Piezoelectric-thermo-optic composite modulator and preparation method thereof

Abstract

The invention relates to the technical field of semiconductors, and discloses a piezoelectric-thermo-optic composite modulator and a preparation method thereof, and the piezoelectric-thermo-optic composite modulator comprises a silicon optical integrated circuit structure which comprises a substrate layer and a waveguide core located at one side of the substrate layer; the thermo-optical modulation structure is positioned on one side, back to the substrate layer, of the waveguide core; the thermo-optical modulation structure comprises a heating fixed-value resistor and a thermo-optical electrode; the position of the heating fixed-value resistor corresponds to the position of the waveguide core; the thermo-optical electrode is connected with a heating fixed-value resistor; the piezoelectric modulation structure is positioned on one side, back to the substrate layer, of the waveguide core; the piezoelectric modulation structure comprises a first piezoelectric electrode, a piezoelectric film material layer and a second piezoelectric electrode which are stacked; the position of the piezoelectric film material layer corresponds to the position of the waveguide core; and the first piezoelectric electrode further extends to the side part of the piezoelectric film material layer. Compared with the prior art, piezoelectric modulation and thermo-optical modulation can be achieved at the same time, the driving voltage of pi phase shift adjustment is reduced, and the modulation speed is increased.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a piezoelectric-thermo-optical composite modulator and a preparation method thereof. Background Art

[0002] Silicon nitride (SiN) has the characteristics of low loss and compatibility with CMOS (complementary metal oxide semiconductor) technology, which can realize high-performance passive devices, but it lacks monolithic integrated high-speed devices, such as optical modulators. In integrated silicon-based optoelectronic chips, optical modulators can control the phase of light waves by changing the refractive index of waveguides, thereby realizing chip function regulation. Among them, thermo-optical modulators are compatible with CMOS technology and can adjust the optical properties of waveguides by changing the temperature of waveguide materials. They play an important role in silicon optical devices. Thermo-optical modulators can be used to realize phase modulation, amplitude modulation and polarization state modulation of light beams. They have the characteristics of low power consumption and easy integration, but their response time is generally in the order of microseconds (μs) and the modulation speed is relatively slow (~kHz). Piezoelectric modulators based on the inverse piezoelectric effect are also an important modulation device. When an external electric field is applied to a crystal material, the crystal material will deform. If the crystal material is combined with an optical waveguide, the stress of the deformation of the crystal material will be transmitted to the optical waveguide, thereby changing the refractive index of the optical waveguide. Compared with thermo-optical modulators, the power consumption of piezoelectric modulators can be reduced by 3-5 orders of magnitude. Piezoelectric modulators also have the characteristics of high modulation speed (~GHz), but they also have the problems of high driving voltage and incompatibility with CMOS process.

[0003] The existing research on silicon nitride chip modulators is relatively simple. On the silicon nitride photonic integration platform, it is difficult to integrate modulators of different materials and performances in terms of process. In particular, for the modulation of the same modulation area of ​​the same waveguide, there is a lack of composite modulators that can integrate modulators with different modulation characteristics in terms of process. Summary of the invention

[0004] In view of this, the present invention provides a piezoelectric-thermo-optical composite modulator and a preparation method thereof to solve the problems in the related art that the response speed and modulation speed of the thermo-optical modulator are relatively slow, the driving voltage of the piezoelectric modulator to achieve π phase shift is high, and there is a lack of a composite modulator that can processally integrate modulators with different modulation characteristics.

[0005] In a first aspect, the present invention provides a piezoelectric-thermo-optical composite modulator, the piezoelectric-thermo-optical composite modulator comprising:

[0006] A silicon photonic integrated circuit structure, comprising a substrate layer and a waveguide core located on one side of the substrate layer;

[0007] The thermo-optic modulation structure is located on the side of the waveguide core facing away from the substrate layer; the thermo-optic modulation structure includes a heating fixed value resistor and a thermo-optic electrode; the position of the heating fixed value resistor corresponds to the position of the waveguide core; the thermo-optic electrode is connected to the heating fixed value resistor;

[0008] The piezoelectric modulation structure is located on the side of the waveguide core facing away from the substrate layer; the piezoelectric modulation structure includes a stacked first piezoelectric electrode, a piezoelectric film material layer, and a second piezoelectric electrode; the position of the piezoelectric film material layer corresponds to the position of the waveguide core; the first piezoelectric electrode also extends to the side of the piezoelectric film material layer;

[0009] The cladding covers the silicon photonic integrated circuit structure, the thermo-optical modulation structure and the piezoelectric modulation structure, and exposes the thermo-optical electrode, part of the first piezoelectric electrode and part of the second piezoelectric electrode.

[0010] The piezoelectric-thermo-optical composite modulator provided by the present invention can realize the modulation mode of thermo-optical modulation by setting the position of the heating fixed value resistor in the thermo-optical modulation structure to correspond to the position of the waveguide core, and has the advantages of low driving voltage for realizing π phase shift, low power consumption, and compatibility with CMOS process; by setting the position of the piezoelectric film material layer in the piezoelectric modulation structure to correspond to the position of the waveguide core, the modulation mode of piezoelectric modulation can be realized, with high modulation speed and low power consumption. The piezoelectric-thermo-optical composite modulator provided by the present invention integrates the piezoelectric modulator and the thermo-optical modulator in the same structure, and can realize the hybrid modulation mode of piezoelectric modulation and thermo-optical modulation at the same time, and can reduce the driving voltage of π phase shift regulation, realize π phase shift regulation at a lower voltage, increase the modulation amplitude, and improve the modulation speed, thereby improving the modulation efficiency and reliability of the composite modulator, reducing the power consumption of the modulator, and increasing the application scenarios of the modulator.

[0011] In an optional embodiment, the cladding includes a first cladding, a second cladding and a third cladding;

[0012] A first cladding layer is located between the substrate layer and the thermo-optical modulation structure, and the first cladding layer covers a surface of the waveguide core that is away from the substrate layer and a side surface of the waveguide core;

[0013] The second cladding is located on the surface of the first cladding on the side facing away from the substrate layer; the second cladding covers the heating fixed value resistor and the thermo-optical electrode; a third groove is provided on the side of the second cladding facing away from the substrate layer; the third groove exposes the surface of the thermo-optical electrode on the side facing away from the substrate layer;

[0014] A third cladding is located on the surface of the second cladding on the side facing away from the first cladding; the third cladding covers the side and partial surface of the first piezoelectric electrode, the piezoelectric film material layer and the second piezoelectric electrode; the surface of the third cladding has a first groove and a second groove; the first groove exposes a partial surface of the first piezoelectric electrode; the second groove exposes a partial surface of the second piezoelectric electrode; the third groove also runs through the third cladding;

[0015] The piezoelectric-thermo-optical composite modulator further comprises: a thermal oxide layer located between the substrate layer and the waveguide core.

[0016] In an optional embodiment, the piezoelectric modulation structure is located on a side of the thermo-optical modulation structure facing away from the waveguide core;

[0017] The projection position of the piezoelectric film material layer on the substrate layer and the projection position of the heating constant value resistor on the substrate layer cover the projection position of the same area of ​​the same waveguide core on the substrate layer.

[0018] The piezoelectric-thermo-optical composite modulator provided by the present invention has a piezoelectric thin film material layer on the substrate layer, and a projection position of the heating fixed value resistor on the substrate layer covers the projection position of the same area of ​​the same waveguide core on the substrate layer. It can realize π phase shift adjustment based on the thermo-optical modulator for the same modulation area of ​​the same optical waveguide, and at the same time realize a high-speed modulation effect based on the piezoelectric modulator. It can realize π phase shift adjustment at a lower voltage, increase the modulation amplitude, and improve the modulation speed, thereby improving the modulation efficiency and reliability of the composite modulator, reducing the power consumption of the modulator, and increasing the application scenarios of the modulator.

[0019] In an optional embodiment, the waveguide core includes a first waveguide core and a second waveguide core;

[0020] The thermo-optic modulation structure is located on a surface of the first cladding layer facing away from the first waveguide core; the projection position of the heating constant value resistor on the substrate layer covers a part of the projection position of the first waveguide core on the substrate layer;

[0021] The piezoelectric modulation structure is located on a surface of the second cladding layer facing away from the second waveguide core; the projection position of the piezoelectric film material layer on the substrate layer covers part of the projection position of the second waveguide core on the substrate layer.

[0022] In an optional embodiment, the first waveguide core and the second waveguide core are different regions of the same waveguide core;

[0023] The projection position of the heating constant value resistor on the substrate layer does not coincide with the projection position of the piezoelectric film material layer on the substrate layer.

[0024] In the piezoelectric-thermo-optical composite modulator provided by the present invention, the first waveguide core and the second waveguide core are different regions of the same waveguide core, the projection position of the heating constant resistor on the substrate layer does not overlap with the projection position of the piezoelectric thin film material layer on the substrate layer, and the thermo-optical modulator and the piezoelectric modulator act on different regions of the same waveguide core respectively, so that thermo-optical modulation and piezoelectric modulation effects can be realized respectively for different modulation regions of the same optical waveguide as required, which can increase the modulation amplitude, improve the modulation efficiency and reliability of the composite modulator, reduce the power consumption of the modulator, and increase the application scenarios of the modulator.

[0025] In an optional embodiment, a portion of the surface of the first piezoelectric electrode exposed by the first groove is a first pad;

[0026] A portion of the surface of the first piezoelectric electrode exposed by the first groove is a second pad;

[0027] The surface of the thermo-optical electrode exposed by the third groove is a third solder pad;

[0028] The first pad, the second pad and the third pad are suitable for connecting to an external power source.

[0029] In an optional embodiment, the material of the substrate layer is silicon;

[0030] The material of the waveguide core is Si3N4; the material of the thermal oxide layer is silicon dioxide;

[0031] The materials of the first cladding, the second cladding and the third cladding are silicon dioxide;

[0032] The material of the heating fixed value resistor is TiN; the material of the thermo-optical electrode is AlCu;

[0033] The material of the piezoelectric film material layer is aluminum nitride, lead zirconate titanate, hafnium oxide, zinc oxide or lithium niobate; the material of the first piezoelectric electrode is Mo, AlCu, Au, Ag or Pt; the material of the second piezoelectric electrode is Mo, AlCu, Au, Ag or Pt.

[0034] In an optional embodiment, the thickness of the substrate layer is 500 μm to 800 μm; the thickness of the thermal oxide layer is 2 μm to 8 μm; the thickness of the waveguide core is 0.075 μm to 0.45 μm; the thickness of the first cladding layer is 0.5 μm to 2 μm;

[0035] The thickness of the heating fixed value resistor is 0.05μm to 0.15μm; the thickness of the thermo-optical electrode is 0.5μm to 1.5μm;

[0036] The thickness of the second cladding layer is 0.5 μm to 1.5 μm;

[0037] The thickness of the piezoelectric film material layer is 0.8 μm to 1.5 μm; the thickness of the first piezoelectric electrode is 0.1 μm to 0.2 μm; and the thickness of the second piezoelectric electrode is 0.1 μm to 0.2 μm.

[0038] In an optional implementation, the driving voltage of the π phase shift of the piezoelectric-thermo-optical composite modulator is less than 10V; and the modulation speed is greater than 1 GHz.

[0039] The piezoelectric-thermo-optical composite modulator provided by the present invention integrates a piezoelectric modulator and a thermo-optical modulator in the same structure, and can realize a hybrid modulation mode of piezoelectric modulation and thermo-optical modulation. The driving voltage of the π phase shift of the piezoelectric-thermo-optical composite modulator is less than 10V, and the modulation speed is greater than 1GHz. The π phase shift adjustment can be realized at a lower voltage, the modulation amplitude is increased, and the modulation speed is increased, thereby improving the modulation efficiency and reliability of the composite modulator, reducing the power consumption of the modulator, and increasing the application scenarios of the modulator.

[0040] In a second aspect, the present invention provides a method for preparing a piezoelectric-thermo-optical composite modulator, which is used to prepare the piezoelectric-thermo-optical composite modulator of the first aspect, and the preparation method comprises:

[0041] A silicon photonic integrated circuit structure is provided, wherein the silicon photonic integrated circuit structure comprises a substrate layer and a waveguide core located on one side of the substrate layer;

[0042] A thermo-optic modulation structure is formed on the side of the waveguide core facing away from the substrate layer; the thermo-optic modulation structure includes a heating fixed value resistor and a thermo-optic electrode; the position of the heating fixed value resistor corresponds to the position of the waveguide core; the thermo-optic electrode is connected to the heating fixed value resistor;

[0043] A piezoelectric modulation structure is formed on the side of the waveguide core facing away from the substrate layer, the piezoelectric modulation structure comprising a stacked first piezoelectric electrode, a piezoelectric film material layer, and a second piezoelectric electrode; the position of the piezoelectric film material layer corresponds to the position of the waveguide core; the first piezoelectric electrode also extends to the side of the piezoelectric film material layer;

[0044] A cladding is formed, which covers the silicon photonic integrated circuit structure, the thermo-optical modulation structure and the piezoelectric modulation structure, and exposes the thermo-optical electrode, part of the first piezoelectric electrode and part of the second piezoelectric electrode.

[0045] The preparation method of the piezoelectric-thermo-optical composite modulator provided by the present invention, on the one hand, the position of the heating fixed value resistor in the formed thermo-optical modulation structure corresponds to the position of the waveguide core, and the modulation mode of thermo-optical modulation can be realized, which has the advantages of low driving voltage for realizing π phase shift, low power consumption, and compatibility with CMOS process; the position of the piezoelectric film material layer in the formed piezoelectric modulation structure corresponds to the position of the waveguide core, and the modulation mode of piezoelectric modulation can be realized, with high modulation speed and low power consumption; on the other hand, the first groove, the second groove and the third groove are formed at the same time, and the electrodes of the thermo-optical modulation structure and the piezoelectric modulation structure can be simultaneously led out, simplifying the process flow and improving the process efficiency. The preparation method of the piezoelectric-thermo-optical composite modulator provided by the present invention, respectively forming the piezoelectric modulation structure and the thermo-optical modulation structure in different structural layers of the modulator, can realize the hybrid modulation mode of piezoelectric modulation and thermo-optical modulation, can realize π phase shift adjustment at a lower voltage, increase the modulation amplitude, and improve the modulation speed, thereby improving the modulation efficiency and reliability of the composite modulator, reducing the power consumption of the modulator, and increasing the application scenarios of the modulator, and simultaneously leading out the electrodes of the thermo-optical modulation structure and the piezoelectric modulation structure, can simplify the process flow and improve the process efficiency.

[0046] In an optional embodiment, the step of forming the cladding layer comprises:

[0047] After the step of providing the silicon photonic integrated circuit structure and before the step of forming the thermo-optical modulation structure, a first cladding layer is formed on one side of the substrate layer; the first cladding layer covers a surface of the waveguide core facing away from the substrate layer and a side surface of the waveguide core;

[0048] After the step of forming the first cladding layer and before the step of forming the piezoelectric modulation structure, a second cladding layer is formed on the surface of the first cladding layer facing away from the substrate layer, wherein the second cladding layer covers the heating constant value resistor and the thermo-optical electrode;

[0049] After the step of forming the piezoelectric modulation structure, a third cladding is formed on the surface of the second cladding facing away from the first cladding, wherein the third cladding covers the surface and side of the first piezoelectric electrode, the piezoelectric film material layer, and the second piezoelectric electrode;

[0050] A first groove, a second groove and a third groove are formed on the surface of the third cladding layer facing away from the first cladding layer; the first groove exposes part of the surface of the first piezoelectric electrode; the second groove exposes part of the surface of the second piezoelectric electrode; the third groove penetrates through the third cladding layer and goes deep into the second cladding layer, exposing the surface of the thermo-optic electrode facing away from the substrate layer.

[0051] In an optional embodiment, in the step of forming the first groove, the second groove and the third groove on the surface of the third cladding layer facing away from the first cladding layer,

[0052] The surface of the first piezoelectric electrode exposed by the first groove forms a first pad, the surface of the second piezoelectric electrode exposed by the second groove forms a second pad, and the surface of the thermo-optical electrode exposed by the third groove forms a third pad. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the related technologies, the drawings required for use in the specific embodiments or the related technical descriptions will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0054] Figure 1 Schematic diagram of the structure of a piezoelectric-thermo-optical composite modulator according to an embodiment of the present invention.

[0055] Figure 2 4 is a schematic structural diagram of another piezoelectric-thermo-optical composite modulator according to an embodiment of the present invention.

[0056] Figure 3 It is a schematic flow chart of a method for preparing a piezoelectric-thermo-optical composite modulator according to an embodiment of the present invention.

[0057] Figure 4 It is a schematic diagram of a specific process of a method for preparing a piezoelectric-thermo-optical composite modulator according to an embodiment of the present invention.

[0058] Figure 5 It is a structural schematic diagram of forming a thermo-optic modulation structure in a method for preparing a piezoelectric-thermo-optic composite modulator according to an embodiment of the present invention.

[0059] Figure 6 It is a structural schematic diagram of forming a silicon photonic integrated circuit structure in a method for preparing a piezoelectric-thermo-optical composite modulator according to an embodiment of the present invention.

[0060] Figure 7 It is a structural schematic diagram of forming a piezoelectric modulation structure in a method for preparing a piezoelectric-thermo-optical composite modulator according to an embodiment of the present invention.

[0061] Reference numerals:

[0062] 10. Waveguide core; 11. First cladding; 12. Thermal oxide layer; 13. Substrate layer; 21. Heating constant resistor; 22. Second cladding; 23. Thermal-optical electrode; 31. First piezoelectric electrode; 32. Piezoelectric film material layer; 33. Second piezoelectric electrode; 34. Third cladding. DETAILED DESCRIPTION

[0063] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0064] In the following description, the description of known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention. Various structural schematic diagrams according to embodiments of the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified for the purpose of clear expression, and some details may be omitted. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships between them are only exemplary, and may be deviated due to manufacturing tolerances or technical limitations in practice, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs. In the context of the present invention, when a layer / element is referred to as being "on" another layer / element, the layer / element may be directly on the other layer / element, or there may be a middle layer / element between them. In addition, if a layer / element is "on" another layer / element in one orientation, then when the orientation is reversed, the layer / element may be "under" the other layer / element.

[0065] Silicon nitride (SiN) has the characteristics of low loss and compatibility with CMOS process, which can realize high-performance passive devices, but it lacks monolithic integrated high-speed devices, such as optical modulators. In integrated silicon-based optoelectronic chips, optical modulators can control the phase of light waves by changing the refractive index of waveguides, thereby realizing chip function regulation. Among them, thermo-optical modulators are compatible with CMOS process and can adjust the optical properties of waveguides by changing the temperature of waveguide materials. They play an important role in silicon optical devices. Thermo-optical modulators can be used to realize phase modulation, amplitude modulation and polarization state modulation of light beams. They have the characteristics of low power consumption and easy integration, but their response time is generally in the order of microseconds (μs) and the modulation speed is relatively slow (~kHz). Piezoelectric modulators based on the inverse piezoelectric effect are also an important modulation device. When an external electric field is applied to a crystal material, the crystal material will deform. If the crystal material is combined with an optical waveguide, the stress of the deformation of the crystal material will be transmitted to the optical waveguide, thereby changing the refractive index of the optical waveguide. Compared with thermo-optical modulators, the power consumption of piezoelectric modulators can be reduced by 3-5 orders of magnitude. Piezoelectric modulators also have the characteristics of high modulation speed (~GHz), but they also have the problems of high driving voltage and incompatibility with CMOS process.

[0066] The existing research on silicon nitride chip modulators is relatively simple. On the silicon nitride photonic integration platform, it is difficult to integrate modulators of different materials and performances in terms of process. In particular, for the modulation of the same modulation area of ​​the same waveguide, there is a lack of composite modulators that can integrate modulators with different modulation characteristics in terms of process.

[0067] Therefore, a composite modulator is needed that can combine the advantages of low driving voltage, low power consumption, and compatibility with CMOS process of the thermo-optical modulator to achieve π phase shift with the advantages of high modulation speed and low power consumption of the piezoelectric modulator.

[0068] like Figure 1 As shown, this embodiment provides a piezoelectric-thermo-optical composite modulator, and the piezoelectric-thermo-optical composite modulator includes:

[0069] A silicon photonic integrated circuit structure comprises a substrate layer 13 and a waveguide core 10 located on one side of the substrate layer 13;

[0070] The thermo-optic modulation structure is located on the side of the waveguide core 10 facing away from the substrate layer 13; the thermo-optic modulation structure includes a heating fixed value resistor 21 and a thermo-optic electrode 23; the position of the heating fixed value resistor 21 corresponds to the position of the waveguide core 10; the thermo-optic electrode 23 is connected to the heating fixed value resistor 21;

[0071] The piezoelectric modulation structure is located on the side of the waveguide core 10 facing away from the substrate layer 13; the piezoelectric modulation structure includes a stacked first piezoelectric electrode 31, a piezoelectric film material layer 32, and a second piezoelectric electrode 33; the position of the piezoelectric film material layer 32 corresponds to the position of the waveguide core 10; the first piezoelectric electrode 31 also extends to the side of the piezoelectric film material layer 32;

[0072] The cladding covers the silicon photonic integrated circuit structure, the thermo-optic modulation structure and the piezoelectric modulation structure, and exposes the thermo-optic electrode, part of the first piezoelectric electrode and part of the second piezoelectric electrode. In specific implementation, the position of the heating constant resistor 21 corresponds to the position of the thermo-optic modulation area of ​​the waveguide core 10; the position of the piezoelectric film material layer 32 corresponds to the position of the electro-optic modulation area of ​​the waveguide core 10. The thermo-optic modulation area and the electro-optic modulation area can be the same area or different areas.

[0073] The piezoelectric-thermo-optical composite modulator provided in this embodiment can realize the modulation mode of thermo-optical modulation by setting the position of the heating fixed value resistor in the thermo-optical modulation structure to correspond to the position of the waveguide core, and has the advantages of low driving voltage for realizing π phase shift, low power consumption, and compatibility with CMOS process; by setting the position of the piezoelectric film material layer in the piezoelectric modulation structure to correspond to the position of the waveguide core, the modulation mode of piezoelectric modulation can be realized, with high modulation speed and low power consumption. The piezoelectric-thermo-optical composite modulator provided in this embodiment integrates the piezoelectric modulator and the thermo-optical modulator in the same structure, and can realize the hybrid modulation mode of piezoelectric modulation and thermo-optical modulation, which can reduce the driving voltage of π phase shift regulation, realize π phase shift regulation at a lower voltage, increase the modulation amplitude, and increase the modulation speed, thereby improving the modulation efficiency and reliability of the composite modulator, reducing the power consumption of the modulator, and increasing the application scenarios of the modulator.

[0074] In some optional embodiments, the cladding includes a first cladding 11, a second cladding 22, and a third cladding 34;

[0075] A first cladding layer 11 is located between the substrate layer 13 and the thermo-optical modulation structure, and the first cladding layer 11 covers a surface of the waveguide core 10 that is away from the substrate layer 13 and a side surface of the waveguide core 10;

[0076] The second cladding 22 is located on the surface of the first cladding 11 on the side facing away from the substrate layer 13; the second cladding 22 covers the heating fixed value resistor 21 and the thermo-optical electrode 23; a third groove is provided on the side of the second cladding 22 facing away from the substrate layer 13; the third groove exposes the surface of the thermo-optical electrode 23 on the side facing away from the substrate layer 13;

[0077] The third cladding 34 is located on the surface of the second cladding 22 on the side facing away from the first cladding 11; the third cladding 34 covers the side and partial surface of the first piezoelectric electrode 31, the piezoelectric film material layer 32 and the second piezoelectric electrode 33; the surface of the third cladding 34 has a first groove and a second groove; the first groove exposes a partial surface of the first piezoelectric electrode 31; the second groove exposes a partial surface of the second piezoelectric electrode 33; the third groove also penetrates the third cladding 34;

[0078] The piezoelectric-thermo-optical composite modulator further includes a thermal oxide layer 12 located between the substrate layer 13 and the waveguide core 10 .

[0079] In some optional embodiments, the piezoelectric modulation structure is located on the side of the thermo-optical modulation structure facing away from the waveguide core 10;

[0080] The projection position of the piezoelectric film material layer 32 on the substrate layer 13 and the projection position of the heating fixed value resistor 21 on the substrate layer 13 cover the same area of ​​the same waveguide core 10 on the substrate layer 13 .

[0081] The piezoelectric-thermo-optical composite modulator provided in this embodiment, in which the projection position of the piezoelectric thin film material layer on the substrate layer and the projection position of the heating fixed value resistor on the substrate layer cover the projection position of the same area of ​​the same waveguide core on the substrate layer, can realize π phase shift adjustment based on the thermo-optical modulator for the same modulation area of ​​the same optical waveguide, and at the same time realize high-speed modulation effect based on the piezoelectric modulator, can realize π phase shift adjustment at a lower voltage, increase the modulation amplitude, and improve the modulation speed, thereby improving the modulation efficiency and reliability of the composite modulator, reducing the power consumption of the modulator, and increasing the application scenarios of the modulator.

[0082] In some optional embodiments, such as Figure 2 As shown, the waveguide core 10 includes a first waveguide core 101 and a second waveguide core 102;

[0083] The thermo-optic modulation structure is located on the surface of the first cladding 11 facing away from the first waveguide core 101; the projection position of the heating constant value resistor 21 on the substrate layer 13 covers part of the projection position of the first waveguide core 101 on the substrate layer 13;

[0084] The piezoelectric modulation structure is located on a surface of the second cladding 22 facing away from the second waveguide core 102 ; the projection position of the piezoelectric film material layer 32 on the substrate layer 13 covers a portion of the projection position of the second waveguide core 102 on the substrate layer 13 .

[0085] In some optional embodiments, such as Figure 2 As shown, the first waveguide core 101 and the second waveguide core 102 are different regions of the same waveguide core 10;

[0086] The projection position of the heating constant value resistor on the substrate layer 13 does not overlap with the projection position of the piezoelectric thin film material layer 32 on the substrate layer 13 .

[0087] In the piezoelectric-thermo-optical composite modulator provided in this embodiment, the first waveguide core and the second waveguide core are different regions of the same waveguide core, and the projection position of the heating constant resistor on the substrate layer does not overlap with the projection position of the piezoelectric thin film material layer on the substrate layer. The thermo-optical modulator and the piezoelectric modulator act on different regions of the same waveguide core respectively, and thermo-optical modulation and piezoelectric modulation effects can be realized respectively for different modulation regions of the same optical waveguide as required, which can increase the modulation amplitude, improve the modulation efficiency and reliability of the composite modulator, reduce the power consumption of the modulator, and increase the application scenarios of the modulator.

[0088] In some optional embodiments, the first waveguide core 101 and the second waveguide core 102 are two different waveguide cores;

[0089] The projection position of the heating constant value resistor on the substrate layer 13 does not overlap with the projection position of the piezoelectric thin film material layer 32 on the substrate layer 13 .

[0090] In some optional embodiments, a portion of the surface of the first piezoelectric electrode 31 exposed by the first groove is a first pad;

[0091] A portion of the surface of the first piezoelectric electrode 31 exposed by the first groove is a second pad;

[0092] The surface of the thermo-optical electrode 23 exposed by the third groove is a third pad;

[0093] The first pad, the second pad and the third pad are suitable for connecting to an external power source.

[0094] In some optional embodiments, the material of the substrate layer 13 is silicon;

[0095] The material of the waveguide core 10 is Si3N4 or other waveguide materials; the material of the thermal oxide layer 12 is silicon dioxide; the waveguide core 10 can be selected from a variety of waveguide structures or composite waveguide structures in the prior art (such as a ridge waveguide, etc.); the materials of the first cladding 11, the second cladding 22 and the third cladding 34 are silicon dioxide;

[0096] The material of the heating fixed value resistor 21 is TiN; the material of the thermo-optical electrode 23 is AlCu;

[0097] The material of the piezoelectric film material layer 32 is aluminum nitride, lead zirconate titanate, hafnium oxide, zinc oxide or lithium niobate; the material of the first piezoelectric electrode 31 is Mo, AlCu, Au, Ag or Pt; the material of the second piezoelectric electrode 33 is Mo, AlCu, Au, Ag or Pt.

[0098] In some optional embodiments, the thickness of the substrate layer 13 is 500 μm to 800 μm, for example, 500 μm, 600 μm, 700 μm and 800 μm; the thickness of the thermal oxide layer 12 is 2 μm to 8 μm, for example, 2 μm, 4 μm, 5 μm, 6 μm and 8 μm; the thickness of the waveguide core 10 is 0.075 μm to 0.45 μm, for example, 0.075 μm, 0.1 μm, 0.2 μm, 0.3 μm and 0.45 μm; the thickness of the first cladding 11 is 0.5 μm to 2 μm, for example, 0.5 μm, 0.85 μm, 1.25 μm, 1.5 μm and 2 μm;

[0099] The thickness of the heating fixed value resistor 21 is 0.05 μm to 0.15 μm; the thickness of the thermo-optical electrode 23 is 0.5 μm to 1.5 μm, for example, 0.5 μm, 0.75 μm, 1 μm, 1.25 μm and 1.5 μm;

[0100] The thickness of the second cladding layer 22 is 0.5 μm to 1.5 μm, for example, 0.5 μm, 0.75 μm, 1 μm, 1.25 μm and 1.5 μm;

[0101] The thickness of the piezoelectric film material layer 32 is 0.8μm to 1.5μm, for example, 0.8μm, 1.1μm, 1.15μm, 1.3μm and 1.5μm; the thickness of the first piezoelectric electrode 31 is 0.1μm to 0.2μm, for example, 0.1μm, 0.12μm, 0.15μm, 0.18μm and 0.2μm; the thickness of the second piezoelectric electrode 33 is 0.1μm to 0.2μm, for example, 0.1μm, 0.12μm, 0.15μm, 0.18μm and 0.2μm.

[0102] In some optional embodiments, the driving voltage of the π phase shift of the piezoelectric-thermo-optical composite modulator is less than 10V; and the modulation speed is greater than 1 GHz.

[0103] The piezoelectric-thermo-optical composite modulator provided in this embodiment integrates a piezoelectric modulator and a thermo-optical modulator in the same structure, and can realize a hybrid modulation mode of piezoelectric modulation and thermo-optical modulation. The driving voltage of the π phase shift of the piezoelectric-thermo-optical composite modulator is less than 10V, and the modulation speed is greater than 1GHz. The π phase shift adjustment can be realized at a lower voltage, the modulation amplitude is increased, and the modulation speed is increased, thereby improving the modulation efficiency and reliability of the composite modulator, reducing the power consumption of the modulator, and increasing the application scenarios of the modulator.

[0104] like Figure 3 As shown, this embodiment provides a method for preparing a piezoelectric-thermo-optical composite modulator, and the preparation method includes but is not limited to steps S101 to S106.

[0105] Step S101 , providing a silicon photonic integrated circuit structure, a silicon photonic integrated circuit structure substrate layer 13 and a waveguide core 10 located on one side of the substrate layer 13 .

[0106] Step S102, forming a thermo-optical modulation structure on the side of the waveguide core 10 facing away from the substrate layer 13; the thermo-optical modulation structure includes a heating fixed value resistor 21 and a thermo-optical electrode 23; the position of the heating fixed value resistor 21 corresponds to the position of the waveguide core 10; the thermo-optical electrode 23 is connected to the heating fixed value resistor 21.

[0107] Step S103, forming a piezoelectric modulation structure on the side of the waveguide core 10 facing away from the substrate layer 13, the piezoelectric modulation structure includes a stacked first piezoelectric electrode 31, a piezoelectric film material layer 32 and a second piezoelectric electrode 33; the position of the piezoelectric film material layer 32 corresponds to the position of the waveguide core 10; the first piezoelectric electrode 31 also extends to the side of the piezoelectric film material layer 32.

[0108] Step S104 , forming a cladding layer, which covers the silicon photonic integrated circuit structure, the thermo-optical modulation structure and the piezoelectric modulation structure, and exposes the thermo-optical electrode 23 , a portion of the first piezoelectric electrode 31 and a portion of the second piezoelectric electrode 33 .

[0109] In some optional embodiments, the step of forming the cladding layer comprises:

[0110] After the step of providing the silicon photonic integrated circuit structure and before the step of forming the thermo-optical modulation structure, a first cladding layer 11 is formed on one side of the substrate layer 13; the first cladding layer 11 covers a surface of the waveguide core 10 facing away from the substrate layer 13 and a side surface of the waveguide core 10;

[0111] After the step of forming the first cladding layer 11 and before the step of forming the piezoelectric modulation structure, a second cladding layer 22 is formed on the surface of the first cladding layer 11 facing away from the substrate layer 13, and the second cladding layer 22 covers the heating fixed value resistor 21 and the thermo-optical electrode 23;

[0112] After the step of forming the piezoelectric modulation structure, a third cladding layer 34 is formed on the surface of the second cladding layer 22 facing away from the first cladding layer 11, and the third cladding layer 34 covers the surface and side surfaces of the first piezoelectric electrode 31, the piezoelectric film material layer 32 and the second piezoelectric electrode 33;

[0113] A first groove, a second groove and a third groove are formed on the side surface of the third cladding 34 facing away from the first cladding 11; the first groove exposes a portion of the surface of the first piezoelectric electrode 31; the second groove exposes a portion of the surface of the second piezoelectric electrode 33; the third groove penetrates the third cladding 34 and penetrates into the second cladding 22, exposing the side surface of the thermo-optical electrode 23 facing away from the substrate layer 13.

[0114] like Figure 4 As shown, this embodiment provides a specific schematic diagram of the process of preparing a piezoelectric-thermo-optical composite modulator, and the preparation method includes but is not limited to steps S201 to S206.

[0115] Step S201, providing a silicon photonic integrated circuit structure, the silicon photonic integrated circuit structure comprising a stacked substrate layer 13, a thermal oxide layer 12, a waveguide core 10, and a first cladding layer 11; the first cladding layer 11 covers a surface of the waveguide core 10 facing away from the substrate layer 13 and a side surface of the waveguide core 10, such as Figure 5 shown.

[0116] In a specific implementation, the material of the substrate layer 13 is silicon, the material of the waveguide core 10 is Si3N4 or TriPleX, the material of the thermal oxide layer 12 is silicon dioxide, and the material of the first cladding 11 is silicon dioxide; the thickness of the substrate layer 13 is 500μm to 800μm, the thickness of the thermal oxide layer 12 is 2μm to 8μm, and the thickness of the first cladding 11 is 0.5μm to 2μm.

[0117] Step S202, forming a thermo-optic modulation structure on the surface of the first cladding 11 facing away from the waveguide core 10; the thermo-optic modulation structure includes a heating fixed value resistor 21 and a thermo-optic electrode 23; the position of the heating fixed value resistor 21 corresponds to the position of the waveguide core 10; the thermo-optic electrode 23 is connected to the heating fixed value resistor 21, such as Figure 6 shown.

[0118] In a specific implementation, a heating fixed value resistor 21 and a thermo-optical electrode 23 on the side thereof are formed on the surface of the first cladding 11 corresponding to the thermo-optical modulation region of the waveguide core 10 and facing away from the waveguide core 10, and a specific morphology is obtained by patterning. The heating fixed value resistor 21 is located above the thermo-optical modulation region of the waveguide core 10 to form a thermo-optical modulation structure. The thermo-optical electrode 23 is located on the side of the heating fixed value resistor 21 and is electrically connected to the heating fixed value resistor 21.

[0119] The material of the heating fixed value resistor 21 is TiN, and the material of the thermo-optical electrode 23 is AlCu; the thickness of the heating fixed value resistor 21 is 0.05 μm to 0.15 μm, and the thickness of the thermo-optical electrode 23 is 0.5 μm to 1.5 μm.

[0120] Step S203, forming a second cladding layer 22 on the surface of the first cladding layer 11 facing away from the substrate layer 13, wherein the second cladding layer 22 covers the heating constant value resistor 21 and the thermo-optical electrode 23. Figure 6 shown.

[0121] In specific implementation, a second cladding layer 22 is deposited on the surface of the first cladding layer 11 facing away from the substrate layer 13. The material of the second cladding layer 22 is silicon dioxide, and the thickness of the second cladding layer 22 is 0.5 μm to 1.5 μm. The second cladding layer can cover and protect the thermo-optical modulation structure to improve the reliability of the modulator.

[0122] Step S204, forming a piezoelectric modulation structure on the surface of the second cladding 22 facing away from the waveguide core 10, the piezoelectric modulation structure includes a stacked first piezoelectric electrode 31, a piezoelectric film material layer 32, and a second piezoelectric electrode 33; the position of the piezoelectric film material layer 32 corresponds to the position of the waveguide core 10; the first piezoelectric electrode 31 also extends to the side of the piezoelectric film material layer 32, such as Figure 7 shown.

[0123] In a specific implementation, a stacked first piezoelectric electrode 31, a piezoelectric film material layer 32 and a second piezoelectric electrode 33 are formed on the surface of the second cladding 22 corresponding to the electro-optical modulation region of the waveguide core 10, which is away from the waveguide core 10. The first piezoelectric electrode 31, the piezoelectric film material layer 32 and the second piezoelectric electrode 33 are patterned and etched in turn to obtain a specific morphology, so that the piezoelectric film material layer 32 is above the electro-optical modulation region of the waveguide core 10, and the first piezoelectric electrode 31 also extends to the side of the piezoelectric film material layer 32, to form a piezoelectric modulation structure.

[0124] The material of the piezoelectric film material layer 32 is aluminum nitride or lead zirconate titanate; the material of the first piezoelectric electrode 31 is Mo, AlCu, Au, Ag or Pt; the material of the second piezoelectric electrode 33 is Mo, AlCu, Au, Ag or Pt. The material of the first piezoelectric electrode 31 and the material of the second piezoelectric electrode 33 can be the same or different.

[0125] Step S205, forming a third cladding layer 34 on the surface of the second cladding layer 22 facing away from the first cladding layer 11, the third cladding layer 34 covers the surface and side of the first piezoelectric electrode 31, the piezoelectric film material layer 32 and the second piezoelectric electrode 33, such as Figure 7 shown.

[0126] In specific implementation, a third cladding layer 34 is deposited on the surface of the second cladding layer 22 facing away from the first cladding layer 11. The material of the third cladding layer 34 is silicon dioxide, and the thickness of the third cladding layer 34 is 0.5 μm to 1.5 μm. The third cladding layer 34 can cover and protect the thermo-optical modulation structure to improve the reliability of the modulator.

[0127] Step S206, forming a first groove, a second groove and a third groove on the side surface of the third cladding layer 34 facing away from the first cladding layer 11; the first groove exposes a portion of the surface of the first piezoelectric electrode 31; the second groove exposes a portion of the surface of the second piezoelectric electrode 33; the third groove penetrates the third cladding layer 34 and penetrates into the second cladding layer 22, exposing a side surface of the thermo-optical electrode 23 facing away from the substrate layer 13, such as Figure 7 shown.

[0128] In specific implementation, the first groove, the second groove and the third groove are formed simultaneously by etching the third cladding 34 and the second cladding 22, respectively exposing a portion of the surface of the first piezoelectric electrode 31, a portion of the surface of the second piezoelectric electrode 33 and a side surface of the thermo-optical electrode 23 facing away from the substrate layer 13; the electrodes of the thermo-optical modulation structure and the piezoelectric modulation structure can be simultaneously led out, simplifying the process flow and improving the process efficiency.

[0129] The preparation method of the piezoelectric-thermo-optical composite modulator provided in this embodiment, on the one hand, the position of the heating fixed value resistor in the formed thermo-optical modulation structure corresponds to the position of the waveguide core, which can realize the modulation mode of thermo-optical modulation, and has the advantages of low driving voltage for realizing π phase shift, low power consumption, and compatibility with CMOS process; the position of the piezoelectric film material layer in the formed piezoelectric modulation structure corresponds to the position of the waveguide core, which can realize the modulation mode of piezoelectric modulation, high modulation speed, and low power consumption; on the other hand, the first groove, the second groove, and the third groove are formed at the same time, and the electrodes of the thermo-optical modulation structure and the piezoelectric modulation structure can be simultaneously led out, simplifying the process flow and improving the process efficiency. The preparation method of the piezoelectric-thermo-optical composite modulator provided in this embodiment, respectively forms a piezoelectric modulation structure and a thermo-optical modulation structure in different structural layers of the modulator, can realize a mixed modulation mode of piezoelectric modulation and thermo-optical modulation, can realize π phase shift adjustment at a lower voltage, increase the modulation amplitude, and improve the modulation speed, thereby improving the modulation efficiency and reliability of the composite modulator, reducing the power consumption of the modulator, and increasing the application scenarios of the modulator, and simultaneously leading out the electrodes of the thermo-optical modulation structure and the piezoelectric modulation structure, can simplify the process flow and improve the process efficiency.

[0130] In some optional embodiments, in the step of forming the first groove, the second groove and the third groove on the surface of the third cladding layer 34 facing away from the first cladding layer 11,

[0131] The surface of the first piezoelectric electrode 31 exposed by the first groove forms a first pad, the surface of the second piezoelectric electrode 33 exposed by the second groove forms a second pad, and the surface of the thermo-optical electrode 23 exposed by the third groove forms a third pad.

[0132] In a specific implementation, the first pad and the second pad forming the piezoelectric modulation structure, and the third pad of the thermo-optical modulation structure are exposed through the first groove, the second groove, and the third groove, respectively, and the electrodes of the thermo-optical modulation structure and the piezoelectric modulation structure can be led out at the same time, simplifying the process flow and improving the process efficiency. By connecting the external leads at the positions of the first pad, the second pad, and the third pad, the external circuit and the first piezoelectric electrode 31, the second piezoelectric electrode 33, and the thermo-optical electrode 23 can be connected to realize the driving and regulation of the thermo-optical modulator and the piezoelectric modulator, which can simplify the process flow and improve the process efficiency.

[0133] In the description of this specification, the description with reference to the terms "this embodiment", "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples, unless otherwise clearly and specifically defined. In addition, the terms "first" and "second" are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" can explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0134] In the above description, the technical details of the patterning and etching of each layer are not described in detail. However, those skilled in the art should understand that various technical means can be used to form layers, regions, etc. of desired shapes. In addition, in order to form the same structure, those skilled in the art can also design methods that are not completely the same as the methods described above. In addition, although the various embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage.

[0135] The above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described above, and that various obvious changes, readjustments, combinations and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention is described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may also include more other equivalent embodiments without departing from the concept of the present invention. The scope of protection of the present invention is determined by the scope of the attached claims.

Claims

1. A piezoelectric-thermo-optical composite modulator, characterized in that: include: A silicon photonic integrated circuit structure, comprising a substrate layer and a waveguide core located on one side of the substrate layer; A thermo-optical modulation structure is located on a side of the waveguide core facing away from the substrate layer; The thermo-optic modulation structure comprises a heating fixed value resistor and a thermo-optic electrode; The position of the heating fixed value resistor corresponds to the position of the waveguide core; The thermo-optical electrode is connected to the heating fixed value resistor; A piezoelectric modulation structure is located on a side of the waveguide core facing away from the substrate layer; The piezoelectric modulation structure comprises a stacked first piezoelectric electrode, a piezoelectric film material layer, and a second piezoelectric electrode; the position of the piezoelectric film material layer corresponds to the position of the waveguide core; the first piezoelectric electrode also extends to the side of the piezoelectric film material layer; A cladding layer covers the silicon photonic integrated circuit structure, the thermo-optical modulation structure and the piezoelectric modulation structure, and exposes the thermo-optical electrode, a portion of the first piezoelectric electrode and a portion of the second piezoelectric electrode.

2. The piezoelectric-thermo-optical composite modulator according to claim 1, characterized in that: The cladding includes a first cladding, a second cladding and a third cladding; A first cladding layer is located between the substrate layer and the thermo-optical modulation structure, and the first cladding layer covers a surface of the waveguide core that is away from the substrate layer and a side surface of the waveguide core; A second cladding layer is located on a surface of the first cladding layer facing away from the substrate layer; The second cladding layer covers the heating fixed value resistor and the thermo-optical electrode; A third groove is provided on the side of the second cladding layer facing away from the substrate layer; the third groove exposes the surface of the thermo-optical electrode facing away from the substrate layer; A third cladding layer is located on a surface of the second cladding layer facing away from the first cladding layer; The third cladding layer covers the side surfaces and partial surfaces of the first piezoelectric electrode, the piezoelectric film material layer and the second piezoelectric electrode; the surface of the third cladding layer has a first groove and a second groove; the first groove exposes a partial surface of the first piezoelectric electrode; The second groove exposes a portion of the surface of the second piezoelectric electrode; The third groove also penetrates the third cladding; The piezoelectric-thermo-optical composite modulator further includes a thermal oxide layer located between the substrate layer and the waveguide core.

3. The piezoelectric-thermo-optical composite modulator according to claim 1, characterized in that: The piezoelectric modulation structure is located on a side of the thermo-optical modulation structure facing away from the waveguide core; The projection position of the piezoelectric film material layer on the substrate layer and the projection position of the heating constant value resistor on the substrate layer cover the same area of ​​the same waveguide core on the substrate layer.

4. The piezoelectric-thermo-optical composite modulator according to claim 1, characterized in that: The waveguide core includes a first waveguide core and a second waveguide core; The thermo-optical modulation structure is located on a surface of the first waveguide core facing away from the substrate layer; the heating constant value resistor covers a portion of the projection position of the first waveguide core on the substrate layer at the projection position of the substrate layer; The piezoelectric modulation structure is located on a surface of the second waveguide core facing away from the substrate layer; The piezoelectric film material layer covers a portion of the projection position of the second waveguide core on the substrate layer at the projection position of the substrate layer.

5. The piezoelectric-thermo-optical composite modulator according to claim 4, characterized in that: The first waveguide core and the second waveguide core are different regions of the same waveguide core; The projection position of the heating constant value resistor on the substrate layer does not overlap with the projection position of the piezoelectric film material layer on the substrate layer.

6. The piezoelectric-thermo-optical composite modulator according to claim 2, characterized in that: The portion of the surface of the first piezoelectric electrode exposed by the first groove is a first pad; The portion of the surface of the first piezoelectric electrode exposed by the first groove is a second pad; The surface of the thermo-optical electrode exposed by the third groove is a third solder pad; The first pad, the second pad and the third pad are suitable for connecting to an external power source.

7. The piezoelectric-thermo-optical composite modulator according to claim 2, characterized in that: The material of the substrate layer is silicon; The material of the waveguide core is Si3N4; The material of the thermal oxygen layer is silicon dioxide; The materials of the first cladding layer, the second cladding layer and the third cladding layer are silicon dioxide; The material of the heating fixed value resistor is TiN; the material of the thermo-optical electrode is AlCu; The material of the piezoelectric film material layer is aluminum nitride, lead zirconate titanate, hafnium oxide, zinc oxide or lithium niobate; the material of the first piezoelectric electrode is Mo, AlCu, Au, Ag or Pt; the material of the second piezoelectric electrode is Mo, AlCu, Au, Ag or Pt.

8. The piezoelectric-thermo-optical composite modulator according to claim 2, characterized in that: The thickness of the substrate layer is 500 μm to 800 μm; the thickness of the thermal oxide layer is 2 μm to 8 μm; the thickness of the waveguide core is 0.075 μm to 0.45 μm; the thickness of the first cladding layer is 0.5 μm to 2 μm; The thickness of the heating fixed value resistor is 0.05 μm to 0.15 μm; the thickness of the thermo-optical electrode is 0.5 μm to 1.5 μm; The thickness of the second cladding layer is 0.5 μm to 1.5 μm; The thickness of the piezoelectric film material layer is 0.8 μm to 1.5 μm; the thickness of the first piezoelectric electrode is 0.1 μm to 0.2 μm; and the thickness of the second piezoelectric electrode is 0.1 μm to 0.2 μm.

9. The piezoelectric-thermo-optical composite modulator according to claim 1, characterized in that: The driving voltage of the π phase shift of the piezoelectric-thermo-optical composite modulator is less than 10V, and the modulation speed is greater than 1GHz.

10. A method for preparing a piezoelectric-thermo-optical composite modulator, characterized in that: include: A silicon photonic integrated circuit structure is provided, wherein the silicon photonic integrated circuit structure comprises a substrate layer and a waveguide core located on one side of the substrate layer; A thermo-optic modulation structure is formed on the side of the waveguide core facing away from the substrate layer; the thermo-optic modulation structure comprises a heating fixed value resistor and a thermo-optic electrode; The position of the heating fixed value resistor corresponds to the position of the waveguide core; The thermo-optical electrode is connected to the heating fixed value resistor; forming a piezoelectric modulation structure on a side of the waveguide core facing away from the substrate layer; The piezoelectric modulation structure comprises a stacked first piezoelectric electrode, a piezoelectric film material layer, and a second piezoelectric electrode; the position of the piezoelectric film material layer corresponds to the position of the waveguide core; the first piezoelectric electrode also extends to the side of the piezoelectric film material layer; A cladding layer is formed, wherein the cladding layer covers the silicon photonic integrated circuit structure, the thermo-optical modulation structure and the piezoelectric modulation structure, and exposes the thermo-optical electrode, a portion of the first piezoelectric electrode and a portion of the second piezoelectric electrode.

11. The method for preparing a piezoelectric-thermo-optical composite modulator according to claim 10, characterized in that: The step of forming the cladding layer comprises: After the step of providing the silicon photonic integrated circuit structure and before the step of forming the thermo-optical modulation structure, a first cladding layer is formed on one side of the substrate layer; the first cladding layer covers a surface of the waveguide core facing away from the substrate layer and a side surface of the waveguide core; After the step of forming the first cladding layer and before the step of forming the piezoelectric modulation structure, a second cladding layer is formed on a surface of the first cladding layer facing away from the substrate layer, wherein the second cladding layer covers the heating constant value resistor and the thermo-optical electrode; After the step of forming the piezoelectric modulation structure, a third cladding is formed on the surface of the second cladding facing away from the first cladding, wherein the third cladding covers the surface and side surfaces of the first piezoelectric electrode, the piezoelectric film material layer and the second piezoelectric electrode; A first groove, a second groove and a third groove are formed on the surface of the third cladding layer facing away from the first cladding layer; the first groove exposes a portion of the surface of the first piezoelectric electrode; the second groove exposes a portion of the surface of the second piezoelectric electrode; the third groove penetrates through the third cladding layer and penetrates into the second cladding layer, exposing the surface of the thermo-optical electrode facing away from the substrate layer.

12. The method for preparing a piezoelectric-thermo-optical composite modulator according to claim 11, characterized in that: In the step of forming the first groove, the second groove and the third groove on the surface of the third cladding layer facing away from the first cladding layer, The surface of the first piezoelectric electrode exposed by the first groove forms a first pad, the surface of the second piezoelectric electrode exposed by the second groove forms a second pad, and the surface of the thermo-optical electrode exposed by the third groove forms a third pad.

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