Micro-ring resonator modulator and optoelectronic hybrid module
By combining a micro-ring resonator and a negative thermo-optic coefficient material layer in a micro-ring resonator modulator, and adjusting the optical field overlap ratio, the temperature sensitivity and heat dissipation problems in the optoelectronic encapsulation module are solved, achieving a low-energy-consumption and stable resonant wavelength, and simplifying the temperature control circuit.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA ACADEMY OF INFORMATION & COMM
- Filing Date
- 2026-04-13
- Publication Date
- 2026-06-05
AI Technical Summary
The micro-ring resonator modulator in the optoelectronic encapsulation module is sensitive to temperature, resulting in high energy consumption and increased complexity in temperature control. Existing technologies cannot effectively solve the problems of heat dissipation and thermal crosstalk.
By employing a combination structure of a micro-ring resonator and a negative thermo-optic coefficient material layer, and by adjusting the optical field overlap ratio of the subwavelength grating, the effective refractive index of the composite waveguide changes close to zero with temperature, thus achieving temperature control without active or with low energy consumption.
Maintaining stable resonant wavelength within the high-temperature operating range reduces temperature control energy consumption, simplifies temperature control circuitry, improves channel uniformity, and reduces crosstalk between adjacent modes, achieving low power consumption and high integration density.
Smart Images
Figure CN122151385A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of communication technology, and in particular to a micro-ring resonant cavity modulator and an optoelectronic encapsulation module. Background Technology
[0002] Heat dissipation and thermal crosstalk are key challenges in co-packaged optoelectronic (CPO) transceiver modules. In the CPO architecture, the optical engine and high-power switching chip are packaged on the same substrate, where the ambient temperature is high and varies significantly. The optical devices in the optical engine, especially the microring resonator modulator based on a microring resonator, are highly sensitive to temperature and typically require integrated heaters to control the temperature and lock the wavelength, increasing overall power consumption and modulation complexity. Summary of the Invention
[0003] This invention provides a micro-ring resonant cavity modulator and an optoelectronic encapsulation module to reduce the energy consumption of temperature control.
[0004] In a first aspect, embodiments of the present invention provide a microring resonant cavity modulator, comprising a microring resonant cavity and a negative thermo-optic coefficient material layer, wherein the microring resonant cavity includes a first subwavelength grating, the grating period of the first subwavelength grating being less than the operating wavelength of the microring resonant cavity; the first subwavelength grating includes an annular waveguide and a plurality of first grooves disposed on the annular waveguide, the plurality of first grooves being disposed circumferentially along the annular waveguide. The negative thermo-optic coefficient material layer includes a negative thermo-optic coefficient material, and the negative thermo-optic coefficient material layer fills the first groove.
[0005] Optionally, the shape of the first groove may include a rectangle.
[0006] Optionally, the opening edge size of the first groove near the inner edge of the first subwavelength grating is smaller than the opening edge size of the first groove near the outer edge of the first subwavelength grating.
[0007] Optionally, it also includes a substrate, wherein the microring resonant cavity is located between the substrate and the negative thermo-optic coefficient material layer; The negative thermo-optic coefficient material layer encapsulates the micro-ring resonant cavity.
[0008] Optionally, it also includes a substrate, wherein the microring resonant cavity is located between the substrate and the negative thermo-optic coefficient material layer; A cavity is provided on the substrate, and the micro-ring resonant cavity is disposed on the substrate, sealing at least part of the opening of the cavity.
[0009] Optionally, at least a portion of the cavity is located outside the region surrounded by the microring resonant cavity.
[0010] Optionally, the microring resonator modulator further includes a bus waveguide, which is coupled to the microring resonator in the coupling region.
[0011] Optionally, the bus waveguide includes a second subwavelength grating, the second subwavelength grating includes a straight waveguide and a plurality of second grooves disposed on the straight waveguide, the plurality of second grooves are disposed along the extension direction of the straight waveguide, the spacing between the centers of two adjacent second grooves is a second groove spacing, and the second groove spacing is smaller than the operating wavelength of the micro-ring resonator. In the coupling region, the equivalent refractive index of the second subwavelength grating gradually changes.
[0012] Optionally, the second slot spacing gradually decreases along the direction away from the coupling region; and / or, the slot length of the second groove gradually decreases along the extension direction of the straight waveguide along the direction away from the coupling region.
[0013] Secondly, embodiments of the present invention provide an optoelectronic encapsulation module, including an optical engine and a switching chip; the optical engine includes the micro-ring resonant cavity modulator described in the first aspect; The optoelectronic encapsulation module further includes an encapsulation substrate, on which the optical engine and the switching chip are encapsulated; and / or, the optoelectronic encapsulation module further includes an encapsulation body, on which the optical engine and the switching chip are encapsulated.
[0014] In this embodiment of the invention, the ring waveguide material has a positive thermo-optic coefficient, and the negative thermo-optic coefficient material layer filling the first groove has a negative thermo-optic coefficient. The grating period of the first subwavelength grating is smaller than the operating wavelength of the micro-ring resonator, so the light wave cannot distinguish the specific physical structure of the first subwavelength grating, but instead perceives an equivalent homogeneous medium. By precisely adjusting the overlap ratio of the light field between the first subwavelength grating and the negative thermo-optic coefficient material layer, the effective refractive index of the composite waveguide formed by the first subwavelength grating and the negative thermo-optic coefficient material layer changes with temperature at a rate close to zero. This ensures that the resonant wavelength of the micro-ring resonator remains stable within the high-temperature operating range (e.g., 40℃-85℃) of the optoelectronic encapsulation module, eliminating or significantly simplifying the metal heating electrodes and temperature control circuits in traditional solutions. This provides a micro-ring resonator modulator that requires no active temperature control or only low-energy temperature control, thereby reducing the energy consumption of temperature control. Attached Figure Description
[0015] Figure 1 A top view of a microring resonant cavity modulator provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the parameters of the micro-ring resonator in the micro-ring resonator modulator; Figure 3A top view of the micro-ring resonator in another micro-ring resonator modulator provided in an embodiment of the present invention; Figure 4 A schematic cross-sectional view of a microring resonator provided in an embodiment of the present invention; Figure 5 This is an overall cross-sectional view of an optoelectronic sealing module provided in an embodiment of the present invention. Detailed Implementation
[0016] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention and not the entire structure.
[0017] Figure 1 A top view of a microring resonant cavity modulator provided in an embodiment of the present invention; Figure 2 This is a schematic diagram showing the parameters of the micro-ring resonator in the micro-ring resonator modulator. (Reference) Figure 1 and Figure 2 The microring resonator modulator 110 includes a microring resonator 111 and a negative thermo-optic coefficient material layer 112. The microring resonator 111 includes a first subwavelength grating, the grating period Λ of which is smaller than the operating wavelength of the microring resonator 111. The first subwavelength grating includes a ring waveguide 114 and a plurality of first grooves 201 disposed on the ring waveguide 114, the plurality of first grooves 201 being disposed circumferentially along the ring waveguide 114. The ring waveguide 114 extends circumferentially to form a ring shape, the circumferential direction being perpendicular to the radial direction. The circumferential spacing between the centers of two adjacent first grooves 201 is the first groove spacing, which is the grating period Λ of the first subwavelength grating. The circumferential spacing refers to the arc distance along the circumferential direction. The negative thermo-optic coefficient material layer 112 includes a negative thermo-optic coefficient material, and the negative thermo-optic coefficient material layer 112 fills the first grooves 201.
[0018] The operating wavelength of the micro-ring resonator 111 is the same as the operating wavelength of the first subwavelength grating. The equivalent refractive index of the first subwavelength grating is ,satisfy: Since light waves cannot distinguish a single period of the first subwavelength grating, they exhibit special equivalent optical properties. The microring resonator 111 is a ring waveguide structure in which light propagates continuously and forms resonance. It can only pass through or couple efficiently when the light wavelength meets specific resonance conditions, thus achieving wavelength selective manipulation of the optical signal.
[0019] In this embodiment of the invention, the material of the ring waveguide 114 has a positive thermo-optic coefficient, and the negative thermo-optic coefficient material layer 112 filled in the first groove 201 has a negative thermo-optic coefficient. The grating period Λ of the first subwavelength grating is smaller than the operating wavelength of the micro-ring resonant cavity 111. The light wave cannot distinguish the specific physical structure of the first subwavelength grating, but instead perceives an equivalent homogeneous medium. The light signal passes sequentially through the ring waveguide 114 with a positive thermo-optic coefficient and the negative thermo-optic coefficient material layer 112 in the propagation direction. By precisely adjusting the overlap ratio of the light field between the first subwavelength grating and the negative thermo-optic coefficient material layer 112, the effective refractive index of the composite waveguide formed by the first subwavelength grating and the negative thermo-optic coefficient material layer 112 changes with temperature to near zero. This ensures that the resonant wavelength of the micro-ring resonant cavity 111 remains stable within the high-temperature operating range (e.g., 40℃-85℃) of the optoelectronic encapsulation module, eliminating or significantly simplifying the metal heating electrodes and temperature control circuits in traditional solutions. A microring resonator modulator 110 is provided that requires no active temperature control or only low-power temperature control, thereby reducing the energy consumption of temperature control. In addition, the equivalent refractive index of the first subwavelength grating is lower than that of the solid waveguide, the microring resonator 111 has a larger free spectral range, reduces crosstalk between adjacent modes, and reduces the requirements for precise temperature control.
[0020] For example, the first subwavelength grating is distributed over the entire area of the microring resonator 111. In other embodiments, the first subwavelength grating is distributed over a portion of the microring resonator 111, the first groove 201 is distributed over a portion of the microring resonator 111, and the first groove 201 is not provided in another portion of the microring resonator 111.
[0021] For example, the first subwavelength grating employs a uniform period setting, with each first slot having the same value. In other embodiments, to address dispersion and loss management requirements, the first subwavelength grating can be designed as a free-form grating, employing structures such as a non-uniform grating period Λ, a slot width w of the first slot 201, and a slot length a of the first slot 201, to reduce bending loss and optimize higher-order mode suppression, further flatten the group refractive index, and improve the channel uniformity of the wavelength division multiplexing system. For example, a topology optimization design algorithm can be used to design the free-form grating.
[0022] For example, the negative thermo-optic coefficient material layer 112 comprises at least one polymer selected from SU-8. The ring waveguide 114 comprises at least one selected from silicon, silicon dioxide, and indium phosphide.
[0023] Optionally, refer to Figure 1 and Figure 2The duty cycle of the first subwavelength grating is greater than or equal to 0.65 and less than or equal to 0.75. The duty cycle is the ratio of the area of the region on the annular waveguide 114 without the first groove 201 within the grating period Λ to the area of the corresponding region of the grating period Λ. The area of the first subwavelength grating is the sum of the area of the region on the annular waveguide 114 without the first groove 201 and the area of the first groove 201. By comprehensively adjusting parameters such as the grating period Λ, the groove width w of the first groove 201, and the groove length a of the first groove 201, the duty cycle δ is precisely adjusted so that δ is between 0.65 and 0.75. This allows control over the energy distribution ratio of the light field in the annular waveguide 114 with a positive thermo-optic coefficient and the negative thermo-optic coefficient material layer 112 with a negative thermo-optic coefficient, making the effective thermo-optic coefficient of the composite waveguide close to zero.
[0024] For example, the center wavelength of the operating wavelength of the micro-ring resonator 111 includes 1550 nm or 1310 nm.
[0025] Figure 3 A top view of the micro-ring resonator in another micro-ring resonator modulator provided in an embodiment of the present invention; see reference. Figure 3 The opening edge size of the first groove 201 near the inner edge of the first subwavelength grating is smaller than the opening edge size of the first groove 201 near the outer edge of the first subwavelength grating. The first groove 201 is arranged in a trapezoidal shape along the radial direction of the microring resonator 111, and the duty cycle of each part in the first groove 201 is gradient-distributed along the radial direction of the microring resonator 111. Radial direction refers to the direction along the width direction of the ring waveguide 114, from the inner radius of the microring resonator 111 to the outer radius of the microring resonator 111.
[0026] Because the ring waveguide 114 is curved, the light wave experiences centrifugal force during propagation, causing the optical mode field to shift outwards. This results in a significant increase in scattering loss on the outer sidewalls of the ring waveguide 114 and facilitates the excitation of higher-order modes. Within the same grating period Λ, the duty cycle δ of the ring waveguide 114 (e.g., made of silicon) gradually changes, with a larger proportion of silicon material at the inner edge (high duty cycle) and a smaller proportion at the outer edge (low duty cycle). Consequently, the effective refractive index is high on the inner side and low on the outer side. According to optical principles, light tends to be confined to regions with higher refractive indices. The high refractive index on the inner side pulls the light field that would otherwise escape outwards, offsetting the mode shift caused by the curvature. This tightly confines the fundamental mode within the ring waveguide 114, greatly reducing radiation loss on the outer walls and scattering loss due to edge roughness. However, for higher-order modes, this disrupts their phase-matching condition, causing them to be in a cutoff state or leak rapidly, thus optimizing higher-order mode suppression.
[0027] Figure 4 This is a schematic cross-sectional view of a microring resonator provided in an embodiment of the present invention, with reference to... Figure 2 and Figure 4 The microring resonator modulator 110 also includes a substrate 113, and a microring resonator 111 is located between the substrate 113 and the negative thermo-optic coefficient material layer 112; the negative thermo-optic coefficient material layer 112 surrounds the microring resonator 111. The negative thermo-optic coefficient material layer 112 is stacked on the substrate 113 and the microring resonator 111. The negative thermo-optic coefficient material layer 112 not only fills the first groove 201, but also covers the top and sides of the microring resonator 111. The negative thermo-optic coefficient material layer 112 also covers the surface of the substrate 113. The microring resonator 111 is located in the closed space formed by the negative thermo-optic coefficient material layer 112 and the substrate 113. This fully enclosed structure allows the light field to fully interact with the negative thermo-optic coefficient material layer 112.
[0028] For example, the first groove 201 has a rectangular shape, and the orthographic projection of the first groove 201 onto the substrate 113 is also rectangular. The groove width w and the groove length a of the first groove 201 are the lengths of the adjacent right-angled sides of the rectangle, respectively.
[0029] Optionally, a cavity 203 is provided on the substrate 113, the cavity 203 being a groove formed on the surface of the substrate 113 facing the micro-ring resonator 111. The micro-ring resonator 111 is disposed on the substrate 113, and the micro-ring resonator 111 blocks at least part of the opening of the cavity 203. The micro-ring resonator 111 and the cavity 203 overlap in a direction perpendicular to the substrate 113. This reduces the vertical stress transmission between the substrate 113 and the micro-ring resonator 111, and reduces the impact of the stress of the packaging substrate on the micro-ring resonator 111. In addition, the cavity 203 also reduces heat conduction from the switching chip. The packaging substrate and the switching chip will be described later.
[0030] Optionally, at least a portion of the cavity 203 is located outside the region surrounded by the microring resonator 111. At least a portion of the cavity 203 is located outside the pattern enclosed by the outer edges of the microring resonator 111. The cavity 203 places the microring resonator 111 in a semi-suspended state. This interrupts the heat conduction path from the outside of the region surrounded by the microring resonator 111 to the microring resonator 111, reducing heat conduction from the switching chip.
[0031] In other embodiments, the radial width of the microring resonator 111 is greater than the radial width of the cavity 203, and the microring resonator 111 completely blocks the opening of the cavity 203. In this embodiment, the negative thermo-optical coefficient material layer 112 cannot enter the cavity 203, so the cavity 203 is not filled with the negative thermo-optical coefficient material layer 112, and the cavity 203 is filled with air. In embodiments where the microring resonator 111 partially blocks the opening of the cavity 203, the negative thermo-optical coefficient material layer 112 can enter the cavity 203, so the cavity 203 is filled with the negative thermo-optical coefficient material layer 112.
[0032] For example, to address the high-stress environment of the optoelectronic encapsulation module, a cavity 203 is formed in the substrate 113 using anisotropic wet etching or deep silicon etching processes. On one hand, the cavity 203 further blocks heat conduction from the switching chip; on the other hand, since the first subwavelength grating is also sensitive to encapsulation stress, the cavity 203 can effectively block the mechanical stress generated during the optoelectronic encapsulation module encapsulation process (such as reflow soldering and underfill curing), ensuring the refractive index stability of the first subwavelength grating. Below the micro-ring resonant cavity 111 region, local etching of the substrate 113 or the creation of deep trench isolation effectively blocks the mechanical stress generated during the optoelectronic encapsulation module encapsulation process and the heat diffusion from the switching chip.
[0033] In this embodiment of the invention, the microring resonator modulator 110 includes a bus waveguide 120, which is coupled to the microring resonator 111 in a coupling region 204. The bus waveguide 120 and the microring resonator 111 are close to each other in the coupling region 204, and energy is exchanged through an evanescent field. The bus waveguide 120 serves as an input waveguide and / or an output waveguide. Taking the bus waveguide 120 as both an input and output waveguide as an example, the bus waveguide 120 couples the light wave into the microring resonator 111. After being modulated by the composite waveguide formed by the microring resonator 111 and the negative thermo-optic coefficient material layer 112, that is, after the light wave is modulated by the microring resonator modulator 110, it is then coupled into the bus waveguide 120.
[0034] Optionally, the bus waveguide 120 includes a second subwavelength grating. The second subwavelength grating includes a straight waveguide 121 and multiple second grooves 202 disposed on the straight waveguide 121. The multiple second grooves 202 are arranged along the extension direction of the straight waveguide 121, and the distance between the centers of two adjacent second grooves 202 is the second groove spacing, which is smaller than the operating wavelength of the microring resonator 111. Light waves cannot distinguish a single period of the second subwavelength grating, thus exhibiting special equivalent optical properties. In the coupling region 204, the equivalent refractive index of the second subwavelength grating gradually changes. Due to the continuous scanning of the equivalent refractive index, a phase-matching point can always be found over a wide wavelength range. This is important for wavelength division multiplexing (WDM) frequently used in optoelectronic encapsulation modules, ensuring consistent coupling efficiency across different wavelength channels. The gradual change in the equivalent refractive index of the second subwavelength grating reduces mode mismatch, enhances the broadband characteristics of the coupling region 204, and maintains a suitable quality factor for the microring resonator 111. Enhance the broadband coupling capability between the microring resonator 111 and the bus waveguide 120 to support multi-wavelength multiplexing of optoelectronic encapsulated modules, such as wavelength division multiplexing optical signal coupling suitable for data center interconnection.
[0035] For example, the negative thermo-optic coefficient material layer 112 fills the second groove 202. The optical signal passes sequentially through the straight waveguide 121 with a positive thermo-optic coefficient and the negative thermo-optic coefficient material layer 112 with a negative thermo-optic coefficient in the propagation direction. The negative thermo-optic coefficient material layer 112 surrounds the straight waveguide 121, and not only fills the second groove 202, but also covers the top and sides of the straight waveguide 121. The negative thermo-optic coefficient material layer 112 also covers the surface of the substrate 113. The straight waveguide 121 is located in the closed space formed by the negative thermo-optic coefficient material layer 112 and the substrate 113. This fully enclosed structure allows the optical field to fully interact with the negative thermo-optic coefficient material layer 112.
[0036] Optionally, refer to Figure 1 Along the direction away from coupling region 204, the length of the second groove 202 gradually decreases along the extension direction of the straight waveguide 121. The duty cycle gradually increases along the direction away from coupling region 204. This achieves a refractive index transition, reducing reflection loss caused by abrupt changes in refractive index. The length of the second groove 202 in coupling region 204 along the extension direction of the straight waveguide 121 is greater than the length of the second groove 202 outside coupling region 204 on bus waveguide 120. Exemplarily, the spacing between the second grooves is equal.
[0037] In another embodiment, a gradually varying grating period can also be used. With the duty cycle remaining essentially constant, as the grating period of the second subwavelength grating increases, according to the Bloch-wave dispersion relation, the equivalent refractive index of the second subwavelength grating will decrease slightly and non-linearly. That is, the grating period is smaller at the beginning of the coupling, gradually increases to a peak in the middle of the coupling (i.e., within the coupling region 204), and gradually decreases at the end of the coupling. In other words, the second slot spacing gradually decreases along the direction away from the coupling region 204. Along the extension direction of the bus waveguide 120, each second slot spacing first gradually increases and then gradually decreases. The value of the second slot spacing within the coupling region 204 is greater than the value of the second slot spacing outside the coupling region 204 on the bus waveguide 120.
[0038] In other embodiments, the above two schemes can be combined to satisfy both the following: the second slot spacing gradually decreases along the direction away from the coupling region 204; and the slot length of the second groove 202 gradually decreases along the extension direction of the straight waveguide 121 along the direction away from the coupling region 204. This makes the second subwavelength grating a gradient subwavelength grating structure, and the refractive index transition is achieved by changing parameters such as the value of the second slot spacing, the slot width of the second groove 202, and the slot length of the second groove 202.
[0039] Figure 5 This is an overall cross-sectional view of an optoelectronic sealing module provided in an embodiment of the present invention; see reference. Figures 1-5The optoelectronic encapsulation module includes the optical engine 103 and the switching chip 102 described in the above embodiments. The optical engine 103 includes the micro-ring resonant cavity modulator 110 described in the above embodiments. The optoelectronic encapsulation module also includes a packaging substrate 101, on which the optical engine 103 and the switching chip 102 are packaged. And / or, the optoelectronic encapsulation module also includes a package ( Figure 5 (Not shown in the image) The optical engine 103 and the switching chip 102 are packaged in the same package. The optoelectronic packaged module can be a signal transceiver module.
[0040] For example, Figure 5 The microring resonator modulator 110 is shown in its position within the optoelectronic encapsulation module. The optoelectronic encapsulation module also includes a printed circuit board 100, an optical fiber 105, a front panel 106, and solder bumps 107. The switching chip 102 and the optical engine 103 are flip-chip bonded to the same packaging substrate 101, which is bonded to the printed circuit board 100. The packaging substrate 101 and the printed circuit board 100 are electrically connected via solder bumps 107. The optical engine 103 integrates the microring resonator modulator 110, and the optical signal modulated by the microring resonator modulator 110 is output to the front panel 106 via the optical fiber 105. In some embodiments, the optical engine 103 may also include devices such as detectors and beam splitters.
[0041] In summary, this invention provides a low-power, stress-resistant, and high-density optoelectronic encapsulation module solution. Utilizing the structural characteristics of a subwavelength grating, it constructs an adiabatic micro-ring resonant cavity modulator that requires no active temperature control or only low-power temperature control, thus solving the heat dissipation, thermal crosstalk, and stress problems in optoelectronic encapsulation modules. Furthermore, the subwavelength grating structure allows for additional adjustment of coupling bandwidth, dispersion, and other parameters. This invention aims for a three-dimensional balance between power consumption, heat, and stress, rather than pursuing extreme thermal insulation. Instead, it seeks to achieve a compromise between low-power temperature control and high-speed signal integrity within the limited heat dissipation budget of the CPO (Content on Power Output).
[0042] For example, taking a ring waveguide 114 comprising silicon and a negative thermo-optical coefficient material layer 112 comprising a polymer as an example, the effective refractive index of the composite waveguide formed by the first subwavelength grating and the negative thermo-optical coefficient material layer 112 is... Rate of change with temperature It can be represented as: in, and These are the confinement factors of the optical field in the core layer (i.e., the ring waveguide 114) and the polymer cladding layer (i.e., the negative thermo-optic coefficient material layer 112), respectively. +1.86×10 -4 / K (positive value, produces redshift); Thermo-optic coefficient of the core layer. The thermo-optic coefficient of the polymer coating is typically -1.0 × 10⁻⁶. -4 / K to -2.5×10 -4 / K (negative value, produces blue shift); The coefficient of thermal expansion of substrate 113 is typically small.
[0043] In traditional solid waveguides, Generally, values greater than 0.8 are difficult to pass. The term cancels out the positive term.
[0044] This scheme employs a first subwavelength grating. By comprehensively adjusting parameters such as the grating period, slot width, and slot length, the duty cycle of the first subwavelength grating is changed. .when When the light field decreases, more of it leaks into the polymer gaps (i.e., the first groove 201 filled with the negative thermo-optic coefficient material layer 112). Decline Rise. Find a specific duty cycle. , can make .
[0045] In one specific embodiment, based on optical simulation and combined with a multiphysics coupling model to simulate the stress environment of CPO packaging, the results show that: with the first subwavelength grating period set to 250nm and the thermo-optic coefficient of the negative thermo-optic coefficient material layer 112 being -1.1×10⁻⁶, -4 Under the condition of / K, when the duty cycle is adjusted to around 0.65, the wavelength drift of the microring resonator with temperature decreases to below 1.5 pm / K. Compared to the approximately 80 pm / K temperature drift of solid silicon microrings in the prior art, the microring resonator modulator 110 provided in this embodiment of the invention achieves a near-adiabatic effect, thereby eliminating the need for thermal tuning within a 40℃ temperature rise range, theoretically saving approximately 15mW of power consumption per channel. In the prior art, solid silicon microrings experience a wavelength drift of approximately 200 pm due to packaging stress. The microring resonator modulator 110 provided in this embodiment of the invention experiences a wavelength drift of less than 50 pm due to packaging stress. The quality factor (i.e., Q value) of the microring resonator modulator 110 provided in this embodiment of the invention is greater than or equal to 10000 and less than or equal to 25000, exhibiting a high quality factor.
[0046] Furthermore, this embodiment of the invention also compares the microring resonator modulator 110 with known related devices. One existing temperature control solution uses a Mach-Zehnder modulator. Mach-Zehnder modulators have low temperature sensitivity and broadband characteristics. Traveling-wave Mach-Zehnder modulators are in the millimeter range (1-3 mm) in length, while the microring resonator modulator 110 provided in this embodiment is only in the micrometer range (radius of 5-10 μm). It maintains the ultra-small size advantage of a microring while achieving temperature stability close to that of a Mach-Zehnder modulator, thus balancing integration density and temperature stability.
[0047] Another existing temperature control solution involves covering a traditional solid waveguide with a polymer having a negative thermo-optic coefficient. Solid silicon waveguides severely restrict the light field, with only a small portion (<15%) of the light field distributed within the polymer cladding, making it difficult to completely offset the positive thermo-optic coefficient of silicon. Regarding dispersion, solid waveguide dispersion is difficult to control flexibly. However, the micro-ring resonator modulator 110 provided in this embodiment of the invention controls the distribution ratio of the light field in the positive and negative thermo-optic coefficient materials (reaching 50%:50% or even higher) by changing parameters such as the grating period, slot width, and slot length of the first subwavelength grating, thus achieving precise adiabatic control.
[0048] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.
Claims
1. A micro-ring resonant cavity modulator, characterized in that, The device includes a microring resonant cavity and a negative thermo-optic coefficient material layer. The microring resonant cavity includes a first subwavelength grating, the grating period of which is less than the operating wavelength of the microring resonant cavity. The first subwavelength grating includes a ring waveguide and a plurality of first grooves disposed on the ring waveguide, the plurality of first grooves being disposed circumferentially along the ring waveguide. The negative thermo-optic coefficient material layer includes a negative thermo-optic coefficient material, and the negative thermo-optic coefficient material layer fills the first groove.
2. The micro-ring resonator modulator according to claim 1, characterized in that, The shape of the first groove includes a rectangle.
3. The micro-ring resonator modulator according to claim 1, characterized in that, The opening edge size of the first groove near the inner edge of the first subwavelength grating is smaller than the opening edge size of the first groove near the outer edge of the first subwavelength grating.
4. The micro-ring resonator modulator according to claim 1, characterized in that, It also includes a substrate, wherein the microring resonant cavity is located between the substrate and the negative thermo-optic coefficient material layer; The negative thermo-optic coefficient material layer encapsulates the micro-ring resonant cavity.
5. The micro-ring resonator modulator according to claim 1, characterized in that, It also includes a substrate, wherein the microring resonant cavity is located between the substrate and the negative thermo-optic coefficient material layer; A cavity is provided on the substrate, and the micro-ring resonant cavity is disposed on the substrate, sealing at least part of the opening of the cavity.
6. The microring resonator modulator according to claim 5, characterized in that, At least a portion of the cavity is located outside the region surrounded by the microring resonant cavity.
7. The micro-ring resonator modulator according to claim 1, characterized in that, It also includes a bus waveguide, which is coupled to the micro-ring resonator in the coupling region.
8. The micro-ring resonator modulator according to claim 7, characterized in that, The bus waveguide includes a second subwavelength grating, which includes a straight waveguide and a plurality of second grooves disposed on the straight waveguide. The plurality of second grooves are disposed along the extension direction of the straight waveguide, and the distance between the centers of two adjacent second grooves is a second groove spacing, which is smaller than the operating wavelength of the micro-ring resonator. In the coupling region, the equivalent refractive index of the second subwavelength grating gradually changes.
9. The micro-ring resonator modulator according to claim 8, characterized in that, Along the direction away from the coupling region, the second slot spacing gradually decreases; and / or, along the direction away from the coupling region, the slot length of the second groove gradually decreases along the extension direction of the straight waveguide.
10. A photoelectric sealing module, characterized in that, Includes an optical engine and a switching chip; the optical engine includes the microring resonator modulator according to any one of claims 1-9; The optoelectronic encapsulation module also includes an encapsulation substrate, on which the optical engine and the switching chip are encapsulated; And / or, the optoelectronic encapsulation module further includes a package, in which the optical engine and the switching chip are encapsulated within the same package.