caused by the side wall can be effectively reduced in this area.

[0030] In some optional embodiments, the cross-sectional width of the non-concentric microring 3 is uniformly widened from the side close to the first straight arm 22 to the side away from the non-concentric microring 3. The uniform change of the cross-sectional width helps to reduce the scattering and reflection of the optical signal during the transmission process, thereby reducing the loss of the optical signal, and can also improve the transmission efficiency of the optical signal, ensuring the stable transmission of the optical signal in the microring; and in the coupling area close to the first straight arm 22, the narrower cross-sectional width can enhance the interaction between the optical signal and the microring, thereby improving the coupling efficiency. As the cross-sectional width gradually widens, the coupling effect gradually weakens, but it can still maintain a certain optical signal transmission capacity, which can ensure the coupling efficiency while avoiding the loss of optical signals caused by excessive coupling. Further, the uniform change of the cross-sectional width is also easier to process, reducing the manufacturing cost and difficulty.

[0031] In some optional embodiments, the non-concentric micro-ring 3 includes a non-concentric coupling section and a non-concentric non-coupling section connected to the non-concentric coupling section, and the non-concentric non-coupling section is provided with a first thermoelectric electrode 31, that is, the first thermoelectric electrode 31 is not arranged in the coupling area between the non-concentric coupling section and the first straight arm 22, so as to reduce the interference of the first thermoelectric motor on the coupling between the first straight arm 22 and the non-concentric coupling section. The first thermoelectric electrode 31 can be arranged to utilize the thermo-optical effect so that the first thermoelectric electrode 31 can tune the Fano resonance of the non-concentric micro-ring 3 and change the resonance peak extinction ratio and profile of the Fano resonance. In the embodiment of the present application, the device reliability of the non-concentric micro-ring 3 can be enhanced and the tuning can be precise by arranging the first thermoelectric electrode 31.

[0032] In some optional embodiments, the non-concentric non-coupling section is provided with at least two first thermoelectrodes 31, and at least two first thermoelectrodes 31 are symmetrically arranged along the central axis of the non-concentric microring 3. In the embodiment of the present application, two first thermoelectrodes 31 are provided, and the two first thermoelectrodes 31 are symmetrically arranged along the central axis of the non-concentric microring 3. In some other embodiments, the two first thermoelectrodes 31 may not be symmetrically arranged along the central axis of the non-concentric microring 3, and the first thermoelectrodes 31 may also be provided in three or more quantities. The symmetrical arrangement of the two first thermoelectrodes 31 along the central axis of the non-concentric microring 3 can more accurately control the temperature distribution of the non-concentric microring 3 to reach the target temperature faster. And by setting multiple first thermoelectrodes 31, the temperature of different positions of the non-concentric microring 3 can be adjusted more flexibly, thereby effectively managing thermal stress and avoiding damage to the microring due to excessive thermal stress. The multiple first thermoelectrodes 31 may also have different heating powers to achieve independent control of the temperature at different positions of the non-concentric microring 3, which can meet more complex application requirements of the non-concentric microring 3. In the embodiment of the present application, precise temperature control and thermal stress management help to improve the performance stability of the non-concentric microring 3, including but not limited to improving the stability of the resonant frequency, reducing insertion loss and enhancing the extinction ratio and other key performance indicators.

[0033] In some optional embodiments, the arc-shaped coupling section 21 has a first radius; the non-concentric microring 3 includes an inner ring 32 and an outer ring 33 arranged around the outer periphery of the inner ring 32, the outer ring 33 has a second radius, and the first radius is greater than twice the second radius. The first radius can be represented by R1, and the second radius can be represented by R2. In the embodiment of the present application, R1 is set to be greater than 2 times R2. This setting method can make the racetrack-type microring 2 have a large enough space to accommodate the non-concentric microring 3, so that the non-concentric microring 3 can be accurately positioned and integrated without interfering with the normal operation of the racetrack-type microring 2. In some cases, the microring resonator may produce performance fluctuations due to temperature changes. By increasing the space between the racetrack-type microring 2 and the non-concentric microring 3, thermal isolation and heat dissipation design can be more easily achieved, thereby optimizing the thermal management performance of the device.

[0034] In some optional embodiments, the racetrack microring 2 further includes a second straight arm 23, the second straight arm 23 is arranged parallel to the first straight arm 22, and the second straight arm 23 and the first straight arm 22 are respectively connected to the two ends of the arc-shaped coupling section 21; the second straight arm 23 is provided with a second thermode 231. That is, the second straight arm 23, the first straight arm 22 and the arc-shaped coupling section 21 can together form a racetrack microring 2, which can ensure that the optical signal can form a closed loop in the racetrack microring 2, wherein the arc-shaped coupling section 21 can be provided with two sections, and the two sections of the arc-shaped coupling sections 21 are respectively located at the two ends of the first straight arm 22 and at the two ends of the second straight arm 23. The second thermode 231 is arranged on the second straight arm 23 to adjust the refractive index of the second straight arm 23, thereby changing the resonance frequency and transmission characteristics of the racetrack microring 2. In addition, the second thermode 231 is provided on the second straight arm 23 to further expand the function of the racetrack microring 2, such as realizing complex functions such as optical switches, optical filters or optical amplifiers, and meeting the needs of more application scenarios. In the embodiment of the present application, by respectively providing the first thermode 31 and the second thermode 231 in the non-concentric microring 3 and the racetrack microring 2, the resonance peak position of the non-concentric microring 3 can be adjusted by the first thermode 31, and the resonance peak position of the racetrack microring 2 can be adjusted by the second thermode 231. When the non-concentric microring 3 and the racetrack microring 2 are both adjusted to a wavelength, the resonance is enhanced.

[0035] In some optional embodiments, the straight waveguide 1 and the racetrack-type microring 2 are made of silicon nitride or lithium niobate. In addition, the non-concentric microring 3 can also be made of silicon nitride or lithium niobate. It should be understood that the straight waveguide 1, the racetrack-type microring 2 and the non-concentric microring 3 are all made of the same material, such as silicon nitride or lithium niobate. In some other embodiments, the racetrack-type microring 2, the non-concentric microring 3 and the straight waveguide 1 can also be made of SOI (silicon on insulating substrate) material. Using silicon nitride (SiN) or lithium niobate (LiNbO3) as a material can enhance the overall stability of the microring resonator. Silicon nitride and lithium niobate both have the characteristics of low loss and high refractive index. These characteristics enable each waveguide in the microring resonator to maintain high efficiency and stability when transmitting optical signals, thereby improving the overall optical performance of the microring resonator. Furthermore, using silicon nitride or lithium niobate as the material for the straight waveguide 1, the racetrack-shaped microring 2, and the non-concentric microring 3 can be more easily integrated with other functional elements, which helps to improve the integration and performance level of the device while reducing the manufacturing cost.

[0036] In the embodiment of the present application, Figure 1The direction indicated by the middle arrow is the moving direction of the photon in the straight waveguide 1. The photon is input from the waveguide input end of the straight waveguide 1, and after coupling with the arc coupling section 21 in the racetrack-type microring 2, it enters the first straight arm 22 in the racetrack-type microring 2, and then moves to the photonic crystal nanobeam 221 to couple with the non-concentric microring 3. After the photon moves in the non-concentric microring 3 to the coupling point between the photonic crystal nanobeam 221 and the non-concentric microring 3, it can re-enter the first straight arm 22 and move in the racetrack-type microring 2. When passing through the second straight arm 23, the temperature is controlled by the second thermode 231, and then it passes through the arc coupling section 21 and is re-counted into the first straight arm 22, and the cycle is repeated. In some other embodiments, after the photons are input from the waveguide input end of the straight waveguide 1, they may first enter the second straight arm 23 having the second hot electrode 231, and then enter the first straight arm 22 through the arc coupling section 21, and move to the photonic crystal nanobeam 221 to couple with the non-concentric microring 3. In the embodiment of the present application, the racetrack-type microring 2 has low round trip loss and high Q value, and its structural characteristics enable the optical signal to propagate on a relatively closed and smooth path, thereby reducing the influence of loss mechanisms such as scattering and absorption; the non-concentric microring 3 has a wide waveguide in the uncoupled region, low loss, and high Q value, that is, the design of the non-concentric microring 3 allows the use of a wider waveguide in the uncoupled region. This helps to reduce the propagation loss of optical signals in the waveguide and improve the transmission efficiency of optical signals; the double-ring nesting (which can refer to the non-concentric micro-rings 3 nested in the cavity of the racetrack-type micro-ring) plus the Fano resonance of the photonic crystal nanobeam 221 enhances the resonance (increases the extinction ratio), that is, introducing the photonic crystal nanobeam 221 in the double-ring nested structure can excite the Fano resonance, thereby further enhancing the resonance effect, which not only improves the extinction ratio, but also makes the resonator have higher performance in applications such as sensing and filtering.

[0037] In the embodiment of the present application, a double-ring nested micro-ring cavity is provided, wherein the double-ring nested micro-ring cavity can specifically refer to an outer ring 33 being a racetrack-type micro-ring 2, which can also be called a racetrack-type micro-ring cavity, and an inner ring 32 being a non-concentric micro-ring 3, which can also be called a non-concentric micro-ring cavity, and a photonic crystal nano-beam 221 structure is provided at the first straight arm 22 of the racetrack-type micro-ring 2. The straight waveguide 1 is coupled with the arc-shaped coupling section 21 of the racetrack-type micro-ring 2 in the double-ring nested micro-ring cavity to form an input end and a straight-through end. Preferably, the structural waveguide medium is silicon, the chip used is silicon on insulator, and the conventional manufacturing process of silicon-based optical chips is used.

[0038] Furthermore, the width of the straight waveguide 1 can be set to d1, and the width of the racetrack microring 2 is also set to d1, so that the racetrack microring 2 can be smoothly coupled with the straight waveguide 1, and the width is also set to d1 at the coupling point between the non-concentric microring 3 and the photonic crystal nanobeam 221. In addition, the length of the first straight arm 22 and the second straight arm 23 of the racetrack microring 2 is set to L, and L is set to be larger than the diameter of the outer ring 33 in the non-concentric microring 3.

[0039] In the description of the present application, it should be noted that the terms "upper", "lower", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0040] It should be noted that, in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0041] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A microring resonator, characterized in that: It includes: Straight waveguide (1); A racetrack-type microring (2), the racetrack-type microring (2) comprising an arc-shaped coupling section (21) and a first straight arm (22) connected to the arc-shaped coupling section (21), the arc-shaped coupling section (21) being coupled to the straight waveguide (1).

2. The microring resonator according to claim 1, characterized in that The microring resonator further comprises: A non-concentric micro-ring (3), wherein the non-concentric micro-ring (3) is accommodated in the racetrack-shaped micro-ring (2), and the non-concentric micro-ring (3) is coupled with the first straight arm (22).

3. The microring resonator according to claim 2, characterized in that: The first straight arm (22) is provided with a photonic crystal nanobeam (221), and the non-concentric micro-ring (3) is coupled to the photonic crystal nanobeam (221).

4. The microring resonator according to claim 2, wherein: The cross-sectional width of the non-concentric micro-ring (3) on the side close to the first straight arm (22) is smaller than the cross-sectional width of the non-concentric micro-ring (3) on the side away from the first straight arm (22).

5. The microring resonator according to claim 4, characterized in that: The cross-sectional width of the non-concentric micro-ring (3) uniformly widens from a side close to the first straight arm (22) to a side away from the first straight arm (22).

6. The microring resonator according to claim 2, characterized in that: The non-concentric circular micro-ring (3) comprises a non-concentric coupling section and a non-concentric non-coupling section connected to the non-concentric coupling section, and the non-concentric non-coupling section is provided with a first hot electrode (31).

7. The microring resonator according to claim 6, characterized in that: The non-concentric non-coupling section is provided with at least two of the first thermoelectrodes (31), and the at least two of the first thermoelectrodes (31) are symmetrically arranged along the central axis of the non-concentric micro-ring (3).

8. The microring resonator according to claim 2, characterized in that: The arc-shaped coupling section (21) has a first radius; The non-concentric micro-ring (3) comprises an inner ring (32) and an outer ring (33) arranged around the outer circumference of the inner ring (32); the outer ring (33) has a second radius, and the first radius is greater than twice the second radius.

9. The microring resonator according to claim 1, wherein: The racetrack-shaped micro-ring (2) further comprises a second straight arm (23), the second straight arm (23) being arranged parallel to the first straight arm (22), and the second straight arm (23) and the first straight arm (22) being respectively connected to two ends of the arc-shaped coupling section (21); The second straight arm (23) is provided with a second hot electrode (231).

10. The microring resonator according to claim 1, wherein: The straight waveguide (1) and the racetrack-shaped microring (2) are both made of silicon nitride or lithium niobate.

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