CN114583420A

CN114583420A - Phase shifter and manufacturing method thereof, semiconductor device and optical communication system

Info

Publication number: CN114583420A
Application number: CN202011373403.2A
Authority: CN
Inventors: 姚湛史; 殷祥; 宋小鹿; 孙梦蝶
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2020-11-30
Filing date: 2020-11-30
Publication date: 2022-06-03

Abstract

The phase shifter can comprise a substrate, a first dielectric layer, a first waveguide, an electro-optic crystal film layer, a second waveguide and a metal electrode, wherein the first dielectric layer is arranged on the substrate, the first waveguide is arranged in the first dielectric layer, the refractive index of the first waveguide is larger than that of the first dielectric layer, the electro-optic crystal film layer is arranged on the first dielectric layer, the second waveguide can be arranged on the electro-optic crystal film layer and is arranged opposite to the first waveguide in the longitudinal direction, and the metal electrode can be arranged on two sides of the second waveguide. Meanwhile, the electro-optic crystal film layer is used as a flat plate structure without being etched, so that the manufacturing process can be simplified, and the manufacturing cost can be reduced.

Description

Phase shifter and manufacturing method thereof, semiconductor device and optical communication system

Technical Field

The present application relates to the field of optical communication technologies, and in particular, to a phase shifter, a method for manufacturing the phase shifter, a semiconductor device, and an optical communication system.

Background

With the continuous emergence and popularization of emerging services such as internet of things, big data, cloud computing, 5G and the like, the total data transmission amount is increased rapidly, so that the existing optical communication system faces huge bearing stress, and how to continuously improve the bandwidth and efficiency of the transmission system is the key point of the development of the optical communication technology. In optical communication systems, a phase shifter is an important component, the phase shifter includes a transmission medium in an electric field, the refractive index of the transmission medium layer is changed by the electric field, so that the phase of an optical signal in the transmission medium can be changed, and a change in the characteristics of the optical signal, such as a change in intensity or a change in phase, can be achieved by one or more phase shifters.

For example, the electro-optical modulator includes a phase shifter structure, so that an electrical signal can be converted into an optical signal by using the electro-optical modulator, which is one of the most core devices in an optical communication system and is also an important factor determining the bandwidth of the optical communication system, and a higher-efficiency and high-bandwidth electro-optical modulator is very important for realizing a higher-performance optical communication system.

However, the current phase shifter has the problems of complex process and low modulation efficiency, which results in limited performance of the optical communication system.

Disclosure of Invention

In view of this, the present application provides a phase shifter, a method for manufacturing the phase shifter, a semiconductor device, and an optical communication system, which simplify a manufacturing process of the phase shifter, obtain higher phase modulation efficiency, and improve performance of the optical communication system.

In order to solve the technical problem, the following technical scheme is adopted in the application:

the first aspect of the present application provides a phase shifter, which includes a substrate, a first dielectric layer, a first waveguide, an electro-optic crystal film layer, a second waveguide, and a metal electrode, wherein the first dielectric layer is disposed on the substrate, the first waveguide is disposed in the first dielectric layer, the refractive index of the first waveguide is greater than that of the first dielectric layer, the electro-optic crystal film layer is disposed on the first dielectric layer, the second waveguide is disposed on the electro-optic crystal film layer and is vertically aligned with the first waveguide, and the metal electrode is disposed on two sides of the second waveguide, so that when there is an optical signal in the electro-optic crystal film layer, the first waveguide can limit an optical field below, the second waveguide can limit an optical field above, the first waveguide and the second waveguide are vertically aligned, and therefore, the optical field is limited in the horizontal direction, and the optical field limiting capability is improved, the absorption loss of the metal electrodes to optical signals is reduced, the metal electrodes are beneficial to realizing smaller distance, the superposition efficiency of an electric field and a light field is improved, and the electro-optic modulation efficiency is improved. Meanwhile, the electro-optic crystal film layer is used as a flat plate structure without being etched, so that the manufacturing process can be simplified, and the manufacturing cost can be reduced.

In some possible embodiments, the electro-optic crystal film layer and the first dielectric layer are bonded by bonding.

In the embodiment of the application, the electro-optic crystal film layer can be bonded with the first medium layer, so that the bonding strength is high, and the process is simple.

In some possible embodiments, the material of the electro-optical crystal film layer is lithium niobate, barium titanate or lead zirconate titanate.

In the embodiment of the application, the material of the electro-optical crystal film layer can be defined as lithium niobate, barium titanate or lead zirconate titanate, and the materials have a good linear electro-optical effect, so that the phase shifter has good modulation efficiency.

In some possible embodiments, the thickness of the electro-optic crystal film layer is less than or equal to 1.5 microns.

In the embodiment of the application, the thickness of the electro-optical crystal film layer can be less than or equal to 1.5 mm, so that the electro-optical crystal film layer is controlled in a single mode state, and the propagation and control of optical signals are facilitated.

In some possible embodiments, the first waveguide is a first ridge structure integrated with a first slab layer, the first ridge structure is disposed toward the electro-optic crystal film layer, and the first dielectric layer is located on the first slab layer on both sides of the first waveguide; and/or the second waveguide is a second ridge structure which forms an integral structure with the second flat plate layer, the second ridge structure is arranged back to the electro-optic crystal film layer, and the metal electrodes are positioned above the second flat plate layer on two sides of the second waveguide.

In the embodiment of the present application, the first waveguide and the second waveguide may be ridge structures that form an integral structure with the slab structure, so that the structural stability of the device may be improved.

In some possible embodiments, the material of the first waveguide and the second waveguide is one or more of silicon, silicon nitride, silicon oxide, and titanium dioxide.

In the embodiment of the application, the materials of the first waveguide and the second waveguide can be limited, and the materials are materials with small etching difficulty, so that the convenience of manufacturing the device can be improved.

In some possible embodiments, the distance between the first waveguide and the electro-optic crystal film layer is less than or equal to 200 nanometers, and/or the distance between the second waveguide and the electro-optic crystal film layer is less than or equal to 200 nanometers.

In the embodiment of the application, the distance between the first waveguide and the electro-optic crystal film layer can be smaller, and the distance between the second waveguide and the electro-optic crystal film layer can also be smaller, so that the optical field in the electro-optic crystal film layer can be effectively limited.

In some possible embodiments, the phase shifter further includes a second dielectric layer;

the second dielectric layer is arranged on the electro-optic crystal film layer and at least covers the second waveguide and the side wall of the metal electrode; the refractive index of the second dielectric layer is less than the refractive index of the second waveguide.

In the embodiment of the application, the device can further comprise a second dielectric layer covering the side walls of the second waveguide and the metal electrode, and the second dielectric layer can protect the second waveguide and the metal electrode, plays an electric isolation role and improves the reliability of the device.

In some possible embodiments, the material of the first dielectric layer is at least one of silicon oxide and silicon nitride, and the material of the second dielectric layer is at least one of silicon oxide and silicon nitride.

In the embodiment of the application, the first dielectric layer and the second dielectric layer may be at least one of silicon oxide and silicon nitride, and the first dielectric layer and the second dielectric layer may have better coverage and a simpler manufacturing process, which is beneficial to device manufacturing.

In some possible embodiments, the phase shifter further includes:

a transparent conductive layer; the transparent conducting layer is connected with the metal electrode, and the transverse distance between the transparent conducting layer and the second waveguide is smaller than the transverse distance between the metal electrode and the second waveguide.

In the embodiment of the application, the transparent conductive layer has the characteristics of low optical loss and high conductivity, and can be closer to the second waveguide compared with the metal electrode without causing high optical loss, so that the superposition efficiency of a more efficient electric field and a light field is easily provided, and the modulation efficiency is improved.

A second aspect of the present application provides a method of manufacturing a phase shifter, including:

providing a substrate;

forming a first medium layer on the substrate, wherein a first waveguide is arranged in the first medium layer, and the refractive index of the first waveguide is greater than that of the first medium layer;

forming an electro-optic crystal film layer on the surface of the first dielectric layer; the electro-optic crystal film layer is made of a material with an electro-optic effect;

forming a second waveguide on the electro-optic crystal film layer, and metal electrodes on two sides of the second waveguide; the second waveguide is opposite to the first waveguide in the longitudinal direction.

In some possible embodiments, the forming an electro-optic crystal film layer on the surface of the first dielectric layer includes:

bonding an electro-optic crystal structure on the surface of the first medium layer; the electro-optic crystal structure comprises a substrate structure and an electro-optic crystal film layer, and the electro-optic crystal film layer is bonded towards the first medium layer;

and removing the substrate structure.

In some possible embodiments, the method further comprises:

forming a second dielectric layer on the electro-optic crystal film layer, wherein the second dielectric layer at least covers the second waveguide and the side wall of the metal electrode; the refractive index of the second dielectric layer is less than the refractive index of the second waveguide.

In some possible embodiments, the method further comprises:

forming a transparent conducting layer on the electro-optic crystal film layer on two sides of the second waveguide; the transparent conducting layer is connected with the metal electrode, and the transverse distance between the transparent conducting layer and the second waveguide is smaller than the transverse distance between the metal electrode and the second waveguide.

A third aspect of the present application provides a semiconductor device comprising the phase shifter provided in the first aspect of the present application.

In some possible embodiments, the semiconductor device further includes:

the optical splitter comprises a first optical splitter of which the output end is connected with the input ends of two first waveguides, a second optical splitter of which the input end is connected with the output ends of the two first waveguides, a third optical splitter of which the output end is connected with the input ends of two second waveguides which are opposite to the two first waveguides in the longitudinal direction, and a fourth optical splitter of which the input end is connected with the output ends of the two second waveguides; the first light splitter and the third light splitter are arranged oppositely in the longitudinal direction, and the second light splitter and the fourth light splitter are arranged oppositely in the longitudinal direction; the first optical splitter and the second optical splitter are positioned in the first medium layer, and the refractive indexes of the first optical splitter and the second optical splitter are greater than that of the first medium layer; the third light splitter and the fourth light splitter are positioned above the electro-optic crystal film layer.

In some possible embodiments, the semiconductor device further includes:

the output end of the first optical splitter is connected with the input ends of the two first optical splitters, the input end of the first optical splitter is connected with the output ends of the two second optical splitters, the output end of the first optical splitter is connected with the input ends of the two first optical splitters, which are opposite to each other, of the two third optical splitters, and the input end of the first optical splitter is connected with the output ends of the two second optical splitters, which are opposite to each other, of the two second optical splitters; the fifth optical splitter and the seventh optical splitter are arranged oppositely in the longitudinal direction, and the sixth optical splitter and the eighth optical splitter are arranged oppositely in the longitudinal direction; the fifth optical splitter and the sixth optical splitter are positioned in the first medium layer, and the refractive indexes of the fifth optical splitter and the sixth optical splitter are greater than that of the first medium layer; the seventh optical splitter and the eighth optical splitter are positioned above the electro-optic crystal film layer.

In some of the possible embodiments, the first and second,

at least one third waveguide is connected between the fifth optical splitter and the first optical splitter, the third waveguide is positioned in the first medium layer, the refractive index of the third waveguide is greater than that of the first medium layer, at least one fourth waveguide is connected between the seventh optical splitter and the third optical splitter, the fourth waveguide is positioned above the electro-optic crystal film layer, metal electrodes are arranged on two sides of the fourth waveguide, and the third waveguide and the fourth waveguide are arranged oppositely in the longitudinal direction; and/or the presence of a gas in the gas,

at least one fifth waveguide is connected between the sixth optical splitter and the second optical splitter, the fifth waveguide is located in the first medium layer, the refractive index of the fifth waveguide is larger than that of the first medium layer, at least one sixth waveguide is connected between the eighth optical splitter and the fourth optical splitter, the sixth waveguide is located above the electro-optic crystal film layer, metal electrodes are arranged on two sides of the sixth waveguide, and the fifth waveguide and the sixth waveguide are arranged oppositely in the longitudinal direction.

In some possible embodiments, the semiconductor device further includes:

an optical coupler; the optical coupler is connected with the input end of the phase shifter through a seventh waveguide and connected with the output end of the phase shifter through an eighth waveguide, and the seventh waveguide, the eighth waveguide and the optical coupler form a micro-ring resonant cavity.

In some possible embodiments, the semiconductor device further includes:

a first partial mirror and a second partial mirror; the first partial reflector is connected with the input end of the phase shifter through a ninth waveguide, and the second partial reflector is connected with the output end of the phase shifter through a tenth waveguide; the first partial mirror, the second partial mirror, the ninth waveguide, and the tenth waveguide constitute a fabry-perot resonator.

A fourth aspect of the present application provides an optical communication system comprising a laser, a photodetector, the semiconductor device provided in the third aspect of the present application; the semiconductor device is arranged between the laser and the optical detector, the laser is used for emitting optical signals, the semiconductor device is used for carrying out electro-optical modulation on the optical signals, and the optical detector is used for detecting the optical signals after the electro-optical modulation.

According to the technical scheme, the embodiment of the application has the following advantages:

the embodiment of the application provides a phase shifter and a manufacturing method thereof, a semiconductor device and an optical communication system, wherein the phase shifter can comprise a substrate, a first dielectric layer, a first waveguide, an electro-optic crystal film layer, a second waveguide and a metal electrode, wherein the first dielectric layer is arranged on the substrate, the first waveguide is arranged in the first dielectric layer, the refractive index of the first waveguide is larger than that of the first dielectric layer, the electro-optic crystal film layer is arranged on the first dielectric layer, the second waveguide is arranged on the electro-optic crystal film layer and is opposite to the first waveguide in the longitudinal direction, the metal electrode can be arranged on two sides of the second waveguide, so that when an optical signal exists in the electro-optic crystal film layer, the first waveguide can limit an optical field below, the second waveguide can limit the optical field above, the first waveguide and the second waveguide are opposite to each other in the longitudinal direction, and therefore the optical field is limited in the transverse direction, the method has the advantages of improving the limiting capacity on the optical field, reducing the absorption loss of the metal electrodes on optical signals, facilitating the realization of smaller distance between the metal electrodes, improving the coincidence efficiency of the electric field and the optical field and improving the electro-optic modulation efficiency. Meanwhile, the electro-optic crystal film layer is used as a flat plate structure without being etched, so that the manufacturing process can be simplified, and the manufacturing cost can be reduced.

Drawings

In order that the detailed description of the present application may be clearly understood, a brief description of the drawings, which will be used when describing the detailed description of the present application, follows. It is to be understood that these drawings are merely illustrative of some of the embodiments of the application.

Fig. 1 is a schematic structural diagram of a phase shifter according to an embodiment of the present disclosure;

fig. 2 is a schematic structural diagram of another phase shifter according to an embodiment of the present disclosure;

FIG. 3 is a schematic diagram illustrating simulation verification of a phase shifter according to an embodiment of the present application;

fig. 4 is a schematic structural diagram of another phase shifter according to an embodiment of the present disclosure;

fig. 5 is a schematic structural diagram of another phase shifter according to an embodiment of the present disclosure;

FIG. 6 is a flow chart illustrating a method for fabricating a phase shifter according to an embodiment of the present invention;

FIGS. 7-24 are schematic views of phase shifters in the manufacturing process according to the embodiments of the present application

Fig. 25 is a schematic structural diagram of a semiconductor device according to an embodiment of the present application;

fig. 26 is a schematic structural diagram of another semiconductor device provided in an embodiment of the present application;

fig. 27 is a schematic structural diagram of another semiconductor device provided in an embodiment of the present application;

fig. 28 is a schematic structural diagram of a semiconductor device according to an embodiment of the present application;

fig. 29 is a schematic structural diagram of an optical communication system according to an embodiment of the present application.

Detailed Description

The embodiment of the application provides a phase shifter and a manufacturing method thereof, a semiconductor device and an optical communication system, which simplify the preparation process of the phase shifter, obtain higher phase modulation efficiency and improve the performance of the optical communication system.

The terms "first," "second," "third," "fourth," and the like in the description and in the claims of the present application and in the drawings described above, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It will be appreciated that the data so used may be interchanged under appropriate circumstances such that the embodiments described herein may be practiced otherwise than as specifically illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The present application will be described in detail with reference to the drawings, wherein the cross-sectional views illustrating the structure of the device are not enlarged partially in general scale for convenience of illustration, and the drawings are only examples, which should not limit the scope of the present application. In addition, the three-dimensional dimensions of length, width and depth should be included in the actual fabrication.

At present, the main ways of converting an electrical signal into an optical signal by an electro-optical modulator are mainly two types: the present invention relates to an optical communication system, and more particularly, to an optical communication system including an internal modulation and an external modulation, where the external modulation mainly includes an electro-absorption modulator (EAM), a silicon optical modulator based on a free-carrier dispersion (FCD) effect, an electro-optical modulator based on a linear electro-optical effect (pockels effect), and the like, where the electro-absorption modulator only changes light intensity, is difficult to be applied to a high-order signal modulation format that can achieve a higher rate using optical phase information, and has a higher intrinsic loss, so that the application of the silicon optical modulator based on the FCD and the electro-optical modulator based on the linear electro-optical effect are more extensive, and the electro-optical modulator based on the linear electro-optical effect may include a phase shifter structure.

Specifically, the silicon optical modulator based on the FCD is based on a silicon optical technology, which is compatible with a conventional microelectronic manufacturing process, for example, a complementary metal-oxide-semiconductor (CMOS) manufacturing process, and has a low manufacturing cost, can implement high-density optoelectronic integration, and has a broad application prospect. However, the crystal structure of the silicon material has central inversion symmetry, cannot generate a second-order nonlinear phenomenon, and does not have a linear electro-optic effect, so that only the FCD effect of the silicon material can be utilized, and the FCD effect changes the refractive index of the silicon by changing the carrier distribution concentration in the silicon waveguide, thereby changing the phase of an optical signal and realizing the conversion from an electrical signal to an optical signal. However, the carrier moving rate in the silicon material can limit the modulation bandwidth, and the theoretical maximum modulation bandwidth of the silicon optical modulator is only about 60 GHz. Furthermore, changing the carrier concentration not only changes the refractive index of silicon, but also changes the absorption of light, resulting in a lower extinction ratio of the modulated optical signal. In addition, since the FCD effect is a non-linear process, the modulation linearity is poor and is far inferior to other electro-optical modulators based on the linear electro-optical effect.

Linear electro-optical effects (linear electro-optical effects or Pockels effects) are widely considered as physical mechanisms well-suited for realizing high-bandwidth electro-optical modulation, and the operation principle is that an external electric field causes the refractive index of the crystal to change, and the change amount is proportional to the electric field strength. Efficient high-speed integrated electro-optical modulators based on the linear electro-optical effect have received much attention in recent years. Existing research schemes are mainly classified into thin-film lithium niobate (TFLN) modulators, polymer (polymer) modulators, and plasmon (plasmon) modulators according to differences in structures and electro-optical materials used. The polymer modulator and the plasmon modulator need to rely on electro-optic polymer materials with poor stability and high optical loss, and need relatively complex preparation processes such as slit filling and polymer polarization, and have a long way to practical use. In contrast, TFLN modulators have advantages in terms of stability, optical loss, mass producibility, and the like.

TFLN modulators use the linear electro-optic effect of Lithium Niobate (LN) materials to achieve electro-optic modulation. A common TFLN modulator uses a TFLN waveguide based on the principle of total internal reflection to confine the optical field, and applies an electric field across the waveguide to change the refractive index of the waveguide, thereby achieving modulation of the optical signal. However, the fabrication of such a structure requires etching of the TFLN layer to form the waveguide pattern on the TFLN layer. Referring to fig. 1, a schematic structural diagram of a phase shifter provided in this embodiment of the present invention is shown, wherein an insulating layer 100 is formed on a substrate 10, a lithium niobate film layer 120 is formed on the insulating layer 100, the lithium niobate film layer 120 has a ridge structure 121, an optical signal in the ridge structure 121 can propagate along an extending direction of the ridge structure 121 (i.e., a direction perpendicular to the paper surface) in a total internal reflection manner, electrode pairs 122 are disposed on two sides of the ridge structure 121, and after a voltage is applied to the electrode pairs 122, an electric field transverse to the extending direction of the ridge structure 121 can be generated, so that the electric field between the electrode pairs 122 can act on the ridge structure 121, so that a refractive index of the ridge structure 121 is changed, an effective refractive index of an optical mode is changed, and phase modulation on the optical signal is achieved. However, TFLN is widely considered as a difficult-to-etch material, and the ridge structure in such a phase shifter structure needs to be formed by an etching process, so that the fabrication process needs to rely on a special and complicated etching process.

In view of the above technical problems, embodiments of the present invention provide a phase shifter, a method for manufacturing the same, a semiconductor device, and an optical communication system, where the phase shifter may include a substrate, a first dielectric layer, a first waveguide, an electro-optic crystal layer, a second waveguide, and a metal electrode, where the first dielectric layer is disposed on the substrate, the first waveguide is disposed in the first dielectric layer, a refractive index of the first waveguide is greater than a refractive index of the first dielectric layer, the electro-optic crystal layer is disposed on the first dielectric layer, the second waveguide is disposed on the electro-optic crystal layer and is opposite to the first waveguide in a longitudinal direction, the metal electrode is disposed on two sides of the second waveguide, so that when there is an optical signal in the electro-optic crystal layer, the first waveguide may limit an optical field below, the second waveguide may limit an optical field above, and the first waveguide and the second waveguide are opposite to the longitudinal direction, therefore, the light field is limited in the transverse direction, the limiting capacity on the light field is improved, the absorption loss of the metal electrodes to light signals is reduced, the metal electrodes can achieve smaller distance, the superposition efficiency of the light field and the electric field is improved, and the electro-optic modulation efficiency is improved. Meanwhile, the electro-optic crystal film layer is used as a flat plate structure without being etched, so that the manufacturing process can be simplified, and the manufacturing cost can be reduced.

In order to make the aforementioned objects, features and advantages of the present application more comprehensible, embodiments accompanying the present application are described in detail below with reference to the accompanying drawings.

Referring to fig. 2, 4, and 5, for a schematic structural diagram of a phase shifter provided in an embodiment of the present application, the phase shifter may include a substrate 10, a first dielectric layer 100, a first waveguide 112, an electro-optic crystal film layer 120, a second waveguide 132, and a metal electrode 140.

In the embodiment of the present application, the substrate 10 may be an insulator substrate, or may also be a semiconductor substrate, for example, a silicon oxide substrate, a lithium niobate substrate, a silicon substrate, a germanium substrate, or the like, and the substrate 10 may provide a certain support for the device. In order to enhance the structural stability of the device, a carrier (not shown) may be disposed below the substrate 10, the material of the carrier may be the same as the substrate 10, or may not be the same as the substrate 10, and the material of the carrier may be, for example, silicon oxide, lithium niobate, silicon, germanium, silicon nitride, or the like.

A first dielectric layer 100 may be formed on the substrate 10, a first waveguide 112 may be disposed in the first dielectric layer 100, the first waveguide 112 may have an extension direction, which is a propagation direction of an optical signal, for example, in fig. 2, 4 and 5, the first waveguide 112 may extend in a direction perpendicular to a paper plane, and a position of the first waveguide 112 may limit a waveguide area of the device. The material of the first dielectric layer 100 may be the same as the material of the substrate 10, or may not be the same as the material of the substrate 10, the material of the first waveguide 112 may be the same as the material of the first dielectric layer 100, or may not be the same as the material of the first dielectric layer 100, the refractive index of the first waveguide 112 is greater than the refractive index of the first dielectric layer 100, and when the material of the first waveguide 112 is the same as the material of the first dielectric layer 100, different forming processes may be used to make the first waveguide 112 and the first dielectric layer 100 have different refractive indexes. When the first waveguide 112 is in contact with the substrate 10, the refractive index of the first waveguide 112 is also simultaneously greater than the refractive index of the substrate 10, so that the principle of total internal reflection is used to confine the optical field within the waveguide. The material of the first dielectric layer 100 may be silicon oxide, silicon nitride, etc., the material of the first waveguide 112 may be silicon, silicon nitride, silicon oxide, titanium dioxide, etc., and when the material of the substrate 10 is silicon oxide and the material of the first waveguide 112 is silicon, the substrate 10 and the first waveguide 112 form a silicon-on-insulator (SOI) structure. The size of the first waveguide 112 can be controlled within a range, and the size is related to the wavelength of the optical signal, specifically, the width of the first waveguide 112 can be less than or equal to 1.5 micrometers, and the height can be less than or equal to 1 micrometer.

The first waveguide 112 may be formed inside the first dielectric layer 100, and may have an upper surface and/or a lower surface flush with the surface of the first dielectric layer 100, or the first waveguide 112 may protrude downward beyond the first dielectric layer 100 to contact the substrate 10, that is, the first dielectric layer 100 covers at least the sidewall of the first waveguide 112. When the electro-optic crystal film layer 120 is formed on the first dielectric layer 100, the distance between the upper surface of the first waveguide 112 and the electro-optic crystal film layer 120 may be less than or equal to 200 nanometers.

The cross section of the first waveguide 112 may be in various shapes, for example, a polygon or a circle, the polygon may be a rectangle or a trapezoid, the first waveguide 112 may also be a first ridge structure on the first slab layer 113, the first slab layer 113 and the first waveguide 112 constitute an integral structure, and both have the same material, as shown in fig. 5, the first ridge structure may be obtained by etching a bulk structure, and the first ridge structure may be disposed toward the electro-optic crystal film layer 120, that is, above the first slab layer 113, so that the first dielectric layer 100 may be disposed on the first slab layer 113 on both sides of the first waveguide 112, or a part of the first dielectric layer 100 may cover the upper surface of the first waveguide 112. Of course, the first ridge structure may also be obtained by etching the first dielectric layer to obtain a first trench, and filling the first trench with the first waveguide material, so that the first ridge structure may also be disposed away from the electro-optic crystal film layer 120, that is, below the first slab layer 113, and thus the first dielectric layer 100 is located below the first slab layer 113 on both sides of the first waveguide 112.

The electro-optic crystal film layer 120 is disposed on the first dielectric layer 100 and used for actually transmitting optical signals, the electro-optic crystal film layer 120 may be a flat plate structure, and the extending direction of the electro-optic crystal film layer is consistent with the extending direction of the first waveguide 112, for example, the electro-optic crystal film layer 120 in fig. 2, fig. 4, and fig. 5 may extend in the direction perpendicular to the paper surface, and the electro-optic crystal may not have a waveguide pattern in the waveguide region, so that an etching process may not be performed, the cost is saved, and the process is simplified, but of course, the electro-optic crystal film layer 120 itself cannot provide strong limitation to the optical field. The electro-optical crystal film layer 120 and the first dielectric layer 100 may be bonded or bonded in other manners, and when the two layers are bonded, a bonding layer may be formed or not formed between the electro-optical crystal film layer 120 and the first dielectric layer 100.

The material of the electro-optic crystal film layer 120 may include an electro-optic material having an electro-optic effect, and specifically, the material of the electro-optic crystal film layer 120 may be a material having a linear electro-optic effect, such as lithium niobate, barium titanate, lead zirconate titanate (PZT), and the like, and these electro-optic crystals generally require a complex and special etching process, are difficult to be compatible with the existing semiconductor manufacturing process, or have a poor etching effect, so that the process may be significantly simplified without performing etching of the waveguide pattern in the waveguide region of the electro-optic crystal film layer 120, and the cost may be reduced.

When the electro-optical crystal film layer 120 is made of lithium niobate, the lattice direction of the lithium niobate should be set to be the Z axis parallel to the surface of the lithium niobate film layer, so that when the electric field and the optical field component are parallel to the Z axis direction (the left and right directions in fig. 2) of the lithium niobate crystal, the electric field can enable the lithium niobate crystal to generate obvious refractive index change, and the change can change the transmission characteristic of an optical signal, for example, change the phase of the optical signal, thereby achieving the purpose of modulation. The thickness of the electro-optic crystal film layer 120 may be less than or equal to 1.5 micrometers, so that the electro-optic crystal film layer 120 is controlled in a single mode state, which is beneficial to the propagation and control of optical signals.

In other scenarios, the material of the electro-optic crystal film layer 120 may also be an electro-optic material with FCD effect, and the material may be, for example, silicon, and will not be described in detail herein.

The electro-optic crystal film layer 120 may further include a second waveguide 132, the second waveguide 132 is disposed opposite to the first waveguide 112 in the longitudinal direction, and the first waveguide 112 and the second waveguide 132 may be exactly opposite to each other or may have a small error. Like the first waveguide 112, the second waveguide 132 has an extension direction which coincides with the first waveguide 112 as a propagation direction of the optical signal, and for example, in fig. 2, 4, and 5, the second waveguide 132 may extend in a direction perpendicular to the plane of the paper. The material of the second waveguide 132 may be the same as the material of the first waveguide 112, or may not be the same as the material of the first waveguide 112, for example, silicon nitride, silicon oxide, titanium dioxide, polymer, etc., and the size of the second waveguide 132 may be the same as or different from that of the first waveguide 112, specifically, the width of the second waveguide 132 may be less than or equal to 1.5 micrometers, and the height may be less than or equal to 1 micrometer.

The shape of the second waveguide 132 may or may not be the same as that of the first waveguide 112, specifically, the cross section of the second waveguide 132 may have various shapes, for example, it may be a polygon or a circle, the polygon may be a rectangle or a trapezoid, the second waveguide 132 may be a second ridge structure on the second slab layer 133, where "on the second slab layer 133" indicates a connection relationship, and in fact, the second ridge structure may be disposed away from the electro-optic crystal film layer 120, that is, the second waveguide 132 may be disposed above the second slab layer 133, as shown in fig. 5A, but of course, the second ridge structure may also be disposed toward the electro-optic crystal film layer 120, that is, the second waveguide 132 may be disposed below the second slab layer 133, as shown in fig. 5B. The second slab layer 133 and the second waveguide 132 constitute a unitary structure, both of the same material. The distance between the lower surface of the second waveguide 132 and the electro-optic crystal film layer 120 may be less than or equal to 200 nanometers.

In this embodiment, a second dielectric layer 130 may be further included, the second dielectric layer 130 may be disposed on the electro-optic crystal film layer 120 and at least cover a sidewall of the second waveguide 132, when the second waveguide 132 is connected to the second slab layer 133, the second dielectric layer 130 may be located on a surface of the second slab layer 133 on two sides of the second waveguide 132, when the second waveguide 132 is disposed below the second slab layer 133, the second dielectric layer 130 is located between the second slab layer 133 and the electro-optic crystal film layer 120, that is, located below the second slab layer 133 on two sides of the second waveguide 132, as shown in fig. 5B, and when the second waveguide 132 is disposed above the second slab layer 133, the second dielectric layer 130 is located above the second slab layer 133 on two sides of the second waveguide 132, as shown in fig. 5A. The refractive index of the second dielectric layer 130 is smaller than that of the second waveguide 132, and it can be understood that if the second dielectric layer 130 is not disposed in the phase shifter, the second waveguide 132 is surrounded by air or vacuum, the refractive index of the second waveguide 132 is still larger than that of air or vacuum, and thus the refractive index of the second waveguide 132 is larger than that of the surrounding medium. The material of the second dielectric layer 130 may or may not be the same as the material of the first dielectric layer 100, and may be, for example, silicon oxide, silicon nitride, or the like.

On the electro-optic crystal film layer 120 on both sides of the second waveguide 132, a metal electrode 140 may be further disposed, and when a voltage is applied, the metal electrode 140 may provide an electric field perpendicular to the transmission direction of the optical signal, so as to change the refractive index of the electro-optic crystal film layer 120, thereby adjusting the characteristics of the optical signal therein. The number of the metal electrodes 140 is at least two, and the metal electrodes 140 located at different sides of the second waveguide 132 are used to be applied with different potentials, thereby generating an electric field. The metal electrode 140 has good conductivity, and the material thereof may be gold, copper, aluminum, or the like.

When the second dielectric layer 130 covers the sidewall of the second waveguide 132, the second dielectric layer 130 may also cover the sidewall of the metal electrode 140, and when the second waveguide 132 is connected to the second slab layer 133, the metal electrode 140 and the second waveguide 132 may be disposed on the same side of the second slab layer 133, or may be disposed on different sides of the second slab layer 133. When the metal electrode 140 and the second waveguide 132 are disposed on the same side of the second slab layer 133, the second dielectric layer 130 is located on the surface of the second slab layer 133 on both sides of the second waveguide 132, and covers the sidewall of the metal electrode 140 while covering the sidewall of the second waveguide 132, and when the metal electrode 140 and the second waveguide 132 are disposed on different sides of the second slab layer 133, the second dielectric layer 130 may be disposed on both sides of the second slab layer 133, and respectively cover the sidewall of the second waveguide 132 and the sidewall of the metal electrode 140. Of course, the second dielectric layer 130 may also cover the top of the second waveguide 132 and the top of the metal electrode 140.

Specifically, when the second waveguide 132 is disposed below the second slab layer 133, the metal electrode 140 may also be disposed below the second slab layer 133, and the second dielectric layer 130 is located below the second slab layer 133 on both sides of the second waveguide 132, as shown in fig. 5B; of course, the metal electrode 140 may also be disposed above the second slab layer 133, and the second dielectric layer 130 may be disposed below the second slab layer 133 on both sides of the second waveguide 132 to cover the sidewalls of the second waveguide 132, while the second dielectric layer 130 is disposed above the second slab layer 133 to cover at least the sidewalls of the metal electrode 140. When the second waveguide 132 is disposed above the second slab layer 133, the metal electrode 140 is also disposed above the second slab layer 133, and the second dielectric layer 130 is disposed above the second slab layer 133 on both sides of the second waveguide 132, as shown in fig. 5A.

Since the metal material absorbs light, the metal electrode 140 cannot be located too close to the second waveguide 132, which would otherwise cause significant optical loss. However, if the distance between the metal electrodes 140 is too far, the electric field between the metal electrodes 140 under the same voltage condition is relatively weak, which affects the modulation efficiency. Thus, at design time, the lateral distance between the metal electrode 140 and the second waveguide 132 may be determined according to the requirements for optical signal loss and modulation efficiency. The metal electrode 140 may be in direct contact with the electro-optic crystal film layer 120, or may have at least one insulating layer (not shown) for isolation, and the material of the insulating layer may be silicon dioxide.

In the embodiment of the present application, the first waveguide 112 is disposed below the electro-optic crystal film layer 120, the second waveguide 132 is disposed above the electro-optic crystal film layer 120, and a multilayer waveguide mode with a three-layer structure is formed, the electro-optic crystal film layer 120 may have an electro-optic effect to perform electro-optic modulation, and the first waveguide 112 and the second waveguide 132 are respectively disposed on two sides of the electro-optic crystal film layer 120 and have a refractive index higher than that of a surrounding dielectric layer, so that an optical field can be limited, in fact, compared with a structure in which a waveguide for limiting an optical field is disposed on a single side, the structure for limiting an optical field on two sides can further improve the optical field limiting capability, so that the area of the optical field is smaller, and therefore, a closer distance can be provided between the metal electrodes 140, and the light absorption intensity cannot be increased due to the closer distance, so that the transverse electric field intensity is enhanced under the same voltage condition, the superposition efficiency of the electric field and the optical field is improved, the modulation efficiency of the phase shifter is improved, the phase change of the optical signal required by modulation can be realized by designing the length of the modulation region to be smaller, the limitation on the modulation bandwidth is reduced, and the size of the phase shifter is favorably reduced. Meanwhile, the electro-optic crystal film layer 120 does not need to be etched, so that the electro-optic crystal film layer can be realized based on a common semiconductor manufacturing process, the preparation process is simple and complex, and the realization difficulty is low.

Referring to fig. 3, a schematic diagram of simulation verification of a phase shifter provided in the embodiment of the present application is shown, where the simulation is based on a two-dimensional finite element analysis (FEM), in which a material of the electro-optic crystal film layer 120 is lithium niobate, materials of the first waveguide 112 and the second waveguide 132 are silicon nitride, a material of the metal electrode 140 is gold, and materials of the substrate 10, the first dielectric layer 100, and the second dielectric layer 130 are all silicon dioxide.

Fig. 3A is a simulation diagram of a scenario in which only the second waveguide 132 is disposed and the first waveguide 112 is not disposed, in which the height of the second waveguide 132 is 0.5 micrometers (μm), the central white region is the region where the optical field is located under simulation conditions, the optical field in the electro-optic crystal film layer 120 is limited by 75%, and if the allowed optical loss is 2dB/cm, the distance between the metal electrodes 140 needs to be set to 4 micrometers, and the corresponding value of V pi L is 1.64V · cm. The value of V pi L means the product of the magnitude of the voltage V pi required to be applied across the electrodes when realizing the optical phase change of pi in the waveguide and the modulation region length L, and therefore, a smaller value means a higher modulation efficiency.

Fig. 3B is a simulation diagram of a scenario in which the first waveguide 112 and the second waveguide 132 are disposed at the same time, in which the heights of the first waveguide 112 and the second waveguide 132 are both 0.25 micrometers (μm), and under simulation conditions, the central white region is the region where the optical field is located, and the optical field in the electro-optic crystal film layer 120 is limited by 76%, and if the allowed optical loss is also 2dB/cm, the distance between the metal electrodes 140 can be shortened to 3.5 micrometers, and the corresponding value of V pi L is reduced to 1.48V · cm, which is about 10% lower. The simulation result shows that compared with the structure of limiting the optical field by a single-sided waveguide, the structure of limiting the optical field by the double-sided waveguide from the upper side and the lower side can shorten the interval between the electrodes on the premise of the same optical loss, thereby improving the modulation efficiency.

In addition, in this embodiment of the application, a transparent conductive layer 142 may be further disposed, the transparent conductive layer 142 is connected to the metal electrode 140, a lateral distance between the transparent conductive layer 142 and the second waveguide 132 is smaller than a lateral distance between the metal electrode 140 and the second waveguide 132, and the transparent conductive layer 142 may be connected to the second waveguide 132 or may have a certain interval with the second waveguide 132. Specifically, the transparent conductive layer 142 may be disposed between the metal electrode 140 and the second waveguide 132, one end of which is close to the second waveguide 132, and the other end of which is far from the second waveguide 132 is electrically connected to the metal electrode 140, or the transparent conductive layer 142 may be disposed between the electro-optic crystal film layer 120 and the metal electrode 140 on both sides of the second waveguide 132 and laterally extend out to be close to the second waveguide 132, as an example, the transparent conductive layer 142 may be in contact with the second waveguide 132, as shown in fig. 4. The transparent conductive layer 142 may be disposed directly on the electro-optic crystal film layer 120, or disposed between the insulating layer and the metal electrode, and when the sidewall of the metal electrode 140 is covered by the second dielectric layer 130, the sidewall of the transparent conductive layer 142 and the upper surface extending beyond the metal electrode 140 may also be covered by the second dielectric layer 130.

The transparent conductive layer 142 may have low optical loss and high conductivity, and may be Transparent Conductive Oxide (TCO) or doped silicon, for example. The transparent conductive layer 142 may thus be closer to the second waveguide 132 than the metal electrode 140, and the transparent conductive layer 142 may be closer to the second waveguide 132 than the metal electrode 140 without causing high optical loss. The transparent conductive layer 142 can share most of the voltage applied by the metal electrode 140 to the position where the transparent conductive layer 142 is close to the second waveguide 132, and compared with a device without the transparent conductive layer 142, the device with the transparent conductive layer 142 can obtain a stronger electric field under the same voltage condition, so that on the premise of not additionally increasing optical loss, more efficient superposition efficiency of the electric field and the optical field can be provided, and modulation efficiency is improved.

The embodiment of the application provides a phase shifter, which can comprise a substrate, a first dielectric layer, a first waveguide, an electro-optic crystal film layer, a second waveguide and a metal electrode, wherein the first dielectric layer is arranged on the substrate, the first waveguide is arranged in the first dielectric layer, the refractive index of the first waveguide is larger than that of the first dielectric layer, the electro-optic crystal film layer is arranged on the first dielectric layer, the second waveguide can be arranged on the electro-optic crystal film layer and is opposite to the first waveguide in the longitudinal direction, the metal electrode can be arranged on two sides of the second waveguide, so that when an optical signal exists in the electro-optic crystal film layer, the first waveguide can limit an optical field below, the second waveguide can limit the optical field above, the first waveguide and the second waveguide are opposite to each other in the longitudinal direction, so that the optical field is limited in the transverse direction, and the limiting capability of the optical field is improved, the absorption loss of the metal electrodes to optical signals is reduced, the metal electrodes are beneficial to realizing smaller distance, the superposition efficiency of an electric field and a light field is improved, and the electro-optic modulation efficiency is improved. Meanwhile, the electro-optic crystal film layer is used as a flat plate structure without being etched, so that the manufacturing process can be simplified, and the manufacturing cost can be reduced.

Based on the phase shifter provided in the embodiments of the present application, a manufacturing method of the phase shifter is also provided in the embodiments of the present application, referring to fig. 6, which is a flowchart of the manufacturing method of the phase shifter provided in the embodiments of the present application, and referring to fig. 7 to fig. 24, which are schematic structural diagrams of the phase shifter in a manufacturing process, the manufacturing method may include:

s101, a substrate 10 is provided, as shown with reference to fig. 7.

In the embodiment of the present application, the substrate 10 may be an insulator substrate, or may also be a semiconductor substrate, for example, a silicon oxide substrate, a lithium niobate substrate, a silicon substrate, a germanium substrate, or the like, and the substrate 10 may provide a certain support for the device. In order to enhance the structural stability of the device, a carrier may be disposed below the substrate 10, the material of the carrier may be the same as the substrate 10 or may not be the same as the substrate 10, and the material of the carrier may be, for example, silicon oxide, lithium niobate, silicon, germanium, silicon nitride, or the like.

S102, a first dielectric layer 100 is formed on the substrate, as shown in fig. 7-9 and 15-17.

A first dielectric layer 100 may be formed on the substrate 10, a first waveguide 112 is disposed in the first dielectric layer 100, and the first waveguide 112 has an extending direction, which is a propagation direction of an optical signal. The material of the first dielectric layer 100 may or may not be the same as the material of the substrate 10, and the refractive index of the first waveguide 112 is greater than the refractive index of the first dielectric layer 100. The material of the first dielectric layer 100 may be silicon oxide, silicon nitride, etc., the material of the first waveguide 112 may be silicon, silicon nitride, silicon oxide, titanium dioxide, etc., and when the material of the substrate 10 is silicon oxide and the material of the first waveguide 112 is silicon, the substrate 10 and the first waveguide 112 form an SOI structure. The size of the first waveguide 112 may be controlled within a range, and the width thereof may be less than or equal to 1.5 micrometers and the height thereof may be less than or equal to 1 micrometer.

The first waveguide 112 may be formed inside the first dielectric layer 100, and may also have an upper surface and/or a lower surface flush with the surface of the first dielectric layer 100, or the first waveguide 112 may also protrude downward beyond the first dielectric layer 100 to contact the substrate 10, and when the electro-optic crystal film layer 120 is formed on the first dielectric layer 100, the distance between the upper surface of the first waveguide 112 and the electro-optic crystal film layer 120 may be less than or equal to 200 nm.

The cross section of the first waveguide 112 may be in various shapes, for example, a polygon or a circle, the polygon may be a rectangle or a trapezoid, the first waveguide 112 may also be a first ridge structure on the first slab layer 113, the first slab layer 113 and the first waveguide 112 constitute an integral structure, both of which have the same material, the ridge structure is obtained by etching a body structure, and the first ridge structure may be disposed toward the electro-optic crystal film layer 120, that is, above the first slab layer 113, so that the first dielectric layer 100 may be disposed on the first slab layer 113 on both sides of the first waveguide 112, or a part of the first dielectric layer 100 may cover the upper surface of the first waveguide 112. Of course, the first ridge structure may also be obtained by etching the first dielectric layer to obtain a first trench, and filling the first trench with the first waveguide material, so that the first ridge structure may also be disposed away from the electro-optic crystal film layer 120, that is, below the first slab layer 113, and thus the first dielectric layer 100 is located below the first slab layer 113 on both sides of the first waveguide 112.

As a possible implementation, the first waveguide 112 may be formed on the substrate 10, as shown in fig. 8 and 16, and then the first dielectric layer 100 may be formed around the first waveguide 112, as shown in fig. 9 and 17. Specifically, the first waveguide material 111 may be deposited on the substrate 10, as shown in fig. 15, and then the first waveguide material 111 is etched by using photolithography and etching techniques to obtain a stripe waveguide pattern, and then the first dielectric material is deposited and planarized to obtain the first dielectric layer 100. The etching of the first waveguide material may be complete etching until the first waveguide material in other regions except the waveguide region is removed to form the independent first waveguides 112, as shown in fig. 8, or may be partial etching of the first waveguide material 111 and thinning of other regions except the stripe waveguide pattern to form the first slab layer 113 and the first ridge structures (i.e., the first waveguides 112) thereon, as shown in fig. 16. The first waveguide material and the first dielectric material may be deposited by Chemical Vapor Deposition (CVD), the first waveguide material may be etched by anisotropic dry etching, and the first dielectric material may be planarized by Chemical Mechanical Polishing (CMP). A first dielectric layer 100 may be formed on the substrate 10 prior to forming the first waveguide 112, as described with reference to fig. 7.

As another possible implementation, the first dielectric layer 100 may be formed on the substrate 10, then the first dielectric layer 100 is etched to obtain a first trench, then the first waveguide material is deposited to fill the first trench with the first waveguide material, and then the first waveguide material is planarized to expose the first dielectric layer 100, so as to obtain the first waveguide 112 in the first trench. Of course, the substrate 10 may also be etched to obtain a first trench, and then the first waveguide material is deposited, so that the first trench is filled with the first waveguide material, and then the first waveguide material may be planarized to expose the substrate 10, so as to obtain the first waveguide 112 in the first trench, where at this time, the substrate 10 on the sidewall of the first waveguide 112 serves as the first dielectric layer 100. The first waveguide material and the first dielectric material may be deposited by CVD, the first dielectric material may be etched by anisotropic dry etching, and the first waveguide material may be planarized by a CMP technique.

S103, forming an electro-optic crystal film layer 120 on the surface of the first dielectric layer 100, as shown in fig. 10, 11, 18, and 19.

The electro-optic crystal film layer 120 is disposed on the first dielectric layer 100 and is used for actually transmitting optical signals, the electro-optic crystal film layer 120 may be a flat plate structure, an extending direction of the electro-optic crystal film layer is the same as an extending direction of the first waveguide 112, and the electro-optic crystal may not have a waveguide pattern in a waveguide region, so that an etching process may not be performed, the cost is saved, and the process is simplified.

The material of the electro-optical crystal film layer 120 may include electro-optical materials with linear electro-optical effect, such as lithium niobate, barium titanate, lead zirconate titanate, etc., wherein lithium niobate has the advantages of high electro-optical coefficient (greater than 30pm/V), low optical loss, and high stability, and when the electro-optical crystal film layer 120 is lithium niobate, the lattice direction of lithium niobate should be set to have its Z axis parallel to the surface of the lithium niobate film layer. The thickness of the electro-optic crystal film layer 120 may be less than or equal to 1.5 microns.

As a possible implementation, the electro-optic crystal film layer 120 may be formed on the surface of the first dielectric layer 100 by bonding. A bonding layer may or may not be formed between the electro-optic crystal film layer 120 and the first dielectric layer 100. Specifically, an electro-optic crystal structure may be bonded on the surface of the first dielectric layer 100, the electro-optic crystal structure may include a substrate structure 122 and an electro-optic crystal film layer 120, after bonding, the electro-optic crystal film layer 120 faces the first dielectric layer 100, as shown in fig. 10 and 18, and then the substrate structure 122 may be removed, so as to form the electro-optic crystal film layer 120 on the surface of the first dielectric layer 100, as shown in fig. 11 and 19. The manner of removing the base structure 122 may include wet etching, dry etching, and/or CMP, etc.

As another possible implementation, the electro-optic crystal film layer 120 may be epitaxially grown on the surface of the first dielectric layer 100, for example, the electro-optic crystal film layer 120 may be formed by CVD or Molecular Beam Epitaxy (MBE), so that the step of removing the substrate structure 122 may not be performed.

And S104, forming a second waveguide 132 on the electro-optic crystal film layer 120 and metal electrodes 140 on two sides of the second waveguide 132, referring to FIGS. 12-14, 20-24, 2, 4 and 5.

The second waveguide 132 can be further disposed on the electro-optic crystal film layer 120, the second waveguide 132 is disposed opposite to the first waveguide 112 in the longitudinal direction, and the first waveguide 112 and the second waveguide 132 can be exactly opposite to each other or have a small error. Like the first waveguide 112, the second waveguide 132 has an extending direction which coincides with the first waveguide 112 as a propagation direction of the optical signal. The material of the second waveguide 132 may be the same as the material of the first waveguide 112, or may not be the same as the material of the first waveguide 112, for example, silicon nitride, silicon oxide, titanium dioxide, polymer, etc., and the size of the second waveguide 132 may be the same as or different from that of the first waveguide 112, specifically, the width of the second waveguide 132 may be less than or equal to 1.5 micrometers, and the height may be less than or equal to 1 micrometer.

Specifically, a second waveguide material may be deposited on the electro-optic crystal film layer 120, and then the second waveguide material is etched by using photolithography and etching techniques to obtain a stripe waveguide pattern, so as to obtain a second waveguide 132, as shown in fig. 12, or the second waveguide material is incompletely etched, and the second waveguide material outside the waveguide region is thinned, so as to obtain the second waveguide 132 and a second slab layer 133 thereunder, as shown in fig. 23, a second dielectric layer material may be formed on the electro-optic crystal film layer 120, as shown in fig. 21, and then a second trench is etched, as shown in fig. 22, and then the second waveguide material is deposited and planarized, so as to form the second waveguide 132 in the second trench and the second slab layer 133 above the second waveguide 132, as shown in fig. 5B. The second waveguide material may be deposited by CVD and etched by anisotropic dry etching.

On the electro-optic crystal film layer 120 on both sides of the second waveguide 132, a metal electrode 140 may be further disposed, and when a voltage is applied, the metal electrode 140 may provide an electric field perpendicular to the transmission direction of the optical signal, so as to change the refractive index of the electro-optic crystal film layer 120, thereby adjusting the characteristics of the optical signal therein. The number of the metal electrodes 140 is at least two, and the metal electrodes 140 located at different sides of the second waveguide 132 are used to be applied with different potentials, thereby generating an electric field. The metal electrode 140 has good conductivity, and the material thereof may be gold, copper, aluminum, or the like. The metal electrode 140 and the electro-optic crystal film layer 120 may be in direct contact, or at least one insulating layer for isolation may be formed, and the material of the insulating layer may be silicon dioxide.

Specifically, the metal electrode 140 may be formed on the electro-optic crystal film layer 120 by metal sputtering, metal lift-off, or the like, as shown in fig. 13, 20, and 24. The metal electrode 140 may be formed before the second waveguide 132, as shown with reference to fig. 20, or may be formed after the second waveguide 132, as shown with reference to fig. 13 and 24. When an insulating layer is formed between the metal electrode 140 and the electro-optic crystal film layer 120, the insulating layer may be formed before the metal electrode 140 is formed, and the forming method may be CVD or Atomic Layer Deposition (ALD).

In addition, in this embodiment of the application, a transparent conductive layer 142 may be further formed, the transparent conductive layer 142 is connected to the metal electrode 140 formed subsequently, a lateral distance between the transparent conductive layer 142 and the second waveguide 132 is smaller than a lateral distance between the metal electrode 140 and the second waveguide 132, and the transparent conductive layer 142 may be connected to the second waveguide 132 or may have a certain interval from the second waveguide 132. The transparent conductive layer 142 may have characteristics of low optical loss and high conductivity, and may be, for example, a transparent conductive oxide or doped silicon. The transparent conductive layer 142 may thus be closer to the second waveguide 132 than the metal electrode 140, and the transparent conductive layer 142 may be closer to the second waveguide 132 than the metal electrode 140 without causing high optical loss.

Specifically, the transparent conductive layer 142 may be disposed between the metal electrode 140 and the second waveguide 132, one end of the transparent conductive layer 142 is close to the second waveguide 132, and the other end of the transparent conductive layer, which is far from the second waveguide 132, is electrically connected to the metal electrode 140, so that the transparent conductive layer 142 may be formed before the metal electrode 140 or after the metal electrode 140, specifically, the transparent conductive layer 142 is formed by depositing a transparent conductive material layer, patterning the transparent conductive material layer to form the transparent conductive layer 142, or forming a silicon layer, and doping the silicon layer. The transparent conductive material layer and the silicon layer may be formed by CVD or ALD, and the transparent conductive material layer may be patterned by photolithography and etching, or by lift-off.

Specifically, the transparent conductive layer 142 may be disposed between the electro-optic crystal film layer 120 and the metal electrode 140 on both sides of the second waveguide 132 and extend in the lateral direction to be close to the second waveguide 132, as an example, the transparent conductive layer 142 may be in contact with the second waveguide 132, as shown in fig. 14, the transparent conductive layer 142 may be formed before the metal electrode 140, and the transparent conductive layer 142 may be formed by depositing a transparent conductive material layer, patterning the transparent conductive material layer to form the transparent conductive layer 142, or forming a silicon layer and doping the silicon layer. The transparent conductive material layer and the silicon layer may be formed by CVD or ALD, and the transparent conductive material layer may be patterned by photolithography and etching, or by lift-off.

The transparent conductive layer 142 may be disposed directly on the electro-optic crystal film layer 120, or disposed between the insulating layer and the metal electrode, and when the sidewall of the metal electrode 140 is covered by the second dielectric layer 130, the sidewall of the transparent conductive layer 142 and the upper surface extending beyond the metal electrode 140 may also be covered by the second dielectric layer 130. Therefore, the transparent conductive layer 142 over the insulating layer may be formed after the insulating layer is formed.

In this embodiment, a second dielectric layer 130 may be further formed, the second dielectric layer 130 may be disposed on the electro-optic crystal film layer 120 and at least cover a sidewall of the second waveguide 132, when the second waveguide 132 is connected to the second slab layer 133, the second dielectric layer 130 may be located on surfaces of the second slab layer 133 on two sides of the second waveguide 132, when the second waveguide 132 is disposed below the second slab layer 133, the second dielectric layer 130 is located between the second slab layer 133 and the electro-optic crystal film layer 120, that is, below the second slab layer 133 on two sides of the second waveguide 132, and when the second waveguide 132 is disposed above the second slab layer 133, the second dielectric layer 130 is located above the second slab layer 133 on two sides of the second waveguide 132. The refractive index of the second dielectric layer 130 is smaller than that of the second waveguide 132, and it can be understood that if the second dielectric layer 130 is not disposed in the phase shifter, the second waveguide 132 is surrounded by air or vacuum, the refractive index of the second waveguide 132 is still larger than that of air or vacuum, and therefore the refractive index of the second waveguide 132 is larger than that of the surrounding medium. The material of the second dielectric layer 130 may or may not be the same as the material of the first dielectric layer 100, and may be, for example, silicon oxide, silicon nitride, or the like.

Specifically, when the second waveguide 132 is disposed below the second slab layer 133, the metal electrode 140 may also be disposed below the second slab layer 133, and the second dielectric layer 130 is located below the second slab layer 133 on both sides of the second waveguide 132; of course, the metal electrode 140 may also be disposed above the second slab layer 133, and the second dielectric layer 130 may be disposed below the second slab layer 133 on both sides of the second waveguide 132 to cover the sidewalls of the second waveguide 132, while the second dielectric layer 130 is disposed above the second slab layer 133 to cover at least the sidewalls of the metal electrode 140. When the second waveguide 132 is disposed above the second slab layer 133, the metal electrode 140 is also disposed above the second slab layer 133, and the second dielectric layer 130 is disposed above the second slab layer 133 on both sides of the second waveguide 132.

As a possible implementation manner, the second dielectric layer 130 may be formed after the second waveguide 132 and the metal electrode 140, and then may be formed after the second waveguide 132 and the metal electrode 140 (see fig. 13, 14, and 24), and a deposition of a second dielectric material is performed, and then a planarization of the second dielectric material is performed, so as to obtain the second dielectric layer 130, so as to cover sidewalls of the second waveguide 132 and the metal electrode 140, or to cover sidewalls and an upper surface of the second waveguide 132 and the metal electrode 140, as shown in fig. 2, 4, and 5A, of course, the second dielectric layer 130 may also be directly used as the second dielectric layer 130 without performing the planarization of the second dielectric material, and the second dielectric layer 130 may protect the device. The second dielectric material may be deposited by CVD and the planarization process may be a CMP technique.

As another possible implementation, the second dielectric layer 130 may be formed before the second waveguide 132 and the metal electrode 140, and the second dielectric layer 130 may be formed by deposition, and then the second dielectric layer 130 is etched to obtain a second trench and a third trench, and the second waveguide 132 is formed in the second trench, and the metal electrode 140 is formed in the third trench. The second trench and the second waveguide 132 may be formed before the third trench and the metal electrode 140 or may be formed after the third trench and the metal electrode 140. The second waveguide 132 may be formed in the second trench using a deposition process and a planarization process, and the metal electrode 140 may be formed in the third trench using a deposition process and a planarization process, or a metal sputtering process and a lift-off process.

Of course, when the second waveguide 132 is connected to the second slab layer 133, the metal electrode 140 may be formed in the third trench, then the second trench is formed, the second waveguide material is deposited, and the second waveguide material is planarized, so that the planarized surface may not expose the second dielectric layer 130, so as to form the second waveguide 132 in the second trench and the second slab layer 133 on the second dielectric layer 130. The deposition method may be CVD, and the planarization process may be CMP.

As another possible implementation, the second dielectric layer 130 may be formed before the second waveguide 132 and after the metal electrode 140, specifically, the metal electrode 140 may be formed on the electro-optic crystal film layer 120, as shown in fig. 20, and then the second dielectric layer 130 is deposited, as shown in fig. 21, and then the second dielectric layer 130 may be etched to obtain a second trench, and then the second waveguide material is deposited and planarized, so that the planarized surface may not expose the second dielectric layer 130, as shown in fig. 5B, to form the second waveguide 132 in the second trench and the second slab layer 133 on the second dielectric layer 130.

The embodiment of the application provides a phase shifter manufacturing method, which comprises the steps of providing a substrate, forming a first medium layer on the substrate, arranging a first waveguide in the first medium layer, enabling the refractive index of the first waveguide to be larger than that of the first medium layer, forming an electro-optic crystal film layer on the surface of the first medium layer, enabling the electro-optic crystal film layer to be made of materials with electro-optic effect, forming a second waveguide on the electro-optic crystal film layer, and forming metal electrodes on two sides of the second waveguide, wherein the second waveguide and the first waveguide are arranged in a manner of being opposite to each other in the longitudinal direction. Therefore, when an optical signal exists in the electro-optic crystal film layer, the first waveguide can limit the optical field below, the second waveguide can limit the optical field above, and the first waveguide and the second waveguide are opposite to each other in the longitudinal direction, so that the optical field is limited horizontally, the limiting capacity of the optical field is improved, the absorption loss of the metal electrodes to the optical signal is reduced, the realization of a smaller distance between the metal electrodes is facilitated, the superposition efficiency of the electric field and the optical field is improved, and the electro-optic modulation efficiency is improved. Meanwhile, the electro-optic crystal film layer is used as a flat plate structure without being etched, so that the manufacturing process can be simplified, and the manufacturing cost can be reduced.

Based on the phase shifter provided by the embodiment of the application, the embodiment of the application also provides a semiconductor device, which may include at least one phase shifter, wherein an electro-optic crystal film layer in the phase shifter is used for transmitting an optical signal, the first waveguide and the second waveguide are used for limiting an optical mode field in the electro-optic crystal film layer, and the metal electrode is used for changing a refractive index of the electro-optic crystal film layer when a modulation voltage is applied so as to electro-optically modulate the optical signal. The semiconductor device is a device capable of converting an electrical signal into an optical signal, and may be, for example, an electro-optical phase shifter, an electro-optical switch, an electric field sensor, an electro-optical modulator, and the like, where the electro-optical phase shifter may perform phase modulation using an electric field and then output a phase-modulated optical signal, the electro-optical modulator may perform phase modulation or intensity modulation on the optical signal using the electric field, the electro-optical switch of the electro-optical phase shifter may control light intensity by adjusting the electric field, the intensity information of the light embodies the switching information, the electric field sensor may be configured to detect the electric field, and the detection result may be embodied in the form of the optical signal.

In this embodiment, a semiconductor device may be formed on the same substrate to form a Mach-Zehnder (MZ) interferometer, where the device may include at least one phase shifter provided in this embodiment, and in addition, a phase shifter having another structure may be provided to cooperate with the phase shifter provided in this embodiment, and the phase shifter may be provided on at least one arm of the interferometer to adjust an optical phase, so as to change an optical signal intensity or a phase at an optical output end. Taking an interferometer including two phase shifters as an example, referring to fig. 25, for a schematic structural diagram of a semiconductor device provided in an embodiment of the present application, the semiconductor device may include an optical input end, a 1 × 2 beam splitter, two optical paths, a phase shifter, a 2 × 1 beam combiner, and an optical output end, wherein, the optical signal enters through the optical input end, is divided into two parts through the 1 multiplied by 2 beam splitter, and is respectively guided to the optical paths of the two arms of the MZ interferometer, the phase shifters described above are provided on both arms of the MZ interferometer, the phase of the optical signal of the arm can be changed, then, the 2 x 1 beam combiner is used for combining the optical signals of the two arms of the MZ interferometer, the optical signals of the two arms generate interference, so that the characteristics of the combined optical signals are changed compared with the characteristics of the optical signals of the optical input end, such as light intensity change or light phase change, the combined light signal is output by the light output terminal.

In a specific implementation, the semiconductor device may include the phase shifter, the phase shifter may include the substrate, the first dielectric layer, the first waveguide, the electro-optic crystal film layer, the second waveguide, and the metal electrode, the semiconductor device may further include a first optical splitter whose output end is connected to the input ends of the two first waveguides, a third optical splitter whose output end is connected to the input end of the second waveguide opposite to the two first waveguides, a second optical splitter whose input end is connected to the output ends of the two first waveguides, and a fourth optical splitter whose input end is connected to the output end of the second waveguide opposite to the two first waveguides, the first optical splitter and the second optical splitter are located in the first dielectric layer, and the refractive indexes of the first optical splitter and the second optical splitter are greater than that of the first dielectric layer, the third optical splitter and the fourth optical splitter are located above the electro-optic crystal film layer, when the second optical crystal film layer is located above the electro-optic crystal film layer, the third and fourth optical splitters may be located in the second dielectric layer, and refractive indices of the third and fourth optical splitters are greater than a refractive index of the second dielectric layer.

The first optical splitter and the third optical splitter are arranged oppositely in the longitudinal direction, the optical field in the electro-optical crystal film layer between the first optical splitter and the third optical splitter is limited in the extending direction of the first optical splitter and the third optical splitter, so that the 1X 2 optical splitter of the optical input end is formed functionally, the second optical splitter and the fourth optical splitter are arranged oppositely in the longitudinal direction, the optical field in the electro-optical crystal film layer between the second optical splitter and the fourth optical splitter is limited in the extending direction of the second optical splitter and the fourth optical splitter, and the 2X 1 beam combiner of the optical output end is formed functionally. For ease of fabrication, the materials of the first and second splitters may be identical to the material of the first waveguide and may be formed simultaneously with the first waveguide, and the materials of the third and fourth splitters may be identical to the material of the second waveguide and may be formed simultaneously with the second waveguide.

It should be noted that two phase shifters in the semiconductor device may be arranged in parallel, each phase shifter includes a pair of metal electrodes, and the two phase shifters may be provided with two pairs of metal electrodes, and when the two phase shifters are located relatively close to each other, the two phase shifters may share a middle metal electrode, thereby simplifying the process.

In the embodiment of the present application, a semiconductor device may be formed on the same substrate, and a plurality of MZ interferometers may be used to form a single-polarization or dual-polarization in-phase/quadrature (IQ) modulator, so as to achieve a higher modulation rate. In the following, an IQ modulator including two MZ interferometers is taken as an example, and referring to fig. 26, a schematic structural diagram of another semiconductor device provided in the embodiments of the present application is shown, the device comprises an optical input end, a 1 multiplied by 2 beam splitter, two MZ interferometers (MZ interferometer 1 and MZ interferometer 2), a 2 multiplied by 1 beam combiner and an optical output end, wherein the MZ interferometers can comprise phase shifters, the 1 multiplied by 2 beam splitter at the optical input end divides light into two parts which are respectively input into the two MZ interferometers, optical signals output from the MZ interferometers can be combined by the 2 multiplied by 1 beam combiner, the two MZ interferometers modulate the optical signals, and the output light of the two MZ interferometers generate interference, so that the characteristics of the combined optical signal are changed compared with the optical signal of the optical input end, such as light intensity change or light phase change, the combined light signal is output by the light output terminal.

In a specific implementation, the semiconductor device may include the MZ interferometer described above, the MZ interferometer includes an optical input end, a 1 × 2 beam splitter, two optical paths, a phase shifter, a 2 × 1 beam combination, and an optical output end, the phase shifter may include a substrate, a first dielectric layer, a first waveguide, an electro-optic crystal film layer, a second waveguide, and metal electrodes, the semiconductor device may further include a fifth beam splitter whose output end is connected to the input ends of the two first beam splitters, a seventh beam splitter whose output end is connected to the input ends of the two third beam splitters whose output ends are right opposite to the two first beam splitters, a sixth beam splitter whose input ends are connected to the output ends of the two second beam splitters, and an eighth beam splitter whose input ends are right opposite to the two fourth beam splitters, the fifth beam splitter and the sixth beam splitter are located in the first dielectric layer, and the refractive indexes of the fifth beam splitter and the sixth beam splitter are greater than the refractive index of the first dielectric layer, the seventh optical splitter and the eighth optical splitter are located above the electro-optic crystal film layer, and when the second medium layer is arranged above the electro-optic crystal film layer, the seventh optical splitter and the eighth optical splitter may be located in the second medium layer, and refractive indexes of the seventh optical splitter and the eighth optical splitter are greater than that of the second medium layer.

The fifth optical splitter and the seventh optical splitter are arranged oppositely in the longitudinal direction, the optical field in the electro-optical crystal film layer is limited in the extending direction of the fifth optical splitter and the seventh optical splitter, so that a 1 × 2 optical splitter of the optical input end is formed functionally, the output end of the optical splitter is connected with the input ends of two 1 × 2 optical splitters in a dashed frame, the sixth optical splitter and the eighth optical splitter are arranged oppositely in the longitudinal direction, the optical field in the electro-optical crystal film layer is limited in the extending direction of the sixth optical splitter and the eighth optical splitter, so that a 2 × 1 optical combiner of the optical output end is formed functionally, and the input end of the optical combiner is connected with the output ends of two 2 × 1 optical combiners in the dashed frame. For ease of manufacturing, the materials of the fifth and sixth splitters may be identical to the material of the first waveguide and may be formed simultaneously with the first waveguide, and the materials of the seventh and eighth splitters may be identical to the material of the second waveguide and may be formed simultaneously with the second waveguide.

It should be noted that four phase shifters in the semiconductor device may be arranged in parallel, each phase shifter includes a pair of metal electrodes, and four pairs of metal electrodes may be arranged in the four phase shifters, and certainly, when two adjacent phase shifters are located relatively close to each other, the two phase shifters may share a middle metal electrode, thereby simplifying the process.

In addition, in the IQ modulator, a phase shifter may not be provided in addition to the MZ interferometer, or may be additionally provided, one phase shifter may be provided, or a plurality of phase shifters may be provided, and the phase shifter may be provided at an input end of the MZ interferometer or at an output end of the MZ interferometer, and in the example shown in fig. 26, the phase shifter is provided at a position of an output end of the MZ interferometer 1, and the phase shifter functions to modulate a relative phase between output optical signals of the two MZ interferometers to a position necessary for operation. The phase shifter arranged outside the MZ interferometer may be the phase shifter provided in the embodiments of the present application, or may be a phase shifter with another structure.

That is, structurally, at least one third waveguide may be connected between the fifth optical splitter and the first optical splitter, the third waveguide is located in the first dielectric layer, the refractive index of the third waveguide is greater than that of the first dielectric layer, at least one fourth waveguide may be connected between the seventh optical splitter and the third optical splitter, the fourth waveguide is located above the electro-optic crystal film, when the second dielectric layer is located above the electro-optic crystal film, the fourth waveguide is located in the second dielectric layer, the refractive index of the fourth waveguide is smaller than that of the second dielectric layer, metal electrodes are disposed on two sides of the fourth waveguide, and the third waveguide and the fourth waveguide are disposed opposite to each other in the longitudinal direction, so that the third waveguide, the fourth waveguide, the electro-optic crystal film and the first dielectric layer constitute a phase shifter, the third waveguide and the fourth waveguide may limit an optical field in the electro-optic crystal film, and the metal electrodes on two sides of the fourth waveguide may be used to generate an electric field, modulation of the optical signal is achieved. For ease of manufacturing, the material of the third waveguide may be identical to the material of the first waveguide and may be formed simultaneously with the first waveguide, and the material of the fourth waveguide may be identical to the material of the second waveguide and may be formed simultaneously with the second waveguide.

Similarly, at least one fifth waveguide may be connected between the sixth beam splitter and the second beam splitter, the fifth waveguide is located in the first dielectric layer, the refractive index of the fifth waveguide is greater than that of the first dielectric layer, at least one sixth waveguide is connected between the eighth beam splitter and the fourth beam splitter, the sixth waveguide is located above the electro-optic crystal film layer, when the second dielectric layer is located above the electro-optic crystal film layer, the sixth waveguide is located in the second dielectric layer, and the refractive index of the sixth waveguide is smaller than that of the second dielectric layer, metal electrodes are arranged on two sides of the sixth waveguide, and the fifth waveguide and the sixth waveguide are arranged to face each other in the longitudinal direction, so that the fifth waveguide, the sixth waveguide, the electro-optic crystal film layer and the first dielectric layer constitute a phase shifter, the fifth waveguide and the sixth waveguide can limit the optical field in the electro-optic crystal film layer, and the metal electrodes on two sides of the sixth waveguide can be used for generating an electric field, modulation of the optical signal is achieved. For ease of manufacturing, the material of the fifth waveguide may be identical to the material of the first waveguide and may be formed simultaneously with the first waveguide, and the material of the sixth waveguide may be identical to the material of the second waveguide and may be formed simultaneously with the second waveguide.

In the embodiment of the present application, the semiconductor device may be formed on the same substrate to form a micro ring resonator (micro resonator) structure, and in the micro ring of the micro ring resonator, at least one phase shifter provided in the embodiment of the present application may be disposed. Referring to fig. 27, a schematic structural diagram of a semiconductor device according to an embodiment of the present disclosure is shown, where the semiconductor device may include an optical input end, an optical output end, a coupler, a micro-ring resonator, and a phase shifter, where an optical signal is input from the optical input end, returns to the coupler through the micro-ring resonator and the phase shifter in the micro-ring resonator, and combines with light input from the optical input end to the coupler to generate interference, the optical signal input from the optical input end may be an optical signal with multiple wavelengths, and due to characteristics of the micro-ring resonator and the phase shifter, optical interference with a certain wavelength may be cancelled, optical interference with a certain wavelength may be longer, and thus wavelength selectivity is provided. The electric signal in the phase shifter applies voltage to the waveguide to generate an electric field, the effective refractive index of the waveguide is changed, the resonance wavelength of the micro-ring resonant cavity is changed, namely the wavelength of the optical signal selected by the micro-ring resonant cavity is adjusted, and the intensity or the phase position of the optical signal at the optical output end is further changed.

Structurally, the semiconductor device may include an optical coupler and a phase shifter, the phase shifter may include a substrate, a first dielectric layer, a first waveguide, an electro-optic crystal film layer, a second waveguide, and a metal electrode, and the optical coupler may be connected to an input terminal of the phase shifter through a seventh waveguide and to an output terminal of the phase shifter through an eighth waveguide. The seventh waveguide and the eighth waveguide can form an integral structure with the electro-optic crystal film layer or can be of a separated structure, the seventh waveguide, the eighth waveguide and the optical coupler form a micro-ring resonant cavity, and the phase shifter is positioned in the micro-ring resonant cavity.

It should be noted that the optical output and the optical input share the same coupler in the foregoing embodiments, and in other embodiments, the optical output and the optical input may not share the same coupler. In addition, the seventh waveguide and the eighth waveguide of the micro-ring resonant cavity may only include a curved waveguide, or may include a curved waveguide and a straight waveguide, and form a racetrack structure. The seventh waveguide and the eighth waveguide in the micro-ring resonant cavity can be electro-optic crystal film layers, the limiting waveguides can be arranged above the electro-optic crystal film layers and can also be arranged below the electro-optic crystal film layers, and the limiting waveguides can have the same limiting effect as the first waveguide and the second waveguide on the electro-optic crystal film layers, so that the optical field in the electro-optic crystal film layers is limited.

In this embodiment, a semiconductor device may be formed on the same substrate to form a Fabry-Perot (FP) cavity structure, and in the FP cavity structure, at least one phase shifter provided in this embodiment may be disposed, and in addition, a phase shifter having another structure may be disposed to cooperate with the phase shifter provided in this embodiment, so that the intensity of an output optical signal may be changed by using a resonance phenomenon of light. Referring to fig. 28, as a schematic structural diagram of a further semiconductor device provided in this embodiment of the present application, the semiconductor device may include an optical input end, an optical output end, a first partial mirror, a second partial mirror, and a phase shifter, where the first partial mirror and the second partial mirror form a resonant cavity, the phase shifter is disposed in the resonant cavity, an optical signal is input from the optical input end, reflected back and forth between the first partial mirror and the second partial mirror, and exits from the partial mirrors after interference, and the optical signal input from the optical input end may be an optical signal with a single wavelength or multiple wavelengths. The electric signal in the phase shifter applies voltage to the waveguide to generate an electric field, the effective refractive index of the waveguide at the position is changed, the resonance wavelength of the FP resonant cavity is changed, namely the wavelength of the optical signal selected by the FP resonant cavity is adjusted, and the intensity or the phase position of the optical signal at the optical output end is further changed.

Structurally, the semiconductor device may include a first partial reflector, a second partial reflector, and a phase shifter, and the phase shifter may include a substrate, a first dielectric layer, a first waveguide, an electro-optic crystal film layer, a second waveguide, and a metal electrode, wherein the first partial reflector and an input end of the phase shifter are connected through a ninth waveguide, and the second partial reflector and an output end of the phase shifter are connected through a tenth waveguide. The ninth waveguide and the tenth waveguide may be integrated with the electro-optic crystal film layer or may be separate structures. The first partial reflector, the second partial reflector, the ninth waveguide and the tenth waveguide form a Fabry-Perot resonant cavity, and the phase shifter is located in the Fabry-Perot resonant cavity.

The ninth waveguide and the tenth waveguide in the micro-ring resonant cavity can be electro-optic crystal film layers, the limiting waveguides can be arranged above the electro-optic crystal film layers and can also be arranged below the electro-optic crystal film layers, and the limiting waveguides can have the same limiting effect as the first waveguide and the second waveguide on the electro-optic crystal film layers, so that the optical field in the electro-optic crystal film layers is limited.

The functional structure of the first partial mirror and the second partial mirror may be a waveguide bragg grating structure having a periodic structural change or a periodic refractive index change along the waveguide direction.

Based on the semiconductor device provided by the embodiment of the present application, an embodiment of the present application further provides an optical communication system, and the optical communication system may include at least one semiconductor device. As an example, the optical communication system may comprise a laser, a light detector, and the aforementioned semiconductor device, wherein the semiconductor device is disposed between the laser and the light detector, the laser is configured to emit a light signal, the semiconductor device is configured to electro-optically modulate the light signal, and the light detector is configured to detect the modulated light signal.

Specifically, referring to fig. 29, a schematic structural diagram of an optical communication system provided in this embodiment of the present application is shown, where the optical communication system may include a transmitter, a transmission medium, and a receiver, where the transmitter is configured to implement electrical/optical conversion, and the receiver is configured to implement optical/electrical conversion, where the laser may output laser light with a specific wavelength, the modulator is driven by an electrical chip in the transmitter, changes a characteristic of the light, such as phase or intensity, according to an input electrical signal, so as to implement conversion from the electrical signal to an optical signal, the wavelength division multiplexer may combine a plurality of optical signals with different wavelengths together and output the optical signals with the same port, the transmission medium is an optical fiber for propagating the optical signal, the wavelength division demultiplexer separates the optical signals with different wavelengths from the same incident port and transmits the optical signals to different output ports, and the optical detector converts the input optical signal into an electrical signal, an electrical chip in the receiver may process the electrical signal output by the photodetector.

The modulator may be the aforementioned semiconductor structure, and may include at least one phase shifter. The modulator of the transmitter is responsible for the key process of converting an electrical signal into an optical signal, and is one of the most core devices in an optical communication system, and is also an important factor for determining the bandwidth of the optical communication system. Further improving the efficiency and bandwidth of the optical signal to electrical signal conversion process plays a key role in improving the performance of the optical communication system. Therefore, a semiconductor device with higher efficiency and high bandwidth is very important for realizing an optical communication system with higher performance.

All the embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, as for the method embodiment, since it is basically similar to the structure embodiment, it is relatively simple to describe, and the relevant points can be referred to the partial description of the structure embodiment.

The above is a specific implementation of the present application. It should be understood that the above-mentioned embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A phase shifter, comprising:

a substrate;

the first dielectric layer is arranged on the substrate, a first waveguide is arranged in the first dielectric layer, and the refractive index of the first waveguide is greater than that of the first dielectric layer;

the electro-optic crystal film layer is arranged on the first medium layer; the electro-optic crystal film layer is made of a material with an electro-optic effect;

the second waveguide is arranged on the electro-optic crystal film layer and is opposite to the first waveguide in the longitudinal direction;

and the metal electrodes are arranged on the electro-optic crystal film layers on two sides of the second waveguide.

2. The phase shifter of claim 1, wherein the electro-optic crystal film layer and the first dielectric layer are bonded by bonding.

3. The phase shifter according to claim 1 or 2, wherein the electro-optical crystal film layer is made of lithium niobate, barium titanate, or lead zirconate titanate.

4. A phase shifter according to any one of claims 1-3, wherein the electro-optic crystal film layer has a thickness of less than or equal to 1.5 μm.

5. The phase shifter according to any one of claims 1-4, wherein the first waveguide is a first ridge structure integrated with a first slab layer, the first ridge structure is disposed toward the electro-optic crystal film layer, and the first dielectric layer is disposed on the first slab layer on both sides of the first waveguide; and/or the second waveguide is a second ridge structure which forms an integral structure with the second flat plate layer, the second ridge structure is arranged back to the electro-optic crystal film layer, and the metal electrodes are positioned above the second flat plate layer on two sides of the second waveguide.

6. The phase shifter according to any one of claims 1-5, wherein the material of the first waveguide and the second waveguide is one or more of silicon, silicon nitride, silicon oxide, and titanium dioxide.

7. The phase shifter of any one of claims 1-6, wherein the first waveguide is spaced from the electro-optic crystal film layer by a distance of less than or equal to 200 nanometers, and/or wherein the second waveguide is spaced from the electro-optic crystal film layer by a distance of less than or equal to 200 nanometers.

8. The phase shifter according to any one of claims 1 to 7, further comprising a second dielectric layer;

9. The phase shifter of claim 8, wherein the first dielectric layer is made of at least one of silicon oxide and silicon nitride, and the second dielectric layer is made of at least one of silicon oxide and silicon nitride.

10. The phase shifter according to any one of claims 1-9, further comprising:

11. A method of manufacturing a phase shifter, comprising:

providing a substrate;

forming an electro-optic crystal film layer on the surface of the first medium layer; the electro-optic crystal film layer is made of a material with an electro-optic effect;

12. The method of claim 11, wherein the forming an electro-optic crystal film layer on the surface of the first dielectric layer comprises:

and removing the substrate structure.

13. The method of claim 11 or 12, wherein the material of the electro-optic crystal film layer is lithium niobate, barium titanate or lead zirconate titanate.

14. The method of any of claims 11-13, wherein the electro-optic crystal film layer has a thickness of less than or equal to 1.5 microns.

15. The method of any of claims 11-14, wherein the first waveguide is a first ridge structure integral with a first slab layer, the first ridge structure being disposed toward the electro-optic crystal film layer, the first dielectric layer being on the first slab layer on both sides of the first waveguide; and/or the second waveguide is a second ridge structure which forms an integral structure with the second flat plate layer, the second ridge structure is arranged back to the electro-optic crystal film layer, and the metal electrodes are positioned above the second flat plate layer on two sides of the second waveguide.

16. A method according to any of claims 11-15, wherein the material of the first waveguide and the second waveguide is one or more of silicon, silicon nitride, silicon oxide and titanium dioxide.

17. The method of any of claims 11-16, wherein the first waveguide is less than or equal to 200 nanometers from the electro-optic crystal film layer, and/or wherein the second waveguide is less than or equal to 200 nanometers from the electro-optic crystal film layer.

18. The method of any one of claims 11-17, further comprising:

19. The method of claim 18, wherein the material of the first dielectric layer is at least one of silicon oxide and silicon nitride, and the material of the second dielectric layer is at least one of silicon oxide and silicon nitride.

20. The method according to any one of claims 11-19, further comprising:

21. A semiconductor device, characterized in that it comprises at least one phase shifter according to any one of claims 1-10.

22. The semiconductor device according to claim 21, further comprising:

23. The semiconductor device according to claim 22, further comprising:

24. The semiconductor device according to claim 23,

the optical fiber laser comprises an electro-optic crystal film layer, a first optical splitter and a second optical splitter, and is characterized in that at least one fifth waveguide is connected between the sixth optical splitter and the second optical splitter, the fifth waveguide is located in the first medium layer, the refractive index of the fifth waveguide is larger than that of the first medium layer, at least one sixth waveguide is connected between the eighth optical splitter and the fourth optical splitter, the sixth waveguide is located above the electro-optic crystal film layer, metal electrodes are arranged on two sides of the sixth waveguide, and the fifth waveguide and the sixth waveguide are arranged right in the longitudinal direction.

25. The semiconductor device according to claim 21, further comprising:

26. The semiconductor device according to claim 21, further comprising:

27. An optical communication system comprising a laser, a photodetector, the semiconductor device of any one of claims 21-26; the semiconductor device is arranged between the laser and the optical detector, the laser is used for emitting optical signals, the semiconductor device is used for carrying out electro-optical modulation on the optical signals, and the optical detector is used for detecting the optical signals after the electro-optical modulation.