WO2024066678A1

WO2024066678A1 - Modulator chip and modulation device comprising same

Info

Publication number: WO2024066678A1
Application number: PCT/CN2023/107729
Authority: WO
Inventors: 杨旻岳; 沈百林; 邵永波; 赵慧; 李蒙; 张琦
Original assignee: 中兴光电子技术有限公司
Priority date: 2022-09-29
Filing date: 2023-07-17
Publication date: 2024-04-04
Also published as: CN117826456A

Abstract

A modulator chip and a modulation device comprising same. The modulator chip sequentially comprises, from top to bottom, a protective layer (100), an electrode layer (200) and a waveguide layer (300). The waveguide layer (300) comprises a flat board layer (310) and a protrusion layer (320), which are connected to each other, and the protrusion layer (320) is fixed to the electrode layer (200) by means of the flat board layer (310). The electrode layer (200) is provided with a first electrode group (210) and second electrode groups (220), which match with the protrusion layer (320), wherein the first electrode group (210) is correspondingly arranged above the protrusion layer (320), and the first electrode group (210) extends in a direction approaching the protrusion layer (320); and the second electrode groups (220) are correspondingly arranged on two sides of the protrusion layer (320).

Description

Modulator chip and modulation device thereof

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on the Chinese patent application with application number 202211198720.4 and application date September 29, 2022, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is hereby introduced into this application as a reference.

Technical Field

The present application relates to the technical field of optical communication devices, and in particular to a modulator chip and a modulation device thereof.

Background technique

The modulator is a structure that converts electrical signals into optical signals. It is the core functional unit of the optical communication transmission component. Its performance indicators generally include insertion loss, efficiency and bandwidth. The thin-film lithium niobate modulator uses the electro-optic effect for phase modulation. Compared with the silicon optical modulator, its bandwidth performance is stronger and it is widely used in the field of optical communications. However, due to the high dielectric constant of lithium niobate material, the electric field entering the material from the normal direction through the side wall of the waveguide is small; at the same time, the refractive index difference of the optical waveguide of lithium niobate material is not large, and the waveguide mode field is not small. In order to prevent the metal electrode from causing waveguide light absorption, the electrode cannot be too close to the waveguide. These factors lead to the height of the lithium niobate waveguide of the modulator generally being selected at 600nm to maintain the working efficiency of the modulator, and the metal electrode is kept at a certain distance from the waveguide. Therefore, thicker waveguides, inclined sidewalls and waveguide spacing that is difficult to reduce make thin-film lithium niobate couplers (Directional Coupler, DC), adiabatic couplers (Adiabatic Directional Coupler, ADC) and polarization rotation combiners (Polarization Revolve Combiner, PRC) structures difficult to manufacture or have poor performance; in addition, related modulators can only use multi-mode interferometers for 2*2 combining and splitting, and cannot guarantee that their working range covers the C+L wide band.

Summary of the invention

The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

The embodiments of the present application provide a modulator chip and a modulation device thereof.

In the first aspect, an embodiment of the present invention provides a modulator chip, which comprises, from top to bottom, a protective layer, an electrode layer and a waveguide layer; the electrode layer and the waveguide layer are fixed in the protective layer; the waveguide layer comprises a flat layer and a protruding layer connected to each other, and the protruding layer is fixed on the electrode layer through the flat layer; the electrode layer is provided with a first electrode group and a second electrode group that cooperate with the protruding layer; the first electrode group is correspondingly arranged above the protruding layer, and the first electrode group extends in a direction close to the protruding layer; the second electrode group is correspondingly arranged on both sides of the protruding layer.

In a second aspect, an embodiment of the present application provides a modulation device, comprising the modulator chip as described above.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a cross-sectional view of a modulator chip in the related art;

FIG2 is a cross-sectional view of a modulator chip provided in an embodiment of the present application;

FIG3 is a cross-sectional view of a modulator chip provided in another embodiment of the present application;

FIG4 is a schematic diagram of the electric field line distribution of the electrode layer in FIG2;

FIG5 is a structural diagram of a modulation device provided in an embodiment of the present application;

FIG6 is a cross-sectional view of the modulator chip in FIG5 ;

FIG7 is a structural diagram of a modulation device provided by another embodiment of the present application;

FIG8 is a cross-sectional view of the modulator chip in FIG7.

Detailed ways

In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the embodiments described herein are only used to explain the present application and are not used to limit the present application.

It should be understood that in the description of the embodiments of the present application, if there is a description of "first", "second", etc., it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or implicitly indicating the order of the indicated technical features. "At least one" means one or more, and "multiple" means two or more. "And/or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and/or B can represent the situation where A exists alone, A and B exist at the same time, and B exists alone. Wherein A and B can be singular or plural. The character "/" generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b and c can represent: a, b, c, a and b, a and c, b and c or a and b and c, where a, b, c can be single or multiple.

In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

The modulator chip and modulation device involved in the embodiments of the present application work by utilizing the electro-optical effect of the change in the refractive index of the crystal material under the action of an external electric field. According to the difference between the direction of the electric field applied to the crystal and the direction of the light beam propagating in the crystal, it can be divided into longitudinal modulation and transverse modulation. When the direction of the electric field is parallel to the direction of light propagation, it is called longitudinal electro-optical modulation; when the direction of the electric field is perpendicular to the direction of light propagation, it is called transverse electro-optical modulation. The advantages of transverse electro-optical modulation are low half-wave voltage, low driving power, and wide application. Among them, lithium niobate is an inorganic substance with the chemical formula LiNbO _3. It is a negative crystal and ferroelectric crystal. The polarized lithium niobate crystal has piezoelectric, ferroelectric, optoelectronic, nonlinear optical, thermoelectric and other multi-performance materials, and also has a photorefractive effect. Therefore, the modulator chip using lithium niobate as the waveguide material has a strong bandwidth performance and is widely used in the field of optical communications.

However, due to the high dielectric constant of lithium niobate material, the electric field entering the material from the normal direction through the waveguide side wall is small; at the same time, the refractive index difference of the optical waveguide of lithium niobate material is not large, and the waveguide mode field is not small. In order to prevent the metal electrode from causing waveguide light absorption, the electrode cannot be too close to the lithium niobate waveguide. These factors make it difficult to control the height of the lithium niobate waveguide, and cause the on-chip modulator to have poor compatibility with high-performance 2*2 adiabatic couplers, polarization beam splitters, etc., affecting the modulation performance and working efficiency of the modulation equipment.

In order to control the thickness of the waveguide and improve the applicability and compatibility of the modulator chip, in the related art, the modulator chip adopts a double-layer waveguide layer 300 as shown in FIG1. However, the structure currently has the following problems: the electrode layer 200 can only be set on both sides of the waveguide layer 300, and the distance between the electrode layer 200 and the waveguide layer 300 cannot be effectively controlled. Under the premise of ensuring that the electrode layer 200 applies an electric field strength to the waveguide layer 300, the height of the waveguide layer 200 is increased, and it is difficult to solve the problem of poor compatibility between the modulator in the chip and the high-performance coupler.

Based on the above, the embodiment of the present application provides a modulator chip and a modulation device thereof. By setting an electrode layer and a waveguide layer, the first electrode group and the second electrode group can apply an electric field to the flat layer and the convex layer from different angles, which can increase the electric field in the waveguide layer. The field strength can effectively control the distance between the electrode layer and the waveguide layer, increase the electric field strength in the waveguide layer, reduce the optical loss of the modulator chip, optimize the modulation efficiency, and effectively control the thickness of the waveguide layer, thereby improving the applicability and compatibility of the modulator chip, thereby effectively solving the problem of poor compatibility between the modulator in the chip and the high-performance coupler.

Please refer to Figures 2 and 3, which show cross-sectional views of a modulator chip provided in an embodiment of the present application. As shown in Figures 2 and 3, the modulator chip in the embodiment of the present application includes a protective layer 100, an electrode layer 200, and a waveguide layer 300 from top to bottom; the electrode layer 200 and the waveguide layer 300 are fixed in the protective layer 100; the waveguide layer 300 includes a flat layer 310 and a protrusion layer 320 connected to each other, and the protrusion layer 320 is fixed on the electrode layer 200 through the flat layer 310; the electrode layer 200 is provided with a first electrode group 210 and a second electrode group 220 that match the protrusion layer 320; the first electrode group 210 is correspondingly arranged above the protrusion layer 320, and the first electrode group 210 extends in a direction close to the protrusion layer 320; the second electrode group 220 is correspondingly arranged on both sides of the protrusion layer 320.

It can be understood that the waveguide layer 300 and the electrode layer 200 are both arranged in multiple layers, so that the first electrode group 210 and the second electrode group 220 surround the flat layer 310 and the protrusion layer 320 from different angles, and the electric field strength in the waveguide layer 300 can be increased while ensuring the distance between the waveguide layer 300 and the electrode layer 200, thereby reducing the optical loss caused by the electrode layer 200 to the waveguide layer 300, and optimizing the modulation efficiency of the modulator chip, so that when the thickness of the waveguide layer 300 is reduced, the modulation effect and working efficiency of the modulation chip with a waveguide layer 300 of 600 nm thickness can be achieved.

In another embodiment of the present application, the cross-sectional area of the flat layer 310 is greater than the cross-sectional area of the protrusion layer 320 .

It is understandable that the cross-sectional area of the planar layer 310 is greater than the cross-sectional area of the raised layer 320, and the raised layer 320 and the planar layer 310 form a ridge waveguide structure. The width of the raised layer 320 can be adjusted according to the requirements of the modulation device. In practical applications, the width of the raised layer 320 can be controlled between 1 μm and 3 μm to meet different application requirements. Among them, the ridge waveguide structure itself can be used as a direct functional device, such as an electro-optic modulator, a nonlinear frequency converter, and a connector between functional devices, etc., and can also be used to construct other devices such as a microring resonator through spatial rotation.

In another embodiment of the present application, the thickness of the planar layer 310 is 40% to 60% of the thickness of the waveguide layer 300 .

It can be understood that the thickness of the flat layer 310 is 40% to 60% of the thickness of the waveguide layer 300, which can effectively ensure the thickness of the protrusion layer 320 and the photoelectric effect generated by the waveguide layer 300. At the same time, the thickness ratio of the flat layer 310 and the protrusion layer 320 can be flexibly adjusted according to application requirements to improve the compatibility of the modulation chip.

In another embodiment of the present application, the thickness of the waveguide layer 300 is between 300 nm and 500 nm.

It can be understood that, since the first electrode group 210 and the second electrode group 220 can apply electric fields to the flat layer 310 and the protruding layer 320 from different angles, the electric field strength in the waveguide layer 300 can be increased, and the distance between the electrode layer 200 and the waveguide layer 300 can be effectively controlled. Therefore, under the premise of ensuring the modulation efficiency of the modulation chip, the thickness of the waveguide layer 300 can be significantly reduced, and the modulation efficiency and bandwidth degradation control effect of the waveguide layer 300 with a thickness of 600nm in the related art can be achieved, thereby improving the compatibility of the modulation chip.

In another embodiment of the present application, the waveguide layer 300 is made of thin film lithium niobate.

It is understandable that lithium niobate is an inorganic substance, a negative crystal, a ferroelectric crystal. The polarized lithium niobate crystal has multiple properties such as piezoelectricity, ferroelectricity, photoelectricity, nonlinear optics, and thermoelectricity, and also has a photorefractive effect. Therefore, lithium niobate crystal is one of the most widely used new inorganic materials. It is a good piezoelectric transducer material, ferroelectric material, and electro-optical material. Lithium niobate, as an electro-optical material, plays a role in light modulation in optical communications. Its single crystal is an important material for optical waveguides, mobile phones, piezoelectric sensors, optical modulators, and various other linear and nonlinear optical applications. With the improvement and perfection of the processing technology of thin-film lithium niobate, many types of lithium niobate waveguides and process implementation methods have emerged, and the transmission loss is gradually decreasing. Therefore, the waveguide layer 300 is made of thin-film lithium niobate with mature process support to ensure the modulation effect of the waveguide layer 300. fruit.

In another embodiment of the present application, the protection layer 100 includes a lower cladding layer 110 and a cover layer 120 ; the electrode layer 200 and the waveguide layer 300 are fixed between the lower cladding layer 110 and the cover layer 120 .

It can be understood that the lower cladding layer 110 and the cover layer 120 wrap the electrode layer 200 and the waveguide layer 300, which can effectively ensure the distance between the electrode layer 200 and the waveguide layer 300, improve the stability between the electrode layer 200 and the waveguide layer 300, and ensure the service life of the modulation chip. In addition, the lower cladding layer 110 can stably support the electrode layer 200 and the waveguide layer 300 to prevent the electrode layer 200 and the waveguide layer 300 from deformation and damage.

In another embodiment of the present application, the lower cladding layer 110 and the cover layer 120 are both made of silicon oxide.

It is understandable that the chemical properties of silicon oxide are relatively stable and do not react with water. In addition, silicon oxide has high fire resistance, high temperature resistance, small thermal expansion coefficient, high insulation, corrosion resistance, piezoelectric effect, resonance effect and its unique optical properties. The cover layer 120 can effectively maintain the insulation performance between the electrode layers 200, thereby ensuring the electric field strength applied by the electrode layer 200 to the waveguide layer 300, and improving the working stability of the modulation chip.

Please refer to Figure 3, which shows a cross-sectional view of a modulator chip provided in an embodiment of the present application. As shown in Figure 3, a third electrode group 230 is further provided below the second electrode group 220 of the embodiment of the present application; and both ends of the flat layer 310 are fixed in the third electrode group 230.

It can be understood that the electrode layer 200 is fixedly connected to the flat layer 310 through the third electrode group 230, which ensures the connection stability between the electrode layer 200 and the waveguide layer 300, improves the integrity of the modulation chip, and avoids displacement between the electrode layer 200 and the waveguide layer 300, which affects the performance of the modulation chip.

It is understandable that, as shown in FIG3 , in practical applications, a fourth electrode group 240 can be provided below the flat layer 310 as required, which can effectively increase the electric field strength of the electrode layer 200 acting on the waveguide layer 300. Under the premise of the same modulation requirement, the potential difference between the electrode layers 200 is effectively reduced, the power consumption of the modulation chip is reduced, and the modulation efficiency of the modulation chip is improved. At the same time, the fourth electrode group 240 also ensures the connection stability between the electrode layer 200 and the protective layer 100.

In some embodiments, the third electrode group 230 and the fourth electrode group 240 are configured to fix and connect the flat layer 310 and the protective layer 100, and in order to ensure the integrity of the modulation chip, the shapes are matched with the shape of the waveguide layer 300. The shapes of the first electrode group 210 and the second electrode group 220 on the side close to the waveguide layer 300 can be flexibly set, including but not limited to circular, elliptical and rectangular as shown in FIG. 3 .

In another embodiment of the present application, the distance between the first electrode groups 210 is greater than or equal to 3 μm, and the distance between the second electrode groups 220 is greater than or equal to 5 μm.

It can be understood that, since the first electrode group 210 and the second electrode group 220 are located above the flat layer 310, the first electrode group 210 can extend inwardly in the direction close to the protruding layer 320, and the distance between the second electrode groups 220 can also be smaller than the width of the flat layer 310. Therefore, the distance between the first electrode groups 210 can reach 3 μm, and the distance between the second electrode groups 220 can reach 5 μm. Since the first electrode group 210 and the second electrode group 220 surround the flat layer 310 and the protruding layer 320 from different angles, the electric field strength in the waveguide layer 300 can be increased while ensuring the distance between the waveguide layer 300 and the electrode layer 200, and the distance between the electrode layers 200 is effectively shortened.

In practical applications, for ridge-type waveguides and linear waveguides, the position and shape of the waveguides are first defined using electron beam lithography or optical lithography, and then ion beam milling, reactive ion etching (RIE), inductively coupled plasma etching (ICP-RIE), wet etching, or crystal ion slicing are used to complete the waveguide fabrication. For channel-type waveguides, after the etching step, an additional silicon dioxide layer needs to be deposited to make the top of the silicon dioxide contact with the lithium niobate waveguide. The top of the guide is flush. For proton exchange optical waveguides, lithium niobate needs to be immersed in a high-temperature acidic solution for proton exchange to form proton exchange lithium niobate. The completed lithium niobate optical waveguide can be used as a device after simple silicon dioxide coating and electrode metal evaporation. The silicon dioxide coating is grown by plasma enhanced chemical vapor deposition (PECVD), chemical vapor deposition (CVD) or physical vapor deposition (PVD). The modulator chips provided in this embodiment can be processed and formed by relevant production technologies. It only needs to adjust the positional relationship between the first electrode group 210, the second electrode group 220 and the covering layer 120. There is no need for large-scale transformation and upgrading of production equipment and production processes, which reduces the processing difficulty and production cost of the modulator chip.

It is understandable that in practical applications, silicon-based electro-optic modulators are currently commonly based on carrier dispersion effects to achieve modulation functions. According to the optical structure, they can be mainly divided into Mach-Zehnder interference modulators (MZI) and micro-ring resonant (MRR) modulators. The working principle of the MZI modulator is that when a beam of light is coupled into the incident waveguide, the incident light is divided into two parts by an optical beam splitter, and enters the upper and lower modulation arms respectively. After a certain distance, it is output through the optical beam combiner, and the light fields of the upper and lower arms are superimposed. When the refractive index or length of one of the arms is changed, the phase difference between the two arms changes accordingly, and the output light field changes through the coherent superposition between the two arms; while the working principle of the MRR modulator is to change the refractive index of the waveguide through different electrical structures so as to achieve the change of the spectrum. Although the MRR modulator has the advantages of high modulation rate and small size, this type of modulator needs to make a compromise between energy efficiency and optical bandwidth, and is greatly affected by process errors and environmental factors. MZI has good process tolerance and stability, so the mainstream in the market is MZI electro-optical modulator. However, this type of modulator is large in size, so reducing the size of MZI modulator, improving modulation efficiency and high-frequency performance of the device are the core of the development of this type of modulator.

Please refer to Figures 5 and 7, which show a modulation device provided by an embodiment of the present application, including the modulator chip as described above. Among them, Figure 5 is an MZI modulator using the modulator chip of the embodiment of the present application, and Figure 7 is an MRR modulator using the modulator chip of the embodiment of the present application.

It can be understood that the modulator chip of the embodiment of the present application is suitable for the thin-film lithium niobate modulation device in the x-direction, please refer to Figure 4, which shows a schematic diagram of the electric field line distribution of the electrode layer 200 provided in the embodiment of the present application. As shown in Figure 4, in order to make the electric field direction along the z-axis direction, the electrode layer 200 of the modulation device is located on the left and right sides of the waveguide layer 300, rather than being arranged directly above and below the waveguide layer 300.

In some embodiments, as shown in FIG. 5 and FIG. 6 , in the mzi modulator using the modulator chip of the embodiment of the present application, the middle of the waveguide arms is a signal S electrode, and the two sides are reference ground G electrodes. The light combining and splitting device of the mzi modulator uses an adiabatic coupler, and the adiabatic coupler can ensure that the loss in the C+L band is maintained at a level less than 0.2dB, and the splitting ratio is 50:50. In some embodiments, during the manufacture of the modulator chip, the electrode layer 200 is etched by the waveguide layer 300 and the lower cladding layer 110 is deposited and etched to form a structure as shown in FIG. 6 near the waveguide layer 300. Exemplarily, the total thickness of the waveguide layer 300 is 350 nm, of which the thickness of the planar layer 310 is 170 nm and the width of the raised layer 320 is 2 μm; then the electrode layer 200 is manufactured, with the goal of forming the fourth electrode group 240, the third electrode group 230, the second electrode group 220 and the first electrode group 210, which are deposited on both sides of the waveguide layer 300 as shown in FIG. 6, from a position below the planar layer 310 to a position above the raised layer 320. The third electrode group 230, the second electrode group 220 and the first electrode group 210 are sequentially used.

During the operation of the MZI modulator, when there is a voltage difference between the electrode layers 200, the electric field lines formed between the two electrode layers 200 partially pass through the protrusion layer 320 and the flat layer 310 of the waveguide layer 300, and the refractive index of the lithium niobate material is changed through the electro-optical effect, thereby modulating the phase of one arm of the Mach-Zehnder interferometer. Compared with the modulator in which only the left and right electrodes are placed on the waveguide layer 300 of FIG. 1, the efficiency of the MZI modulator of the embodiment of the present application is improved by 27%.

In some embodiments, as shown in FIG. 7 and FIG. 8 , in the mrr modulator using the modulator chip of the present invention, the signal S and the reference ground G electrodes on both sides of the waveguide layer 300 have the same orientation. The thickness of the waveguide layer 300 is 400 nm, and the slab layer The thickness of 310 is 200nm. During the manufacturing process of the modulator chip, the electrode layer 200 forms a structure as shown in FIG8 near the waveguide layer 300 through etching of the waveguide layer 300 and deposition and etching of the lower cladding layer 110; and then the electrode layer 200 is manufactured, the goal is to form the third electrode group 230, the second electrode group 220 and the first electrode group 210 deposited on both sides of the waveguide layer 300 from the flat layer 310 to the position higher than the raised layer 320 as shown in FIG8. Among them, the width of the raised layer 320 in the ring of the MRR modulator is 1μm, and the width of the straight waveguide on the left side gradually changes from 2μm to 1.4μm in the coupling zone, forming an adiabatic coupler or a semi-adiabatic coupler to reduce the wavelength dependence of the splitting ratio of the coupler and increase the available wavelength range.

During the operation of the MRR modulator, when there is a voltage difference between the electrode layers 200, the electric field lines formed between the two electrode layers 200 partially pass through the protrusion layer 320 and the flat layer 310 of the waveguide layer 300, and change the refractive index of the lithium niobate material through the electro-optical effect, thereby modulating the resonant wavelength of the ring resonator.

In the embodiment of the present application, by setting an electrode layer and a waveguide layer, the first electrode group and the second electrode group can apply an electric field to the flat layer and the protrusion layer from different angles, which can increase the electric field strength in the waveguide layer, effectively control the distance between the electrode layer and the waveguide layer, increase the electric field strength in the waveguide layer, reduce the optical loss of the modulator chip, optimize the modulation efficiency, and effectively control the thickness of the waveguide layer, thereby improving the applicability and compatibility of the modulator chip.

The above described embodiments are merely illustrative, and the units described as separate components may or may not be physically separated, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the present embodiment.

It will be appreciated by those skilled in the art that all or some of the steps and systems in the disclosed method above may be implemented as software, firmware, hardware and appropriate combinations thereof. Some physical components or all physical components may be implemented as software executed by a processor, such as a central processing unit, a digital signal processor or a microprocessor, or may be implemented as hardware, or may be implemented as an integrated circuit, such as an application specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer storage medium (or a non-transitory medium) and a communication medium (or a temporary medium). As known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tapes, disk storage or other magnetic storage devices, or any other medium that may be used to store desired information and may be accessed by a computer. Furthermore, it is well known to those skilled in the art that communication media generally include computer readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

Claims

A modulator chip comprises, from top to bottom, a protective layer, an electrode layer and a waveguide layer; the electrode layer and the waveguide layer are fixed in the protective layer; the waveguide layer comprises a flat layer and a raised layer connected to each other, and the raised layer is fixed to the electrode layer through the flat layer; the electrode layer is provided with a first electrode group and a second electrode group matched with the raised layer; the first electrode group is correspondingly arranged above the raised layer, and the first electrode group extends in a direction close to the raised layer; the second electrode group is correspondingly arranged on both sides of the raised layer.
The modulator chip according to claim 1, wherein the cross-sectional area of the planar layer is larger than the cross-sectional area of the raised layer.
The modulator chip according to claim 2, wherein the thickness of the slab layer is 40% to 60% of the thickness of the waveguide layer.
The modulator chip according to claim 3, wherein the thickness of the waveguide layer is between 300 nm and 500 nm.
The modulator chip of claim 4, wherein the waveguide layer is made of thin film lithium niobate.
The modulator chip according to claim 1, wherein the protective layer comprises a lower cladding layer and a cover layer; and the electrode layer and the waveguide layer are fixed between the lower cladding layer and the cover layer.
The modulator chip according to claim 6, wherein the lower cladding layer and the cover layer are both made of silicon oxide.
The modulator chip according to claim 1, wherein a third electrode group is further provided below the second electrode group; and both ends of the flat layer are fixed within the third electrode group.
The modulator chip according to claim 8, wherein the distance between the first electrode groups is greater than or equal to 3 μm, and the distance between the second electrode groups is greater than or equal to 5 μm.
A modulation device, comprising the modulator chip as claimed in any one of claims 1 to 9.