阅读说明：本技术 基于电光调制器及驱动电路的三维集成器件及方法 (Three-dimensional integrated device and method based on electro-optical modulator and driving circuit ) 是由 黄北举 张赞允 陈弘达 于 2021-09-13 设计创作，主要内容包括：本发明揭示了一种基于电光调制器及驱动电路的三维集成器件及方法,所述器件包括驱动电路结构、及集成于驱动电路结构上的电光调制器,所述电光调制器包括层叠设置于驱动电路结构上的隔离层、倒脊型波导结构、包层、及行波电极,所述倒脊型波导结构包括氮化硅层及位于氮化硅层上方的铌酸锂单晶薄膜,氮化硅层中形成有若干刻蚀区域,所述行波电极与驱动电路结构电气连接。本发明中驱动电路与电光调制器通过垂直三维集成和通孔的方式进行电气连接,可将驱动电路中的高频电信号传输到电光调制器的行波电极中,通过电光效应将高频信号加载到氮化硅/铌酸锂光波导的光波中,从而实现电信号到光信号的转换。(The invention discloses a three-dimensional integrated device and a method based on an electro-optical modulator and a driving circuit, wherein the device comprises a driving circuit structure and the electro-optical modulator integrated on the driving circuit structure, the electro-optical modulator comprises an isolation layer, an inverted ridge waveguide structure, a cladding and a traveling wave electrode which are stacked on the driving circuit structure, the inverted ridge waveguide structure comprises a silicon nitride layer and a lithium niobate single crystal film positioned above the silicon nitride layer, a plurality of etching areas are formed in the silicon nitride layer, and the traveling wave electrode is electrically connected with the driving circuit structure. The driving circuit and the electro-optical modulator are electrically connected in a vertical three-dimensional integration and through hole mode, a high-frequency electric signal in the driving circuit can be transmitted to a traveling wave electrode of the electro-optical modulator, and the high-frequency signal is loaded to an optical wave of the silicon nitride/lithium niobate optical waveguide through an electro-optical effect, so that the conversion from the electric signal to the optical signal is realized.)

1. The three-dimensional integrated device is characterized by comprising a driving circuit structure and the electro-optical modulator integrated on the driving circuit structure, wherein the electro-optical modulator comprises an isolation layer, an inverted ridge waveguide structure, a cladding and a traveling wave electrode which are arranged on the driving circuit structure in a stacked mode, the inverted ridge waveguide structure comprises a silicon nitride layer and a lithium niobate single crystal film located above the silicon nitride layer, a plurality of etching areas are formed in the silicon nitride layer, and the traveling wave electrode is electrically connected with the driving circuit structure.

2. The three-dimensional integrated device based on the electro-optic modulator and the driving circuit as claimed in claim 1, wherein a dielectric layer is filled in the etching region, and the dielectric layer is an air dielectric layer or a benzocyclobutene dielectric layer.

3. The electro-optic modulator and driving circuit based three-dimensional integrated device according to claim 1, wherein the driving circuit structure comprises a plurality of driving electrodes, and the traveling wave electrode in the electro-optic modulator is electrically connected with the driving electrodes in the driving circuit structure.

4. The electro-optic modulator and driving circuit based three-dimensional integrated device according to claim 3, wherein the driving electrode is located on the upper surface of the driving circuit structure, the traveling wave electrode is located on the upper surface of the electro-optic modulator, the electro-optic modulator further comprises a through hole penetrating through the isolation layer, the inverted ridge waveguide structure and the cladding layer, and a conductive pillar located in the through hole, and the traveling wave electrode is electrically connected with the driving electrode through the conductive pillar.

5. The electro-optic modulator and driver circuit based three-dimensional integrated device of claim 1, wherein the isolation layer is a silicon dioxide isolation layer; and/or, the cladding is a silica cladding; and/or the driving circuit structure is a CMOS driving circuit structure.

6. A three-dimensional integration method based on an electro-optical modulator and a driving circuit is characterized by comprising the following steps:

preparing a first epitaxial structure, providing a driving circuit structure, epitaxially growing an isolation layer and a silicon nitride layer on the driving circuit structure in sequence, and etching the silicon nitride layer in a partial region to form an etching region penetrating through the silicon nitride layer;

preparing a second epitaxial structure, providing a substrate, and sequentially epitaxially growing a cladding and a lithium niobate single crystal film on the substrate;

inversely bonding the second epitaxial structure on the first epitaxial structure based on a wafer bonding process;

removing the substrate in the second epitaxial structure;

a traveling wave electrode electrically connected to the driving circuit structure is formed on the cladding layer.

7. The method of claim 6, further comprising:

and filling a dielectric layer in the etching area, wherein the dielectric layer is an air dielectric layer or a benzocyclobutene dielectric layer.

8. The three-dimensional integration method based on the electro-optical modulator and the driving circuit as claimed in claim 6, wherein the driving circuit structure comprises a plurality of driving electrodes, and the traveling wave electrode in the electro-optical modulator is electrically connected with the driving electrodes in the driving circuit structure.

9. The method of claim 8, wherein the step of forming the traveling wave electrode on the cladding layer to be electrically connected to the driving circuit structure comprises:

etching the isolation layer, the inverted ridge waveguide structure and the cladding to form a through hole communicated with the driving electrode;

forming a conductive column electrically connected with the driving electrode in the through hole;

forming a traveling wave electrode on the cladding layer, the traveling wave electrode being electrically connected to the conductive post;

or, the "forming a traveling wave electrode electrically connected to the driving circuit structure on the cladding" is specifically:

etching the isolation layer, the inverted ridge waveguide structure and the cladding to form a through hole communicated with the driving electrode;

etching the cladding to form an electrode region;

forming a conductive column electrically connected with the driving electrode in the through hole;

a traveling wave electrode is formed in the electrode region of the cladding layer in electrical connection with the conductive post.

10. The electro-optic modulator and driver circuit based three dimensional integration method of claim 6, wherein the isolation layer is a silicon dioxide isolation layer; and/or, the cladding is a silica cladding; and/or the driving circuit structure is a CMOS driving circuit structure.

Technical Field

The invention belongs to the technical field of integrated circuits and optical communication, and particularly relates to a three-dimensional integrated device and a three-dimensional integrated method based on an electro-optical modulator and a driving circuit.

Background

Over the last half century, as integrated circuits have evolved, microelectronic processes have matured tremendously, and as process feature sizes have continued to shrink, the level of integration of integrated circuits has progressed rapidly in accordance with moore's law. The higher integration of the chip brings about not only an increase in the number of transistors but also an increase in the chip functionality and processing speed. However, as feature sizes continue to shrink and integration increases, the limitations of microelectronic processes become more apparent. On the one hand, due to the ever decreasing line widths of devices, the traditional photolithographic processing approaches are approaching the limit, and furthermore, as the device dimensions approach the nanometer scale, undesirable quantum physical effects are introduced, leading to device failure. On the other hand, as the sizes of the transistors and the size of the interconnection line are synchronously reduced, the delay and the power consumption of the single transistor are smaller and smaller, and the delay and the power consumption of the interconnection line are larger and gradually dominate. In today's processors, the power consumption caused by the electrical interconnects accounts for over 80% of the total power consumption of the entire chip. Thus, one can see the bottlenecks in electrical interconnect delay and power consumption at deep sub-micron feature sizes, which have severely limited further improvements in chip performance. On-chip interconnects are highly desirable for a faster and more broadband interconnection than electrical interconnects.

Compared with the microelectronic technology, the optical fiber communication technology starts later, but has a remarkable development speed. Optical fiber communication has the advantages of small optical fiber size, long service life, low transmission loss, small signal interference, strong electromagnetic interference resistance and the like, and therefore, the optical fiber communication has attracted attention. No doubt, the advantages of optical interconnection are obvious and widely applied and successful in long-distance communication, so that researchers can imagine whether optical interconnection can be introduced to chip-scale size to replace electrical interconnection, and along with research of people in recent decades, the communication mode has gradually transited from traditional electrical interconnection to optical interconnection, especially medium-short distance communication, and at present, although electrical interconnection is dominant, optical interconnection also occupies a part of market. The field in which optical interconnections are not currently involved is inter-chip and intra-chip communications. Compared with the two interconnection modes, the optical interconnection has obvious advantages, such as high bandwidth, electromagnetic interference resistance, small delay and the like, which are incomparable with the electrical interconnection line in the chip. Therefore, the research of photonic technology at the chip level is one of the current research hotspots.

In recent years, SOI materials have become an attractive platform for silicon photonics due to their strong optical confinement and transparency of silicon in the optical communication band, and have been developed rapidly. The advent of grating couplers, electro-optic modulators, photodetectors, wavelength division multiplexing/demultiplexing devices, etc., has promulgated the possibility of implementing chip-scale optical interconnection techniques. However, for the electro-optical modulator, the Pockels effect and Kerr effect of the silicon material are weak, and the existing silicon-based electro-optical modulator is mainly based on an SOI optical waveguide structure and utilizes the plasma dispersion effect to realize the silicon-based electro-optical modulation function. The plasma dispersion effect is a physical effect based on free carrier scattering and absorption, and free carriers in a doped region are injected or extracted through a specific electrical structure so as to cause the change of the refractive index of an optical waveguide region. In order to realize ultra-high-speed optical modulation, a mainstream silicon-based optical modulator usually adopts a PN junction phase shifter structure based on carrier depletion, and simultaneously adopts a micro-ring resonant cavity structure or a mach-zehnder interferometer structure to realize light intensity modulation. Through research and development in recent years, silicon-based electro-optical modulators make great progress in communication speed, insertion loss, power consumption and the like. However, the natural light absorption characteristics due to the plasma dispersion effect and the applied voltage cause signal distortion. In addition, because the plasma dispersion effect of silicon based on a carrier depletion mechanism is weak, a silicon-based mach-zehnder electro-optic modulator usually needs a larger phase shift arm length to achieve a sufficient modulation depth, and the larger phase shift length means a longer coplanar waveguide traveling wave electrode, so that the active transmission line structure of the modulator with the electrode microwave loss as the main bandwidth limitation faces a transmission bandwidth limit of about 60 GHz. Although the technical schemes of reducing PN junction series resistance by doping optimization, reducing driving capacitance by a single-drive push-pull structure, reducing electrode loss by adopting a copper electrode and a Ti/TiN/AlCu electrode material, reducing substrate microwave loss by a substrate removal technology and the like have been proved to be capable of effectively improving the microwave loss of a high-frequency downlink wave electrode, the technologies also have difficulty in fundamentally solving the problems of bandwidth bottleneck and performance compromise of the existing silicon-based electro-optical modulator.

In order to solve the problems, people comb the existing materials, and find that the lithium niobate material has a good linear Pockels effect and a good photorefractive performance and is a good phase shifter material at present, but because the lithium niobate material has a large volume relative to an optical waveguide structure, people process the lithium niobate material, and prepare the lithium niobate single crystal thin film material by means of ion implantation and direct bonding, and because the lithium niobate single crystal thin film material has good chemical stability and low toughness, the lithium niobate waveguide is difficult to etch. Therefore, the purpose of modulation is usually achieved by combining a lithium niobate single crystal thin film material with other optical waveguide materials. Compared with a silicon waveguide, the silicon nitride waveguide not only has the characteristics of ultralow loss, ultracompactness, CMOS process compatibility and the like, but also has the advantages that the silicon waveguide has better thermal stability, the refractive index is similar to that of a lithium niobate monocrystal film material and the like. Thus, silicon nitride waveguides are considered to be well suited for implementing hybrid electro-optic modulators with lithium niobate single crystal thin film materials. In addition, although silicon nitride is an excellent choice for passive optical devices, doping cannot be achieved, and thus the field of active devices is still blank. The silicon nitride waveguide and lithium niobate single crystal thin film material are adopted to realize mixed electro-optic modulation, which is significant to a silicon nitride-based optoelectronic integration scheme, and meanwhile, due to the characteristic of compatibility of the post-CMOS process of the silicon nitride waveguide, the development of the optoelectronic integration of the silicon nitride lithium niobate thin film material can provide an excellent technical scheme for silicon nitride optoelectronic three-dimensional integration.

The traditional hybrid integration mode is realized by a wire bonding and flip chip method, and the wire bonding can cause unnecessary electric signal loss and signal delay; flip chips require high alignment accuracy, high heat concentration, and high heat dissipation requirements.

Disclosure of Invention

In view of the above, the present invention provides a three-dimensional integrated device and method based on an electro-optical modulator and a driving circuit, which has high bandwidth, small parasitic effect and easy packaging.

In order to achieve the above object, an embodiment of the present invention provides the following technical solutions:

the device comprises a driving circuit structure and an electro-optical modulator integrated on the driving circuit structure, wherein the electro-optical modulator comprises an isolation layer, an inverted ridge waveguide structure, a cladding and a traveling wave electrode which are arranged on the driving circuit structure in a stacked mode, the inverted ridge waveguide structure comprises a silicon nitride layer and a lithium niobate single crystal film located above the silicon nitride layer, a plurality of etching areas are formed in the silicon nitride layer, and the traveling wave electrode is electrically connected with the driving circuit structure.

In one embodiment, a dielectric layer is filled in the etching region, and the dielectric layer is an air dielectric layer or a benzocyclobutene dielectric layer.

In one embodiment, the driving circuit structure comprises a plurality of driving electrodes, and the traveling wave electrode in the electro-optical modulator is electrically connected with the driving electrodes in the driving circuit structure.

In one embodiment, the driving electrode is located on the upper surface of the driving circuit structure, the traveling wave electrode is located on the upper surface of the electro-optical modulator, the electro-optical modulator further includes a through hole penetrating through the isolation layer, the inverted ridge waveguide structure and the cladding layer, and a conductive pillar located in the through hole, and the traveling wave electrode is electrically connected with the driving electrode through the conductive pillar.

In one embodiment, the isolation layer is a silicon dioxide isolation layer; and/or, the cladding is a silica cladding; and/or the driving circuit structure is a CMOS driving circuit structure.

The technical scheme provided by one embodiment of the invention is as follows:

a method of three-dimensional integration based on an electro-optic modulator and a driver circuit, the method comprising:

preparing a first epitaxial structure, providing a driving circuit structure, epitaxially growing an isolation layer and a silicon nitride layer on the driving circuit structure in sequence, and etching the silicon nitride layer in a partial region to form an etching region penetrating through the silicon nitride layer;

preparing a second epitaxial structure, providing a substrate, and sequentially epitaxially growing a cladding and a lithium niobate single crystal film on the substrate;

inversely bonding the second epitaxial structure on the first epitaxial structure based on a wafer bonding process;

removing the substrate in the second epitaxial structure;

a traveling wave electrode electrically connected to the driving circuit structure is formed on the cladding layer.

In one embodiment, the method further comprises:

and filling a dielectric layer in the etching area, wherein the dielectric layer is an air dielectric layer or a benzocyclobutene dielectric layer.

In one embodiment, the driving circuit structure comprises a plurality of driving electrodes, and the traveling wave electrode in the electro-optical modulator is electrically connected with the driving electrodes in the driving circuit structure.

In one embodiment, the "forming the traveling wave electrode electrically connected to the driving circuit structure on the cladding" includes:

etching the isolation layer, the inverted ridge waveguide structure and the cladding to form a through hole communicated with the driving electrode;

forming a conductive column electrically connected with the driving electrode in the through hole;

forming a traveling wave electrode on the cladding layer, the traveling wave electrode being electrically connected to the conductive post;

or, the "forming a traveling wave electrode electrically connected to the driving circuit structure on the cladding" is specifically:

etching the isolation layer, the inverted ridge waveguide structure and the cladding to form a through hole communicated with the driving electrode;

etching the cladding to form an electrode region;

forming a conductive column electrically connected with the driving electrode in the through hole;

a traveling wave electrode is formed in the electrode region of the cladding layer in electrical connection with the conductive post.

In one embodiment, the isolation layer is a silicon dioxide isolation layer; and/or, the cladding is a silica cladding; and/or the driving circuit structure is a CMOS driving circuit structure.

The invention has the following beneficial effects:

the driving circuit and the electro-optical modulator are electrically connected in a vertical three-dimensional integration and through hole mode, a high-frequency electric signal in the driving circuit can be transmitted to a traveling wave electrode of the electro-optical modulator, and the high-frequency signal is loaded to a light wave of the silicon nitride/lithium niobate optical waveguide through an electro-optical effect, so that the conversion from the electric signal to the optical signal is realized;

the invention is beneficial to integration, the isolation layer can control the height difference between the circuit and the optical path part, and the diffusion from the circuit heat source to the optical path part is reduced, thereby controlling the temperature variation amplitude of the optical path part and improving the communication quality.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present application, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a schematic structural diagram of a three-dimensional integrated device according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a silicon nitride/lithium niobate optical waveguide in an embodiment of the present invention;

FIG. 3 is a schematic flow chart of a three-dimensional integration method according to an embodiment of the invention;

fig. 4a to 4i are process flow diagrams of a three-dimensional integration method according to an embodiment of the invention.

Detailed Description

In order to make those skilled in the art better understand the technical solution of the present invention, the technical solution in the embodiment of the present invention will be clearly and completely described below with reference to the drawings in the embodiment of the present invention, and it is obvious that the described embodiment is only a part of the embodiment of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention discloses a three-dimensional integrated device based on an electro-optical modulator and a driving circuit, which comprises a driving circuit structure and the electro-optical modulator integrated on the driving circuit structure, wherein the electro-optical modulator comprises an isolation layer, an inverted ridge waveguide structure, a cladding and a traveling wave electrode which are arranged on the driving circuit structure in a laminated mode, the inverted ridge waveguide structure comprises a silicon nitride layer and a lithium niobate single crystal film positioned above the silicon nitride layer, a plurality of etching areas are formed in the silicon nitride layer, and the traveling wave electrode is electrically connected with the driving circuit structure.

The invention also discloses a three-dimensional integration method based on the electro-optical modulator and the driving circuit, which comprises the following steps:

preparing a first epitaxial structure, providing a driving circuit structure, epitaxially growing an isolation layer and a silicon nitride layer on the driving circuit structure in sequence, and etching the silicon nitride layer in a partial region to form an etching region penetrating through the silicon nitride layer;

preparing a second epitaxial structure, providing a substrate, and sequentially epitaxially growing a cladding and a lithium niobate single crystal film on the substrate;

inversely bonding the second epitaxial structure on the first epitaxial structure based on a wafer bonding process;

removing the substrate in the second epitaxial structure;

a traveling wave electrode electrically connected to the driving circuit structure is formed on the cladding layer.

The three-dimensional integrated device and method of the present invention are further described with reference to the following embodiments.

Referring to fig. 1 and 2, a three-dimensional integrated device according to an embodiment of the invention includes a driving circuit structure 100 and an electro-optic modulator 200 integrated on the driving circuit structure.

The driving circuit structure 100 is a CMOS driving circuit structure, which uses a silicon substrate and has a plurality of driving electrodes 101 on its upper surface.

The electro-optical modulator 200 comprises an isolation layer 201, an inverted ridge waveguide structure, a cladding 204 and a traveling wave electrode 205 which are stacked on a driving circuit structure, wherein the inverted ridge waveguide structure comprises a silicon nitride layer 202 and a lithium niobate single crystal thin film 203 positioned above the silicon nitride layer, a plurality of etching regions 2021 are formed in the silicon nitride layer 202, and the traveling wave electrode 205 is electrically connected with the driving electrode 101 in the driving circuit structure.

The etching region in this embodiment is filled with a dielectric layer, preferably, the dielectric layer in this embodiment is an air dielectric layer, and in other embodiments, the dielectric layer may also be a benzocyclobutene dielectric layer.

Preferably, the isolation layer in this embodiment is a silica isolation layer, and the cladding layer is a silica cladding layer.

Further, the electro-optic modulator 200 further includes a through hole penetrating through the isolation layer, the inverted ridge waveguide structure and the cladding, and a conductive pillar 206 located in the through hole, an electrode region is formed on the cladding by etching, the traveling wave electrode 205 is formed in the electrode region, and the traveling wave electrode 205 is electrically connected to the driving electrode 101 through the conductive pillar 206.

Because the lithium niobate single crystal film has good linear Pockels effect, low loss and similar refractive index to silicon nitride material, the invention designs an inverted ridge waveguide structure with silicon nitride below the lithium niobate single crystal film and above the lithium niobate single crystal film to realize the function of optical phase modulation, and the waveguide structure has the advantages of low loss and high mode field limiting factor.

Referring to fig. 3, the three-dimensional integration method based on the electro-optic modulator and the driving circuit in the present embodiment includes:

preparing a first epitaxial structure, providing a driving circuit structure, epitaxially growing an isolation layer and a silicon nitride layer on the driving circuit structure in sequence, and etching the silicon nitride layer in a partial region to form an etching region penetrating through the silicon nitride layer;

preparing a second epitaxial structure, providing a substrate, and sequentially epitaxially growing a cladding and a lithium niobate single crystal film on the substrate;

inversely bonding the second epitaxial structure on the first epitaxial structure based on a wafer bonding process;

removing the substrate in the second epitaxial structure;

a traveling wave electrode electrically connected to the driving circuit structure is formed on the cladding layer.

Specifically, the three-dimensional integration method in this embodiment specifically includes the following steps:

1. first, a first epitaxial structure is prepared.

Referring to fig. 4a, first, a matched driving circuit structure 100 is provided, in which the driving circuit structure 100 in this embodiment is a CMOS driving circuit structure, the CMOS driving circuit structure uses a silicon substrate, and a plurality of driving electrodes 101 are disposed on an upper surface of the CMOS driving circuit structure.

Referring to fig. 4b, an isolation layer 201 is epitaxially grown on the CMOS driving circuit structure 100, and the isolation layer 201 in this embodiment is a silicon dioxide isolation layer. The isolation layer is used for realizing photoelectric layering and isolating heat generated by the circuit from heat generated by the optical path, and reducing the influence of temperature on the phase of light.

Referring to fig. 4c and 4d, a silicon nitride layer 202 is epitaxially grown on the isolation layer 201, and the silicon nitride layer is etched in a partial region to form an etched region 2021 penetrating the silicon nitride layer. The silicon nitride layer 202 is capable of forming an optical waveguide required for light transmission.

Further, the etching region is filled with an air dielectric layer in this embodiment, and other dielectric layers may be filled in other embodiments.

2. And then a second epitaxial structure is prepared.

Referring to fig. 4e, a substrate 207 is provided, and a clad layer 204 and a lithium niobate single crystal thin film 203 are epitaxially grown in this order on the substrate 207. In this embodiment, the cladding 204 is a silica cladding, and the preparation of the lithium niobate single crystal thin film belongs to the prior art, and is not described herein again.

3. And bonding the first epitaxial structure and the second epitaxial structure.

Referring to fig. 4f, based on the wafer bonding process, the second epitaxial structure is bonded upside down to the first epitaxial structure, so as to form an inverted ridge waveguide structure with the lithium niobate single crystal thin film on the upper side and the silica cladding on the lower side, and an optical signal is transmitted in the hybrid waveguide.

4. Referring to fig. 4g, the substrate in the second epitaxial structure is removed to facilitate the subsequent processes.

5. Finally, a traveling wave electrode electrically connected to the driving circuit structure is formed on the cladding layer.

First, referring to fig. 4h, the isolation layer, the inverted ridge waveguide structure and the cladding layer are etched until the CMOS driving circuit structure at the bottom layer forms a through hole 2061 communicating with the driving electrode; the cladding is etched again to form an electrode region 2051;

then, as shown in fig. 4i, metal is deposited in the through holes 2061 to form conductive posts 206 electrically connected to the driving electrodes; and metal is deposited within the electrode region 2051 of the cladding to form traveling wave electrode 205 electrically connected to conductive post 206, traveling wave electrode 205 being electrically connected to drive electrode 101 through conductive post 206.

The conductive column 206 and the traveling wave electrode 205 are arranged, so that high-frequency electric signals of the bottom layer CMOS driving circuit structure can be transmitted to the upper layer traveling wave electrode 205.

Of course, in other embodiments, only the via may be etched, and the electrode region may not be etched, and the traveling-wave electrode 205 may be formed directly on the cladding layer.

In this embodiment, a high-frequency electrical signal is transmitted to the traveling wave electrode on the upper layer in a through hole electrode manner through the CMOS driving circuit structure, and since the lithium niobate single crystal thin film has a good linear Pockels effect, the phase of light in the silicon nitride/lithium niobate optical waveguide is changed by the change of the electric field of the high-frequency electrical signal, so that the conversion from the electrical signal to the optical signal is realized, and the electro-optical modulation is completed.

According to the technical scheme, the invention has the following advantages:

the driving circuit and the electro-optical modulator are electrically connected in a vertical three-dimensional integration and through hole mode, a high-frequency electric signal in the driving circuit can be transmitted to a traveling wave electrode of the electro-optical modulator, and the high-frequency signal is loaded to a light wave of the silicon nitride/lithium niobate optical waveguide through an electro-optical effect, so that the conversion from the electric signal to the optical signal is realized;

the invention is beneficial to integration, the isolation layer can control the height difference between the circuit and the optical path part, and the diffusion from the circuit heat source to the optical path part is reduced, thereby controlling the temperature variation amplitude of the optical path part and improving the communication quality.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.