Optical chip and preparation method therefor, and electronic device

Abstract

The present application relates to the technical field of optical communication. Disclosed are an optical chip and a preparation method therefor, and an electronic device. The preparation method comprises: acquiring a substrate, wherein the substrate comprises a first base and a first device layer that are stacked, and the first device layer comprises a detection portion for preparing a photoelectric detector; forming a first waveguide on the substrate, removing the first base, and bonding a second base, wherein the first device layer and the first waveguide are located on the same side of the second base, and the resistivity of the second base is greater than the resistivity of the first base; and forming a first electrode of an electro-optic modulator on the first waveguide, and forming a second electrode of the photoelectric detector on the detection portion. By means of the preparation method and an optical chip obtained thereby, the process compatibility of the optical chip can be enhanced, the loss of optical signals is reduced, the communication bandwidth of the optical chip is increased, and the communication performance of an electronic device is thus improved.

Description

Optical chips and their fabrication methods, electronic devices

[0001] This application claims priority to Chinese Patent Application No. 202410707085.0, filed on May 31, 2024, entitled "Optical Chip and Preparation Method Thereof, Electronic Device", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of optical communication technology, and in particular to an optical chip and its fabrication method, and an electronic device. Background Technology

[0003] Optical modulators in optical chips include various devices such as electro-optic modulators, acousto-optic modulators, and magneto-optic modulators. Among them, electro-optic modulators utilize the electro-optic effect to modulate the phase, amplitude, intensity, and polarization state of optical signals, exhibiting high-speed bandwidth characteristics and thus finding wide application. Lithium niobate (LiNbO3 / lithium niobate, LN) crystals possess many excellent optical properties, making them suitable for fabricating optical waveguides and electro-optic modulators constructed from optical waveguides.

[0004] However, the current lithium niobate electro-optic modulators consume a relatively large amount of power, which affects the communication performance of optical chips. How to reduce the power consumption of lithium niobate electro-optic modulators is an urgent problem to be solved. Summary of the Invention

[0005] This application provides an optical chip and its fabrication method, as well as an electronic device, which are used to reduce the loss of electro-optic modulators, increase the communication bandwidth of optical chips, and improve the communication performance of electronic devices.

[0006] In a first aspect, this application provides a method for fabricating an optical chip, comprising: obtaining a substrate, the substrate comprising a first substrate and a first device layer stacked on each other, the first device layer comprising a detector portion for fabricating a photodetector; forming a first waveguide on the substrate; removing the first substrate; bonding a second substrate, wherein the first device layer and the first waveguide are located on the same side of the second substrate, and the resistivity of the second substrate is greater than the resistivity of the first substrate; forming a first electrode of an electro-optic modulator on the first waveguide; and forming a second electrode of a photodetector on the detector portion.

[0007] According to the embodiments of this application, since the second substrate has high resistivity, it can reduce optical signal loss and crosstalk. Therefore, without a cavity, the second substrate can also reduce the microwave transmission loss of the electro-optic modulator, improving the robustness of the optical chip. Furthermore, the optical chip can inherit the advantages of single-crystal thin-film lithium niobate waveguides, such as small size, high bandwidth, and low half-wave voltage. Moreover, the electro-optic modulator in the optical chip is used for optical signal modulation and transmission, and the photodetector is used for optical signal reception, thus realizing integrated optical signal transmission and reception functionality.

[0008] In some embodiments of the first aspect described above, the bonding method for bonding the second substrate includes, but is not limited to, temporary bonding and permanent bonding.

[0009] Thus, during the fabrication of the optical chip, a specific bonding method can be selected according to the actual application requirements to bond the second substrate to the first device layer, thereby combining the second substrate with the first device layer, reducing the transmission loss of related devices in the first device layer, and improving the transmission performance of the optical chip.

[0010] In some embodiments of the first aspect described above, the material of the second substrate includes one or more of high-resistivity silicon, quartz, sapphire, and trap-rich silicon.

[0011] Thus, the impurity concentration in the high-resistivity silicon substrate is very low, resulting in high resistivity. Trap-rich silicon substrates can restore the high resistivity property of silicon substrates, thereby reducing the insertion loss of the chip. Quartz and sapphire can also reduce the loss and crosstalk of optical signals.

[0012] In some embodiments of the first aspect described above, forming a first waveguide on a substrate includes: bonding a lithium niobate thin film on the substrate and etching the lithium niobate thin film to obtain the first waveguide.

[0013] In this way, lithium niobate thin films can significantly reduce modulation voltage and power consumption by compressing the cross-sectional area of ​​the optical wave mode, and can greatly reduce the size of photonic devices, thus facilitating the realization of small-sized, high-performance optical chips.

[0014] In some embodiments of the first aspect described above, the process for removing the first substrate includes one or more of the following: grinding process, polishing process, dry etching process, and wet etching process.

[0015] In some embodiments of the first aspect above, obtaining a substrate includes: obtaining an SOI substrate; the SOI substrate includes a top silicon layer, a buried oxide layer, and a first substrate stacked along the thickness direction; fabricating an optical transmitter and a detector portion of a photodetector on the top silicon layer to obtain a first device layer; wherein the optical transmitter includes a second waveguide and a third waveguide stacked along the thickness direction; wherein the second waveguide and the third waveguide are made of different materials.

[0016] In some embodiments of the first aspect described above, the first waveguide includes a lithium niobate waveguide.

[0017] In some embodiments of the first aspect described above, the second waveguide includes a silicon waveguide.

[0018] In some embodiments of the first aspect described above, the third waveguide includes a silicon nitride waveguide.

[0019] It can be understood that an optical chip is an integrated optical chip made of a mixture of different materials, including lithium niobate waveguides, silicon waveguides, and silicon nitride waveguides. Among them, composite waveguides formed by silicon waveguides and lithium niobate waveguides, as well as silicon nitride waveguides, have excellent passive performance. The optical signals transmitted by them do not need to be modulated by an electro-optic modulator, thereby reducing the loss of optical signals during the modulation process and helping to improve the output ratio and extinction ratio of the optical chip.

[0020] In some embodiments of the first aspect described above, the detector includes a light-absorbing region and a silicon waveguide, wherein the silicon waveguide is partially embedded in the middle of the light-absorbing region along the length direction of the first substrate; wherein the thickness direction of the first substrate intersects the length direction of the first substrate.

[0021] Thus, the light absorption region and silicon waveguide are used to form a photodetector for receiving optical signals, which, when combined with an electro-optic modulator, achieves the purpose of transmitting and receiving optical signals in the same optical chip.

[0022] In some embodiments of the first aspect described above, the material of the light-absorbing region includes germanium.

[0023] Thus, germanium materials are used to form photodetectors to receive and transmit optical signals.

[0024] In some embodiments of the first aspect described above, the fabrication method further includes: fabricating one or more of a variable optical attenuator, a heater, and a polarization beam splitter on the top silicon layer to obtain a first device layer.

[0025] Thus, the variable optical attenuator is a passive optical device that achieves real-time control of the signal by attenuating the transmitted optical power; the heater is used for thermal control during the transmission of the optical signal; and the polarization beam splitter can output the optical signal in two beams with the same polarization state, thereby improving the problem of the large effective refractive index difference between the transverse electric mode and the transverse magnetic mode.

[0026] In some embodiments of the first aspect described above, the fabrication method further includes forming one or more cavities within a second substrate adjacent to the photodetector and / or electro-optic modulator along its thickness direction.

[0027] Thus, since the dielectric constant of the air in the cavity is less than that of the substrate material, the reduction in dielectric constant can further reduce the loss of optical signals during the entire transmission process, thereby further improving the communication performance of the optical chip.

[0028] Secondly, this application provides a method for fabricating an optical chip, comprising: obtaining a substrate, the substrate comprising a first substrate and a first device layer stacked on top of each other, the first device layer comprising a detector portion for fabricating a photodetector; bonding a second substrate to the side of the first device layer away from the first substrate, and removing the first substrate, wherein the resistivity of the second substrate is greater than the resistivity of the first substrate; forming a first waveguide on the side of the first device layer away from the second substrate; forming a first electrode of an electro-optic modulator on the first waveguide, and forming a second electrode of a photodetector on the detector portion; wherein the first electrode extends from the side of the first waveguide away from the second substrate along a first direction to the surface of the first device layer away from the second substrate, and the second electrode extends from the side of the detector portion toward the second substrate along a first direction to the surface of the first device layer away from the second substrate, the first direction being the direction from the second substrate toward the first device layer.

[0029] According to the embodiments of this application, the first electrode extends from the side of the first waveguide away from the second substrate along the first direction to the surface of the first device layer away from the second substrate, that is, the electro-optic modulator is a right-mounted structure, and the second electrode extends from the side of the detector facing the second substrate along the first direction to the surface of the first device layer away from the second substrate, that is, the photodetector is a flip-chip structure. In this way, according to the needs of process simplification and process compatibility, by changing the formation order of the devices, each optical transceiver device can be set as a right-mounted or flip-chip structure as needed, thereby improving the process compatibility of the optical chip.

[0030] In some embodiments of the second aspect described above, the bonding method for bonding the second substrate includes, but is not limited to, temporary bonding and permanent bonding.

[0031] Thus, during the fabrication of the optical chip, a specific bonding method can be selected according to the actual application requirements to bond the second substrate to the first device layer, thereby combining the second substrate with the first device layer, reducing the transmission loss of related devices in the first device layer, and improving the transmission performance of the optical chip.

[0032] Thirdly, this application provides a method for fabricating an optical chip, comprising: obtaining a substrate, the substrate comprising a first substrate and a first device layer stacked on top of each other, the first device layer comprising a detector portion for fabricating a photodetector; forming a first waveguide on the side of the first device layer away from the first substrate; forming a second substrate on the side of the first waveguide away from the first device layer, and removing the first substrate, wherein the resistivity of the second substrate is greater than the resistivity of the first substrate; forming a first electrode of an electro-optic modulator on the first waveguide, and forming a second electrode of a photodetector on the detector portion; wherein the first electrode extends from the side of the first waveguide toward the second substrate along a first direction to the surface of the first device layer away from the second substrate, and the second electrode extends from the side of the detector portion toward the second substrate along a first direction to the surface of the first device layer away from the second substrate, the first direction being the direction from the second substrate toward the first device layer.

[0033] According to the embodiments of this application, the first electrode extends from the side of the first waveguide toward the second substrate along the first direction to the surface of the first device layer away from the second substrate, that is, the electro-optic modulator is a flip-chip structure, and the second electrode extends from the side of the detector toward the second substrate along the first direction to the surface of the first device layer away from the second substrate, that is, the photodetector is a flip-chip structure. In this way, the electro-optic modulator, photodetector or other optical transceiver devices can be set as upright or flip-chip structures to be compatible with the fabrication and packaging processes of optical chips.

[0034] In some embodiments of the third aspect described above, the formation of the second substrate includes bonding methods, wherein the bonding methods include, but are not limited to, temporary bonding methods and permanent bonding methods.

[0035] Fourthly, this application provides a method for fabricating an optical chip, comprising: obtaining a substrate and obtaining a first waveguide, the substrate comprising a first base and a first device layer stacked on each other, the first device layer comprising a detector portion for fabricating a photodetector; bonding the first waveguide and the first device layer to a surface away from the first base; removing the first base and forming a second base on a side of the first device layer away from the first waveguide, wherein the resistivity of the second base is greater than the resistivity of the first base; forming a first electrode of an electro-optic modulator on the first waveguide, and forming a second electrode of a photodetector on the detector portion; wherein the first electrode extends from the first waveguide toward the second base along a first direction to the surface of the first device layer away from the second base, and the second electrode extends from the detector portion away from the second base along a first direction to the surface of the first device layer away from the second base, the first direction being the direction from the second base toward the first device layer.

[0036] According to the embodiments of this application, the first electrode extends from the side of the first waveguide toward the second substrate along the first direction to the surface of the first device layer away from the second substrate, that is, the electro-optic modulator is a flip-chip structure, and the second electrode extends from the side of the detector away from the second substrate along the first direction to the surface of the first device layer away from the second substrate, that is, the photodetector is a standard-mount structure, thereby improving the process compatibility of the optical chip.

[0037] In some embodiments of the fourth aspect described above, the formation of the second substrate includes a bonding method, wherein the bonding method includes, but is not limited to, a temporary bonding method and a permanent bonding method.

[0038] Fifthly, this application provides an optical chip, comprising: a second substrate and a first device layer stacked on top of each other, the first device layer including an electro-optic modulator and a photodetector; wherein, the electro-optic modulator includes a first electrode and a first waveguide, the first electrode extending from the side of the first waveguide away from the second substrate along a first direction to the surface of the first device layer away from the second substrate; the photodetector includes a detection part and a second electrode, the second electrode extending from the side of the detection part toward the second substrate along a first direction to the surface of the first device layer away from the second substrate, the first direction being the direction from the second substrate toward the first device layer.

[0039] In a sixth aspect, this application provides an optical chip, comprising: a second substrate and a first device layer stacked on top of each other, the first device layer including an electro-optic modulator and a photodetector; wherein, the electro-optic modulator includes a first electrode and a first waveguide, the first electrode extending from the first waveguide toward the second substrate along a first direction to the surface of the first device layer opposite to the second substrate; the photodetector includes a detection part and a second electrode, the second electrode extending from the detection part toward the second substrate along a first direction to the surface of the first device layer opposite to the second substrate, the first direction being the direction from the second substrate toward the first device layer.

[0040] In a seventh aspect, this application provides an optical chip, comprising: a second substrate and a first device layer stacked on top of each other, the first device layer including an electro-optic modulator and a photodetector; wherein, the electro-optic modulator includes a first electrode and a first waveguide, the first electrode extending from the first waveguide toward the second substrate along a first direction to the surface of the first device layer opposite to the second substrate; the photodetector includes a detection portion and a second electrode, the second electrode extending from the detection portion away from the second substrate along a first direction to the surface of the first device layer opposite to the second substrate, the first direction being the direction from the second substrate toward the first device layer.

[0041] In some embodiments of the optical chip described above, the material of the second substrate includes one or more of high-resistivity silicon, quartz, sapphire, and trap-rich silicon.

[0042] In some embodiments of the optical chip described above, the first device layer further includes at least one of an optical transmitter, a variable optical attenuator, a heater, and a polarization beam splitter; wherein the optical transmitter includes a stacked second waveguide and a third waveguide, the second waveguide and the third waveguide being made of different materials.

[0043] In some embodiments of the optical chip described above, the first waveguide includes a lithium niobate waveguide.

[0044] In some embodiments of the optical chip described above, the second waveguide includes a silicon waveguide.

[0045] In some embodiments of the optical chip described above, the third waveguide includes a silicon nitride waveguide.

[0046] Eighthly, this application provides an optical chip, which is obtained according to the optical chip fabrication method described in any one of the embodiments of this application.

[0047] Ninthly, this application provides an electronic device including the optical chip described in any one of the embodiments of this application.

[0048] The beneficial effects of the fifth to ninth aspects described above can be referred to the relevant descriptions of the first to fourth aspects and the various embodiments of the first to fourth aspects, which will not be repeated here. Attached Figure Description

[0049] To more clearly illustrate the technical solution of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0050] Figure 1A shows a partial cross-sectional structural schematic diagram of an optical chip 200 according to some embodiments of this application;

[0051] Figure 1B shows a schematic planar structure of an electro-optic modulator 210 according to some embodiments of this application;

[0052] Figure 2A shows a three-dimensional structural schematic diagram of an optical chip 200' according to some embodiments of this application;

[0053] Figure 2B shows a schematic cross-sectional structure of an optical chip 200' according to some embodiments of this application;

[0054] Figure 3 shows a cross-sectional structural schematic diagram of an optical chip 300a according to some embodiments of this application;

[0055] Figure 4 shows a flowchart of a method for fabricating an optical chip 300a according to some embodiments of this application;

[0056] Figure 5 shows a schematic cross-sectional structure of a first substrate 400 according to some embodiments of this application;

[0057] Figure 6 shows a cross-sectional structural schematic diagram of a target substrate 320 formed on the structure shown in Figure 5, according to some embodiments of this application;

[0058] Figure 7 shows a cross-sectional schematic diagram of a lithium niobate material layer 305 formed on the structure shown in Figure 6, according to some embodiments of this application.

[0059] Figure 8 shows a schematic cross-sectional structure of a lithium niobate waveguide 341 / 362 formed on the structure shown in Figure 7, according to some embodiments of the present application.

[0060] Figure 9 shows a schematic cross-sectional structure of an optical chip 300b according to some embodiments of this application;

[0061] Figure 10 shows a flowchart of a method for fabricating an optical chip 300b according to some embodiments of this application;

[0062] Figure 11 shows a schematic cross-sectional structure of the second substrate 400 according to some embodiments of this application;

[0063] Figure 12 shows a cross-sectional schematic diagram of a lithium niobate material layer 305 formed on the structure shown in Figure 11, according to some embodiments of this application.

[0064] Figure 13 shows a schematic cross-sectional structure of a lithium niobate waveguide 341 / 362 formed on the structure shown in Figure 12, according to some embodiments of the present application.

[0065] Figure 14 shows a schematic cross-sectional structure diagram of an electrode 342' formed on the structure shown in Figure 13, according to some embodiments of the present application.

[0066] Figure 15 shows a cross-sectional structural schematic diagram of a target substrate 320 formed on the structure shown in Figure 14, according to some embodiments of the present application.

[0067] Figure 16 shows a cross-sectional structural diagram of the structure shown in Figure 15 after removing the initial substrate 310, according to some embodiments of the present application.

[0068] Figure 17 shows a schematic cross-sectional structure of an optical chip 300c according to some embodiments of this application;

[0069] Figure 18 shows a flowchart of a method for fabricating an optical chip 300c according to some embodiments of this application;

[0070] Figure 19 shows a schematic cross-sectional structure of a third substrate 400 according to some embodiments of this application;

[0071] Figure 20 shows a cross-sectional schematic diagram of a lithium niobate material layer 305 formed on a substrate 310' according to some embodiments of this application;

[0072] Figure 21 shows a schematic cross-sectional structure of a lithium niobate waveguide 341 formed on the structure shown in Figure 20, according to some embodiments of the present application.

[0073] Figure 22 shows a schematic cross-sectional structure diagram of the structure shown in Figure 21 and the structure shown in Figure 19 after bonding, according to some embodiments of this application.

[0074] Figure 23 shows a cross-sectional structural schematic diagram of a target substrate 320 formed on the structure shown in Figure 22, according to some embodiments of the present application;

[0075] Figure 24 shows a cross-sectional structural schematic diagram of the structure shown in Figure 23 with the substrate 310' removed, according to some embodiments of the present application.

[0076] Figure 25 shows a schematic diagram of the structure of an electronic device 100 according to some embodiments of this application. Detailed Implementation

[0077] The illustrative embodiments of this application include, but are not limited to, optical chips and their fabrication methods, and electronic devices.

[0078] It should be noted that the directional terms such as "up," "down," "left," and "right" used in this document are exemplary orientations of the optical chip, and do not indicate or imply that the components referred to must have a specific orientation. These orientations can vary depending on actual use and should not be construed as limiting this application. Furthermore, the length direction described in the embodiments of this application can be the x-direction in the accompanying drawings, and the thickness direction can be the y-direction in the accompanying drawings.

[0079] It is understood that the optical chip mentioned in the embodiments of this application can be applied to any electronic device including communication functions. These electronic devices include, but are not limited to, mobile phones, tablets, personal computers, electronic watches, electronic bracelets, cameras, wearable devices, augmented reality (AR) devices, telecommunications rooms, data centers, routers, switches, and servers, etc., which are electronic devices with communication functions. The embodiments of this application do not limit the type or form of the electronic device. It should be noted that the optical chip mentioned in the embodiments of this application can also be applied to other types of communication electronic devices, which are not limited here.

[0080] For ease of description, some basic concepts and technical terms involved in this application will be introduced first.

[0081] An optical waveguide is a dielectric device that guides light waves to propagate; it is also called a dielectric waveguide. There are two main types of optical waveguides: one is integrated optical waveguides, including planar (thin-film) dielectric waveguides and strip dielectric waveguides. These are usually part of optoelectronic integrated devices or systems (such as electro-optic modulators), hence the name integrated optical waveguides; the other is cylindrical optical waveguides, commonly known as optical fibers.

[0082] Electro-optic modulators are modulators made using the electro-optic effect of certain electro-optic crystals, such as lithium niobate crystals, gallium arsenide crystals (GaAs), and lithium tantalate crystals (LiTaO3). The electro-optic effect occurs when a voltage is applied to the electro-optic crystal, causing a change in its refractive index. This change results in a change in the optical wave characteristics passing through the crystal, thus modulating the phase, amplitude, intensity, and polarization state of the optical signal.

[0083] Thin-film lithium niobate (TFLN) is a thin-film lithium niobate material formed by ion slicing, peeling off a thin film of lithium niobate from a bulk lithium niobate crystal, and then bonding it to a silicon wafer with a silicon dioxide (SiO2) buffer layer. Compared with ordinary lithium niobate crystal materials, thin-film lithium niobate retains its inherent advantages such as strong linear electro-optic effect and low intrinsic optical loss. It can also construct optical waveguides with high refractive index differences, significantly reducing modulation voltage and power consumption by compressing the cross-sectional area of ​​the optical wave mode, and greatly miniaturizing photonic device size. Therefore, it is beneficial for realizing small-size, high-performance optoelectronic chips for large-scale integration.

[0084] Integrated coherent transmitter and receiver (ICTR) refers to the optoelectronic integration of optical chips, electrical chips, carrier substrates / casings, and other auxiliary components to achieve coherent modulation and demodulation functions.

[0085] Insertion loss (IL) is a measure of the amount of light lost between two fixed points in an optical fiber. It can be understood as the loss of optical power caused by the intervention of optical devices in the optical fiber link of an optical communication system.

[0086] Microwave loss is the ratio of output power to input power, referring to the loss of power caused by factors such as the transmission medium during transmission. The spatial propagation of microwave signals can introduce various transmission impairments.

[0087] The extinction ratio is the ratio between the maximum transmitted light intensity and the minimum transmitted light intensity. A low extinction ratio will lead to decreased receiver sensitivity and a series of problems such as misinterpretation of symbols; a high extinction ratio will increase pattern-dependent jitter in the laser. Therefore, the extinction ratio should be selected based on the actual situation.

[0088] Figures 1A and 1B, according to some embodiments of this application, respectively show a partial cross-sectional structural schematic of an optical chip 200 and a planar structural schematic of an electro-optic modulator 210. It can be understood that the electro-optic modulator 210 is integrated on the optical chip 200.

[0089] As shown in Figure 1A, the optical chip 200 includes a substrate 220 and a dielectric layer 230 from bottom to top. The dielectric layer 230 includes a lithium niobate waveguide 211 and a metal electrode 212 located on the lithium niobate waveguide 211. The lithium niobate waveguide 211 and the metal electrode 212 are part of the electro-optic modulator 210 (Figure 1B).

[0090] As shown in Figure 1B, the electro-optic modulator 210 includes a lithium niobate waveguide 211, a metal electrode 212, and a directional coupler 213. The lithium niobate waveguide 211, from left to right, includes an input waveguide 211a, a waveguide modulation arm 211b, and an output waveguide 211c. The metal electrode 212 is located on both sides of the extension direction of the waveguide modulation arm 211b. The directional coupler 213 is located on one side of the input waveguide 211a and on one side of the waveguide modulation arm 211b closest to the input waveguide 211a.

[0091] The aforementioned electro-optic modulator 210 is a modulator based on a lithium niobate-on-insulator (LNOI) thin film material platform. Its working principle is as follows: the optical signal is input from the input waveguide 211a, and the beam of the optical signal is split and enters the waveguide modulation arm 211b respectively. The metal electrode loads the modulation signal onto the waveguide modulation arm 211b, and adjusts the effective refractive index of the waveguide modulation arm 211b, thereby changing the phase difference between the optical signals transmitted in each waveguide modulation arm 211b, and thus realizing the modulation of the optical signal. The modulated optical signal is output through the output waveguide 211c.

[0092] However, the aforementioned optical chip 200 is fabricated based on a silicon-on-insulator (SOI) substrate. The substrate 220 is the bottom silicon layer in SOI, the dielectric layer 230 is the buried oxide layer in SOI, and the waveguide 211 is obtained by etching the top silicon layer of SOI, depositing lithium niobate material, and then etching it. However, because the silicon material used in the bottom silicon layer has a high dielectric constant, and the dielectric constant characterizes the degree of signal attenuation by the medium, the higher the dielectric constant, the greater the loss of the optical signal. Therefore, the substrate 220 causes significant loss to the optical signal transmitted within the electro-optic modulator 210 on top, thus reducing the bandwidth of the electro-optic modulator 210 and affecting the performance of the communication equipment.

[0093] Figures 2A and 2B, according to some embodiments of this application, show a three-dimensional structure and cross-sectional schematic diagram of an optical chip 200'. Compared with optical chip 200, optical chip 200' reduces the dielectric constant of the substrate by setting a cavity in the substrate, thereby reducing microwave loss and improving communication bandwidth.

[0094] As shown in Figures 2A and 2B, the optical chip 200' is similar to the optical chip 200 in Figure 1A, comprising a substrate 220' and a dielectric layer 230 from bottom to top. The dielectric layer 230 includes a lithium niobate waveguide 211 and a metal electrode 212 located on the lithium niobate waveguide 211. The only difference between the optical chip 200' and the optical chip 200 is that the substrate 220' of the optical chip 200' has a cavity 221 located directly below the lithium niobate waveguide 211. Since the dielectric constant of the air in the cavity 221 is lower than that of the substrate 220' material, by setting the cavity 221 in the substrate 220' corresponding to the position of the lithium niobate waveguide 211, the overall dielectric constant of the substrate 220' can be reduced, thereby reducing the loss of the optical signal by the substrate 220' and increasing the bandwidth of the electro-optic modulator 210 above the cavity 221.

[0095] However, in the optical chip 200' of Figures 2A and 2B above, the substrate 220' with a large area cavity 221 causes the electro-optic modulator 210 above it to be suspended, making the chip structure unstable and reducing the robustness of the optical chip 200'.

[0096] To address the aforementioned problems, this application provides an optical chip, its fabrication method, and an electronic device. The optical chip includes a high-resistivity substrate and an electro-optic modulator mounted on top of it. The high-resistivity substrate is obtained by removing the underlying silicon from the original SOI substrate and bonding a new material. The increased resistivity of the substrate improves its insulation properties, thereby reducing the transmission loss of optical signals within the electro-optic modulator and consequently reducing microwave transmission loss. Furthermore, the elimination of a cavity in the substrate beneath the modulator enhances the mechanical robustness of the optical chip, thereby improving the communication performance of the electronic device.

[0097] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0098] The first embodiment of the optical chip and its fabrication method of this application will be described in detail below with reference to Figures 3-8.

[0099] Figure 3 shows a schematic cross-sectional structure of an optical chip 300a according to some embodiments of this application. The optical chip 300a employs a target substrate 320 with high resistivity, and an electro-optic modulator 340 is located above the target substrate 320. The target substrate 320 is made of one or more of high-resistivity silicon, quartz, sapphire, and trap-rich silicon. Because the impurity concentration in the high-resistivity silicon substrate is very low, it has high resistivity; the trap-rich silicon substrate can restore the high resistivity property of the silicon substrate, thereby reducing the insertion loss of the chip. Since the target substrate 320 has high resistivity, it can reduce optical signal loss and crosstalk. Therefore, without having a cavity, the target substrate 320 can also reduce the microwave transmission loss of the electro-optic modulator 340, improving the robustness of the optical chip 300a.

[0100] Referring again to Figure 3, the optical chip 300a includes a target substrate 320 and a first device layer stacked from bottom to top. The first device layer includes a target dielectric layer 330, which includes the following optical transceivers: an electro-optic modulator 340, a photodetector 350, and an optical transmitter 360.

[0101] The electro-optic modulator 340 is a front-mounted structure. Specifically, the electro-optic modulator 340 includes an interconnected lithium niobate waveguide 341 and electrodes 342 on both sides along its length direction (x direction).

[0102] It should be noted that the electro-optic modulator 340 has a forward-mounted structure, which can be understood as follows: the electrode 342 extends from the side of the lithium niobate waveguide 341 away from the target substrate 320 along the first direction to the surface of the first device layer away from the target substrate 320.

[0103] In addition, the first direction mentioned in the embodiments of this application is the direction in which the target substrate 320 points to the first device layer.

[0104] The photodetector 350 has a flip-chip structure. Specifically, the photodetector 350 includes a light-absorbing region 351, a silicon waveguide 352, and electrodes 353. The light-absorbing region 351 is partially embedded in the middle of the silicon waveguide 352, and the electrodes 353 are connected to both sides of the silicon waveguide 352 along its length (x-direction). For example, the light-absorbing region 351 can be made of germanium (Ge) material.

[0105] It should be noted that the photodetector 350 has an inverted structure, which can be understood as follows: the electrode 353 extends along the first direction from the side of the detection part (light absorption region 351 and silicon waveguide 352) toward the target substrate 320 to the surface of the first device layer away from the target substrate 320.

[0106] The optical transmitter 360 is a composite waveguide, comprising a silicon waveguide 361 and a lithium niobate waveguide 362. An insulating medium exists between the silicon waveguide 361 and the lithium niobate waveguide 362 along the y-direction.

[0107] In addition, the target dielectric layer 330 may also include a silicon nitride waveguide 370.

[0108] It is understood that the aforementioned silicon waveguide 361 and silicon waveguide 352 can be fabricated from the same silicon material layer 303. The aforementioned lithium niobate waveguide 341 and lithium niobate waveguide 362 can be fabricated from the same lithium niobate material layer 305. The silicon nitride waveguide 370 can be fabricated from a silicon nitride material layer 304.

[0109] It should be noted that the quantity and position of each device in Figure 3 are only examples. During the fabrication of the optical chip 300a, etching can be performed at other positions on the silicon material layer 303, lithium niobate material layer 305, and silicon nitride material layer 304 to prepare other waveguides such as the silicon waveguides 352 / 361, lithium niobate waveguides 341 / 362, and silicon nitride waveguide 370, depending on the actual application requirements. Furthermore, the lithium niobate material layer mentioned in the embodiments of this application can be based on a lithium niobate thin film.

[0110] Therefore, the optical chip 300a is an integrated optical chip composed of various materials, including but not limited to SOI, silicon nitride (SIN), germanium (Ge), and TFLN. These materials can form multiple waveguides of different materials, such as the aforementioned silicon waveguides 352 / 361, lithium niobate waveguides 341 / 362, and silicon nitride waveguide 370. Among these, the composite waveguide formed by silicon waveguide 361 and lithium niobate waveguide 362, and the silicon nitride waveguide 370, possess excellent passive performance. The transmitted optical signal does not require modulation by the electro-optic modulator 340, thereby reducing optical signal loss during modulation and contributing to improved output ratio and extinction ratio of the optical chip.

[0111] Furthermore, the optical chip 300a provided in this application inherits the advantages of single-crystal thin-film lithium niobate waveguides, such as small size, high bandwidth, and low half-wave voltage. In addition, the electro-optic modulator 340 in the optical chip 300a is used for optical signal modulation and transmission, and the photodetector 350 is used for optical signal reception, thereby realizing integrated optical signal transmission and reception. Furthermore, this facilitates the integration of ICTR, reduces the size of optoelectronic integrated chips, and promotes the miniaturization and packaging process of optical modules containing the optical chip 300a.

[0112] Figure 4 illustrates a method for fabricating an optical chip according to some embodiments of this application. This method yields the structure of the optical chip 300a shown in Figure 3. The fabrication method may include the following steps S31 to S34:

[0113] S31: Obtain a substrate, the substrate comprising a first substrate and a first device layer stacked on top of each other, the first device layer comprising a detector portion for fabricating a photodetector;

[0114] S32: Bond the second substrate to the side of the first device layer away from the first substrate, and remove the first substrate, wherein the resistivity of the second substrate is greater than the resistivity of the first substrate;

[0115] S33: A first waveguide is formed on the side of the first device layer that is away from the second substrate;

[0116] S34: A first electrode of an electro-optic modulator is formed on a first waveguide, and a second electrode of a photodetector is formed on a detection section; wherein the first electrode extends from the side of the first waveguide away from the second substrate along a first direction to the surface of the first device layer away from the second substrate, and the second electrode extends from the side of the detection section toward the second substrate along a first direction to the surface of the first device layer away from the second substrate, the first direction being the direction from the second substrate toward the first device layer.

[0117] In step S31, as shown in FIG5, specifically, a substrate 400 is obtained. The substrate 400 includes an initial substrate 310 (an example of a first substrate in this application) and a first device layer stacked on top of each other. The first device layer may include an initial dielectric layer 330' and a silicon material layer 303 and a silicon nitride material layer 304 stacked from bottom to top within the initial dielectric layer 330'. The silicon material layer 303 includes one or more silicon waveguides arranged along the x-direction, and the silicon nitride material layer 304 includes one or more silicon nitride waveguides arranged along the x-direction.

[0118] It is understood that the substrate 400 can be obtained based on the basic structure of SOI substrate (silicon-buried oxide-silicon). Therefore, the initial substrate 310 can be the bottom silicon in SOI substrate, the initial dielectric layer 330' in the first device layer can be the buried oxide layer, and the silicon material layer 303 can be the top silicon.

[0119] By etching the silicon material layer 303, a silicon waveguide 352 for use in a photodetector can be obtained. Furthermore, by etching the silicon material layer 303 to the buried oxide layer and then depositing silicon nitride material, a silicon nitride waveguide 370 can be formed by etching in the silicon nitride material layer 304.

[0120] It should be noted that in other embodiments, other waveguides can also be etched in other parts of the silicon material layer 303 and other parts of the silicon nitride material layer 304 for transmitting optical signals.

[0121] Referring again to Figure 5, in some embodiments, the first device layer further includes a light-absorbing region 351 and an electrode 353' for forming a photodetector (the light-absorbing region 351 and the silicon waveguide 352 together form an example of the detection section of this application). A portion of the light-absorbing region 351 is embedded in the middle of the silicon waveguide 352, and the electrode 353' is connected to both sides of the silicon waveguide 352 along its length direction (x direction). The light-absorbing region 351 and the silicon waveguide 352 are used to form a photodetector for receiving optical signals, thereby achieving the purpose of transmitting and receiving optical signals in the same optical chip.

[0122] In some embodiments, the material of the initial dielectric layer 330' may include silicon dioxide.

[0123] In some embodiments, the material of the light absorption region 351 may include germanium, which is used to form a photodetector to receive and transmit light signals.

[0124] In some embodiments, the first device layer may further include device structures such as a variable optical attenuator (VOA), a heater, and a polarization splitter rotator (PSR). The variable optical attenuator is a passive optical device that achieves real-time signal control by attenuating the transmitted optical power; the heater is used for thermal control during optical signal transmission; and the polarization splitter rotator can output the optical signal in two identical polarization modes, thereby improving the problem of a large effective refractive index difference between the transverse electric mode and the transverse magnetic mode. It should be noted that other devices may be integrated into the first device layer as needed, and this is not limited thereto.

[0125] In some embodiments, as shown in Figures 5-7, S32 includes:

[0126] S321: A target substrate 320 (an example of a second substrate in this application) is formed on the surface of the first device layer away from the initial substrate 310, wherein the resistivity of the target substrate 320 is greater than the resistivity of the initial substrate 310;

[0127] S322: Remove the initial substrate 310;

[0128] S323: Rotate the first device layer and the target substrate 320 together by 180° so that the target substrate 320 is located below the first device layer.

[0129] It should be noted that the order of S321, S322, and S323 can be changed, and different ones can be performed simultaneously; there are no restrictions here.

[0130] For example, the material of the target substrate 320 includes, but is not limited to, high-resistivity silicon, quartz, sapphire, and trap-rich silicon.

[0131] In S321, as shown in Figure 6, specifically, the process of forming the target substrate 320 can be a bonding process.

[0132] In some embodiments, the process for forming the target substrate 320 includes, but is not limited to, temporary bonding and permanent bonding. Therefore, during the fabrication of the optical chip, a specific bonding method can be selected according to the actual application requirements to bond the second substrate to the first device layer, thereby combining the second substrate with the first device layer, reducing the transmission loss of related devices in the first device layer, and improving the transmission performance of the optical chip.

[0133] In S322, continuing as shown in Figure 6, the removal process of the initial substrate 310 includes one or more of the following: grinding, polishing, dry etching, and wet etching. It should be noted that other process methods can also be used to remove the initial substrate 310, and are not limited here.

[0134] In S323, as shown in Figure 7, specifically, the first device layer and the target substrate 320 are flipped so that the target substrate 320 replaces the position of the initial substrate 310 and serves as the substrate for each optical transceiver device in the optical chip 300a.

[0135] It is understood that, since the first device layer is flipped in S32, and the first device layer includes the light absorption region 351 and the silicon waveguide 352 that make up the photodetector, the light absorption region 351 and the silicon waveguide 352 together form the detection part. Therefore, the photodetector obtained in this embodiment is a flip-chip structure.

[0136] In the above S32, since the resistivity of the target substrate 320 is greater than that of the initial substrate 310, using the target substrate 320 as the substrate for the first device layer and subsequent device formation can reduce the loss of the target substrate 320 for optical signal transmission, thereby improving the communication bandwidth of the optical chip 300a.

[0137] In some embodiments, as shown in Figures 7 and 8, S33 includes:

[0138] S331: A lithium niobate material layer 305 is formed on the side of the first device layer opposite to the target substrate 320;

[0139] S332: Etch lithium niobate material layer 305 to obtain lithium niobate waveguide 341 / 362.

[0140] In step S331, as shown in Figure 7, specifically, the surface of the first device layer facing away from the target substrate 320 is mechanically and chemically polished, and a lithium niobate material layer 305 is formed thereon. The lithium niobate material layer 305 can be formed using a bonding process.

[0141] In step S332, as shown in Figure 8, specifically, a lithium niobate material layer 305 is etched to form one or more lithium niobate waveguides arranged along the x-direction. Among them, the lithium niobate waveguide 341 (an example of the first waveguide in this application), which has no other waveguides below it, forms an electro-optic modulator for modulating and transmitting optical signals. The lithium niobate waveguide 362 forms the optical transmitter 360. Therefore, the use of waveguides made of different materials in this application can improve the integration density of the optical chip.

[0142] In some embodiments of this application, the etching method for the lithium niobate material layer 305 includes one or more of dry etching, wet etching, and focused ion beam etching. It should be noted that other etching methods may also be used, and are not limited thereto.

[0143] It is understood that since the lithium niobate waveguide 341 that makes up the electro-optic modulator is formed after the flipping operation, the electro-optic modulator obtained in this embodiment is a positive mounting structure.

[0144] In some embodiments of this application, S34 performs electrode fabrication based on the optical chip 300a shown in FIG7.

[0145] In some embodiments of this application, as shown in FIG3, S34 includes:

[0146] S341: A dielectric layer is formed above the initial dielectric layer 330', thereby forming the target dielectric layer 330 together with the initial dielectric layer 330'; wherein, the material of the dielectric layer can be the same as the material of the initial dielectric layer 330';

[0147] S342: Electrodes 342 (an example of the first electrode of this application) are formed on both sides of the lithium niobate waveguide 341 along the x direction to obtain an upright photoelectric modulator 340. Furthermore, an electrode is formed again on the electrode 353' to obtain electrode 353 (an example of the second electrode of this application), thereby obtaining an inverted photodetector 350.

[0148] The reasons for the formation of upright electro-optic modulators and inverted photodetectors are described above and will not be repeated here.

[0149] In some embodiments of this application, the composite waveguide composed of silicon nitride waveguide 370, lithium niobate waveguide 362 and silicon waveguide 361 adjacent along the y-direction in optical chip 300a can all be used to transmit optical signals.

[0150] In some embodiments of this application, both electrode 342 and electrode 353 are metal electrodes and are fabricated using a metal interconnect process. The metal interconnect process may include one or more of pure aluminum interconnect, copper interconnect, gold-aluminum interconnect, and tungsten-aluminum interconnect. It should be noted that other materials may also be used to fabricate electrode 342 and electrode 353, and this is not limited thereto.

[0151] The aforementioned method for fabricating optical chips utilizes a bonding process to replace the silicon substrate of the optical chip with a high-resistivity target substrate, achieving an integrated optical transceiver structure. This improves the microwave performance of the electro-optic modulator without creating cavities within the target substrate. Furthermore, it significantly reduces the suspended area of ​​the device, thereby enhancing the chip's mechanical robustness.

[0152] In addition, the substrate 220' with cavity 221 in Figure 2A will also affect the subsequent process, increasing the complexity of the fabrication and packaging process in the optical chip 200', thus making it difficult to be compatible with advanced packaging processes.

[0153] Compared with optical chip 200', the fabrication method of optical chip 300a provided in this embodiment can reduce losses without setting a cavity in the substrate below the electro-optic modulator. While simplifying the process, it can also enhance the process compatibility of optical chip 300a with advanced packaging.

[0154] It should be noted that, depending on the actual application requirements, a cavity can also be selectively provided within the target substrate 320 below the electro-optic modulator 340, photodetector 350, optical transmitter 360, silicon nitride waveguide 370, or other devices in the optical chip 300a (extending along the y-direction), and this application does not limit this. Specifically, the cavity can also be located within the target substrate 320 below one or more devices among the variable optical attenuator, heater, and polarization beam splitter. Since the dielectric constant of air in the cavity is lower than that of the target substrate material, the target substrate can further reduce the loss of optical signals during the entire transmission process due to the reduced dielectric constant, thereby further improving the communication performance of the optical chip.

[0155] The second embodiment of the optical chip and its fabrication method of this application will be described in detail below with reference to Figures 9-16. The main difference between optical chip 300b and optical chip 300a (Figure 3) is that the electro-optic modulator and photodetector in optical chip 300b are both flip-chip structures.

[0156] Figure 9 shows a schematic cross-sectional structure of an optical chip 300b according to some embodiments of this application. Similar to optical chip 300a, optical chip 300b also employs a target substrate 320 with high resistivity, and an electro-optic modulator 340 is located on the target substrate 320. The target substrate 320 is made of one or more of high-resistivity silicon, quartz, sapphire, and trap-rich silicon. The target substrate 320 can reduce the microwave transmission loss of the electro-optic modulator 340, improving the robustness and stability of the optical chip 300b.

[0157] Referring again to Figure 9, the optical chip 300b includes a target substrate 320 and a first device layer stacked from bottom to top. The first device layer includes a target dielectric layer 330, which includes the following optical transceivers: an electro-optic modulator 340, a photodetector 350, and an optical transmitter 360.

[0158] The electro-optic modulator 340 is a flip-chip structure. Specifically, the electro-optic modulator 340 includes an interconnected lithium niobate waveguide 341 and electrodes 342 on both sides along its length direction (x direction).

[0159] It should be noted that the electro-optic modulator 340 is a flip-chip structure, which can be understood as follows: the electrode 342 extends from the lithium niobate waveguide 341 toward the target substrate 320 along the first direction to the surface of the first device layer away from the target substrate 320.

[0160] In addition, the first direction mentioned in the embodiments of this application is the direction in which the target substrate 320 points to the first device layer.

[0161] The photodetector 350 has a flip-chip structure. Specifically, the photodetector 350 includes a light-absorbing region 351, a silicon waveguide 352, and electrodes 353. The light-absorbing region 351 is partially embedded in the middle of the silicon waveguide 352, and the electrodes 353 are connected to both sides of the silicon waveguide 352 along its length (x-direction). For example, the light-absorbing region 351 can be made of germanium (Ge) material.

[0162] It should be noted that the photodetector 350 has an inverted structure, which can be understood as follows: the electrode 353 extends along the first direction from the side of the detection part (light absorption region 351 and silicon waveguide 352) toward the target substrate 320 to the surface of the first device layer away from the target substrate 320.

[0163] The optical transmitter 360 is a composite waveguide, comprising a silicon waveguide 361, a lithium niobate waveguide 362, and a silicon nitride waveguide 363. Along the y-direction, there is an isolation medium between the silicon waveguide 361 and the silicon nitride waveguide 363, and between the lithium niobate waveguide 362 and the silicon nitride waveguide 363.

[0164] In addition, the target dielectric layer 330 may also include a silicon nitride waveguide 370.

[0165] It is understood that the silicon waveguides 361 and 352 can be fabricated from the same silicon material layer 303. The lithium niobate waveguides 341 and 362 can be fabricated from the same lithium niobate material layer 305. The silicon nitride waveguides 363 and 370 can be fabricated from the same silicon nitride material layer 304.

[0166] It should be noted that the number and position of each device in Figure 9 are only examples. During the fabrication of the optical chip 300b, etching can be performed at other positions of the silicon material layer 303, lithium niobate material layer 305, and silicon nitride material layer 304 to prepare other waveguides such as silicon waveguides 352 / 361, lithium niobate waveguides 341 / 362, and silicon nitride waveguides 370 / 363, depending on the actual application requirements.

[0167] Therefore, optical chip 300b is an optical chip integrated with a variety of different materials. Its excellent passive performance can be referred to the description of optical chip 300a above, and will not be repeated here.

[0168] Furthermore, the optical chip 300b provided in this application can realize the function of transmitting and receiving optical signals. Its specific beneficial effects can be referred to the description of the optical chip 300a above, and will not be repeated here.

[0169] Figure 10 illustrates a method for fabricating an optical chip according to some embodiments of this application. This method yields the structure of the optical chip 300b shown in Figure 9. The fabrication method may include the following steps S41 to S44:

[0170] S41: Obtain a substrate, the substrate comprising a first substrate and a first device layer stacked on top of each other, the first device layer comprising a detector portion for fabricating a photodetector;

[0171] S42: A first waveguide is formed on the side of the first device layer that is away from the first substrate;

[0172] S43: A second substrate is formed on the side of the first waveguide away from the first device layer, and the first substrate is removed, wherein the resistivity of the second substrate is greater than the resistivity of the first substrate;

[0173] S44: A first electrode of an electro-optic modulator is formed on a first waveguide, and a second electrode of a photodetector is formed on a detection section; wherein the first electrode extends from the first waveguide toward the second substrate along a first direction to the surface of the first device layer away from the second substrate, and the second electrode extends from the detection section toward the second substrate along a first direction to the surface of the first device layer away from the second substrate, the first direction being the direction from the second substrate toward the first device layer.

[0174] In step S41, as shown in FIG11, a substrate 400 is specifically obtained. The substrate 400 includes an initial substrate 310 (an example of the first substrate of this application) and a first device layer stacked on top of each other. Since step S41 is the same as step S31, the specific structure of the first device layer in FIG11 can be referred to the above-described related information and will not be repeated here.

[0175] It is understood that the substrate 400 can be obtained based on the basic structure of SOI substrate (silicon-buried oxide-silicon). Therefore, the initial substrate 310 can be the bottom silicon in SOI substrate, the initial dielectric layer 330' in the first device layer can be the buried oxide layer, and the silicon material layer 303 can be the top silicon.

[0176] In addition, the formation process of silicon waveguide 352 and silicon nitride waveguide 370 can be referred to the above description, and will not be repeated here.

[0177] It should be noted that in other embodiments, other waveguides can also be etched in other parts of the silicon material layer 303 and other parts of the silicon nitride material layer 304 for transmitting optical signals.

[0178] It should be noted that the stacked silicon material layer 303 and silicon nitride material layer 304 can be disposed at different positions within the initial dielectric layer 330' in different embodiments as needed to form a passive waveguide or other optical transceiver device, and are not limited to the positions shown in the figure.

[0179] Referring again to FIG11, in some embodiments, the first device layer further includes a light absorption region 351 and an electrode 353' for forming a photodetector (the light absorption region 351 and the silicon waveguide 352 together form an example of the detection section of this application), the specific structure of which can be referred to the above description and will not be repeated here.

[0180] In some embodiments, the material of the initial dielectric layer 330' may include silicon dioxide.

[0181] In some embodiments, the material of the light absorption region 351 may include germanium.

[0182] In some embodiments, the first device layer may also include device structures such as a variable optical attenuator, a heater, and a polarization beam splitter. Other devices may also be integrated into the first device layer as needed, without limitation.

[0183] In some embodiments of this application, as shown in Figures 12-14, S42 includes:

[0184] S421: A lithium niobate material layer 305 is formed on the side of the first device layer opposite to the initial substrate 310;

[0185] S422: Etch lithium niobate material layer 305 to obtain lithium niobate waveguide 341 / 362;

[0186] S423: Electrodes 342' are formed on both sides of the lithium niobate waveguide 341 along the length direction (x direction).

[0187] In step S421, as shown in Figure 12, specifically, the surface of the first device layer facing away from the initial substrate 310 is mechanically and chemically polished, and a lithium niobate material layer 305 is formed thereon. The lithium niobate material layer 305 can be formed using a bonding process.

[0188] The etching method for the lithium niobate material layer 305 can be found in the relevant paragraphs above, and will not be repeated here.

[0189] In S422, as shown in Figure 13, a lithium niobate waveguide 341 (an example of the first waveguide of this application) without any other waveguides below it forms an electro-optic modulator for modulating and transmitting optical signals. A lithium niobate waveguide 362 forms an optical transmitter 360.

[0190] In S423, as shown in Figure 14, the material of electrode 342' includes, but is not limited to, metallic materials such as aluminum, copper, and gold. It should be noted that electrode 342' is not the final electrode of the electro-optic modulator. The formation of electrode 342' facilitates subsequent electrode fabrication processes, thereby obtaining electrode 342 of the electro-optic modulator (Figure 9).

[0191] In some embodiments of this application, as shown in Figures 15-16, S43 includes:

[0192] S431: A waveguide dielectric layer is formed in the gap and on the surface of the lithium niobate material layer 305. The waveguide dielectric layer and the initial dielectric layer 330' together form the target dielectric layer 330.

[0193] S432: A target substrate 320 (an example of a second substrate in this application) is formed on the side of the lithium niobate material layer 305 away from the first device layer, wherein the resistivity of the target substrate 320 is greater than the resistivity of the initial substrate 310;

[0194] S433: Remove the initial substrate 310;

[0195] S434: Rotate the structure obtained in S433 by 180° so that the target substrate 320 is located below the first device layer.

[0196] It should be noted that the order of S431, S432, S433 and S434 can be changed, and different ones can be performed simultaneously, without any restrictions.

[0197] In S431, as shown in Figure 15, the material of the waveguide dielectric layer can be the same as the material of the initial dielectric layer 330', and both can be oxide layers. Specifically, the waveguide dielectric layer and the initial dielectric layer 330' can be silicon dioxide layers, that is, the target dielectric layer 330 is a silicon dioxide layer.

[0198] In S432, continuing as shown in Figure 15, the target substrate 320 is a substrate with high resistivity. Due to the increased resistivity, the transmission loss of the optical signal in the electro-optic modulator above the target substrate 320 can be reduced, thereby reducing microwave transmission loss. In addition, not fabricating a cavity can enhance the mechanical robustness and process compatibility of the chip, thereby improving the stability of the chip.

[0199] It should be noted that the process for forming the target substrate 320 can be referred to the description in the above embodiments, and will not be repeated here.

[0200] For example, the material of the target substrate 320 includes, but is not limited to, high-resistivity silicon, quartz, sapphire, and trap-rich silicon.

[0201] In S433, as shown in Figure 16, a detailed description of removing the initial substrate 310 can be found in the relevant paragraphs of the above-mentioned method for fabricating the optical chip 300a, and will not be repeated here.

[0202] In S434, continuing as shown in Figure 16, since the optical chip 300b is flipped as a whole in S433, and the optical chip 300b includes the light absorption region 351 and silicon waveguide 352 that constitute the photodetector, and the lithium niobate waveguide 341 that constitutes the electro-optic modulator, the photodetector and electro-optic modulator obtained in this embodiment are both flip-chip structures.

[0203] In step S44, as shown in FIG9, electrode fabrication is performed based on the optical chip 300b shown in FIG16. Specifically, in step S34, electrode fabrication is performed again on electrode 342' to form electrode 342 of electro-optic modulator 340 (an example of the first electrode in this application), resulting in a flip-chip photoelectric modulator 340. Furthermore, electrode fabrication is performed again on electrode 353' to form electrode 353 of photodetector 350 (an example of the second electrode in this application), resulting in a flip-chip photodetector 350. The reasons for the flip-chip formation of photodetector 350 and electro-optic modulator 340 are described above and will not be repeated here.

[0204] The above-mentioned method for fabricating optical chip 300b can be adapted to simplify the process and improve the integration by changing the bonding order of the target substrate 320 in the process and the formation order of the devices (e.g., the electro-optic modulator 340). This allows each optical transceiver device to be configured as a conventional or flip-chip structure as needed, thereby improving the fabrication efficiency and integration of the optical chip.

[0205] It should be noted that, depending on the actual application requirements, a cavity may also be selectively provided within the target substrate 320 below the electro-optic modulator 340, photodetector 350, optical transmitter 360, silicon nitride waveguide 370, or other devices in the optical chip 300b (extending along the y-direction), and this application does not limit this. Specifically, the cavity may also be located within the target substrate 320 below one or more devices among the variable optical attenuator, heater, and polarization beam splitter rotator.

[0206] The third embodiment of the optical chip and its fabrication method of this application will be described in detail below with reference to Figures 17-24. The main difference between optical chip 300c and optical chip 300a (Figure 3) and optical chip 300b (Figure 9) is that the electro-optic modulator in optical chip 300c is a flip-chip structure and the photodetector is a regular-mount structure.

[0207] Figure 17 shows a schematic cross-sectional structure of an optical chip 300c according to some embodiments of this application. Similar to optical chips 300a / 300b, optical chip 300c also employs a target substrate 320 with high resistivity, and an electro-optic modulator 340 is located on the target substrate 320. The target substrate 320 is made of one or more of high-resistivity silicon, quartz, sapphire, and trap-rich silicon. The target substrate 320 can reduce the microwave transmission loss of the electro-optic modulator 340, improving the robustness and stability of the optical chip 300c.

[0208] Referring again to Figure 17, the optical chip 300c includes a target substrate 320 and a first device layer stacked from bottom to top. The first device layer includes a target dielectric layer 330, which includes the following optical transceivers: an electro-optic modulator 340, a photodetector 350, and an optical transmitter 360.

[0209] The electro-optic modulator 340 is a flip-chip structure. Specifically, the electro-optic modulator 340 includes an interconnected lithium niobate waveguide 341 and electrodes 342 on both sides along its length direction (x direction).

[0210] It should be noted that the electro-optic modulator 340 is a flip-chip structure, which can be understood as follows: the electrode 342 extends from the lithium niobate waveguide 341 toward the target substrate 320 along the first direction to the surface of the first device layer away from the target substrate 320.

[0211] In addition, the first direction mentioned in the embodiments of this application is the direction in which the target substrate 320 points to the first device layer.

[0212] The photodetector 350 has a front-mounted structure. Specifically, the photodetector 350 includes a light-absorbing region 351, a silicon waveguide 352, and electrodes 353. The light-absorbing region 351 is partially embedded in the middle of the silicon waveguide 352, and the electrodes 353 are connected to both sides of the silicon waveguide 352 along its length (x-direction). For example, the light-absorbing region 351 can be made of germanium (Ge) material.

[0213] It should be noted that the photodetector 350 has a positive mounting structure, which can be understood as follows: the electrode 353 extends along the first direction from the side of the detection part (light absorption region 351 and silicon waveguide 352) away from the target substrate 320 to the surface of the first device layer away from the target substrate 320.

[0214] The optical transmitter 360 is a composite waveguide, comprising a silicon waveguide 361, a lithium niobate waveguide 362, and a silicon nitride waveguide 363. Along the y-direction, there is an isolation medium between the silicon waveguide 361 and the silicon nitride waveguide 363, and between the lithium niobate waveguide 362 and the silicon nitride waveguide 363.

[0215] In addition, the target dielectric layer 330 may also include a silicon nitride waveguide 370.

[0216] It is understood that the silicon waveguides 361 and 352 can be fabricated from the same silicon material layer 303. The lithium niobate waveguides 341 and 362 can be fabricated from the same lithium niobate material layer 305. The silicon nitride waveguides 363 and 370 can be fabricated from the same silicon nitride material layer 304.

[0217] It should be noted that the number and position of each device in Figure 17 are only examples. During the fabrication of the optical chip 300c, etching can be performed at other positions of the silicon material layer 303, lithium niobate material layer 305, and silicon nitride material layer 304 to prepare other waveguides such as silicon waveguides 352 / 361, lithium niobate waveguides 341 / 362, and silicon nitride waveguides 370 / 363, depending on the actual application requirements.

[0218] Therefore, optical chip 300c is an optical chip that integrates multiple different materials. Its excellent passive performance can be referred to the description of optical chip 300a above, and will not be repeated here.

[0219] Furthermore, the optical chip 300c provided in this application can realize the function of transmitting and receiving optical signals. Its specific beneficial effects can be referred to the description of the optical chip 300a mentioned above, and will not be repeated here.

[0220] Figure 18 illustrates a method for fabricating an optical chip according to some embodiments of this application. This method yields the structure of the optical chip 300c shown in Figure 17. The fabrication method may include the following steps S51 to S54:

[0221] S51: Obtain a substrate and a first waveguide, the substrate comprising an initial substrate (an example of a first substrate in this application) and a first device layer stacked on top of each other, the first device layer comprising a detector portion for fabricating a photodetector;

[0222] S52: Bond the first waveguide and the first device layer to the surface opposite to the initial substrate;

[0223] S53: Remove the initial substrate and form a target substrate (an example of a second substrate in this application) on the side of the first device layer away from the first waveguide, wherein the resistivity of the target substrate is greater than the resistivity of the initial substrate.

[0224] S54: A first electrode of an electro-optic modulator is formed on a first waveguide, and a second electrode of a photodetector is formed on a detection section; wherein the first electrode extends from the side of the first waveguide toward the second substrate along a first direction to the surface of the first device layer away from the second substrate, and the second electrode extends from the side of the detection section away from the second substrate along a first direction to the surface of the first device layer away from the second substrate, the first direction being the direction from the second substrate toward the first device layer.

[0225] In some embodiments of this application, as shown in FIG19, S51 includes:

[0226] S511: Obtain substrate 400; substrate 400 includes an initial substrate 310 and a first device layer stacked on top of each other, the first device layer including a light absorption region 351 and a silicon waveguide 352 for fabricating a detector (the light absorption region 351 and the silicon waveguide 352 constitute an example of the detector section of this application);

[0227] S512: Obtain lithium niobate waveguide 341 (an example of the first waveguide of this application).

[0228] It should be noted that the order of S511 and S512 can be changed, or they can be performed simultaneously; there are no restrictions on this.

[0229] In S511, as shown in Figure 19, specifically, S511 is the same as S31. The specific structure of the first device layer can be referred to the above-mentioned description, and will not be repeated here.

[0230] It is understandable that the initial substrate 310 can be the bottom silicon in the SOI substrate, the initial dielectric layer 330' in the first device layer can be the buried oxide layer, and the silicon material layer 303 can be the top silicon.

[0231] In addition, the formation process of silicon waveguide 352 and silicon nitride waveguide 370 can be referred to the above description, and will not be repeated here.

[0232] It should be noted that in other embodiments, other waveguides can also be etched in other parts of the silicon material layer 303 and other parts of the silicon nitride material layer 304 for transmitting optical signals.

[0233] It should be noted that the stacked silicon material layer 303 and silicon nitride material layer 304 can be disposed at different positions within the initial dielectric layer 330' in different embodiments as needed to form a passive waveguide or other optical transceiver device, and are not limited to the positions shown in the figure.

[0234] Referring again to FIG19, in some embodiments, the first device layer further includes a light absorption region 351 and an electrode 353' for forming a photodetector (the light absorption region 351 and the silicon waveguide 352 together form an example of the detection section of this application), the specific structure of which can be referred to the above description and will not be repeated here.

[0235] In some embodiments, the material of the initial dielectric layer 330' may include silicon dioxide.

[0236] In some embodiments, the material of the light absorption region 351 may include germanium.

[0237] In some embodiments, the first device layer may also include device structures such as a variable optical attenuator, a heater, and a polarization beam splitter. Other devices may also be integrated into the first device layer as needed, without limitation.

[0238] In some embodiments of this application, as shown in Figures 20-21, S512 includes:

[0239] S5121: Obtain a substrate 310' and form a lithium niobate material layer 305 thereon;

[0240] S5122: Etch lithium niobate material layer 305 to obtain lithium niobate waveguide 341 / 362;

[0241] S5123: Electrodes 342' are formed on both sides of the lithium niobate waveguide 341 along the length direction (x direction);

[0242] S5124: A waveguide dielectric layer 331 is formed in the gaps and on the surface of the lithium niobate material layer 305.

[0243] In S5121, as shown in Figure 20, specifically, the substrate 310' includes a silicon substrate.

[0244] In S5122, as shown in Figure 21, the etching method of the lithium niobate material layer 305 can be referred to the relevant paragraphs of the above-mentioned preparation method of the optical chip 300a, and will not be repeated here.

[0245] In S5123, as shown in Figure 21, electrodes 342' are formed on both sides of the lithium niobate waveguide 341 along the length direction (x direction). The description of electrodes 342' can be found in the description of the fabrication method of the optical chip 300b described above, and will not be repeated here.

[0246] In S5124, continuing as shown in Figure 21, specifically, the material of the waveguide dielectric layer 331 can be the same as the material of the initial dielectric layer 330', and both can be oxide layers. Specifically, both the waveguide dielectric layer and the initial dielectric layer 330' can be silicon dioxide layers.

[0247] In S52, as shown in Figure 22, specifically, the surface of the waveguide dielectric layer 331 facing away from the substrate 310' is bonded to the surface of the first device layer facing away from the initial substrate 310. The bonded waveguide dielectric layer 331 and the initial dielectric layer 330' together form an intermediate dielectric layer 330". The intermediate dielectric layer 330" can be a silicon dioxide layer.

[0248] In some embodiments of this application, as shown in Figures 23 and 24, S53 includes:

[0249] S531: Remove the initial substrate 310;

[0250] S532: A target substrate 320 is formed at the position before the initial substrate 310 is removed, wherein the resistivity of the target substrate 320 is greater than the resistivity of the initial substrate 310.

[0251] S533: Remove substrate 310'.

[0252] In S531 and S533, as shown in Figures 23 and 24, the process of removing the initial substrate 310 or removing the substrate 310' includes one or more of the following processes: grinding, polishing, dry etching, and wet etching.

[0253] In S532, continuing as shown in Figure 23, since the resistivity of the target substrate 320 is greater than that of the initial substrate 310, the loss and crosstalk of the optical signal can be reduced. In the absence of a cavity in the target substrate 320, the microwave transmission loss of the electro-optic modulator 340 can be reduced, and the robustness and stability of the optical chip 300c can be improved.

[0254] It should be noted that the process for forming the target substrate 320 can be referred to the description in the above embodiments, and will not be repeated here.

[0255] In S54, as shown in FIG17, electrode fabrication is performed based on the structure shown in FIG24. In S34, specifically, electrode fabrication is performed again on electrode 342' to form electrode 342 of electro-optic modulator 340 (an example of the first electrode of this application), resulting in a flip-chip photoelectric modulator 340. Furthermore, an electrode is formed on electrode 353' to form electrode 353 of photodetector 350 (an example of the second electrode of this application), resulting in a properly mounted photodetector 350.

[0256] In this embodiment, the lithium niobate material layer 305 is flipped and bonded to the first device layer, and no other structures are flipped. Therefore, the photodetector 350 obtained in this embodiment is a right-mounted structure, and the electro-optic modulator 340 is a flip-chip structure.

[0257] It should be noted that, depending on the actual application requirements, a cavity may also be selectively provided within the target substrate 320 below the electro-optic modulator 340, photodetector 350, optical transmitter 360, silicon nitride waveguide 370, or other devices in the optical chip 300c (extending along the y-direction), and this application does not limit this. Specifically, the cavity may also be located within the target substrate 320 below one or more devices among the variable optical attenuator, heater, and polarization beam splitter rotator.

[0258] The fabrication methods for optical chip 300c, optical chip 300a, and optical chip 300b can all improve the process compatibility of the optical chip by changing the bonding order of the target substrate in the process and changing the formation order of the device (e.g., electro-optic modulator). The optical chip provided in the above embodiments of this application uses a high-resistivity substrate, which reduces the loss of the electro-optic modulator, increases the communication bandwidth of the optical chip, and thus improves the communication performance of the electronic device.

[0259] Figure 25 shows a schematic diagram of the structure of an electronic device 100 according to some embodiments of this application. The electronic device includes the optical chip described in any of the above embodiments. The above-described electronic device can reduce losses during optical signal transmission, increase the transmission bandwidth of optical signals, and thus improve the communication performance of the electronic device.

[0260] The aforementioned electronic device 100 may include a processor 110, an external memory interface 120, an internal memory 121, a universal serial bus (USB) port 130, a charging management module 140, a power management module 141, a battery 142, an antenna 1, an antenna 2, a mobile communication module 150, a wireless communication module 160, an audio module 170, a speaker 170A, a receiver 170B, a microphone 170C, a headphone jack 170D, a sensor module 180, buttons 190, a motor 191, an indicator 192, a camera 193, a display screen 194, and a subscriber identification module (SIM) card interface 195, etc. The sensor module 180 may include a pressure sensor 180A, a gyroscope sensor 180B, a barometric pressure sensor 180C, a magnetic sensor 180D, an accelerometer sensor 180E, a distance sensor 180F, a proximity sensor 180G, a fingerprint sensor 180H, a temperature sensor 180J, a touch sensor 180K, an ambient light sensor 180L, a bone conduction sensor 180M, etc.

[0261] It is understood that the structures illustrated in the embodiments of the present invention do not constitute a specific limitation on the electronic device 100. In other embodiments of this application, the electronic device 100 may include more or fewer components than illustrated, or combine some components, or split some components, or have different component arrangements. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.

[0262] Processor 110 may include one or more processing units, such as: application processor (AP), modem processor, graphics processing unit (GPU), image signal processor (ISP), controller, video codec, digital signal processor (DSP), baseband processor, and / or neural network processing unit (NPU), etc. Different processing units may be independent devices or integrated into one or more processors.

[0263] The processor 110 may also include a memory for storing instructions and data. In some embodiments, the memory in the processor 110 is a cache memory. This memory can store instructions or data that the processor 110 has just used or that are used repeatedly. If the processor 110 needs to use the instruction or data again, it can retrieve it directly from the memory. This avoids repeated accesses, reduces the waiting time of the processor 110, and thus improves the efficiency of the system.

[0264] In some embodiments, the processor 110 may include one or more interfaces. Interfaces may include an inter-integrated circuit (I2C) interface, an inter-integrated circuit sound (I2S) interface, a pulse code modulation (PCM) interface, a universal asynchronous receiver / transmitter (UART) interface, a mobile industry processor interface (MIPI), a general-purpose input / output (GPIO) interface, a subscriber identity module (SIM) interface, and / or a universal serial bus (USB) interface, etc.

[0265] In some embodiments, the charging management module 140 is used to receive charging input from the charger.

[0266] In some embodiments, the power management module 141 is used to connect the battery 142, the charging management module 140 and the processor 110.

[0267] In some embodiments, the wireless communication function of the electronic device 100 can be implemented by antenna 1, antenna 2, mobile communication module 150, wireless communication module 160, modem processor, and baseband processor.

[0268] In some embodiments, antenna 1 and antenna 2 are used to transmit and receive electromagnetic wave signals. Each antenna in electronic device 100 can be used to cover one or more communication frequency bands. Different antennas can also be multiplexed to improve antenna utilization. For example, antenna 1 can be multiplexed as a diversity antenna for a wireless local area network. In other embodiments, the antennas can be used in conjunction with a tuning switch.

[0269] In some embodiments, the mobile communication module 150 can provide wireless communication solutions, including 2G / 3G / 4G / 5G, applied to the electronic device 100.

[0270] In some embodiments, a modem processor may include a modulator and a demodulator.

[0271] In some embodiments, the wireless communication module 160 can provide wireless communication solutions applied to the electronic device 100, including wireless local area networks (WLANs) (such as wireless fidelity (Wi-Fi) networks), Bluetooth (BT), global navigation satellite system (GNSS), frequency modulation (FM), near field communication (NFC), and infrared (IR) technologies. The wireless communication module 160 can be one or more devices integrating at least one communication processing module. The wireless communication module 160 receives electromagnetic waves via antenna 2, performs frequency modulation and filtering of the electromagnetic wave signals, and sends the processed signal to processor 110. The wireless communication module 160 can also receive signals to be transmitted from processor 110, perform frequency modulation and amplification, and convert them into electromagnetic waves for radiation via antenna 2.

[0272] In some embodiments, antenna 1 of electronic device 100 is coupled to mobile communication module 150, and antenna 2 is coupled to wireless communication module 160, enabling electronic device 100 to communicate with networks and other devices via wireless communication technology. The wireless communication technology may include Global System for Mobile Communications (GSM), General Packet Radio Service (GPRS), Code Division Multiple Access (CDMA), Wideband Code Division Multiple Access (WCDMA), Time-Division Code Division Multiple Access (TD-SCDMA), Long Term Evolution (LTE), BT, GNSS, WLAN, NFC, FM, and / or IR technologies, etc. The GNSS may include the Global Positioning System (GPS), the Global Navigation Satellite System (GLONASS), the BeiDou Navigation Satellite System (BDS), the Quasi-Zenith Satellite System (QZSS), and / or satellite-based augmentation systems (SBAS).

[0273] In some embodiments, the electronic device 100 implements display functions through a GPU, a display screen 194, and an application processor.

[0274] In some embodiments, the display screen 194 is used to display images, videos, etc.

[0275] In some embodiments, the electronic device 100 may implement the shooting function through an ISP, a camera 193, a video codec, a GPU, a display 194, and an application processor.

[0276] In some embodiments, camera 193 is used to capture still images or videos.

[0277] In some embodiments, the external memory interface 120 can be used to connect an external memory card, such as a Micro SD card, to expand the storage capacity of the electronic device 100.

[0278] In some embodiments, internal memory 121 may be used to store computer executable program code, which includes instructions.

[0279] In some embodiments, the electronic device 100 may implement audio functions such as audio module 170, speaker 170A, receiver 170B, microphone 170C, headphone jack 170D, and application processor. Examples include music playback and recording.

[0280] In some embodiments, the audio module 170 is used to convert digital audio information into analog audio signal output, and also to convert analog audio input into digital audio signal.

[0281] In some embodiments, the loudspeaker 170A, also known as a "horn", is used to convert audio electrical signals into sound signals.

[0282] In some embodiments, the receiver 170B, also known as the "earpiece", is used to convert audio electrical signals into sound signals.

[0283] In some embodiments, the microphone 170C, also known as a "microphone" or "microphone device," is used to convert sound signals into electrical signals.

[0284] In some embodiments, the headphone jack 170D is used to connect wired headphones.

[0285] In some embodiments, button 190 includes a power button, volume buttons, etc.

[0286] In some embodiments, motor 191 may generate a vibration alert.

[0287] In some embodiments, indicator 192 may be an indicator light, which can be used to indicate charging status, power changes, messages, missed calls, notifications, etc.

[0288] In some embodiments, the SIM card interface 195 is used to connect a SIM card.

[0289] It should be noted that in the examples and description of this application, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one" does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0290] Although this application has been illustrated and described with reference to certain preferred embodiments thereof, those skilled in the art will understand that various changes in form and detail may be made thereto without departing from the scope of this application.

Claims

1. A method of fabricating an optical chip, characterized by, The method comprises: obtaining a substrate, the substrate comprising a first base and a first device layer stacked with each other, the first device layer comprising a detection portion for preparing a photodetector; forming a first waveguide on the substrate, removing the first base, and bonding a second base, wherein the first device layer and the first waveguide are located on the same side of the second base, and the electrical resistivity of the second base is greater than that of the first base; forming a first electrode of an electro-optical modulator on the first waveguide, and forming a second electrode of the photodetector on the detection portion.

2. The production method according to claim 1, characterized by, The material of the second base comprises one or more of high-resistance silicon, quartz, sapphire, and trap-rich silicon.

3. The production method according to claim 1, characterized by, The forming of the first waveguide on the substrate comprises: bonding a lithium niobate film on the substrate, and etching the lithium niobate film to obtain the first waveguide.

4. The method of claim 1, wherein, The process for removing the first base comprises one or more of a grinding process, a polishing process, a dry etching process, and a wet etching process.

5. The preparation method according to claim 1, characterized in that, The method comprises: obtaining an SOI substrate, the SOI substrate comprising a top layer of silicon, a buried oxygen layer, and the first base stacked along a thickness direction; preparing an optical transmitter on the top layer of silicon and the detection portion of the photodetector to obtain the first device layer; wherein the optical transmitter comprises a second waveguide and a third waveguide stacked along the thickness direction, and the materials of the second waveguide and the third waveguide are different.

6. The preparation method according to claim 5, characterized in that, At least one of the following features is included: The first waveguide comprises a lithium niobate waveguide. The second waveguide comprises a silicon waveguide. The third waveguide comprises a silicon nitride waveguide.

7. The preparation method according to claim 1, characterized in that, The detection portion comprises a light absorption region and a silicon waveguide, the silicon waveguide being partially embedded in a middle portion of the light absorption region along a length direction of the first base; wherein the thickness direction of the first base intersects the length direction of the first base.

8. The preparation method according to claim 7, characterized in that, The material of the light absorption region comprises germanium.

9. The preparation method according to claim 5, characterized in that, Further comprising: preparing one or more of a variable optical attenuator, a heater, and a polarization beam splitting rotator on the top layer of silicon to obtain the first device layer.

10. The method of claim 1, wherein, Further comprising: forming one or more cavities in the interior of the second base adjacent to the photodetector and / or the electro-optical modulator along the thickness direction thereof.

11. A method of fabricating an optical chip, characterized by, The method comprises: obtaining a substrate, the substrate comprising a first base and a first device layer stacked with each other, the first device layer comprising a detection portion for preparing a photodetector; bonding a second base on a side of the first device layer away from the first base, and removing the first base, wherein the electrical resistivity of the second base is greater than that of the first base; forming a first waveguide on a side of the first device layer away from the second base; forming a first electrode of an electro-optical modulator on the first waveguide, and forming a second electrode of the photodetector on the detection portion. The first electrode extends from a side of the first waveguide facing the second substrate to a surface of the first device layer away from the second substrate in a first direction, and the second electrode extends from a side of the detection portion facing the second substrate to the surface of the first device layer away from the second substrate in the first direction, the first direction being a direction in which the second substrate points to the first device layer.

12. A method for fabricating an optical chip, characterized in that, The method comprises: obtaining a substrate comprising a first substrate and a first device layer stacked with each other, the first device layer comprising a detection portion for preparing a photodetector; forming a first waveguide on a side of the first device layer away from the first substrate; forming a second substrate on a side of the first waveguide away from the first device layer, and removing the first substrate, wherein the second substrate has a resistivity greater than that of the first substrate; forming a first electrode of an electro-optic modulator on the first waveguide, and forming a second electrode of the photodetector on the detection portion; The first electrode extends from a side of the first waveguide facing the second substrate to a surface of the first device layer away from the second substrate in a first direction, and the second electrode extends from a side of the detection portion facing the second substrate to the surface of the first device layer away from the second substrate in the first direction, the first direction being a direction in which the second substrate points to the first device layer.

13. A method for fabricating an optical chip, characterized in that, The method comprises: obtaining a substrate and obtaining a first waveguide, the substrate comprising a first substrate and a first device layer stacked with each other, the first device layer comprising a detection portion for preparing a photodetector; surface bonding the first waveguide and the first device layer away from a side of the first substrate; removing the first substrate, and forming a second substrate on a side of the first device layer away from the first waveguide, wherein the second substrate has a resistivity greater than that of the first substrate; forming a first electrode of an electro-optic modulator on the first waveguide, and forming a second electrode of the photodetector on the detection portion; The first electrode extends from a side of the first waveguide facing the second substrate to a surface of the first device layer away from the second substrate in a first direction, and the second electrode extends from a side of the detection portion facing the second substrate to the surface of the first device layer away from the second substrate in the first direction, the first direction being a direction in which the second substrate points to the first device layer.

14. An optical chip, characterized by The method comprises: a second substrate and a first device layer stacked with each other, the first device layer comprising an electro-optic modulator and a photodetector; The electro-optic modulator comprises a first electrode and a first waveguide, the first electrode extending from a side of the first waveguide away from the second substrate to a surface of the first device layer away from the second substrate in a first direction; The photodetector comprises a detection portion and a second electrode, the second electrode extending from a side of the detection portion facing the second substrate to the surface of the first device layer away from the second substrate in the first direction, the first direction being a direction in which the second substrate points to the first device layer.

15. An optical chip, characterized by The method comprises: a second substrate and a first device layer stacked with each other, the first device layer comprising an electro-optical modulator, an optical detector; wherein the electro-optical modulator comprises a first electrode and a first waveguide, the first electrode extending from a side of the first waveguide facing the second substrate to a surface of the first device layer away from the second substrate in a first direction, the first direction being a direction in which the second substrate points to the first device layer. the optical detector comprises a detection part and a second electrode, the second electrode extending from a side of the detection part facing the second substrate to the surface of the first device layer away from the second substrate in the first direction, the first direction being the direction in which the second substrate points to the first device layer.

16. An optical chip, comprising: comprising: a second substrate and a first device layer stacked with each other, the first device layer comprising an electro-optical modulator, an optical detector; wherein the electro-optical modulator comprises a first electrode and a first waveguide, the first electrode extending from a side of the first waveguide facing the second substrate to a surface of the first device layer away from the second substrate in a first direction, the first direction being a direction in which the second substrate points to the first device layer. the optical detector comprises a detection part and a second electrode, the second electrode extending from a side of the detection part facing the second substrate to the surface of the first device layer away from the second substrate in the first direction, the first direction being the direction in which the second substrate points to the first device layer.

17. The optical chip of any of claims 14-16, wherein, the material of the second substrate comprises one or more of high-resistivity silicon, quartz, sapphire, and trap-rich silicon.

18. The optical chip of any of claims 14-16, wherein, the first device layer further comprises at least one of an optical transmitter, a variable optical attenuator, a heater, and a polarization beam splitting rotator; wherein the optical transmitter comprises a second waveguide and a third waveguide stacked with each other, the second waveguide and the third waveguide being made of different materials.

19. The optical chip of claim 18, wherein, comprising at least one of the following features: the first waveguide comprises a lithium niobate waveguide; the second waveguide comprises a silicon waveguide; the third waveguide comprises a silicon nitride waveguide.

20. An optical chip, comprising: obtained by a method according to any one of claims 1-13.

21. An electronic device, comprising: comprising the optical chip according to any one of claims 14-19.

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