Optical chip and optical chip preparation method

Abstract

The present application discloses an optical chip and an optical chip preparation method. The optical chip comprises: a thermal isolation substrate; and an optical device structure layer located above the thermal isolation substrate and formed on the basis of a top silicon layer in an SOI substrate. The thermal isolation substrate has a single-layer material structure or has a laminated structure comprising a plurality of material layers, and the thermal isolation substrate at least comprises one material layer formed from a material having a thermal conductivity of less than 100 W / (m·K). The optical device structure layer formed on the basis of the top silicon layer in the SOI substrate sequentially comprises, from bottom to top: a protective layer located above the thermal isolation substrate and fixedly connected to the thermal isolation substrate; and a first optical device layer located on the protective layer and comprising at least one first optical device, wherein a light beam emitted via the optical device structure layer is emitted upwards toward a detection space.

Description

Optical chip and method for preparing the same Technical Field

[0001] The present application belongs to the field of semiconductor technology, and specifically relates to an optical chip and a method for preparing the optical chip. Background Art

[0002] Current silicon photonic chips typically use SOI (Silicon On Insulator) as a substrate, and process and manufacture integrated optical devices on the top silicon layer. After fabrication, a silicon dioxide layer is grown on top to protect the optical devices. However, the substrate silicon in the SOI substrate is typically about 700μm (micrometers) thick. Even if it can be thinned to about 400μm thick through a grinding and polishing process, it is still 2 to 3 orders of magnitude lower than the 220nm thick top silicon and 2 or 3μm thick silicon dioxide layer in the SOI substrate. The thermal conductivity of silicon is about 150W / (m·K), making it a very good thermal conductor. If there are optical devices in the optical chip that generate local heat, the heat will be quickly conducted to the entire optical chip through the very thick substrate silicon, resulting in severe thermal crosstalk.

[0003] To reduce thermal crosstalk, conventional techniques often add a TEC (Thermo Electric Cooler) to the bottom of an optical chip as a heat sink to quickly dissipate heat generated within the chip and reduce internal heat accumulation. While this solution can partially address the thermal crosstalk issue, achieving better results requires increasing the TEC's power consumption to the watt level, and the increased heat generated by the TEC is also difficult to address. Consequently, conventional optical chips suffer from a serious thermal crosstalk problem.

[0004] Summary of the Invention

[0005] The embodiments of the present application provide an optical chip and a method for preparing the optical chip, so as to address the serious thermal crosstalk problem of the optical chip in the related art.

[0006] According to one aspect of an embodiment of the present application, an optical chip is provided, comprising: a thermal isolation substrate and an optical device structure layer formed based on a top silicon layer in an SOI substrate and located above the thermal isolation substrate; wherein the thermal isolation substrate is a single-layer material structure or a stacked structure comprising multiple material layers, and the thermal isolation substrate comprises at least one material layer formed of a material having a thermal conductivity less than 100 W / (m·K); the optical device structure layer formed based on the top silicon layer in the SOI substrate comprises, from bottom to top: a protective layer located above the thermal isolation substrate and fixedly connected to the thermal isolation substrate; and a first optical device layer located on the protective layer and comprising at least one first optical device; wherein the light beam emitted through the optical device structure layer is emitted upward to a detection space.

[0007] As an optional solution, the thickness of the thermal isolation substrate is greater than 100 μm.

[0008] As an optional solution, when the thermal isolation substrate is a laminated structure, the thickness of the material layer formed of a material with a thermal conductivity less than 100 W / (m·K) is greater than or equal to 10 μm.

[0009] As an optional solution, the material of the thermal isolation substrate includes one or more of silicon dioxide, quartz, glass and plastic.

[0010] As an optional solution, the first optical device layer is formed of silicon material; the optical device structure layer also includes: a second optical device layer, located between the first optical device layer and the protective layer, formed of silicon nitride material, and including at least one second optical device; and a first spacer layer, located between the first optical device layer and the second optical device layer, for separating the first optical device layer and the second optical device layer.

[0011] As an optional solution, the first optical device in the first optical device layer includes a first coupler, a first beam splitter, a first phase shifter and a first optical antenna; the second optical device in the second optical device layer includes a second coupler, a second beam splitter, a second phase shifter and a second optical antenna; wherein, when the first optical device in the first optical device layer is combined with the second optical device in the second optical device layer, the coupling forms at least part of a third coupler, a third beam splitter, a third phase shifter and a third optical antenna.

[0012] As an optional solution, the optical device structure layer also includes: a reflective layer, which is located between the second optical device layer and the protective layer, and the reflective layer includes a reflective structure, which is used to reflect the light beams emitted by at least part of the first optical antenna, the second optical antenna and the third optical antenna upward; a second spacer layer, which is located between the reflective layer and the second optical device layer and is used to separate the reflective layer and the second optical device structure.

[0013] As an optional solution, the projection of the reflective layer in the vertical direction partially overlaps or completely overlaps with the projection of any one or more of the first optical antenna, the second optical antenna and the third optical antenna in the vertical direction.

[0014] As an optional solution, the optical device structure layer also includes: an optical correction structure located between the reflective layer and the protective layer, used to heat the first optical antenna to change the refractive index of any one or more of the first optical antenna, the second optical antenna and the third optical antenna.

[0015] As an optional solution, the optical correction structure includes multiple groups of heating structures, and different groups of heating structures in the multiple groups of heating structures are used to heat different parts of any one or more optical antennas among the first optical antenna, the second optical antenna and the third optical antenna.

[0016] According to another aspect of an embodiment of the present application, a method for preparing an optical chip is also provided, comprising: providing an SOI substrate; forming an optical device structure layer on the top silicon layer of the SOI substrate, comprising: forming a first optical device layer in the top silicon layer of the SOI substrate, wherein the first optical device layer comprises at least one first optical device; depositing a silicon oxide material on the SOI substrate after forming the first optical device layer to form a protective layer; providing a thermal isolation substrate and fixing it above the protective layer, and then removing all or part of the substrate silicon layer in the SOI substrate; wherein the thermal isolation substrate is a single-layer material structure or a stacked structure comprising multiple material layers, and the thermal isolation substrate comprises at least one material layer formed of a material having a thermal conductivity of less than 100 W / (m·K); and the light beam emitted through the optical device structure layer is emitted upward to a detection space.

[0017] As an optional solution, the thickness of the thermal isolation substrate is greater than 100 μm; when the thermal isolation substrate is a laminated structure, the thickness of the material layer formed by a material with a thermal conductivity less than 100 W / (m·K) is greater than or equal to 10 μm.

[0018] As an optional solution, the thermal isolation substrate is formed by using one or more materials selected from silicon dioxide, quartz, glass and plastic.

[0019] As an optional solution, the forming of the optical device structure layer on the top silicon layer of the SOI substrate further includes: before forming the protective layer, depositing a silicon oxide material on the SOI substrate after forming the first optical device layer to form a first spacer layer; forming a silicon nitride material layer on the first spacer layer, and forming a second optical device layer in the silicon nitride material layer, wherein the second optical device layer includes at least one second optical device; wherein the first optical device in the first optical device layer includes a first coupler, a first beam splitter, a first phase shifter and a first optical antenna, and the second optical device in the second optical device layer includes a second coupler, a second beam splitter, a second phase shifter and a second optical antenna, and when the first optical device in the first optical device layer is combined with the second optical device in the second optical device layer, they are coupled to form at least part of a third coupler, a third beam splitter, a third phase shifter and a third optical antenna.

[0020] As an optional solution, the forming of the optical device structure layer on the top silicon layer of the SOI substrate further includes: before forming the protective layer, depositing a silicon oxide material on the SOI substrate on which the second optical device layer is formed to form a second spacer layer; forming a reflective layer on the second spacer layer, wherein the reflective layer includes a reflective structure, and the reflective structure is used to reflect the light beams emitted by at least part of the first optical antenna, the second optical antenna and the third optical antenna, so that the light beams penetrate the SOI substrate and are emitted into the detection space.

[0021] As an optional solution, the forming of the optical device structure layer on the top silicon layer of the SOI substrate further includes: before forming the protective layer, depositing a silicon dioxide material on the SOI substrate having the reflective layer formed thereon to form a third spacer layer; forming a metal material layer on the third spacer layer, and forming an optical correction structure through a composition process, wherein the optical correction structure is used to change the refractive index of any one or more optical antennas among the first optical antenna, the second optical antenna and the third optical antenna.

[0022] In an embodiment of the present application, the optical chip includes a thermal isolation substrate and an optical device structure layer located above the thermal isolation substrate, wherein the thermal isolation substrate is a single-layer material structure or a stacked structure including multiple material layers, and the thermal isolation substrate includes at least one material layer formed by a material with a thermal conductivity of less than 100W / (m·K), and the optical device structure layer is formed based on the top silicon layer in the SOI substrate. Through the above-mentioned optical chip design, the substrate silicon layer is removed, and a low thermal conductivity substrate material is used. The heat transferred from the substrate to the entire optical chip can be reduced without introducing additional power consumption, thereby effectively preventing thermal crosstalk problems. In addition, the light beam emitted from the optical device structure layer in the optical chip is emitted upward to the detection space without passing through the thermal isolation substrate, thereby avoiding the influence of the thermal isolation substrate on the quality of the light beam emission. In addition, the optical chip includes, from bottom to top, a thermal isolation substrate and an optical device structure layer. The overall process is simple, the integration of the optical device is high, the structure is compact, it is conducive to mass production, and the cost of the product can be greatly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0024] FIG1 is a schematic diagram of an optional optical chip according to an embodiment of the present application;

[0025] FIG2 is a schematic diagram of light emitted from an optional optical chip according to an embodiment of the present application;

[0026] FIG3 is a schematic diagram of another optional optical chip according to an embodiment of the present application;

[0027] FIG4 is a schematic diagram of an optional optical device layer according to an embodiment of the present application;

[0028] FIG5 is a schematic diagram of another optional optical device layer according to an embodiment of the present application;

[0029] FIG6 is a schematic diagram of another optional optical chip according to an embodiment of the present application;

[0030] FIG7 is a schematic diagram of another optional optical chip according to an embodiment of the present application;

[0031] FIG8 is a schematic diagram of another optional optical chip according to an embodiment of the present application;

[0032] FIG9 is a schematic diagram of another optional optical chip according to an embodiment of the present application;

[0033] FIG10 is a schematic diagram of another optional optical chip according to an embodiment of the present application;

[0034] FIG11 is a schematic flow chart of an optional method for preparing an optical chip according to an embodiment of the present application;

[0035] FIG12 is a schematic diagram of an optional method for preparing an optical chip according to an embodiment of the present application;

[0036] FIG13 is a schematic diagram of another optional method for preparing an optical chip according to an embodiment of the present application;

[0037] FIG14 is a schematic diagram of another optional method for preparing an optical chip according to an embodiment of the present application;

[0038] FIG15 is a schematic diagram of another optional method for preparing an optical chip according to an embodiment of the present application;

[0039] FIG16 is a schematic diagram of another optional method for preparing an optical chip according to an embodiment of the present application;

[0040] FIG17 is a schematic diagram of another optional method for preparing an optical chip according to an embodiment of the present application. DETAILED DESCRIPTION

[0041] The following describes in detail embodiments of the present application, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0042] In the description of this application, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0043] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0044] In this application, unless otherwise expressly specified or limited, terms such as "mounted," "connected," "connect," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components or interactions between two components. Those skilled in the art will understand the specific meanings of these terms in this application based on specific circumstances.

[0045] In order to make the purpose, technical solutions and advantages of this application more clear, this application is further described in detail below with reference to the accompanying drawings and embodiments.

[0046] According to one aspect of an embodiment of the present application, an optical chip is provided. An optical chip is an integrated circuit that uses optical technology to process and transmit information. It uses photons to transmit data, enabling high-speed, high-bandwidth, and low-energy data transmission and processing. As a type of optical chip, a silicon photonic chip is an optical chip made of silicon material and can be used in optical communications, optical sensing, lidar, and other fields. Silicon photonic chips can convert optical signals into electrical signals or electrical signals into optical signals, and have excellent optoelectronic properties.

[0047] Silicon photonic chips include substrates and functional layers. The substrate is the basic part of the silicon photonic chip and is usually made of silicon material. The substrate plays the role of support and carrier during the manufacturing process of the silicon photonic chip. The functional layer of the silicon photonic chip is based on the patterns and structures formed by the silicon-based material layer and CMOS process. These patterns and structures include optical devices such as couplers, beam splitters, phase shifters, optical antennas, and electrodes connected to each optical device, which form the functional part of the chip.

[0048] At present, silicon photonic chips usually use SOI as the substrate, and the integrated optical devices are processed and manufactured on the top silicon. After the production is completed, a silicon dioxide layer is grown on the top to protect the optical devices. However, the substrate silicon in the SOI substrate is usually about 700μm thick. Even if it can be thinned to about 400μm thick through the grinding and polishing process, it is still 2 to 3 orders of magnitude different from the 220nm thick top silicon and 2 or 3μm thick silicon dioxide layer in the SOI substrate. The thermal conductivity of silicon is about 150W / (m·K), which is a material with good thermal conductivity. If there is an optical device that generates local heat in the optical chip, the heat will be quickly conducted to the entire optical chip through the thicker substrate silicon, resulting in severe thermal crosstalk.

[0049] In related technologies, a TEC (Transistor Electron Device) can be added to the bottom of an optical chip as a heat sink to quickly dissipate heat generated within the chip and reduce internal heat accumulation. However, while this solution can partially address the thermal crosstalk issue, achieving optimal results requires increasing the TEC's power consumption to the watt level, which generates even more heat, an unacceptable level for the optical chip.

[0050] In order to at least partially solve the above technical problems, in this embodiment, for the optical chip, the substrate silicon layer is removed and a low thermal conductivity substrate material is used. This can reduce the heat transferred from the substrate to the entire optical chip without introducing additional power consumption, thereby effectively preventing thermal crosstalk problems.

[0051] As an optional implementation, FIG1 is a schematic diagram of an optional optical chip according to an embodiment of the present application. As shown in FIG1 , the optical chip may include: a thermal isolation substrate 11 and an optical device structure layer 12 .

[0052] The thermal isolation substrate 11 can be a single-layer material structure or a stacked structure including multiple material layers, and the thermal isolation substrate includes at least one material layer formed by a material with a thermal conductivity of less than 100 W / (m·K) (for example, quartz, glass, etc., but not limited thereto). Compared with the thermal conductivity of silicon of approximately 150 W / (m·K), this material layer has a better thermal isolation effect, which can effectively reduce the heat conducted to the entire optical chip through the substrate and effectively prevent thermal crosstalk.

[0053] The optical device structure layer 12 may include a layer located above the thermal isolation substrate, which is formed based on the top silicon layer in the SOI substrate. The light beam emitted through the optical device structure layer 12 may be emitted upward to the detection space, as shown in FIG2 (the upward arrow in FIG2 is used to indicate the direction of the emitted light). It can be understood that the upward emission of the light beam refers to the emission of the light beam along the direction from the thermal isolation substrate to the optical device structure layer. In the optical chip shown in FIG2 , the thermal isolation substrate is at the bottom and the optical device structure layer is at the top. Therefore, the upward emission of the light beam refers to the emission of the light beam along the direction from the thermal isolation substrate to the optical device structure layer.

[0054] The optical device structure layer 12 formed based on the top silicon layer in the SOI substrate can be obtained in the following manner: during the preparation of the optical chip, the optical device structure layer 12 is first formed on the top silicon layer in the SOI substrate, and then all or part of the substrate silicon layer in the SOI substrate is removed. It can also be obtained in other ways, as long as the optical device structure layer formed based on the top silicon layer in the SOI substrate can be obtained.

[0055] The optical device structure layer 12 includes, from bottom to top (in the direction from close to the substrate to away from the substrate), a protective layer 121 and a first optical device layer 122. Here, the protective layer 121 is located above the thermal isolation substrate 11 and is fixedly connected to the thermal isolation substrate 11 to play a fixed protection role and improve the structural stability of the optical chip. Its material can be silicon dioxide (SiO2); the first optical device layer 122 is located on the protective layer 121 and can include at least one first optical device, such as a light source (laser light source), a coupler, a beam splitter, a phase shifter, or all or part of an optical antenna. Here, through the design of the above-mentioned optical chip, the overall process of the optical chip is simple, the integration of optical devices is high, the structure is compact, it is conducive to mass production, and the cost of the product can be greatly reduced.

[0056] It should be noted that a protective layer (for example, formed of silicon dioxide) is usually placed over the optical device to prevent the optical device layer from being directly exposed to the air. At the same time, after the optical device is formed, corresponding metal wiring is also performed. By adding a protective layer after the metal wiring is performed, the metal wires can be prevented from being oxidized or damaged due to contact with the air. The thickness of the protective layer is usually 1μm to 2μm, or 3μm, as long as it can play a protective role. In short, the protective layer can protect both optical devices and metal devices. While playing the role of electrical isolation, it prevents the device from being directly exposed to the air, and can also prevent the device from being dirty and human damage. The transmittance of the protective layer is the transmittance that meets the light beam's transmission or high transmittance requirements (that is, the transmittance of the protective layer meets the transmittance requirements of the emitted light beam).

[0057] According to the embodiments provided in the present application, the optical chip includes: a thermal isolation substrate and an optical device structure layer formed based on the top silicon layer in the SOI substrate and located above the thermal isolation substrate; wherein the thermal isolation substrate is a single-layer material structure or a stacked structure including multiple material layers, and the thermal isolation substrate includes at least one material layer formed by a material with a thermal conductivity of less than 100 W / (m·K); the optical device structure layer formed based on the top silicon layer in the SOI substrate includes, from bottom to top: a protective layer located above the thermal isolation substrate and fixedly connected to the thermal isolation substrate; and a first optical device layer located on the protective layer and including at least one first optical device; wherein the light beam emitted through the optical device structure layer is emitted upward to the detection space, thereby solving the problem of severe thermal crosstalk in the optical chip in the related art, reducing thermal crosstalk, and improving the service life of the optical chip.

[0058] As an optional solution, the thickness of the thermal isolation substrate is not fixed based on factors such as the different structures of the thermal isolation substrate and the different materials used in the material layer. Although the thermal isolation substrate uses a material with low thermal conductivity, and its thermal isolation ability is not only related to the thermal conductivity of the material, but also to the thickness of the thermal isolation substrate (the thermal conductivity of the thermal isolation substrate and the thickness of the thermal isolation substrate can be negatively correlated). In order to improve the thermal resistance of the thermal isolation substrate, the thickness of the thermal isolation substrate can be greater than 100μm. At the same time, setting the thickness of the thermal isolation substrate to greater than 100μm can also play a better supporting role.

[0059] Here, simulation experiments have shown that for materials with low thermal conductivity (low thermal conductivity coefficient), the greater the thickness, the worse the heat conduction effect (greater thermal resistance), while the smaller the thickness, the better the heat conduction effect (lower thermal resistance). Therefore, for thermal isolation substrates, to ensure better thermal resistance, their thickness can be controlled to above 100μm, while also taking into account mechanical stress requirements and improving the mechanical strength of the thermal isolation substrate.

[0060] Optionally, for a thermal isolation substrate with a laminated structure, the thickness of the material layer formed by a material with a thermal conductivity less than 100 W / (m·K) can be controlled to be greater than or equal to 10 μm to improve the thermal isolation effect of the thermal isolation substrate. When combined with a design in which the thickness of the thermal isolation substrate is greater than 100 μm, the support capacity and thermal resistance capacity of the thermal isolation substrate can be simultaneously guaranteed.

[0061] Through the embodiments provided in the present application, the thickness of the thermal isolation substrate is controlled to be greater than 100 μm, which not only ensures the thermal resistance of the thermal isolation substrate but also provides good support. The thickness of the material layer formed by a material with a thermal conductivity less than 100 W / (m·K) is controlled to be greater than or equal to 10 μm, which can improve the thermal resistance of the thermal isolation substrate.

[0062] As an optional solution, the thermal isolation substrate can be a single-layer material structure or a stacked structure containing multiple material layers. The materials forming the single-layer material structure or the individual material layers in the stacked structure can include one or more of silicon dioxide, quartz, glass, low-density silicon and plastic.

[0063] The thermal conductivity of silicon dioxide is approximately 1.4 W / (m·K), the thermal conductivity of quartz is approximately 7 W / (m·K), the thermal conductivity of low-density silicon can be controlled to be less than 100 W / (m·K), and the thermal conductivity of plastic is generally within the range of 0.1-0.5 W / (m·K). The material layer formed of a material with a thermal conductivity less than 100 W / (m·K) can be made of, but is not limited to, silicon dioxide, quartz, glass, low-density silicon, and plastic. Other materials with a thermal conductivity less than 100 W / (m·K) may also be used.

[0064] According to the embodiments provided in this application, the thermal isolation substrate adopts a glass substrate (which can be silica glass or quartz glass) because the glass substrate not only has lower thermal conductivity but is also easier to obtain and has lower cost.

[0065] As an optional solution, the first optical device layer is formed of silicon material. The SOI substrate is a stacked structure formed by substrate silicon, a buried oxide layer and a top silicon layer, and optical devices are usually formed in the top silicon layer. In the embodiment of the present application, the first optical device is formed in the top silicon layer. Although silicon material has the advantages of being common and low cost, silicon material is a strong nonlinear material, especially it has a strong two-photon absorption effect and free carrier absorption effect, and its low-order nonlinear coefficient is also large, so it is not suitable for high-power light injection. In this regard, an optical device layer of another material can be used to adapt to high-power light injection.

[0066] Optionally, a material with a lower nonlinear coefficient than silicon (for example, silicon nitride material) can be used to form a second optical device layer. The light coupled to the optical chip is first split in the second optical device layer. After splitting, the optical power of each portion of light is much lower than that of the light coupled to the chip. When the light is divided into a sufficient number of portions, the optical power of each portion of light is small enough so that each portion of light can be transmitted normally in the optical device layer. Therefore, it is possible to adapt to light injection with better power. For example, the second optical device layer includes a second beam splitter, and an interlayer coupling structure (for example, a wedge coupler or a grating coupler) is provided between the first beam splitter and the second beam splitter, and the light is coupled and connected through the interlayer coupling structure to form a third coupler (which is an interlayer coupler). Therefore, after coupling high-power light onto the optical chip, the light beam is first split by a second beam splitter (for example, one into two, two into four, four into eight, etc.). After the splitting is completed, the single light beam is guaranteed to be able to be transmitted normally in the optical device layer. At this time, the split light beam is introduced into the silicon material through an interlayer coupler (here, an optical waveguide optically connected to the coupler can be provided after the coupler, and the material used for the optical waveguide can be silicon material) for propagation, which can avoid the occurrence of two-photon absorption and other problems. The above method can combine the advantages of different materials and improve the reliability of light beam propagation. Of course, the first optical device layer and the second optical device layer can also be used separately and do not have to be used in combination.

[0067] In this embodiment, the second optical device layer is located between the first optical device layer and the protective layer. The two optical device layers can be adjacent structures, that is, the two optical device layers can be directly grown together. With this preparation method, the two optical device layers may affect each other and have high requirements for preparation accuracy. To this end, a spacer layer (buffer layer) can be added between the first optical device layer and the second optical device layer to physically isolate the adjacent optical device layers (separate the adjacent optical device layers). As shown in Figure 3, in addition to the first optical device layer 122, the optical device structure layer 12 can also include a second optical device layer 123 and a first spacer layer 124.

[0068] The second optical device layer 123 is located between the first optical device layer 122 and the protective layer 121. The optical device layer can be formed of silicon nitride material and includes at least one second optical device. The type, quantity and position of the second optical device included can be the same or corresponding to the type, quantity and position of the first optical device included in the first optical device layer 122, or can be at least partially different.

[0069] The first spacer layer 124 is located between the first optical device layer 122 and the second optical device layer 123 , and is used to separate the first optical device layer 122 and the second optical device layer 123 .

[0070] Optionally, the first spacer layer 124 can be formed of a silicon dioxide material. In scenarios where the same optical devices on two optical device layers need to be coupled, the thickness of the spacer layer (i.e., all isolation layers in the embodiments of the present application, including the first spacer layer) can be tens of nanometers (e.g., 50 nm) to hundreds of nanometers (e.g., 100 nm) to meet the requirements for optical device coupling. The transmittance of the first spacer layer 124 is a transmittance that meets the requirements for light beam transmission or high transmittance (i.e., the transmittance of the first spacer layer 124 meets the transmittance requirements of the emitted light beam).

[0071] Through the embodiments provided in the present application, the optical device structure layer includes multiple optical device layers formed of different materials, which can combine the advantages of different materials to improve the reliability of light beam propagation; a spacer layer is set between adjacent optical device layers to separate the adjacent optical device layers, which can reduce the difficulty of preparing the optical device layers.

[0072] As an optional solution, the optical devices included in the first optical device layer 122 may be a first coupler, a first beam splitter, a first phase shifter and a first optical antenna, and the positional relationship of each optical device may be as shown in FIG. 4 .

[0073] Optionally, the optical devices included in the second optical device layer 123 may be a second coupler, a second beam splitter, a second phase shifter, and a second optical antenna. The positional relationship of the optical devices in the second optical device layer may be as shown in FIG5 . It should be noted that FIG5 is only an example, and the projections of the same optical devices in the vertical direction may partially overlap or completely not overlap; for example, the projections of the first optical antenna and the second optical antenna in the vertical direction may completely overlap, partially overlap, or completely not overlap.

[0074] Here, some of the same optical devices in the first optical device layer 122 and the second optical device layer 123 may be coupled. For example, when the optical devices in the first optical device layer are combined with the optical devices in the second optical device layer, an interlayer optical device may be formed, which may include all or part of a third coupler, a third beam splitter, a third phase shifter, and a third optical antenna. That is, the first coupler and the second coupler can form an interlayer third coupler, which couples light to the optical chip through this third coupler, thereby improving optical coupling efficiency and reducing the size of the coupling device. The first beam splitter and the second beam splitter can be combined to form a third beam splitter. By coupling the beam splitters, a SiN beam splitter + Si beam splitter cascade can be achieved, allowing the light beam to be split by the SiN beam splitter first to reduce the optical power, ensuring that each beam can be properly transmitted in the optical device layer, thereby significantly increasing the optical power input to the optical chip. The first phase shifter and the second phase shifter can be combined to form a third phase shifter. By coupling the phase shifters, the phase of the light beam can be changed by utilizing electro-optical / thermo-optical effects while maintaining the phase shifter function. The first optical antenna and the second optical antenna can be combined to form a third optical antenna. By coupling the optical antennas, the light output power can be increased. Here, the coupled third coupler, third beam splitter, third phase shifter, and third optical antenna can serve as the third optical device layer, i.e., the structure shown in the dotted box in Figure 5.

[0075] Through the embodiments provided in the present application, different light beam transmission requirements can be met by performing interlayer coupling through the same optical devices in different optical device layers.

[0076] It should be noted that the first optical antenna and the second optical antenna can be locally coupled, the part of the first optical antenna that is not coupled with the second optical antenna is still the first optical antenna, and the part coupled with the second optical antenna is coupled into a third optical antenna, the part of the second optical antenna that is not coupled with the first optical antenna is still the second optical antenna, and the part coupled with the first optical antenna is coupled into a third optical antenna. That is to say, the part of the first optical antenna that is not coupled with the second optical antenna is still the first optical antenna, the part of the second optical antenna that is not coupled with the first optical antenna is still the second optical antenna, and the part of the first optical antenna coupled with the second optical antenna is the third optical antenna.

[0077] As an optional solution, it can be understood that the optical antenna will emit light beams upward and downward, and only the upward light beam can be used for target detection, while light beams in other directions will be wasted, and may even become noise, affecting the detection accuracy. To this end, in this embodiment, a reflective layer can be added to the optical device structure layer. The reflective layer can be located between the first optical device layer and the protective layer. The reflective layer may include a reflective structure, which is used to reflect the light beam emitted by the optical antenna (for example, the first optical antenna) upward. As shown in Figure 6, a reflective layer 125 is added between the first optical device layer 122 and the protective layer 121, which can be used to reflect the light beam emitted by the first optical antenna upward. The light emitted by the optical antenna is reflected by the reflective structure, so that the reflected light is emitted upward to the detection space, which can improve the emission efficiency of the optical antenna, reduce light loss, and improve the utilization efficiency of the input light.

[0078] It should be noted that the reflective layer can be a stacked structure, one of which is a reflective structure, and the other structures can be structures with other functions, that is, at least part of the structure in the reflective layer can reflect light, but not necessarily the entire reflective layer.

[0079] In the case where the optical device structure layer includes a second optical device layer, a reflective layer can be located between the second optical device layer and the protective layer. The reflective structure of the reflective layer is configured to reflect upwardly at least a portion of the light beams emitted by the first, second, and third optical antennas. Here, the reflective structure reflects the light emitted by the optical antennas, causing the reflected light to be emitted upwardly into the detection space, thereby improving the transmission efficiency of the optical antennas, reducing light loss, and increasing the utilization efficiency of the input light.

[0080] Optionally, a second spacer layer may be provided between the reflective layer and the second optical device layer to separate the reflective layer and the second optical device layer. The material and thickness of the second spacer layer may be the same as or similar to those of the first spacer layer, and are not further described here. Typically, silicon dioxide is used to form the spacer layer and the protective layer.

[0081] For example, as shown in Figure 7, a reflective layer 125 is located between the second optical device layer 123 and the protective layer 121. It can be used to reflect upward at least some of the light beams emitted by the first, second, and third optical antennas. A second spacer layer 126 is provided between the reflective layer 125 and the second optical device layer 123. This second spacer layer 126 separates the reflective layer 125 and the second optical device layer 123, preventing damage to the optical devices in the second optical device layer during the formation of the reflective layer and reducing the difficulty of manufacturing the optical chip.

[0082] As an optional solution, the position of the reflective layer can be set based on the positions of the first, second, and third optical antennas, and the reflective layer partially or completely overlaps with the vertical projection of any one or more of the first, second, and third optical antennas. To ensure that the reflective layer can adapt to the first, second, and third optical antennas, the vertical projection of the reflective layer at least partially overlaps with the vertical projection of any one of the first, second, and third optical antennas. For example, the vertical projection of the reflective layer completely covers the vertical projections of the first, second, and third optical antennas.

[0083] As an optional solution, to improve the detection capability of the optical antenna, an optical correction structure can be provided in the optical device structure layer. As shown in FIG8 , the optical device structure layer 12 further includes an optical correction structure 127, which can be located between the reflective layer 125 and the protective layer 121. The optical correction structure 127 can be used to change the refractive index of at least some of the first, second, and third optical antennas. To protect the reflective layer 125, a spacer layer, namely, a third spacer layer 128, can be provided between the reflective layer 125 and the optical correction structure 127. This third spacer layer 128 is used to separate the reflective layer 125 and the optical correction structure 127.

[0084] The optical correction structure 127 can change the refractive index of the antenna by heating any one or more of the first optical antenna, the second optical antenna and the third optical antenna. The method of heating the optical antenna can be flexibly configured according to needs, so as to adjust the refractive index of the optical antenna according to different needs, realize light spot alignment, and thus improve detection accuracy.

[0085] Optionally, the optical correction structure 127 may include a heating electrode and a heating structure (e.g., a heating resistor). By applying a bias voltage to the heating electrode, the heating structure generates heat and conducts heat to the optical antenna, thereby heating the optical antenna, changing the refractive index of the antenna, and then changing the direction of the outgoing light corresponding to the antenna to achieve light spot alignment. The optical correction structure 127 may include multiple groups of heating structures, each of which can be individually controlled for heating to achieve precise control of the optical antenna that needs to be heated, compensate for inconsistencies in the optical antenna aperture caused by the process, and thus improve the light spot quality of the outgoing light beam. The heating structures can be evenly distributed above the corresponding optical antenna, and the specific number can be set as needed, which is not limited in this embodiment.

[0086] For example, as shown in FIG9 and FIG10 , the optical correction structure 127 may include multiple sets of heating structures to heat the optical antenna as needed.

[0087] Through the embodiments provided in the present application, the refractive index of the optical antenna is changed by heating the optical antenna through an optical correction structure, thereby changing the direction of the outgoing light corresponding to the antenna, achieving light spot alignment, and improving the detection capability of the optical chip.

[0088] As an optional solution, when the optical correction structure includes multiple groups of heating structures (i.e., the aforementioned multiple groups of local heating structures), the heating parameters of different groups of heating structures in the multiple groups of heating structures (for example, the applied bias voltage) may be the same or different. For each group of heating structures, it can be used to locally heat the first optical antenna. The optical antenna can be divided into an antenna matrix (including a group of local antennas), and a local antenna into which the optical antenna is divided can be heated by a group of heating structures, or there may be no corresponding heating structure. The heating parameters of the heating structures corresponding to different local antennas of the optical antenna may be the same or different. In addition, the sizes of the individual heating structures within a group of heating structures may be the same or different.

[0089] The optical chip in the embodiment of the present application is explained below with reference to optional examples. As shown in Figure 10, the optical chip includes: an optical device structure layer 12 and a thermal isolation substrate 11; the optical device structure layer 12 includes, from top to bottom,: a first optical device layer 122, a first spacer layer 124, a second optical device layer 123, a second spacer layer 126, a reflective layer 125, a third spacer layer 128, an optical correction structure 127, and a protective layer 121, wherein the material of the thermal isolation substrate 11 can be glass (Glass), and the material of the protective layer 121 can be silicon dioxide. Here, the thermal isolation substrate contains at least one material layer formed by a material with a thermal conductivity of less than 100W / (m·K). Through the above structure, not only can a better thermal isolation effect be achieved, but also the emission efficiency of the optical antenna can be improved and the light loss can be reduced.

[0090] According to another aspect of the embodiments of the present application, a method for preparing an optical chip is also provided. This method for preparing an optical chip can be used to prepare the optical chip in any of the above embodiments. The above description has been provided and will not be repeated here. FIG11 is a flow diagram of an optional method for preparing an optical chip according to an embodiment of the present application. As shown in FIG11 , the flow of the above method can include the following steps:

[0091] Step S1102: providing an SOI substrate.

[0092] In this embodiment, after completing the front-side processing (optical device structure) on the SOI substrate, the device is bonded to another carrier substrate (thermal isolation substrate) from the front side, and then all or part of the SOI substrate silicon is removed to complete the fabrication of the optical chip. Specifically, the optical device structure layer is first formed on the top silicon layer of the SOI substrate, and then a thermal isolation substrate is bonded to the formed optical device structure layer. Finally, all or part of the SOI substrate silicon is removed. This optical chip fabrication setup utilizes the support capacity of the SOI substrate, improving the efficiency and convenience of optical chip fabrication.

[0093] It should be noted that the term "substrate" can refer to the substrate of a diced wafer or the substrate of an undiced wafer. The term "layer" includes thin films and should not be interpreted as indicating vertical or horizontal thickness unless otherwise specified. SOI substrates are readily available and have good properties for integrated photonic devices.

[0094] Based on the above-mentioned optical chip preparation plan, an SOI substrate can be provided first. Here, the SOI substrate can be provided by a robotic arm or other control component, and the SOI substrate is placed on an insulator placed on an operating table. The SOI substrate can be pre-produced and placed in a specified position, or other SOI substrate providing methods can be used.

[0095] Step S1104 , forming an optical device structure layer on the top silicon layer of the SOI substrate.

[0096] The SOI substrate may include a top silicon layer, a buried oxide layer (i.e., a silicon dioxide buried layer), and a substrate silicon layer. An optical device structure layer (e.g., the aforementioned optical device structure layer) may be formed on the top silicon layer of the provided SOI substrate, and the light beam emitted through the optical device structure layer is emitted upward to the detection space. The optical device structure layer may include a first optical device layer, and the first optical device layer includes at least one first optical device (a first integrated optical device, such as a first coupler, a first optical waveguide, a first beam splitter, a first phase shifter, a first optical antenna, etc.). Correspondingly, forming the optical device structure layer on the top silicon layer of the SOI substrate may include: forming the first optical device layer in the top silicon layer of the SOI substrate.

[0097] There are one or more methods for forming the first optical device layer on the top silicon layer. Different first optical devices may have the same or different formation methods. The optical device formation method may include, but is not limited to, at least one of the following: a micromachining process (e.g., a bulk silicon processing process), a patterning process, or other processing methods, which are not limited in this embodiment.

[0098] Optionally, at least one first optical device may include a coupler, which may be manufactured using any appropriate micromachining process. Taking the bulk silicon processing process as an example, a portion of the silicon material is selectively removed from the top silicon layer according to the designed pattern to form the designed micro three-dimensional structure. The patterning process of the coupler may include etching, such as wet etching and dry etching. Depending on the etching rate along different crystal directions in the etching solution, wet etching can be divided into isotropic etching and anisotropic etching. Dry etching uses physical methods (e.g., sputtering, ion etching) or chemical methods (e.g., reactive ion etching). At least one first optical device may also be an optical waveguide (which may be optically coupled with the coupler, for example, a strip optical waveguide) and other optical devices, such as end couplers, waveguide crossers, beam splitters and optical antennas, and may also include active devices based on optical waveguides (e.g., phase shifters), which are not limited in this embodiment.

[0099] After forming the first optical device layer, the removed portion of the top silicon layer can be filled with a suitable dielectric material (e.g., silicon dioxide) to prevent voids in the top silicon layer. For example, silicon dioxide can be deposited in the patterned top silicon layer using a high-density plasma (HDP) deposition process.

[0100] A protective layer may be formed on the SOI substrate after the first optical device layer is formed. The material, thickness, and transmittance of the protective layer are similar to those of the aforementioned embodiment and are not further described here. The protective layer may be formed by depositing a silicon dioxide material, for example, by a plasma-enhanced chemical vapor deposition (PECVD) process.

[0101] Optionally, in addition to the first optical device layer, other device layers may be formed before forming the protective layer, such as at least one of a second optical device layer, a reflective layer, and an optical correction structure. Different device layers may be separated by a spacer layer. The spacer layer may be formed in the same or similar manner as the protective layer.

[0102] Step S1106: providing a thermal isolation substrate and fixing it on the protective layer, and then removing all or part of the substrate silicon layer in the SOI substrate.

[0103] After forming the protective layer, a thermal isolation substrate may be provided, and the provided thermal isolation substrate is fixed to the top of the protective layer. There may be a variety of ways to fix the thermal isolation substrate to the top of the protective layer. For example, the thermal isolation substrate may be fixed to the top of the protective layer by bonding, or may be fixed to the top of the protective layer by gluing (for example, gluing the thermal isolation substrate to the top of the protective layer by glue), or may be fixed to the top of the protective layer by other means, which are not limited in this embodiment. Here, the bonding process used for bonding may be a low-temperature bonding process or other bonding processes, as long as the thermal isolation substrate and the protective layer can be tightly connected together.

[0104] After the thermal isolation substrate is fixed to the protective layer, the device (semi-finished product, the optical chip is not completed at this time) can be inverted (i.e., flipped) to expose the substrate silicon layer in the bottommost SOI substrate, and all or part of the substrate silicon layer in the SOI substrate is removed to obtain the optical chip structure in the above embodiment. The process of removing at least part of the substrate silicon layer can be achieved by etching, specifically, TMAH (Tetra Methyl Ammonium Hydroxide) solution can be used for etching, or the substrate silicon layer can be thinned by wet etching, and then part of the substrate silicon layer can be removed by dry etching. If the substrate silicon layer in the SOI substrate is partially removed, the thickness of the retained part of the substrate silicon layer is less than 100μm.

[0105] Similar to the aforementioned embodiments, the thermal isolation substrate is a single-layer material structure or a stacked structure comprising multiple material layers, and the thermal isolation substrate includes at least one material layer formed from a material having a thermal conductivity of less than 100 W / (m·K). For example, the thermal isolation substrate can be a material having a thermal conductivity of less than 100 W / (m·K), such as quartz glass. As another example, the thermal isolation substrate can be a stacked structure of quartz glass and silicon dioxide material layers. It should be noted that when the thermal isolation substrate is a stacked structure, the thickness of the material layer formed from a material having a thermal conductivity of less than 100 W / (m·K) is greater than or equal to 10 μm.

[0106] The optical chip formed by the method provided in this embodiment uses a thermal isolation substrate with low thermal conductivity, which can reduce the heat transferred from the substrate to the entire optical chip without introducing additional power consumption, thereby effectively preventing thermal crosstalk problems. In addition, the light beam emitted from the optical device structure layer in the optical chip is emitted upward to the detection space without passing through the thermal isolation substrate, thereby avoiding the influence of the thermal isolation substrate on the quality of the light beam emission. In addition, the optical chip includes, from bottom to top, a thermal isolation substrate, a protective layer, and an optical device structure scale. The overall process is simple, the optical device has a high degree of integration, and the structure is compact, which is conducive to mass production and can significantly reduce the cost of the product.

[0107] As an optional solution, similar to the above embodiment, the thickness of the thermal isolation substrate is greater than 100 μm; when the thermal isolation substrate is a laminated structure, the thickness of the material layer formed by a material with a thermal conductivity less than 100 W / (m·K) is greater than or equal to 10 μm.

[0108] As an optional solution, similar to the above embodiments, one or more materials selected from silicon dioxide, quartz, glass and plastic are used to form the thermal isolation substrate.

[0109] As an optional solution, forming an optical device structure layer on the top silicon layer of the SOI substrate also includes: before forming the protective layer, depositing silicon dioxide material on the SOI substrate after forming the first optical device layer to form a first spacer layer; forming a silicon nitride material layer on the first spacer layer, and forming a second optical device layer in the silicon nitride material layer, wherein the second optical device layer includes at least one second optical device.

[0110] In this embodiment, similar to the aforementioned embodiments, the process of forming the second optical device layer in the silicon nitride material layer is similar to the process of forming the first optical device in the top silicon layer, and will not be repeated here. In this embodiment, the optical devices in the first optical device layer include a first coupler, a first beam splitter, a first phase shifter, and a first optical antenna. In addition to the first optical device layer, the optical device structure layer also includes the aforementioned second optical device layer. The optical devices in the second optical device layer include a second coupler, a second beam splitter, a second phase shifter, and a second optical antenna. When the first optical device in the first optical device layer is combined with the second optical device in the second optical device layer, they couple to form at least a portion of a third coupler, a third beam splitter, a third phase shifter, and a third optical antenna.

[0111] To separate the first optical device layer from the second optical device layer, before forming the protective layer, a silicon dioxide material can be deposited on the SOI substrate after the first optical device layer is formed to form a first spacer layer. A silicon nitride material is then deposited on the first spacer layer to form a silicon nitride material layer, and the second optical device layer is formed in the silicon nitride material layer. The formation of the first spacer layer is similar to that of the protective layer, and the formation of the second optical device layer is similar to that of the first optical device layer, and will not be described in detail here.

[0112] For example, when preparing an optical chip, an optical device layer can be first formed on an SOI substrate, as shown in Figure 12. Figure 12 shows a substrate, namely, an SOI substrate, which includes a top silicon layer, a buried oxide layer, and a base silicon layer. First, a first optical device is fabricated on the top silicon layer to obtain a first optical device layer 122. The first optical device includes a first coupler, a first beam splitter, a first phase shifter, and a first optical antenna. It may also include a first optical waveguide located between the first coupler and the first beam splitter.

[0113] Silicon dioxide is first grown on top of the top silicon layer in the SOI substrate to form a spacer layer, namely, the first spacer layer 124, which is used to protect the first optical device. A silicon nitride layer is then grown on the first-grown silicon dioxide. A second optical device is fabricated on the silicon nitride layer, resulting in a second optical device layer 123. The second optical device includes a second coupler, a second beam splitter, a second phase shifter, a second optical antenna, and may also include a second optical waveguide located between the second coupler and the second beam splitter. The optical devices in the silicon nitride layer can be combined with the optical devices in the top silicon layer to form optical devices such as a third coupler, a third beam splitter, a third phase shifter, and a third optical antenna (the third optical device integrated on the optical chip).

[0114] The thickness of the first spacer layer is adjustable and can be achieved by, for example, oxide deposition and planarization. The planarization here can be achieved by a CMP (Chemical Mechanical Polishing) process to meet different thickness requirements for the first spacer layer while meeting the flatness requirements of the upper surface of the first spacer layer.

[0115] Through the embodiments provided in the present application, the optical device structure layer includes multiple optical device layers formed of different materials, which can combine the advantages of different materials to improve the reliability of light beam propagation; a spacer layer is set between adjacent optical device layers to separate the adjacent optical device layers, which can reduce the difficulty of preparing the optical device layers.

[0116] As an optional solution, forming an optical device structure layer on the top silicon layer of the SOI substrate also includes: before forming the protective layer, depositing silicon dioxide material on the SOI substrate forming the second optical device layer to form a second spacer layer; and forming a reflective layer on the second spacer layer.

[0117] Similar to the aforementioned embodiment, a reflective layer can be added to the optical device structure layer. The reflective layer includes a reflective structure, which is used to reflect the light beams emitted by at least a portion of the first optical antenna, the second optical antenna, and the third optical antenna, so that the light beams penetrate the SOI substrate and are emitted into space, that is, the light beams are emitted upward to the detection space. At the same time, in order to separate the reflective layer and the second optical device layer, a second spacer layer can be formed between the reflective layer and the second optical device layer. The formation method of the second spacer layer is the same as or similar to the formation method of the aforementioned first spacer layer, and will not be repeated here.

[0118] For example, silicon dioxide is grown a second time on top of the silicon nitride layer (second optical device layer 123) to form a spacer layer, i.e., a second spacer layer 126, which is used to protect the second optical device and the third optical device, and metal is grown or deposited on the second grown silicon dioxide (forming a metal material layer, which can be a first metal material layer), or a dielectric film is evaporated, or a reflection grating is made to form a reflective layer 125, as shown in FIG13 . The reflective layer 125 can reflect the upwardly emitted signal light downward, pass through the SOI substrate and then emit it into space. Here, the signal light reflected downward through the SOI substrate and then emitted into space only needs to pass through the remaining portion of the SOI substrate to be emitted into the detection space, as shown in FIG14 . The various optical devices in FIG14 can be the corresponding optical devices in the first optical device layer, the second optical device layer and the third optical device layer, wherein the substrate silicon layer in the SOI substrate is removed.

[0119] The reflective layer 125 will reflect the upwardly emitted signal light downward, pass through the SOI substrate and then be emitted into space. Here, the signal light reflected downward and passed through the SOI substrate and then emitted into space only needs to pass through the remaining part of the SOI substrate to be emitted into the detection space. Here, when the reflective layer is prepared, the thermal isolation substrate has not yet been fixed above the protective layer, and the direction of the device is flipped. In actual use, the thermal isolation substrate is below the protective layer. At this time, the emitted light beam is reflected upward into the detection space. The light beam emitted by the optical device layer is emitted upward to the detection space, which means that according to the placement of the optical device structure layer on top and the reflective layer on the bottom, the light beam emitted by the optical device structure layer is emitted upward to the detection space. When the optical chip is prepared, the reflective layer reflects the upwardly emitted signal light downward, passes through the SOI substrate and then is emitted into space, which means that according to the placement of the optical device structure layer on the bottom and the reflective layer on the top, the reflective layer reflects the upwardly emitted signal light downward, passes through the SOI substrate and then is emitted into the detection space.

[0120] Through the embodiments provided in the present application, a reflective layer is formed before forming a protective layer, so that the emitted light of the optical antenna can be emitted only from the other side, thereby improving the emission efficiency of the optical antenna, reducing light loss, and improving the utilization efficiency of the input light; before forming the reflective layer, a spacer layer is formed first, which can separate the reflective layer and the optical device structure, thereby reducing the difficulty of preparing the optical chip.

[0121] As an optional solution, forming an optical device structure layer on the top silicon layer of the SOI substrate further includes:

[0122] Before forming the protective layer, a silicon dioxide material is deposited on the SOI substrate having the reflective layer formed thereon to form a third spacer layer;

[0123] A metal material layer is formed on the third spacer layer (the formed metal material layer can be a second metal material layer), and an optical correction structure is formed through a composition process. The optical correction structure is used to change the refractive index of at least part of the optical antennas from the first optical antenna, the second optical antenna and the third optical antenna.

[0124] In order to improve the beam emission capability of the optical antenna, an optical correction structure can be formed based on the position of the optical antennas (for example, the first optical antenna, the second optical antenna, the third optical antenna, etc.) in the optical device structure layer, where the optical correction structure is used to change the refractive index of at least part of the optical antennas from the first optical antenna, the second optical antenna and the third optical antenna.

[0125] The optical correction structure can be formed through a patterning process. Patterning refers to the process of transferring designed patterns, structures, and circuit patterns to the chip surface through photolithography, etching, deposition, and other process steps (similar to those in the previous embodiments). The accuracy and stability of the patterning process have a significant impact on the performance and stability of the chip.

[0126] To protect the reflective layer, before forming the optical correction structure, a silicon dioxide material can be deposited on the SOI substrate with the reflective layer to form a third spacer layer to protect the reflective layer. The formation of the third spacer layer is similar or identical to the formation of the first and second spacer layers and is not further described here.

[0127] For example, as shown in FIG15 , silicon dioxide is grown a third time above reflective layer 125 to form a spacer layer, i.e., third spacer layer 128, which protects reflective layer 125. Metal is grown or deposited on the third-grown silicon dioxide to form a thermal resistor, PZT (lead zirconate titanate thin film, i.e., piezoelectric ceramic), or acoustic field device, greater than or equal to one, to form an optical correction structure 127 (optical correction device), which can adjust the refractive index of different regions of the first, second, and third optical antennas. Furthermore, silicon dioxide can be grown a fourth time above the optical correction structure 127 to form a protective layer 121, which protects the optical correction structure 127, as shown in FIG16 .

[0128] Optionally, multiple through holes can be formed in the quadruple grown silicon dioxide by etching, the through holes extending to the required first optical device, second optical device, third optical device and optical correction device respectively, and metal is grown or deposited to form electrical connections.

[0129] Optionally, metal is grown or deposited on the fourth grown silicon dioxide and patterned to form a first metal wiring layer. Multiple back holes are formed on the back surface of the SOI substrate from which the substrate silicon layer has been completely or partially removed by etching. The back holes extend to the required first metal wiring layer, and metal is grown or deposited, and an electrode pad is formed on the top, which can be electrically connected to the outside through wire bonding or flip-chip bonding; as shown in Figure 10, a pad electrode corresponding to the phase shifter is formed, and the operating voltage is provided to the phase shifter through this electrode. Silicon dioxide is grown for the fifth time above the first metal wiring layer to protect the first metal wiring layer. Here, the total thickness of the silicon dioxide grown for the first, second, third, fourth and fifth times is 0.2μm to 20μm.

[0130] Then, a thermal isolation substrate 11 can be provided and fixed to the fifth grown silicon dioxide surface. Fixing the thermal isolation substrate 11 can be achieved by bonding the thermal isolation substrate 11 to the fifth grown silicon dioxide surface. Thereafter, the device is flipped over, and the substrate silicon layer in the SOI substrate is completely or partially removed, for example, the bottom silicon layer is removed, as shown in FIG17 .

[0131] If there are few metal wirings, only the first metal wiring layer mentioned above can be formed. If there are many metal wirings, one or more additional metal wiring layers will be needed. For example, metal is grown or deposited on the back surface of the SOI substrate, with the underlying silicon layer completely or partially removed, and then patterned to form a second metal wiring layer. Silicon dioxide is then grown a sixth time above the second metal wiring layer to protect it. This process continues until the metal wiring layers formed meet the metal wiring requirements. At this point, the optical chip is fabricated.

[0132] Through the embodiments provided in this application, the refractive index of the optical antenna is changed by heating the optical antenna through the optical correction structure, thereby changing the direction of the outgoing light corresponding to the antenna and achieving light spot alignment. The optical correction structure may also include multiple groups of local heating structures, each of which can be individually controlled for heating to achieve precise control of the optical antenna that needs to be heated, compensate for inconsistencies in the optical antenna aperture caused by the process, and thus improve the light spot quality of the outgoing light beam. Each group of local heating structures is evenly distributed above the corresponding optical antenna, and the specific number can be set as needed, which is not limited in this embodiment.

[0133] It should be noted that for the aforementioned method embodiments, for the sake of simplicity, they are all expressed as a series of action combinations, but those skilled in the art should be aware that this application is not limited by the order of the actions described, because according to this application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by this application.

[0134] If the integrated units in the above embodiments are implemented in the form of software functional units and sold or used as independent products, they can be stored in the above-mentioned computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the relevant technology, or all or part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for enabling one or more computer devices (which can be personal computers, servers or network devices, etc.) to execute all or part of the steps of the methods described in each embodiment of the present application.

[0135] In the above embodiments of the present application, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0136] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0137] In addition, the functional units in the various embodiments of the present application may be integrated into a processing unit, or each unit may exist physically separately, or at least two units may be integrated into a single unit. The above-mentioned integrated units may be implemented in the form of hardware or software functional units.

[0138] The above is only an optional implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as within the scope of protection of the present application.

Claims

1. An optical chip, characterized in that, Comprising: A thermal isolation substrate and an optical device structure layer formed on a top silicon layer in a SOI substrate above the thermal isolation substrate; wherein, The thermal isolation substrate is a single-layer material structure or a stacked structure including multiple material layers, and at least one material layer formed of a material with a thermal conductivity less than 100 W / (m·K) is included in the thermal isolation substrate; The optical device structure layer formed on the top silicon layer in the SOI substrate sequentially includes, from bottom to top: A protective layer, located above the thermal isolation substrate and fixedly connected to the thermal isolation substrate; and A first optical device layer, located above the protective layer and including at least one first optical device; Wherein, the light beam emitted through the optical device structure layer is emitted upward into the detection space.

2. The optical chip according to claim 1, wherein The thickness of the thermal isolation substrate is greater than 50 μm.

3. The optical chip according to claim 2, wherein When the thermal isolation substrate is a stacked structure, the thickness of the material layer formed of a material with a thermal conductivity less than 100 W / (m·K) is greater than or equal to 10 μm.

4. The optical chip according to claim 1, wherein The material of the thermal isolation substrate includes one or more of silicon dioxide, quartz, glass, and plastic.

5. The optical chip according to claim 1, characterized in that, The first optical device layer is formed of silicon material; the optical device structure layer further includes: A second optical device layer, located between the first optical device layer and the protective layer, formed of silicon nitride material and including at least one second optical device; and A first spacer layer, located between the first optical device layer and the second optical device layer, for spacing apart the first optical device layer and the second optical device layer.

6. The optical chip according to claim 5, wherein, The first optical devices in the first optical device layer include a first coupler, a first beam splitter, a first phase shifter, and a first optical antenna; The second optical devices in the second optical device layer include a second coupler, a second beam splitter, a second phase shifter, and a second optical antenna; Wherein, when the first optical devices in the first optical device layer are combined with the second optical devices in the second optical device layer, at least part of a third coupler, a third beam splitter, a third phase shifter, and a third optical antenna are coupled and formed.

7. The optical chip according to claim 6, wherein The optical device structure layer further includes: A reflection layer, the reflection layer is located between the second optical device layer and the protective layer, the reflection layer includes a reflection structure, and the reflection structure is used to reflect upward the light beam emitted by at least part of the optical antennas among the first optical antenna, the second optical antenna, and the third optical antenna; A second spacer layer, located between the reflection layer and the second optical device layer, for spacing apart the reflection layer and the second optical device structure.

8. The optical chip according to claim 7, characterized in that, The projection of the reflection layer in the vertical direction partially overlaps or completely overlaps with the projection in the vertical direction of any one or more of the first optical antenna, the second optical antenna, and the third optical antenna.

9. The optical chip according to claim 7 or 8, characterized in that, The optical device structure layer further includes: An optical correction structure, located between the reflection layer and the protective layer, for heating the first optical antenna to change the refractive index of any one or more of the first optical antenna, the second optical antenna, and the third optical antenna.

10. The optical chip according to claim 9, wherein The optical correction structure includes multiple groups of heating structures, and different groups of heating structures in the multiple groups of heating structures are used to heat different parts of any one or more of the first optical antenna, the second optical antenna, and the third optical antenna.

11. A method for preparing an optical chip, characterized in that, Including: Providing an SOI substrate; Forming an optical device structure layer on the top silicon layer of the SOI substrate, including: forming a first optical device layer in the top silicon layer of the SOI substrate, where the first optical device layer includes at least one first optical device; depositing a silicon dioxide material On the SOI substrate after forming the first optical device layer to form a protective layer; Providing a thermal isolation substrate and fixing it above the protective layer, and then removing all or part of the substrate silicon layer in the SOI substrate; Wherein, the thermal isolation substrate is a single-layer material structure or a laminated structure including multiple material layers, and at least one material layer formed of a material with a thermal conductivity less than 100 W / (m·K) is included in the thermal isolation substrate; and, the light beam emitted from the optical device structure layer is emitted upward into the detection space.

12. The preparation method according to claim 11, characterized in that, The thickness of the thermal isolation substrate is greater than 100 μm; When the thermal isolation substrate is a laminated structure, the thickness of the material layer formed of a material with a thermal conductivity less than 100 W / (m·K) is greater than or equal to 10 μm.

13. The preparation method according to claim 11, characterized in that, The thermal isolation substrate is formed of one or more materials selected from silicon dioxide, quartz, glass, and plastic.

14. The preparation method according to claim 11, characterized in that, The forming of the optical device structure layer on the top silicon layer of the SOI substrate further includes: Before forming the protective layer, depositing a silicon dioxide material on the SOI substrate after forming the first optical device layer to form a first spacer layer; Forming a silicon nitride material layer on the first spacer layer and forming a second optical device layer in the silicon nitride material layer, where the second optical device layer includes at least one second optical device; Wherein, the first optical device in the first optical device layer includes a first coupler, a first beam splitter, a first phase shifter, and a first optical antenna, and the second optical device in the second optical device layer includes a second coupler, a second beam splitter, a second phase shifter, and a second optical antenna. When the first optical device in the first optical device layer is combined with the second optical device in the second optical device layer, at least part of a third coupler, a third beam splitter, a third phase shifter, and a third optical antenna is coupled and formed.

15. The preparation method according to claim 14, characterized in that, The forming of the optical device structure layer on the top silicon layer of the SOI substrate further includes: Before forming the protective layer, depositing A silicon dioxide material on the SOI substrate after forming the second optical device layer to form a second spacer layer; Forming a reflective layer on the second spacer layer, where the reflective layer includes a reflective structure, and the reflective structure is used to reflect the light beam emitted by at least part of the optical antennas among the first optical antenna, the second optical antenna, and the third optical antenna, so that the light beam penetrates the SOI substrate and then is emitted into the detection space.

16. The preparation method according to claim 15, wherein The forming of the optical device structure layer on the top silicon layer of the SOI substrate further includes: Before forming the protection layer, a silicon dioxide material is deposited on the SOI substrate on which the reflection layer is formed to form a third spacer layer; A metal material layer is formed on the third spacer layer, and an optical correction structure is formed through a patterning process. The optical correction structure is used to change the refractive index of any one or more of the first optical antenna, the second optical antenna, and the third optical antenna.

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