Micro-ring resonator and micro-ring modulator with the same

Abstract

The present application provides a kind of micro ring resonator cavity based on adiabatic waveguide, Euler waveguide and photonic crystal waveguide to design and the micro ring modulator with the micro ring resonator cavity, it includes: micro ring, the micro ring is made of closed circular shape waveguide, and the closed circular shape waveguide is made of any one of the adiabatic waveguide, the Euler waveguide, the photonic crystal waveguide and their combination;And outside waveguide arm, the outside waveguide arm is arranged outside the micro ring.

Description

Technical Field

[0001] This invention relates to the field of optical communication, and more particularly to a microring resonator and a microring modulator having the microring resonator. Background Technology

[0002] With the rapid development of artificial intelligence (AI), machine learning (ML), and high-performance computing (HPC), the ever-increasing data transmission volume demands higher bandwidth, lower power consumption, and lower latency for chip-to-chip interconnects. Data transmission over cables is limited by bandwidth and power density, becoming a performance bottleneck for modern computer systems and data centers. However, these limitations can be overcome through optical communication, achieved through integrated optoelectronic technology. Optical communication is a communication method that uses light waves as the information carrier to transmit information through optical fibers or free space. It is an important component of modern communication technology and is widely used in fields such as the Internet, telephone, television, data centers, and satellite communications.

[0003] Silicon-based optoelectronics technology provides a mature and cost-effective platform that integrates microring modulators, lasers, photodetectors, and passive optical devices. It can even integrate microelectronic circuits using standard processes, enabling high-efficiency, high-bandwidth data transfer between computing nodes. Optical communication is one of the most important solutions for achieving large-scale data exchange. As one of the most critical devices for electro-optic signal conversion, silicon optical modulators must exhibit excellent performance in energy efficiency, bandwidth, and reliability to ensure the competitiveness of optical interconnects and modules. As an example, microring resonator-based electro-optic modulators utilize the optical characteristics of microring resonators for electro-optic modulation. These modulators have important applications in optical communication and photonic integrated circuits, attracting widespread attention due to their miniaturization, high speed, and low power consumption.

[0004] In traditional electrical interconnects, bandwidth density expansion relies on all-electrical connections that increase baud rate and / or the number of package pins. Dense wavelength division multiplexing (DWDM), however, offers a more energy-efficient method for expanding bandwidth density by independently modulating many closely spaced optical wavelengths on a single fiber. On-chip DWDM technology allows for the simultaneous modulation and probing of multiple signals on a single physical channel. As an integrated filtering and modulation device in on-chip WDM systems, microring modulators offer ultra-compact device size, low power consumption, and enhanced light-matter interaction through high-quality factor (Q-value) resonant cavities, thereby improving the bandwidth density and energy efficiency of optical interconnects. Summary of the Invention

[0005] The technical problem to be solved by the present invention

[0006] However, current electro-optic modulators based on micro-ring resonators also have some problems.

[0007] First, when there are static process deviations and dynamic temperature changes, the quality factor and resonant wavelength of the micro-ring resonator will change, thereby affecting the device yield and the stability of the system operation.

[0008] Furthermore, silicon-based microring modulators in existing foundry processes are typically based on reverse-biased PN junctions. Due to the weak plasmon dispersion effect of silicon, the modulation efficiency that can be achieved is usually low, and high drive voltages (e.g., voltages above 2V) are usually required. This is incompatible with digital integrated circuits using advanced CMOS process nodes, requiring additional modulator drive circuitry, which causes additional power consumption and cost.

[0009] Furthermore, because microring resonators with higher Q values ​​are very sensitive to the environment during operation and are difficult to maintain a stable operating state, they limit the further enhancement of light-matter interaction.

[0010] This invention was made in view of the above-mentioned problems, and its purpose is to provide a microring resonator and a microring modulator having the microring resonator, which can significantly enhance process tolerance, keep the performance of different microring resonators consistent, reduce waveguide bending loss and intermode crosstalk, provide a higher Q value for the microring resonator, introduce a slow light effect through photonic crystal, improve the modulation efficiency of the microring modulator, thereby reducing costs, increasing the scale of photonic integrated chips, reducing the power consumption of the modulator, and thus improving the energy efficiency of the system.

[0011] Technical solutions adopted to solve technical problems

[0012] In one aspect of the present invention, a microring resonator is provided, which is designed based on an adiabatic waveguide, an Euler waveguide, and a photonic crystal waveguide, comprising: a microring composed of a closed annular waveguide, wherein the closed annular waveguide is composed of any one of the adiabatic waveguide, the Euler waveguide, the photonic crystal waveguide, and combinations thereof; and an outer waveguide arm disposed outside the microring.

[0013] In one aspect of the present invention, a microring modulator is provided, comprising: a microring resonant cavity as described above and a modulation section, the modulation section comprising: a power supply for applying a voltage; a PN junction formed by contact between an N-type semiconductor and a P-type semiconductor, wherein the refractive index of a waveguide is changed by applying a voltage to the PN junction; an electrode for adjusting the carrier distribution of the PN junction by applying a voltage to the electrode; and a heater for adjusting the resonant conditions of the waveguide based on a thermo-optic effect.

[0014] The effects of the invention

[0015] The microring resonator and microring modulator with the microring resonator according to the present invention can significantly reduce process tolerances, maintain consistent performance between different microring resonators, reduce waveguide bending loss and intermode crosstalk, provide a higher Q value to the microring resonator, introduce a slow light effect through photonic crystals to improve the modulation efficiency of the microring modulator, reduce costs, increase the scale of photonic integrated chips, reduce the power consumption and driving voltage of the modulator, thereby improving the energy efficiency of the system. Attached Figure Description

[0016] This disclosure can be better understood by describing exemplary embodiments of the present disclosure in conjunction with the accompanying drawings, in which:

[0017] Figure 1 (a) is a diagram showing an existing microring resonator. Figure 1 (b) is a diagram showing the structure of the modulation section of the microring resonator. Figure 1 (c) is a graph showing the relationship between transmittance and wavelength.

[0018] Figure 2 This is a schematic diagram illustrating the microring resonator according to Embodiment 1 of the present invention.

[0019] Figure 3 This is a schematic diagram illustrating the microring resonator according to Embodiment 2 of the present invention.

[0020] Figure 4 This is a schematic diagram illustrating the microring resonator according to Embodiment 3 of the present invention.

[0021] Figure 5 This is a schematic diagram illustrating the microring resonator according to Embodiment 4 of the present invention.

[0022] Figure 6 This is a schematic diagram illustrating the microring resonator according to Embodiment 5 of the present invention.

[0023] Figure 7 This is a schematic diagram illustrating the microring resonator according to Embodiment 6 of the present invention.

[0024] Figure 8 This is a schematic diagram illustrating the microring resonator according to Embodiment 7 of the present invention.

[0025] Reference numerals: 100 adiabatic microring resonator, 200 Euler-bent microring resonator, 300 photonic crystal microring resonator, 400 adiabatic Euler-bent microring resonator, 500 adiabatic photonic crystal microring resonator, 600 Euler-bent photonic crystal microring resonator, 700 adiabatic Euler-bent photonic crystal microring resonator. Detailed Implementation

[0026] The following describes specific embodiments of this disclosure. It should be noted that, in order to maintain brevity, this specification cannot provide a detailed description of all features of the actual embodiments. It should be understood that, in the actual implementation of any embodiment, just as in any engineering or design project, various specific decisions are often made to achieve the developer's specific goals and to meet system-related or business-related constraints, and this can change from one embodiment to another. Furthermore, it is understood that although the efforts made in this development process may be complex and lengthy, for those skilled in the art related to the content of this application, changes in design, manufacturing, or production based on the technical content disclosed in this disclosure are merely conventional technical means and should not be construed as insufficient content of this disclosure.

[0027] Unless otherwise defined, the technical or scientific terms used in the claims and description shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this patent application description and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. The terms “an” or “a” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “comprising” or “including” and similar terms mean that the element or object preceding “comprising” or “including” encompasses the element or object listed following “comprising” or “including” and its equivalents, and do not exclude other elements or objects. The terms “connected” or “linked” and similar terms are not limited to physical or mechanical connections, nor are they limited to direct or indirect connections.

[0028] Unless otherwise specified, all embodiments and preferred embodiments mentioned herein can be combined to form new technical solutions. Similarly, unless otherwise specified, all technical features and preferred features mentioned herein can be combined to form new technical solutions.

[0029] Hereinafter, the microring resonator and the electro-optic modulator based on the microring resonator according to embodiments of the present invention will be described with reference to the accompanying drawings.

[0030] Figure 1 (a) is a diagram showing an existing microring resonator 100. Figure 1 (b) is a diagram showing the structure of the modulation section of the microring resonator. Figure 1 (c) is a graph showing the relationship between transmittance and wavelength.

[0031] like Figure 1 As shown in (a), an existing microring resonator comprises a closed circular microring and a straight outer waveguide arm. The arrow indicates the direction of optical signal propagation within the microring. The optical signal propagates cyclically within the microring through coupling and resonates at a specific wavelength. Microring resonators utilize the resonant characteristics of light to enhance optical signals at specific wavelengths and are widely used in optical communication and photonic integrated circuits.

[0032] Figure 1 In (a), light enters from the left waveguide. When the wavelength of the incident light satisfies the resonance condition of the microring, only a very weak light signal can be detected at the output end. Light of other wavelengths will not resonate in the microring, and a stronger light signal can be detected at the output end.

[0033] Figure 1 (b) is a diagram showing the structure of the modulation section of the microring resonant cavity, which includes contacts of N-type and P-type semiconductor materials. The refractive index of the waveguide is changed through a thermo-optical effect; applying a voltage alters the refractive index of the waveguide, thereby changing the resonant wavelength of the microring. The modulation section includes contacts of N-type and P-type semiconductor materials, and electrodes are used to apply an electric field to adjust the refractive index of the microring. The contacts of the N-type and P-type semiconductors form a PN junction, allowing light propagation to be controlled by applying a voltage. By using a heater, the resonant conditions of the microring can be adjusted through thermal effects, further enhancing the modulation effect. The modulation section modulates the optical signal by changing the refractive index of the microring, achieving modulation and control of the optical signal.

[0034] Figure 1 (c) is a graph showing the relationship between transmittance and wavelength. For example... Figure 1 As shown in (c), a significant decrease in transmittance occurs at a specific wavelength (λ0), forming a transmission peak. This indicates that the microring resonator exhibits enhanced selectivity for optical signals at this wavelength. The change in transmittance reflects the modulation characteristics of the microring resonator, which allows for control of optical signal transmission by adjusting the voltage.

[0035] according to Figure 1 (a) to Figure 1 (c) The electro-optic modulator based on this microring resonator forms a PN junction by doping in a silicon waveguide and an ohmic contact by heavy doping, controlling the carrier concentration in the PN junction through electrodes. Since the waveguide has different refractive indices at different carrier concentrations, the resonant peak position of the microring resonator changes under different voltages, such as... Figure 1 As shown in (c), when the wavelength of the incident light is near the resonance peak (λ0), an electrical signal is applied to both sides of the PN junction. Since the transmittance of the micro-ring resonator is different under different voltages, the output light wave will carry the same signal.

[0036] Although traditional micro-ring modulators have developed rapidly in recent years and can already achieve electro-optic signal conversion with large bandwidth and high energy efficiency, further improving the process tolerance and modulation efficiency of micro-ring modulators is still the key to realizing high-performance optical interconnects.

[0037] This embodiment discloses a method for solving the above-mentioned problems. In this embodiment, the main improvement is made to the structure of the micro-ring resonator, thereby enhancing various performance parameters of the electro-optic modulator based on the micro-ring resonator.

[0038] Implementation Method 1

[0039] Figure 2 This is a schematic diagram showing the adiabatic microring resonant cavity 100 according to Embodiment 1 of the present invention.

[0040] like Figure 2 As shown, in this embodiment, an adiabatic microring resonator 100 is used to construct the microring resonator. An adiabatic microring resonator is a special type of microring resonator that utilizes an adiabatic process to achieve the modulation and transmission of optical signals. An adiabatic process refers to the process by which a system maintains its instantaneous ground state when the rate of change of the system is much lower than the system's intrinsic time scale. This characteristic gives adiabatic microring resonators unique advantages in photonics and optical communication.

[0041] Adiabatic microring resonator, such as Figure 2 As shown, this structure is designed and fabricated on a ridged waveguide formed by shallow etching. Traditional microring waveguides typically have a fixed width, which can lead to mode mismatch or loss when light propagates within the ring. The improvement in thermal design lies in the fact that the width of the microring waveguide can gradually vary along the ring's circumference to optimize the light propagation path. This width variation reduces scattering loss and improves the quality factor. Specifically, different waveguide widths are used in the coupling region and other parts of the ring. The width variation is designed to match the light propagation characteristics by calculating the distribution of optical modes. Furthermore, for the optimization of the microring shape, traditional microring resonators typically use perfectly circular ring waveguides, but this design can lead to bending losses. The shape of the microring can be optimized from circular to elliptical, tapered, or other asymmetrical shapes to reduce bending losses. This design can improve light propagation efficiency while optimizing resonant performance.

[0042] Therefore, Embodiment 1 of the present invention provides a microring resonator, which is composed of an adiabatic microring resonator and includes: a microring, which is configured in a circular shape and the width of the circular shape varies along the circumference of the circular shape; and an outer waveguide arm, which is disposed outside the microring and has a straight waveguide portion located at both ends of the outer waveguide arm and a curved waveguide portion located at the center of the outer waveguide arm, the shape of the curved waveguide portion matching the circular shape of the microring.

[0043] As an example, the geometry of the microring of the adiabatic microring resonator 100 in Embodiment 1 of the present invention can be defined by two mutually offset circles, the characteristic parameters of which include the outer radius, the inner radius and the displacement between the centers of the two circles.

[0044] according to Figure 2 As can be seen, the micro-ring of the micro-ring resonator involved in Embodiment 1 of the present invention is an eccentric ring shape composed of an outer circle and an inner circle. The outer circle is a circle with a first radius, and the inner circle is a circle with a second radius smaller than the first radius. The center of the outer circle is offset from the center of the inner circle.

[0045] The waveguide in the microring of the adiabatic microring resonator 100 is divided into a waveguide with a wider side. Figure 2 The middle is the upper side) and the waveguide on one side is narrower ( Figure 2 (The middle section is the lower side). The narrower region on the lower side effectively prevents the excitation of higher-order resonant modes in the microring and suppresses non-ideal higher-order resonant peaks. In the wider section of the upper waveguide, the resonant optical portion in the adiabatic microring propagates in a whispering-gallery mode. The overlap between the optical mode and the sidewall is reduced, so the optical scattering loss is insensitive to changes in sidewall roughness, thereby significantly reducing process tolerances and ensuring consistent performance across different microring resonators.

[0046] Furthermore, the mode discretization of the adiabatic microring resonator 100 in the wider portion reduces the sensitivity of the mode refractive index to the waveguide width, which helps to stabilize the resonant frequency, improve the overall performance of the microring modulator, and reduce the energy consumption required for thermal tuning control to stabilize the resonant wavelength.

[0047] Implementation Method 2

[0048] Figure 3 This is a schematic diagram showing the Euler-bent microring resonator 200 according to Embodiment 2 of the present invention.

[0049] like Figure 3 As shown, in this embodiment, an Euler-bent microring resonator 200 is used to construct the microring resonator. Specifically, in this embodiment 2, the concept of Euler bending theory is incorporated to adjust the geometry and bending parameters of the waveguide, thereby achieving flexible tuning of the resonant frequency to adapt to different application requirements and optimize the propagation characteristics of the optical signal.

[0050] like Figure 3 As shown, the Euler-bent microring resonator 200 in Embodiment 2 is a racetrack-shaped microring resonator composed of two U-shaped Euler-bent waveguides and two straight waveguides.

[0051] Each of the two U-shaped Euler bend waveguides is composed of two L-shaped Euler bend waveguides corresponding to a central angle of 90°. Furthermore, each L-shaped Euler bend waveguide corresponding to a central angle of 90° is composed of a combination of unit Euler bend waveguides corresponding to a central angle of 45°.

[0052] For a unit Euler bend waveguide corresponding to a central angle of 45°, its characteristic parameters are determined by the maximum radius of curvature (Rmax) and the minimum radius of curvature (Rmin). The position of the Euler bend can be calculated using the following equation (1).

[0053]

[0054] Where L is the length of the curve from the starting point (0,0) to the position (x,y), R is the radius of curvature, and A is a constant. The expression for the constant A is given by the following equation (2).

[0055] A = [L0 / (1 / R)] min -1 / R max )] 1 / 2 ...Equation (2)

[0056] Where L0 is the position relative to the endpoint R = Rmin (x E ,y E The curve length corresponding to the above calculations, the coordinates of each point of the Euler curve in the Cartesian coordinate system can be expressed as the following formula (3).

[0057]

[0058] Using the above method, the structural parameters of the Euler curved waveguide corresponding to a 45° central angle can be accurately defined. Two Euler curved waveguides corresponding to a 45° central angle can be spliced ​​together to form an L-shaped Euler curved waveguide corresponding to a 90° central angle. Two L-shaped Euler curved waveguides can form a U-shaped Euler curved waveguide. Finally, the two U-shaped Euler curved waveguides and the straight waveguide are combined to form the micro-ring shape of the Euler curved micro-ring resonator 200.

[0059] As described above, Embodiment 2 of the present invention provides a microring resonator, which is composed of an Euler-bent microring resonator, comprising: a microring, which is configured as a racetrack-shaped ring, consisting of two straight waveguides, a U-shaped Euler-bent waveguide on the left and a U-shaped Euler-bent waveguide on the right; and an outer waveguide arm, which is straight, disposed outside the microring, and parallel to the straight waveguides.

[0060] The U-shaped Euler bend waveguide is composed of an L-shaped Euler bend waveguide corresponding to a central angle of 90°, and the L-shaped Euler bend waveguide is composed of a unit Euler bend waveguide corresponding to a central angle of 45°. The coordinates of each point of the unit Euler bend waveguide in the Cartesian coordinate system are obtained by the above equations (1) to (3).

[0061] According to Embodiment 2 of the present invention, the microring resonator 200 can reduce the bending loss and intermode crosstalk of the waveguide, thus providing a higher Q value for the microring resonator, thereby improving the modulation efficiency of the electro-optic modulator based on the microring resonator.

[0062] Implementation Method 3

[0063] Figure 4 This is a schematic diagram showing the photonic crystal microring resonator 300 according to Embodiment 3 of the present invention.

[0064] like Figure 4 As shown, in this embodiment, a photonic crystal microring resonator 300 is used to construct the microring resonator.

[0065] Photonic crystals are artificial structures with a periodic refractive index distribution that can control the propagation properties of light. They utilize this periodic structure to create a photonic band gap, meaning that photons cannot propagate through the material within a specific wavelength range. This property allows photonic crystals to effectively control the propagation, reflection, and refraction of light. The reflection and refraction properties of light can be controlled by adjusting the structural parameters of photonic crystals (such as periodicity and material refractive index).

[0066] A photonic crystal micro-ring resonator is a miniature resonator that utilizes a photonic crystal structure. It is widely used in fields such as optical communication, sensors, and quantum information processing. It combines the excellent optical properties of photonic crystals with the high quality factor (Q factor) of micro-ring resonators, enabling effective control and modulation of optical signals.

[0067] As described above, Embodiment 3 of the present invention provides a microring resonator, which is composed of a photonic crystal microring resonator and includes: a microring, the outer part of which is circular and the inner part has multiple repeating radial shapes to form a photonic crystal structure; and an outer waveguide arm, which is linear and disposed outside the microring.

[0068] The multiple repeating radial shapes inside the microrings can be gear-shaped, star-shaped, petal-shaped, or sun-shaped.

[0069] According to Embodiment 3, by combining the concepts of photonic crystal (PhC) and whispering-gallery mode (WGM), the inner boundary of the microring resonator is periodically modulated using a photonic crystal metamaterial inside the microring resonator, thereby opening a bandgap and achieving a strong slow-light effect at the bandgap edge. It should be noted that the slow-light effect can also be achieved by introducing etched holes in the microring. Increasing the light-matter interaction time through the slow-light effect improves the modulation efficiency of the electro-optic modulator based on this microring resonator, and the photonic crystal metamaterial inside the microring can modulate the dispersion and reflection characteristics of the microring waveguide, thus controlling the spectrum of the microring modulator.

[0070] Implementation Method 4

[0071] Figure 5 A schematic diagram of the adiabatic Euler-bent microring resonator 400 according to Embodiment 4 of the present invention is shown.

[0072] like Figure 5 As shown, in this embodiment, an adiabatic Euler-bent microring resonator 400 is used to construct the microring resonator.

[0073] Specifically, such as Figure 5 As shown, the adiabatic microring resonator 100 and the Euler-bent microring resonator 200 are combined to obtain the adiabatic Euler-bent microring resonator 400 in this embodiment 4.

[0074] Therefore, embodiment 4 of the present invention provides a microring resonator, which is composed of an adiabatic Euler-bent microring resonator, comprising: a microring, which is configured as a racetrack-shaped ring, consisting of two straight waveguides, a U-shaped Euler-bent waveguide on the left and a U-shaped Euler-bent waveguide on the right, and the width of the racetrack-shaped ring varies along its circumference; and an outer waveguide arm, which is straight, disposed outside the microring, and parallel to the straight waveguides.

[0075] As an example, the geometry of the microring of the adiabatic Euler-bent microring resonator 400 in Embodiment 4 of the present invention can be composed of two mutually offset racetrack-shaped rings. In both the inner and outer racetrack-shaped rings, each of the two U-shaped Euler-bent waveguides is composed of two L-shaped Euler-bent waveguides corresponding to a 90° central angle. Furthermore, each L-shaped Euler-bent waveguide corresponding to a 90° central angle is composed of unit Euler-bent waveguides corresponding to a 45° central angle. The difference lies in the fact that the centers of the 45° central angles corresponding to the inner and outer unit Euler-bent waveguides are offset from each other.

[0076] According to Embodiment 4 of the present invention, the adiabatic Euler-bent microring resonator 400 has waveguides in its microring divided into waveguides with a wider side. Figure 5 The middle is the upper side) and the waveguide on one side is narrower ( Figure 5 (The middle section is the lower side). The narrower region on the lower side effectively prevents the excitation of higher-order resonant modes in the microring and suppresses non-ideal higher-order resonant peaks. In the wider section of the upper waveguide, the resonant optical portion in the adiabatic microring propagates in a whispering-gallery mode. The overlap between the optical mode and the sidewall is reduced, so the optical scattering loss is insensitive to changes in sidewall roughness, thereby significantly reducing process tolerances and ensuring consistent performance across different microring resonators.

[0077] Furthermore, it can reduce the bending loss and intermode crosstalk of the waveguide, thus providing a higher Q value for the microring resonator, which in turn can improve the modulation efficiency of the electro-optic modulator based on the microring resonator.

[0078] Implementation Method 5

[0079] Figure 6 A schematic diagram of the thermally adiabatic photonic crystal microring resonator 500 according to Embodiment 5 of the present invention is shown.

[0080] like Figure 6 As shown, in this embodiment, an adiabatic photonic crystal microring resonator 500 is used to construct the microring resonator. Specifically, as... Figure 6 As shown, the adiabatic microring resonator 100 and the photonic crystal microring resonator 300 are combined to obtain the adiabatic photonic crystal microring resonator 500 in this embodiment 5.

[0081] Therefore, this embodiment 5 provides a microring resonator, which is composed of an adiabatic photonic crystal microring resonator, comprising: a microring, which is configured in a circular shape, with a circular outer shape and multiple repeating radial shapes inside to form a photonic crystal structure, and the width of the circular shape varies along the circumference of the ring; and an outer waveguide arm, which is disposed outside the microring and has straight waveguide portions at both ends of the outer waveguide arm and a curved waveguide portion at the center of the outer waveguide arm, the shape of the curved waveguide portion matching the circular shape of the microring.

[0082] The multiple repeating radial shapes inside the microrings can be gear-shaped, star-shaped, petal-shaped, or sun-shaped.

[0083] According to Embodiment 5 of the present invention, the waveguide in the microring of the thermally adiabatic photonic crystal microring resonator 500 is divided into waveguides with a wider side. Figure 6 The middle is the upper side) and the waveguide on one side is narrower ( Figure 6(The middle section is the lower side). The narrower region on the lower side effectively prevents the excitation of higher-order resonant modes in the microring and suppresses non-ideal higher-order resonant peaks. In the wider section of the upper waveguide, the resonant optical portion in the adiabatic microring propagates in a whispering-gallery mode. The overlap between the optical mode and the sidewall is reduced, so the optical scattering loss is insensitive to changes in sidewall roughness, thereby significantly reducing process tolerances and ensuring consistent performance across different microring resonators.

[0084] Furthermore, by combining the concepts of photonic crystal (PhC) and whispering-gallery mode (WGM), a photonic crystal metamaterial inside the microring resonator is used to periodically modulate the inner boundary of the microring resonator, thereby opening a bandgap and achieving a strong slow-light effect at the bandgap edge. Increasing the light-matter interaction time through the slow-light effect improves the modulation efficiency of the electro-optic modulator based on this microring resonator, and the photonic crystal metamaterial inside the microring can modulate the dispersion and reflection characteristics of the microring waveguide, enabling control over the spectrum of the microring modulator.

[0085] Implementation Method 6

[0086] Figure 7 A schematic diagram of the Euler-bent photonic crystal microring resonator 600 according to Embodiment 6 of the present invention is shown.

[0087] like Figure 7 As shown, in this embodiment, an Euler-bent photonic crystal microring resonator 600 is used to construct the microring resonator. Specifically, as... Figure 7 As shown, the Euler-bent microring resonator 200 and the photonic crystal microring resonator 300 are combined to obtain the Euler-bent photonic crystal microring resonator 600 in this embodiment 6.

[0088] Therefore, this embodiment 6 provides a microring resonator, which is composed of an Euler-bent photonic crystal microring resonator, comprising: a microring, the outer side of which is elliptical and the inner side has multiple repeating radial shapes to form a photonic crystal structure; and an outer waveguide arm, which is linear and disposed outside the microring.

[0089] The outer elliptical shape of the microring is composed of a U-shaped Euler bend waveguide on the left and a U-shaped Euler bend waveguide on the right. The U-shaped Euler bend waveguide is composed of an L-shaped Euler bend waveguide corresponding to a central angle of 90°. The L-shaped Euler bend waveguide is composed of a unit Euler bend waveguide corresponding to a central angle of 45°. The coordinates of each point of the unit Euler bend waveguide in the Cartesian coordinate system are obtained by the above equations (1) to (3).

[0090] In addition, the multiple repeating radial shapes inside the microrings can be gear-shaped, star-shaped, petal-shaped, or sun-shaped.

[0091] According to Embodiment 6, the Euler-bent photonic crystal microring resonator 600 can reduce the bending loss and intermode crosstalk of the waveguide, thus providing a higher Q value for the microring resonator and improving the modulation efficiency of the electro-optic modulator based on the microring resonator.

[0092] Furthermore, by combining the concepts of photonic crystal (PhC) and whispering-gallery mode (WGM), the inner boundary of the microring resonator can be periodically modulated using a photonic crystal metamaterial inside the microring, thereby opening a bandgap and achieving a strong slow-light effect at the bandgap edge. It is worth noting that the slow-light effect can also be achieved by introducing etched holes in the microring. Increasing the light-matter interaction time through the slow-light effect improves the modulation efficiency of the electro-optic modulator based on this microring resonator, and the photonic crystal metamaterial inside the microring can modulate the dispersion and reflection characteristics of the microring waveguide, enabling control over the spectrum of the microring modulator.

[0093] Implementation Method 7

[0094] Figure 8 A schematic diagram of the adiabatic Euler-bent photonic crystal microring resonator 700 according to Embodiment 7 of the present invention is shown.

[0095] like Figure 8 As shown, in this embodiment, an adiabatic Euler-bent photonic crystal microring resonator 700 is used to construct the microring resonator. Specifically, as... Figure 8 As shown, the adiabatic microring resonator 100, the Euler-bent microring resonator 200 and the photonic crystal microring resonator 300 are combined to obtain the Euler-bent photonic crystal microring resonator 700 in this embodiment 7.

[0096] Therefore, Embodiment 7 provides a microring resonator, which is composed of an adiabatic Euler-bent photonic crystal microring resonator, comprising: a microring, which is configured as an elliptical ring, the outer side of which is elliptical and the inner side has multiple repeating radial shapes to form a photonic crystal structure, and the width of the elliptical ring varies along its circumference; and an outer waveguide arm, which is disposed outside the microring and has straight waveguide portions at both ends of the outer waveguide arm and a curved waveguide portion at the center of the outer waveguide arm, the shape of which matches the shape of the elliptical ring of the microring.

[0097] The outer elliptical shape of the microring is composed of a U-shaped Euler bend waveguide on the left and a U-shaped Euler bend waveguide on the right. The U-shaped Euler bend waveguide is composed of an L-shaped Euler bend waveguide corresponding to a central angle of 90°. The L-shaped Euler bend waveguide is composed of a unit Euler bend waveguide corresponding to a central angle of 45°. The coordinates of each point of the unit Euler bend waveguide in the Cartesian coordinate system are obtained by the above equations (1) to (3).

[0098] The multiple repeating radial shapes inside the microrings can be gear-shaped, star-shaped, petal-shaped, or sun-shaped.

[0099] According to the adiabatic Euler-bent photonic crystal microring resonator 700 in Embodiment 7, the waveguide in the microring is divided into a waveguide with a wider side ( Figure 8 The middle is the upper side) and the waveguide on one side is narrower ( Figure 8 (The middle section is the lower side). The narrower region on the lower side effectively prevents the excitation of higher-order resonant modes in the microring and suppresses non-ideal higher-order resonant peaks. In the wider section of the upper waveguide, the resonant optical portion in the adiabatic microring propagates in a whispering-gallery mode. The overlap between the optical mode and the sidewall is reduced, thus the optical scattering loss is insensitive to changes in sidewall roughness, significantly reducing process tolerances and ensuring consistent performance across different microring resonators. The mode discretization in the wider section of the adiabatic microring resonator 700 reduces the sensitivity of the mode refractive index to the waveguide width, contributing to stable resonant frequencies, improving the overall performance of the microring modulator, and reducing the energy consumption required for thermal tuning control to stabilize the resonant wavelength.

[0100] Furthermore, it can reduce the bending loss and intermode crosstalk of the waveguide, thus providing a higher Q value for the microring resonator, which in turn can improve the modulation efficiency of the electro-optic modulator based on the microring resonator.

[0101] Furthermore, by combining the concepts of photonic crystal (PhC) and whispering-gallery mode (WGM), the inner boundary of the microring resonator can be periodically modulated using a photonic crystal metamaterial inside the microring, thereby opening a bandgap and achieving a strong slow-light effect at the bandgap edge. It is worth noting that the slow-light effect can also be achieved by introducing etched holes in the microring. Increasing the light-matter interaction time through the slow-light effect improves the modulation efficiency of the electro-optic modulator based on this microring resonator, and the photonic crystal metamaterial inside the microring can modulate the dispersion and reflection characteristics of the microring waveguide, enabling control over the spectrum of the microring modulator.

[0102] Implementation Method 8

[0103] In embodiment 8, an electro-optic modulator based on a micro-ring resonator is provided, including a micro-ring resonator and a modulation unit. The modulation unit modulates the refractive index of the micro-ring resonator to modulate the optical signal, thereby achieving modulation and control of the optical signal.

[0104] The micro-ring resonator may include any one of 7 in Embodiment 1 above, and the modulation unit may be adopted. Figure 1 The modulation section is as shown in (b). Specifically, the modulation section includes: a power source for applying a voltage; a PN junction formed by the contact of an N-type semiconductor and a P-type semiconductor, the refractive index of the waveguide being changed by applying a voltage to the PN junction; an electrode for adjusting the carrier distribution of the PN junction by applying a voltage to the electrode; and a heater for adjusting the resonant conditions of the waveguide by a thermo-optical effect.

[0105] It should be understood that the above description is illustrative and not restrictive. For example, the above embodiments (and / or aspects thereof) can be used in combination with each other. Furthermore, many modifications can be made to adapt particular conditions or materials to the teachings of the various embodiments of the invention without departing from the scope of the invention. While the dimensions and types of materials described herein are used to define parameters of the various embodiments of the invention, the embodiments are not intended to be restrictive but are exemplary. Many other embodiments will become apparent to those skilled in the art upon reading the above description. Therefore, the scope of the various embodiments of the invention should be determined by reference to the appended claims and the full scope of their equivalents.

Claims

1. A microring resonator, the microring resonator being designed based on an adiabatic waveguide, an Euler waveguide, and a photonic crystal waveguide, characterized in that, include: A microring, comprising a closed annular waveguide, wherein the closed annular waveguide is composed of any one of the thermally insulating waveguide, the Euler waveguide, the photonic crystal waveguide, and combinations thereof; and An outer waveguide arm is disposed on the outside of the microring.

2. The microring resonator as described in claim 1, characterized in that, The closed annular waveguide is an eccentric annular shape composed of an outer circle and an inner circle. The outer circle is a circle with a first radius, and the inner circle is a circle with a second radius smaller than the first radius. The centers of the outer circle and the inner circle are offset. The outer waveguide arm has straight waveguide sections at both ends and curved waveguide sections at the center of the outer waveguide arm, the shape of which matches the shape of the closed annulus.

3. The microring resonator as described in claim 1, characterized in that, The closed, annular waveguide is configured as a racetrack-shaped ring, consisting of two straight waveguides, a U-shaped Euler-bent waveguide on the left, and a U-shaped Euler-bent waveguide on the right. The outer waveguide arm is straight, positioned outside the microring, and parallel to the straight waveguide.

4. The microring resonator as described in claim 3, characterized in that, The U-shaped Euler bend waveguide on the left and the U-shaped Euler bend waveguide on the right are each composed of an L-shaped Euler bend waveguide corresponding to a central angle of 90°, and the L-shaped Euler bend waveguide is composed of a unit Euler bend waveguide corresponding to a central angle of 45°.

5. The microring resonator as described in claim 1, characterized in that, The closed, annular waveguide has a circular outer shape and multiple repeating radial patterns inside to form a photonic crystal structure. The outer waveguide arm is linear and is positioned outside the microring.

6. The microring resonator as described in claim 1, characterized in that, The closed, annular waveguide is configured as a racetrack-shaped ring, consisting of two straight waveguides, a U-shaped Euler-bent waveguide on the left, and a U-shaped Euler-bent waveguide on the right. The width of the racetrack-shaped ring varies along its circumference. The outer waveguide arm is straight, positioned outside the microring, and parallel to the straight waveguide.

7. The microring resonator as described in claim 1, characterized in that, The closed, annular waveguide is configured in an annular shape, with a circular outer surface and multiple repeating radial patterns inside to form a photonic crystal structure. The width of the annular shape varies along the circumference of the annulus. The outer waveguide arm is disposed outside the microring and has a straight waveguide portion at both ends of the outer waveguide arm and a curved waveguide portion at the center of the waveguide arm. The shape of the curved waveguide portion matches the annular shape of the microring.

8. The microring resonator as described in claim 1, characterized in that, The closed, annular waveguide has an elliptical outer shape and multiple repeating radial patterns inside to form a photonic crystal structure. The outer waveguide arm is linear and is positioned outside the microring.

9. The microring resonator as described in claim 1, characterized in that, The closed, annular waveguide is configured as an elliptical ring. The outer surface of this elliptical ring is elliptical, while the inner surface has multiple repeating radial shapes to form a photonic crystal structure. The width of the elliptical ring varies along its circumference. The outer waveguide arm is disposed outside the microring and has a straight waveguide portion at both ends of the outer waveguide arm and a curved waveguide portion at the center of the outer waveguide arm. The shape of the curved waveguide portion matches the shape of the elliptical ring of the microring.

10. The microring resonator as described in any one of claims 5, 7 to 9, characterized in that, The microrings have multiple repeating radial shapes inside, including any one of gear-shaped, star-shaped, petal-shaped, and sun-shaped.

11. A micro-ring modulator, characterized in that, include: The microring resonator and modulation unit according to any one of claims 1 to 10, The modulation unit includes: a power supply for applying a voltage; A PN junction is formed by the contact between an N-type semiconductor and a P-type semiconductor. The refractive index of the waveguide is changed by applying a voltage to the PN junction. An electrode, wherein a voltage is applied to the electrode to adjust the carrier distribution of the PN junction; and A heater that modulates the resonant conditions of a waveguide based on the thermo-optic effect.

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