An optical transceiver and a manufacturing method thereof

Abstract

The embodiment of the present disclosure provides an optical transceiver and a manufacturing method thereof. The manufacturing method comprises the following steps: providing a substrate, wherein the substrate comprises a substrate, a buried oxygen layer and a lithium niobate layer which are sequentially stacked; the substrate comprises a light modulation area and a light detection area; etching the lithium niobate layer located in the light modulation area to form a thin film lithium niobate waveguide; removing the lithium niobate layer and part of the buried oxygen layer located in the light detection area to form a groove; the bottom of the groove exposes the substrate; forming a light absorption layer in the groove; wherein the thin film lithium niobate waveguide is used for modulating an optical signal and outputting the modulated optical signal; and the light absorption layer is used for detecting the modulated optical signal and converting the modulated optical signal into an electrical signal.

Description

Technical Field

[0001] This disclosure relates to the field of integrated optical devices, and more particularly to an optical transceiver and its manufacturing method. Background Technology

[0002] Lithium niobate possesses photorefractive, nonlinear, electro-optic, acousto-optic, piezoelectric, and thermoelectric effects, and is widely used in acousto-optic modulation, electro-optic modulation, and wavelength conversion applications. Compared to conventional lithium niobate (LN), lithium niobate on insulators (LNOI) achieves a refractive index contrast of approximately 0.7 between the thin-film lithium niobate layer and the buried oxide layer by introducing a buried oxide layer (i.e., silicon dioxide). Therefore, thin-film lithium niobate can be used to fabricate optical devices with smaller size, stronger electro-optic interactions, and higher response rates, making it an important platform for integrated photonics.

[0003] However, due to the lack of physical mechanisms for luminescence and photoelectric conversion in lithium niobate, integrated photonic circuits based on thin-film lithium niobate lack both a light source and a photodetector to convert optical signals into electrical signals. The absence of a light source and photodetector prevents on-chip electro-optical and optical-electrical conversion in thin-film lithium niobate integrated photonic circuits, becoming a major bottleneck hindering the practical application of thin-film lithium niobate integrated photonics technology. Summary of the Invention

[0004] In view of this, the present disclosure provides an optical transceiver and a method for manufacturing the same.

[0005] To achieve the above objectives, the technical solution disclosed herein is implemented as follows:

[0006] In a first aspect, embodiments of this disclosure provide a method for manufacturing an optical transceiver, the method comprising:

[0007] A substrate is provided, the substrate comprising a substrate, a buried oxide layer and a lithium niobate layer stacked sequentially; the substrate includes an optical modulation region and a optical detection region;

[0008] The lithium niobate layer located in the optical modulation region is etched to form a thin-film lithium niobate waveguide;

[0009] The lithium niobate layer and part of the buried oxide layer located in the photodetector region are removed to form a groove; the bottom of the groove exposes the substrate.

[0010] A light absorption layer is formed within the groove; wherein the thin-film lithium niobate waveguide is used to modulate the optical signal and output the modulated optical signal; the light absorption layer is used to detect the modulated optical signal and convert the modulated optical signal into an electrical signal.

[0011] In some embodiments, the etching of the lithium niobate layer located in the optical modulation region to form a thin-film lithium niobate waveguide includes:

[0012] The lithium niobate layer located in the optical modulation region is etched along a direction perpendicular to the substrate to form a thin-film lithium niobate waveguide; wherein the depth of etching the lithium niobate layer is less than the thickness of the lithium niobate layer;

[0013] After etching the lithium niobate layer located in the optical modulation region to form a thin-film lithium niobate waveguide, the manufacturing method further includes:

[0014] Multiple first metal electrodes are formed on the lithium niobate layer.

[0015] In some embodiments, the etching of the lithium niobate layer located in the optical modulation region to form a thin-film lithium niobate waveguide includes:

[0016] The lithium niobate layer located in the optical modulation region is etched along a direction perpendicular to the substrate to form a thin-film lithium niobate waveguide and expose the buried oxide layer; wherein the depth of etching the lithium niobate layer is the same as the thickness of the lithium niobate layer;

[0017] After etching the lithium niobate layer located in the optical modulation region to form a thin-film lithium niobate waveguide, the manufacturing method further includes:

[0018] Multiple first metal electrodes are formed on the buried oxide layer.

[0019] In some embodiments, the substrate further includes an optical coupling region located between the optical modulation region and the optical detection region;

[0020] The lithium niobate layer and part of the substrate located in the optical coupling region are removed to form an air cavity between the remaining substrate and the buried oxide layer; wherein the buried oxide layer located in the optical coupling region forms a suspended waveguide; the suspended waveguide is used to couple the modulated optical signal to the light absorption layer.

[0021] In some embodiments, removing the lithium niobate layer and a portion of the buried oxide layer located in the photodetector region to form a groove includes:

[0022] Remove the lithium niobate layer located in the photodetector region to expose the buried oxide layer;

[0023] The buried oxide layer located in the photodetector region is etched along a direction perpendicular to the substrate to form a groove; wherein the depth of the groove is the same as the thickness of the buried oxide layer.

[0024] In some embodiments, after removing the lithium niobate layer and part of the buried oxide layer located in the photodetector region to form the groove, the manufacturing method further includes:

[0025] The substrates on both sides of the bottom of the groove, which are arranged opposite each other along the direction perpendicular to the optical signal transmission direction, are doped to form a first doped region and a second doped region, respectively.

[0026] After forming the light-absorbing layer in the groove, the manufacturing method further includes:

[0027] Remove the buried oxide layer located in the photodetector region to expose the surfaces of the first doped region and the second doped region;

[0028] A second metal electrode and a third metal electrode are formed on the first doped region and the second doped region, respectively.

[0029] In some embodiments, the substrate is made of silicon;

[0030] The material of the light-absorbing layer includes germanium or a group III-V material.

[0031] Secondly, embodiments of this disclosure provide an optical transceiver, the optical transceiver comprising: a lithium niobate modulator, an optical coupling structure, and a photodetector located on a substrate, the optical coupling structure being located between the lithium niobate modulator and the photodetector; the substrate comprising a substrate, a buried oxide layer, and a lithium niobate layer sequentially stacked thereon.

[0032] The lithium niobate modulator includes: the substrate, a buried oxide layer on the substrate, and a thin-film lithium niobate waveguide on the buried oxide layer; the thin-film lithium niobate waveguide is formed by etching the lithium niobate layer;

[0033] The optical coupling structure includes: a silicon layer, a suspended waveguide, and an air cavity located between the silicon layer and the suspended waveguide; the silicon layer is formed by etching a portion of the substrate; the suspended waveguide is formed from the buried oxide layer.

[0034] The photodetector includes: the substrate and a light-absorbing layer located on the substrate; wherein, the thin-film lithium niobate waveguide is used to modulate the optical signal and output the modulated optical signal; the suspended waveguide is used to couple the modulated optical signal to the light-absorbing layer; the light-absorbing layer is used to detect the modulated optical signal and convert the modulated optical signal into an electrical signal.

[0035] In some embodiments, the lithium niobate modulator further includes:

[0036] The first metal electrode is in contact with the thin-film lithium niobate waveguide or the first metal electrode is in contact with the buried oxide layer.

[0037] In some embodiments, the photodetector further includes:

[0038] The first doped region and the second doped region are formed by doping the substrate; the light-absorbing layer is located between the first doped region and the second doped region.

[0039] The second metal electrode and the third metal electrode are located on the first doped region and the second doped region, respectively.

[0040] This disclosure provides an optical transceiver and a method for manufacturing the same. The manufacturing method includes: providing a substrate comprising a substrate, a buried oxide layer, and a lithium niobate layer stacked sequentially; the substrate comprising an optical modulation region and a photodetector region; etching the lithium niobate layer located in the optical modulation region to form a thin-film lithium niobate waveguide; removing the lithium niobate layer and a portion of the buried oxide layer located in the photodetector region to form a groove; exposing the substrate at the bottom of the groove; and forming a light absorption layer within the groove; wherein the thin-film lithium niobate waveguide is used to modulate an optical signal and output the modulated optical signal; and the light absorption layer is used to detect the modulated optical signal and convert the modulated optical signal into an electrical signal. In this embodiment, the substrate includes a substrate, a buried oxide layer, and a lithium niobate layer stacked sequentially. The lithium niobate layer located in the optical modulation region is etched to form a thin-film lithium niobate waveguide, and the lithium niobate layer and the buried oxide layer located in the optical detection region are etched away to form a groove exposing the substrate. A light absorption layer is then formed in the groove, thereby integrating the lithium niobate modulator and the photodetector on the same substrate. The thin-film lithium niobate waveguide is used to modulate the optical signal and output the modulated optical signal to the light absorption layer. The light absorption layer detects the modulated optical signal and converts the modulated optical signal into an electrical signal. Attached Figure Description

[0041] Figure 1 A schematic flowchart illustrating a method for manufacturing an optical transceiver provided in an embodiment of this disclosure;

[0042] Figure 2A This is a schematic diagram of the structure of an optical transceiver provided in an embodiment of this disclosure;

[0043] Figure 2B A side view of an optical transceiver provided in an embodiment of this disclosure;

[0044] Figures 3A to 3H A cross-sectional structural diagram of the lithium niobate modulator provided in the embodiments of this disclosure during the manufacturing process;

[0045] Figures 4A to 4H A cross-sectional structural diagram of the optical transceiver provided in the embodiments of this disclosure during the manufacturing process;

[0046] Figure 5 A three-dimensional structural schematic diagram of the photodetector provided in the embodiments of this disclosure;

[0047] Figure 6 A schematic cross-sectional view of the photodetector and lithium niobate modulation provided in the embodiments of this disclosure;

[0048] Figure 7 This is a cross-sectional structural diagram of an optical transceiver provided in an embodiment of this disclosure. Detailed Implementation

[0049] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0050] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of this disclosure. However, it will be apparent to those skilled in the art that this disclosure may be practiced without one or more of these details. In other instances, to avoid confusion with this disclosure, certain technical features well-known in the art have not been described; that is, not all features of actual embodiments are described herein, nor are well-known functions and structures described in detail.

[0051] In the accompanying drawings, for clarity, the dimensions of layers, areas, and elements, as well as their relative dimensions, may be exaggerated. The same reference numerals denote the same elements throughout.

[0052] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this disclosure, the first element, component, area, layer, or portion discussed below may be referred to as a second element, component, area, layer, or portion. And the discussion of a second element, component, area, layer, or portion does not imply that the first element, component, area, layer, or portion necessarily exists in this disclosure.

[0053] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein for convenience of description to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms are intended to also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, then the element or feature described as “below,” “under,” or “below” other elements or features will be oriented “above” other elements or features. Therefore, the exemplary terms “below” and “under” can include both above and below orientations. The device may be otherwise oriented (rotated 90 degrees or otherwise) and the spatial descriptive terms used herein will be interpreted accordingly.

[0054] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprise” and / or “comprising,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0055] To fully understand this disclosure, detailed steps and structures will be presented in the following description to illustrate the technical solutions of this disclosure. Preferred embodiments of this disclosure are described in detail below; however, other embodiments may also be implemented in addition to these detailed descriptions.

[0056] Silicon photonics is a next-generation technology based on silicon and silicon-based substrate materials such as silicon-germanium / silicon (SiGe / Si) and silicon-on-insulator (SOI). It utilizes existing complementary metal-oxide-semiconductor (CMOS) processes for the development and integration of optical devices. Combining the ultra-large-scale, ultra-high-precision manufacturing capabilities of integrated circuit technology with the ultra-high speed and ultra-low power consumption advantages of photonics, it represents a disruptive technology for addressing the failure of Moore's Law. This combination benefits from the scalability of semiconductor wafer manufacturing, enabling large-scale production and cost reduction. Optical modulators and detectors are core active devices in silicon photonics.

[0057] The bandwidth limit of pure silicon optical modulators based on carrier dispersion effects is approximately 80 GHz, with limited room for improvement at present. Lithium niobate thin-film optical modulators, on the other hand, theoretically have a bandwidth of up to 500 GHz, showing very promising development prospects and experiencing rapid growth both domestically and internationally in recent years. III-V group and germanium-silicon photodetectors have even higher bandwidth limits, with 265 GHz already reported. Therefore, integrating lithium niobate thin-film optical modulators and photodetectors into photonic chips will be a technological trend, effectively addressing the current bandwidth limitations. Furthermore, heterogeneous integration of photonic chips, electrical chips, and laser chips through three-dimensional stacking will further improve the overall chip performance.

[0058] In related technologies, the main method for integrating light sources and detectors on thin-film lithium niobate integrated photonic circuits is hybrid integration, such as bonding. However, the lithium niobate modulators and photodetectors obtained through this hybrid integration method face challenges in terms of reliability and manufacturability.

[0059] In view of this, the present disclosure provides an optical transceiver and a method for manufacturing the same.

[0060] refer to Figure 1 , Figure 1 This is a schematic flowchart illustrating a method for manufacturing an optical transceiver provided in an embodiment of this disclosure.

[0061] like Figure 1 As shown, this disclosure provides a method for manufacturing an optical transceiver, the method comprising:

[0062] Step S101: Provide a substrate, the substrate comprising a substrate, a buried oxide layer and a lithium niobate layer stacked sequentially; the substrate includes an optical modulation region and a optical detection region;

[0063] Step S102: Etch the lithium niobate layer located in the optical modulation region to form a thin-film lithium niobate waveguide;

[0064] Step S103: Remove the lithium niobate layer and part of the buried oxide layer located in the photodetector area to form a groove; the bottom of the groove exposes the substrate;

[0065] Step S104: A light absorption layer is formed in the groove; wherein, the thin-film lithium niobate waveguide is used to modulate the optical signal and output the modulated optical signal; the light absorption layer is used to detect the modulated optical signal and convert the modulated optical signal into an electrical signal.

[0066] In this embodiment, after forming the thin-film lithium niobate waveguide, the lithium niobate layer and buried oxide layer located in the photodetector region are etched away to form a groove exposing the substrate. A light absorption layer is then formed within the groove, allowing the lithium niobate modulator and photodetector to be integrated on the same substrate. The thin-film lithium niobate waveguide modulates the optical signal and outputs the modulated optical signal to the light absorption layer. The light absorption layer detects the modulated optical signal and converts it into an electrical signal. In this embodiment, the thin-film lithium niobate waveguide and the photoabsorbing layer (e.g., III-V materials and germanium materials) can be integrated on the same substrate, achieving heterogeneous integration of the lithium niobate modulator and the photodetector.

[0067] Before introducing the optical transceiver and its manufacturing method provided in the embodiments of this disclosure, the various directions that may be involved in the embodiments of this disclosure are first defined. The direction perpendicular to the substrate is defined as the Z direction. The X and Y directions are defined in a plane perpendicular to the Z direction, and the X and Y directions may intersect. In a specific embodiment, the X and Y directions may be perpendicular to each other, thus the X, Y, and Z directions are mutually perpendicular. Here, the direction of optical signal transmission is defined as the X direction, and the cross-section perpendicular to the direction of optical signal transmission is the YZ plane.

[0068] refer to Figure 2A and Figure 2B , Figure 2A This is a schematic diagram of the structure of an optical transceiver provided in an embodiment of this disclosure. Figure 2B A side view of an optical transceiver provided in an embodiment of this disclosure.

[0069] like Figure 2A and Figure 2BAs shown, the optical transceiver 100 includes an optical modulation region 102, a first optical coupling region 106, and a photodetector region 110; wherein, the first optical coupling region 106 is located between the optical modulation region 102 and the photodetector region 110. A modulator, such as a lithium niobate modulator 104, can be formed in the optical modulation region 102; a first optical coupling structure 108 can be formed in the first optical coupling region 106; and a photodetector 112 can be formed in the photodetector region 110. That is, the lithium niobate modulator 104 in the optical modulation region 102 can be used to modulate the optical signal and output the modulated optical signal; the first optical coupling structure 108 in the first optical coupling region 106 can be used to couple the modulated optical signal to the photodetector region 110; and the photodetector 112 in the photodetector region 110 can be used to convert the modulated optical signal into an electrical signal.

[0070] In some embodiments, the optical transceiver 100 may further include a second optical coupling region 114. Along the optical signal transmission direction, the optical transceiver 100 sequentially includes a lithium niobate modulator 104, a first optical coupling structure 108, a photodetector 112, and a second optical coupling structure 116. For optical signals not coupled to the photodetector region 110, they can be coupled to the second optical coupling structure 116 within the second optical coupling region 114 and output.

[0071] refer to Figures 3A to 3H , Figures 3A to 3H This is a cross-sectional structural diagram of the lithium niobate modulator provided in the embodiments of this disclosure during the manufacturing process. Figures 3A to 3H A schematic diagram of the cross-sectional structure of the optical modulation region is shown. This cross-section is perpendicular to the optical signal transmission direction; that is, this cross-section is the YZ plane of the optical modulation region. The following will combine... Figures 3A to 3H The manufacturing process of the lithium niobate modulator provided in the embodiments of this disclosure is described in detail.

[0072] In this embodiment of the present disclosure, in step S101, a substrate 118 is provided. The substrate 118 includes a substrate 120, a buried oxide layer 122 and a lithium niobate layer 124 stacked sequentially. The substrate 118 includes a light modulation region 102 and a light detection region 110.

[0073] Combination Figure 2A and Figure 3A As shown, the substrate 118 includes a substrate 120, a buried oxide layer 122 and a lithium niobate layer 124 stacked sequentially; wherein, the substrate 118 includes a light modulation region 102, a first light coupling region 106, a light detection region 110 and a second light coupling region 114 stacked sequentially. Figure 3A The schematic diagram only shows the cross-sectional structure of the substrate 118 located in the optical modulation region 102.

[0074] Here, the substrate can be, for example, lithium niobate on an insulator, and along the optical signal transmission direction (i.e., the X direction) includes an optical modulation region and a optical detection region, as well as a first optical coupling region located between the optical modulation region and the optical detection region. Along the Z direction, the substrate includes a substrate, a buried oxide layer, and a lithium niobate layer stacked sequentially, wherein the substrate material can be, for example, silicon, the buried oxide layer material is silicon dioxide, and the lithium niobate layer is a lithium niobate thin film.

[0075] In this embodiment of the present disclosure, in step S102, the lithium niobate layer 124 located in the optical modulation region 102 is etched to form a thin-film lithium niobate waveguide 130.

[0076] Here, along the Z-direction, the lithium niobate layer located in the optical modulation region is etched. Depending on the etching depth, there are two scenarios. In some embodiments, the etching depth of the lithium niobate layer is less than the thickness of the lithium niobate layer. In other words, the buried oxide layer is not exposed after etching the lithium niobate layer to form the thin-film lithium niobate waveguide. In other embodiments, the etching depth of the lithium niobate layer is the same as the thickness of the lithium niobate layer. In other words, the buried oxide layer is exposed after etching the lithium niobate layer to form the thin-film lithium niobate waveguide.

[0077] In some embodiments, step S102 includes:

[0078] The lithium niobate layer 124 located in the optical modulation region 102 is etched along a direction perpendicular to the substrate 120 (i.e., the Z direction) to form a thin-film lithium niobate waveguide 130; wherein the depth of etching the lithium niobate layer 124 is less than the thickness of the lithium niobate layer 124.

[0079] Following step S102, the manufacturing method further includes:

[0080] Multiple first metal electrodes 136 are formed on the lithium niobate layer 124.

[0081] like Figure 3A As shown, a first photoresist layer 126 is formed covering the substrate 118.

[0082] For example, the first photoresist layer can be formed by spin coating. A first photoresist solution is coated on a substrate; the centrifugal force generated by rotation allows the first photoresist solution to be uniformly distributed on the substrate surface; and the first photoresist layer is formed by baking to evaporate the solvent in the first photoresist solution.

[0083] In one specific embodiment, the material of the first photoresist layer can be, for example, an electron beam photoresist, such as hydrogen silsesquioxane polymers (HSQ). Of course, other materials can also be used to form the first photoresist layer in the embodiments of this disclosure.

[0084] It should be noted that the first photoresist layer can cover the light modulation region, the first light coupling region, the light detection region, and the second light coupling region of the substrate. Figure 3A This only illustrates the first photoresist layer covering the substrate located within the light modulation region.

[0085] Combination Figure 3A and Figure 3B After forming the first photoresist layer 126 covering the substrate 118, a mask layer ( Figure 3B (Not shown in the diagram) The first photoresist layer 126 is patterned to form a patterned first photoresist layer 128.

[0086] For example, a mask layer can be formed on the first photoresist layer, and after alignment, an exposure process can be performed to transfer the pattern of the mask layer to the first photoresist layer. After removing part of the first photoresist layer material, a patterned first photoresist layer is formed.

[0087] Combination Figure 3B and Figure 3C Along the Z-direction, a portion of the lithium niobate layer 124 is etched away using a patterned first photoresist layer 128 to form a thin-film lithium niobate waveguide 130. At this point, the etching depth of the lithium niobate layer 124 is less than the thickness of the lithium niobate layer 124, and the buried oxide layer 122 is not exposed after the thin-film lithium niobate waveguide 130 is formed. Here, both the etching depth and the thickness of the lithium niobate layer 124 refer to dimensions along the Z-direction.

[0088] In some embodiments, the thin-film lithium niobate waveguide can be, for example, a ridge waveguide, which may include a 2×2 beamsplitter, a Mach-Zehnder waveguide, and a 2×2 combiner; wherein the Mach-Zehnder waveguide may include two waveguide arms. The output of the 2×2 beamsplitter is connected to the input of the 2×2 combiner via the Mach-Zehnder waveguide. That is, the 2×2 beamsplitter and the 2×2 combiner are connected via two waveguide arms. In fact, the shape of the thin-film lithium niobate waveguide is not particularly limited in the embodiments of this disclosure.

[0089] In some embodiments, the etching process for forming a thin-film lithium niobate waveguide may include, but is not limited to, dry etching. In fact, this disclosure does not impose any particular limitation on the etching process for forming a thin-film lithium niobate waveguide.

[0090] Combination Figure 3C and Figure 3D After etching to form the thin-film lithium niobate waveguide 130, the patterned first photoresist layer 128 is removed to expose the thin-film lithium niobate waveguide 130.

[0091] In some embodiments, the patterned first photoresist layer can be removed by solvent dissolution, or by etching. This disclosure does not impose any particular limitation on the process for removing the patterned first photoresist layer.

[0092] like Figure 3E As shown, a second photoresist layer 132 is formed to cover the thin-film lithium niobate waveguide 130.

[0093] For example, the second photoresist layer can be formed by spin coating. A second photoresist solution is coated onto a substrate; the centrifugal force generated by rotation allows the second photoresist solution to be uniformly distributed on the substrate surface; and the second photoresist layer is formed by baking to evaporate the solvent in the second photoresist solution.

[0094] In this embodiment, there is no particular limitation on the material of the second photoresist layer. In some embodiments, the materials of the first photoresist layer and the second photoresist layer may be the same or different.

[0095] like Figure 3F As shown, after forming the second photoresist layer 132 covering the thin-film lithium niobate waveguide 130, a mask layer ( Figure 3F (Not shown in the diagram) The second photoresist layer 132 is patterned to form an opening 134 that exposes the lithium niobate layer. Figure 3F The diagram illustrates that the opening 134 of the second photoresist layer can be located between adjacent ridge waveguides.

[0096] Similarly, a mask layer can be formed on the second photoresist layer, and after alignment, an exposure process is performed to transfer the pattern of the mask layer to the second photoresist layer. After removing part of the second photoresist layer material, a patterned second photoresist layer is formed.

[0097] like Figure 3G As shown, conductive material is deposited within the opening 134 of the second photoresist layer to form a first metal electrode 136. The first metal electrode 136 is in contact with the lithium niobate layer 124. During the deposition of the conductive material within the opening 134 of the second photoresist layer, the conductive material also covers the second photoresist layer 132.

[0098] In some embodiments, the process for forming the first metal electrode may include, but is not limited to, chemical vapor deposition (CVD), physical vapor deposition (PVD), plasma enhanced chemical vapor deposition (PECVD), sputtering, and electroplating.

[0099] In some embodiments, the material of the first metal electrode may include, but is not limited to, gold (Au), indium (In), or a gold-tin alloy (AuSn).

[0100] like Figure 3H As shown, the conductive material covering the second photoresist layer 132 is removed, and the second photoresist layer 132 is removed to expose the surface of the thin-film lithium niobate waveguide 130.

[0101] In this embodiment of the present disclosure, a lithium niobate modulator is formed in the optical modulation region. The optical signal is transmitted to the thin-film lithium niobate waveguide. By applying a voltage to the first metal electrode, the refractive index of the thin-film lithium niobate waveguide is changed, so that the optical signal passing through the two waveguide arms of the Mach-Zehnder generates a phase difference. After passing through the 2×2 beam combiner, the amplitude of the output light changes due to interference, thereby achieving modulation of the optical signal.

[0102] refer to Figures 4A to 4H , Figures 4A to 4H This is a cross-sectional structural diagram of the optical transceiver provided in the embodiments of this disclosure during the manufacturing process. Figures 4A to 4D Only a schematic diagram of the cross-sectional structure of the optical modulation region is shown, combined with Figure 2A As shown, Figures 4A to 4D A schematic diagram of the cross-sectional structure of the optical modulation region perpendicular to the direction of optical signal transmission is shown, that is, the cross-section is the YZ plane of the optical modulation region. Figures 4E to 4H This illustrates the cross-sectional structure of the optical modulation region and the optical detection region, combined with... Figure 2A As shown, Figures 4E to 4H This diagram illustrates the cross-sectional structure of the optical modulation region and the optical detection region perpendicular to the optical signal transmission direction; that is, this cross-section is the YZ plane of the optical modulation region. The following will combine... Figures 4A to 4H The manufacturing process of the optical transceiver provided in the embodiments of this disclosure is described in detail.

[0103] For ease of explanation, Figures 4E to 4H The illustration shows the photodetector region located between adjacent photomodulation regions; however, this does not represent the actual relative positional relationship between the photomodulation regions and the photodetector. Figures 4E to 4H The illustrated optical modulation region can be considered as along... Figure 2A A schematic diagram of the cross-sectional structure along the AA direction. Figures 4E to 4H The illustrated light detection area can be considered as Figure 2A A schematic diagram of the cross-sectional structure along the BB direction.

[0104] The following will combine Figures 4A to 4D This paper details the process of forming a thin-film lithium niobate waveguide in the optical modulation region.

[0105] Combination Figure 2A and Figure 4AAs shown, the substrate 118 includes a substrate 120, a buried oxide layer 122 and a lithium niobate layer 124 stacked sequentially; wherein, the substrate 118 includes a light modulation region 102, a first light coupling region 106, a light detection region 110 and a second light coupling region 114 stacked sequentially. Figure 4A The schematic diagram only shows the cross-sectional structure of the substrate 118 located in the optical modulation region 102.

[0106] In this embodiment of the disclosure, step S102 includes:

[0107] Along a direction perpendicular to the substrate 120 (i.e., the Z direction), the lithium niobate layer 124 located in the optical modulation region 102 is etched to form a thin-film lithium niobate waveguide 130 and expose the buried oxide layer 122; wherein the depth of etching the lithium niobate layer 124 is the same as the thickness of the lithium niobate layer 124.

[0108] Following step S102, the manufacturing method further includes:

[0109] Multiple first metal electrodes 136 are formed on the buried oxide layer 122.

[0110] like Figure 4A As shown, a first photoresist layer 126 is formed covering the substrate 118.

[0111] like Figure 4B As shown, after forming the first photoresist layer 126 covering the substrate 118, a mask layer ( Figure 4B (Not shown in the diagram) The first photoresist layer 126 is patterned to form a patterned first photoresist layer 128.

[0112] Combination Figure 4B and Figure 4C Along the Z-direction, a portion of the lithium niobate layer 124 is etched away using a patterned first photoresist layer 128 to form a thin-film lithium niobate waveguide 130. At this point, the etching depth of the lithium niobate layer 124 is the same as its thickness, and after etching to form the thin-film lithium niobate waveguide 130, the buried oxide layer 122 is exposed. Here, the etching depth and the thickness of the lithium niobate layer 124 both refer to dimensions along the Z-direction.

[0113] Combination Figure 4C and Figure 4D After etching to form the thin-film lithium niobate waveguide 130, the patterned first photoresist layer 128 is removed to expose the thin-film lithium niobate waveguide 130.

[0114] Figures 3A to 3H In the schematic lithium niobate modulator 104, the first metal electrode 136 is in contact with the lithium niobate layer 124, while Figures 4A to 4DIn the illustrated lithium niobate modulator 104, a first metal electrode 136 is subsequently formed in contact with the buried oxide layer 122. The specific process for forming the first metal electrode 136 can be found in [reference needed]. Figures 3E to 3H The relevant textual descriptions will not be repeated here.

[0115] The following will combine Figures 4E to 4H The process of forming a light absorption layer in the light detection region is explained in detail.

[0116] In this embodiment of the present disclosure, in step S103, the lithium niobate layer 124 and part of the buried oxide layer 122 located in the photodetector region 110 are removed to form a groove 142; the bottom of the groove 142 exposes the substrate 120.

[0117] In this embodiment of the disclosure, step S103 includes:

[0118] Remove the lithium niobate layer 124 located in the photodetector region 110 to expose the buried oxide layer 122;

[0119] Along a direction perpendicular to the substrate 120 (i.e., the Z direction), the buried oxide layer 122 located in the photodetector region 110 is etched to form a groove 142; wherein the depth of the groove 142 is the same as the thickness of the buried oxide layer 122.

[0120] Combination Figure 2B and Figure 4E The lithium niobate layer 124 located in the photodetector region 110 can be removed to expose the surface of the buried oxide layer 122; a third photoresist layer 138 is formed covering the buried oxide layer 122 located in the photodetector region 110. Here, the third photoresist layer 138 simultaneously covers the buried oxide layer 122 located in the photodetector region 110 and the thin-film lithium niobate waveguide 130 located in the optical modulation region 102.

[0121] For example, the formation of the third photoresist layer can be achieved by spin coating.

[0122] In this embodiment, there is no particular limitation on the material of the third photoresist layer. In some embodiments, the materials of the first, second, and third photoresist layers may be the same or different.

[0123] Combination Figure 4E and Figure 4F After forming the third photoresist layer 138 covering the thin-film lithium niobate waveguide 130, a mask layer ( Figure 4F (Not shown in the diagram) The third photoresist layer 138 is patterned to form an opening 140 that exposes the buried oxide layer 122. Figure 4F The diagram shows the opening 140 of the third photoresist layer exposing the buried oxide layer 122 located in the photodetector region 110.

[0124] Similarly, a mask layer can be formed on the third photoresist layer, and after alignment, an exposure process is performed to transfer the pattern of the mask layer to the third photoresist layer. After removing part of the third photoresist layer material, a patterned third photoresist layer is formed.

[0125] like Figure 4G As shown, along the Z-direction, the buried oxide layer 122 located in the photodetector region 110 is etched to form a groove 142; wherein the depth of the groove 142 is the same as the thickness of the buried oxide layer 122. The etching depth of the buried oxide layer 122 is the same as the thickness of the buried oxide layer 122, that is, the etching penetrates the buried oxide layer 122. In other words, the bottom of the etched groove 142 exposes the surface of the substrate 120.

[0126] In some embodiments, a process combining dry etching and wet etching can be used to etch the buried oxide layer located in the photodetector region.

[0127] In this embodiment of the present disclosure, in step S104, a light absorption layer 144 is formed in the groove 142; wherein, the thin-film lithium niobate waveguide 130 is used to modulate the optical signal and output the modulated optical signal; the light absorption layer 144 is used to detect the modulated optical signal and convert the modulated optical signal into an electrical signal.

[0128] like Figure 4H As shown, a light absorption layer 144 can be formed in the groove 142, and the light absorption layer 144 is in contact with the buried oxide layer 122.

[0129] In some embodiments, the process for forming the light-absorbing layer may include, but is not limited to, CVD.

[0130] It should be noted that the bottom of the thin-film lithium niobate waveguide in the optical modulation region is in contact with the buried oxide layer, while the bottom of the light-absorbing layer in the optical detection region is in contact with the substrate. In other words, the bottom of the thin-film lithium niobate waveguide in the optical modulation region and the bottom of the light-absorbing layer in the optical detection region have different heights along the Z-direction. This height difference between the bottom of the thin-film lithium niobate waveguide in the optical modulation region and the bottom of the light-absorbing layer in the optical detection region is precisely for the purpose of illustrating this difference. Figures 4E to 4H The schematic diagram also shows the cross-sectional structure of the optical modulation region 102 and the optical detection region 110.

[0131] In this embodiment of the disclosure, the material of the light absorption layer 144 includes germanium or a group III-V material.

[0132] It should be noted that the lithium niobate crystal used in the modulator belongs to the trigonal crystal system, with lattice constants of 0.5147 nm and 1.3856 nm, respectively. However, the lattice constants of group III-V materials used in the light-absorbing layer of the photodetector, such as gallium arsenide, are 0.565 nm, and those of germanium are 0.5657 nm. Therefore, the lattice mismatch between the lithium niobate crystal used in the modulator and the group III-V and germanium materials used in the photodetector is >9%. In other words, it is difficult to obtain high-quality gallium arsenide and germanium single crystals directly by epitaxial growth on lithium niobate crystals. Consequently, the fabricated optical transceiver will face challenges in terms of reliability and manufacturability.

[0133] In this embodiment, the lithium niobate layer located in the light modulation region is etched to form a thin-film lithium niobate waveguide, and the lithium niobate layer and buried oxide layer located in the light detection region are etched away to form a groove exposing the substrate, thereby forming a light absorption layer in the groove. The lattice mismatch between the substrate (e.g., silicon) and the light absorption layer (e.g., group III-V materials and germanium) is small, and high-quality group III-V materials or germanium materials can be deposited on the substrate, thereby integrating the lithium niobate modulator and the photodetector on the same substrate.

[0134] refer to Figure 5 and Figure 6 , Figure 5 This is a three-dimensional structural diagram of the photodetector provided in an embodiment of this disclosure. Figure 6 A schematic cross-sectional view of the photodetector and lithium niobate modulation provided in an embodiment of this disclosure.

[0135] For ease of explanation, Figure 6 The schematic diagram also shows the cross-sectional structure of the optical modulation region 102 and the optical detection region 110 perpendicular to the direction of optical signal transmission. This does not represent the actual relative positional relationship between the optical modulation region 102 and the photodetector. Figure 6 The illustrated optical modulation region 102 can be considered as along... Figure 2A A schematic diagram of the cross-sectional structure along the AA direction. Figure 6 The illustrated light detection area 110 can be considered as along... Figure 2A A schematic diagram of the cross-sectional structure along the BB direction.

[0136] Combination Figure 5 and Figure 6 As shown in this embodiment of the disclosure, after step S103, the manufacturing method further includes:

[0137] The substrates 120 on both sides of the bottom of the groove are doped along the direction perpendicular to the optical signal transmission direction (i.e., the Y direction) to form a first doped region 146 and a second doped region 148, respectively.

[0138] After step S104, the manufacturing method further includes:

[0139] Remove the buried oxide layer 122 located in the photodetector region 110 to expose the surfaces of the first doped region 146 and the second doped region 148;

[0140] A second metal electrode 150 and a third metal electrode 152 are formed on the first doped region 146 and the second doped region 148, respectively.

[0141] In some embodiments, the first doped region 146 can be an N-type doped region, and the second doped region 148 can be a P-type doped region. In other embodiments, the first doped region 146 can be a P-type doped region, and the second doped region 148 can be an N-type doped region.

[0142] For example, after forming the light absorption layer 144, the buried oxide layer 122 located in the photodetector region 110 is removed to expose the surfaces of the first doped region 146 and the second doped region 148, while simultaneously exposing the sidewalls of the light absorption layer 144 that are disposed opposite each other along the Y direction; a dielectric layer may also be formed covering the substrate 120 (including the first doped region 146 and the second doped region 148) located in the photodetector region 110 and the sidewalls of the light absorption layer 144; a first via and a second via are etched to form through the dielectric layer and expose the first doped region 146 and the second doped region 148 respectively; conductive materials are deposited in the first via and the second via to form the second metal electrode 150 and the third metal electrode 152 respectively.

[0143] In this embodiment of the disclosure, the materials of the second metal electrode and the third metal electrode may include, but are not limited to, gold (Au), platinum (Pt), titanium (Ti), etc.

[0144] Figure 6 The diagram also shows a thin-film lithium niobate waveguide 130 located in the optical modulation region 102. The bottom of the thin-film lithium niobate waveguide 130 is in contact with the buried oxide layer 122, and the bottom of the light-absorbing layer 144 located in the photodetector region 110 is in contact with the substrate 120. That is, the bottom of the thin-film lithium niobate waveguide 130 in the optical modulation region 102 and the bottom of the light-absorbing layer 144 in the photodetector region 110 have different heights along the Z-direction. More specifically, the height difference along the Z-direction between the bottom of the thin-film lithium niobate waveguide 130 in the optical modulation region 102 and the bottom of the light-absorbing layer 144 in the photodetector region 110 is the same as the thickness of the buried oxide layer 122. This height difference is provided for ease of explanation. Figure 6 The schematic diagram also shows the cross-sectional structure of the optical modulation region 102 and the optical detection region 110.

[0145] refer to Figure 7 , Figure 7This is a cross-sectional structural diagram of an optical transceiver provided in an embodiment of this disclosure. Figure 7 The thin-film lithium niobate waveguide 130 located in the optical modulation region 102, the first suspended waveguide 156 located in the first optical coupling region 106, and the light absorption layer 144 located in the optical detection region 110 are also shown. Figure 7 The schematic cross-sectional structure is shown in the XZ plane.

[0146] Combination Figure 2B and Figure 7 As shown in the present embodiment, the substrate 118 further includes a first optical coupling region 106, which is located between the optical modulation region 102 and the optical detection region 110.

[0147] The lithium niobate layer 124 and part of the substrate 120 located in the first optical coupling region 106 are removed to form a first air cavity 154 between the remaining substrate (i.e., the first silicon layer 158) and the buried oxide layer 122; wherein the buried oxide layer 122 located in the first optical coupling region 106 forms a first floating waveguide 156; the first floating waveguide 156 is used to couple the modulated optical signal to the light absorption layer 144.

[0148] In some embodiments, the surface of the light absorption layer 144 located in the light detection region 110 and the surface of the buried oxide layer 122 located in the first optical coupling region 106 can be substantially flush. Substantially flush means that the thickness of the light absorption layer 144 along the Z direction is the same as the thickness of the buried oxide layer 122 along the Z direction.

[0149] In other embodiments, the surface of the light-absorbing layer 144 located in the photodetector region 110 may be lower than the surface of the buried oxide layer 122 located in the first optical coupling region 106. In subsequent processes, a dielectric layer 166 can be formed on the surface of the light-absorbing layer 144. The sum of the thicknesses of the light-absorbing layer 144 and the dielectric layer 166 along the Z-direction is equal to the thickness of the buried oxide layer 122 along the Z-direction. The material of the dielectric layer 166 may be the same as the material of the buried oxide layer 122.

[0150] In this embodiment, the thin-film lithium niobate waveguide 130 in the optical modulation region 102 is in contact with the buried oxide layer 122, and the light absorption layer 144 in the optical detection region 110 is in contact with the substrate 120. Because the bottom of the thin-film lithium niobate waveguide 130 and the bottom of the light absorption layer 144 have different heights along the Z-direction, the thin-film lithium niobate waveguide 130 in the lithium niobate modulator 104 cannot directly couple the modulated optical signal to the light absorption layer 144 in the photodetector 112. Therefore, a first optical coupling region 106 can be provided between the lithium niobate modulator 104 and the photodetector 112, and the buried oxide layer 122 within the first optical coupling region 106 can be fabricated as a first suspended waveguide 156, thereby coupling the modulated optical signal to the light absorption layer 144 through the first suspended waveguide 156.

[0151] Here, the refractive index of the substrate 120 (e.g., silicon) is greater than that of the buried oxide layer 122 (e.g., silicon dioxide), and the refractive index of the buried oxide layer 122 is greater than that of air. The buried oxide layer has two surfaces disposed opposite each other along the Z direction. A first air cavity 154 is formed on one surface of the buried oxide layer 122, while the other surface of the buried oxide layer 122 is in direct contact with air, using air as a cladding to better prevent the leakage of modulated optical signals.

[0152] For example, a portion of the buried oxide layer located in the first optical coupling region can be etched to form a via exposing the substrate; the via etching can be used to remove a portion of the substrate to form a first air cavity between the remaining substrate and the buried oxide layer. In fact, the embodiments of this disclosure do not impose any special limitations on the process for forming the first suspended waveguide.

[0153] In addition, return to reference Figure 2A and 2B As shown, the substrate also includes a second optical coupling region 114, within which a second optical coupling structure 116 can be formed. The process of forming the second optical coupling structure 116 is similar to that of forming the first optical coupling structure 108, that is, the lithium niobate layer 124 and part of the substrate 120 located in the second optical coupling region 114 are removed to form a second air cavity 160 between the remaining substrate (i.e., the second silicon layer 164) and the buried oxide layer 122, and the buried oxide layer 122 located in the second optical coupling region 114 forms a second suspended waveguide 162.

[0154] In this embodiment, the optical transceiver sequentially includes an optical modulator, a first optical coupling structure, and a photodetector along the optical signal transmission direction (i.e., the X direction). The optical transceiver includes three operating modes: In the first mode, the optical signal is input to the modulator (i.e., a lithium niobate modulator), modulated, and then output as a modulated optical signal; in the second mode, the optical signal is input to the photodetector, and after passing through the photodetector, the optical signal is converted into an electrical signal for output; in the third mode, the optical signal is input to the modulator, modulated, and then output as a modulated optical signal to the first optical coupling structure. A first suspended waveguide in the first optical coupling structure couples the modulated optical signal to the photodetector, and after passing through the photodetector, the optical signal is converted into an electrical signal for output.

[0155] This disclosure also provides an optical transceiver.

[0156] Combination Figure 2A and Figure 2B As shown, in this embodiment of the present disclosure, the optical transceiver 100 includes: a lithium niobate modulator 104 located on a substrate 118 (e.g., ...). Figure 2A (as shown in the dashed box in the middle), the first optical coupling structure 108 and the photodetector 112 (as shown in the dashed box in the middle) Figure 2A(As shown in the dashed box), the first optical coupling structure 108 is located between the lithium niobate modulator 104 and the photodetector 112; the substrate 118 includes a substrate 120, a buried oxide layer 122 and a lithium niobate layer 124 stacked sequentially (as shown in the dashed box). Figure 3A (as shown); wherein, the lithium niobate modulator 104, the first optical coupling structure 108 and the photodetector 112 are located in the optical modulation region 102, the first optical coupling region 106 and the optical detection region 110, respectively.

[0157] The lithium niobate modulator 104 includes: a substrate 120, a buried oxide layer 122 on the substrate 120, and a thin-film lithium niobate waveguide 130 on the buried oxide layer 122; the thin-film lithium niobate waveguide 130 is formed by etching the lithium niobate layer 124.

[0158] The first optical coupling structure 108 includes: a first silicon layer 158, a first floating waveguide 156, and a first air cavity 154 located between the first silicon layer 158 and the first floating waveguide 156; the first silicon layer 158 is formed by etching a portion of the substrate 120 located in the first optical coupling region 106; the first floating waveguide 156 is formed by a buried oxide layer 122 located in the first optical coupling region 106;

[0159] The photodetector 112 includes a substrate 120 and a light-absorbing layer 144 located on the substrate 120; wherein, a thin-film lithium niobate waveguide 130 is used to modulate the optical signal and output the modulated optical signal; a first suspended waveguide 156 is used to couple the modulated optical signal to the light-absorbing layer 144; the light-absorbing layer 144 is used to detect the modulated optical signal and convert the modulated optical signal into an electrical signal.

[0160] To illustrate the remaining substrate 120 (i.e., the first silicon layer 158 and the second silicon layer 164) located in the first optical coupling region 106 and the second optical coupling region 114, Figure 2A The buried oxide layers located in the first optical coupling region and the second optical coupling region are not shown in the diagram. In fact, a first air cavity 154 is formed between the remaining substrate 120 (i.e., the first silicon layer 158) and the buried oxide layer 122 in the first optical coupling region 106, and the buried oxide layer 122 can serve as a first floating waveguide 156; a second air cavity 160 is formed between the remaining substrate 120 (i.e., the second silicon layer 164) and the buried oxide layer 122 in the second optical coupling region 114, and the buried oxide layer 122 can serve as a second floating waveguide 162.

[0161] like Figure 3H As shown in this embodiment, the lithium niobate modulator 104 further includes:

[0162] The first metal electrode 136 is in contact with the thin-film lithium niobate waveguide 130.

[0163] like Figure 2A As shown, the lithium niobate modulator 104 further includes a first metal electrode 136, which is in contact with the buried oxide layer 122.

[0164] like Figure 6 As shown in this embodiment, the photodetector 112 further includes:

[0165] The first doped region 146 and the second doped region 148 are formed by doping the substrate 120; the light absorption layer 144 is located between the first doped region 146 and the second doped region 148.

[0166] The second metal electrode 150 and the third metal electrode 152 are located on the first doped region 146 and the second doped region 148, respectively.

[0167] like Figure 2A and Figure 2B As shown, the optical transceiver 100 further includes a second optical coupling structure 116, which includes a second silicon layer 164, a second floating waveguide 162, and a second air cavity 160 located between the second silicon layer 164 and the second floating waveguide 162. The second silicon layer 164 is formed by etching a portion of the substrate 120 located in the second optical coupling region 114. The second floating waveguide 162 is formed by a buried oxide layer 122 located in the second optical coupling region 114.

[0168] This disclosure provides an optical transceiver and a method for manufacturing the same. The manufacturing method includes: providing a substrate comprising a substrate, a buried oxide layer, and a lithium niobate layer stacked sequentially; the substrate comprising an optical modulation region and a photodetector region; etching the lithium niobate layer located in the optical modulation region to form a thin-film lithium niobate waveguide; removing the lithium niobate layer and a portion of the buried oxide layer located in the photodetector region to form a groove; exposing the substrate at the bottom of the groove; and forming a light absorption layer within the groove; wherein the thin-film lithium niobate waveguide is used to modulate an optical signal and output the modulated optical signal; and the light absorption layer is used to detect the modulated optical signal and convert the modulated optical signal into an electrical signal. In this embodiment, the substrate includes a substrate, a buried oxide layer, and a lithium niobate layer stacked sequentially. The lithium niobate layer located in the optical modulation region is etched to form a thin-film lithium niobate waveguide, and the lithium niobate layer and the buried oxide layer located in the optical detection region are etched away to form a groove exposing the substrate. A light absorption layer is then formed in the groove, thereby integrating the lithium niobate modulator and the photodetector on the same substrate. The thin-film lithium niobate waveguide is used to modulate the optical signal and output the modulated optical signal to the light absorption layer. The light absorption layer detects the modulated optical signal and converts the modulated optical signal into an electrical signal.

[0169] It should be understood that the phrase "an embodiment" or "one embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this disclosure. Therefore, "in one embodiment" or "one embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. It should be understood that in the various embodiments of this disclosure, the sequence numbers of the above-described processes do not imply a sequential order of execution; the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this disclosure. The sequence numbers of the above-described embodiments are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0170] The above description is merely a preferred embodiment of this disclosure and does not limit the patent scope of this disclosure. Any equivalent structural transformations made using the contents of this specification and drawings under the inventive concept of this disclosure, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this disclosure.

Claims

1. A method of manufacturing an optical transceiver, characterized by, The manufacturing method comprises: providing a substrate, the substrate comprising a substrate, a buried oxygen layer and a lithium niobate layer arranged in sequence; the substrate comprising a light modulation region and a light detection region; etching the lithium niobate layer in the light modulation region to form a thin-film lithium niobate waveguide; removing the lithium niobate layer and part of the buried oxygen layer in the light detection region to form a groove; the bottom of the groove exposes the substrate; forming a light absorption layer in the groove; wherein the thin-film lithium niobate waveguide is used for modulating a light signal and outputting the modulated light signal to the buried oxygen layer; the light absorption layer is used for detecting the modulated light signal from the buried oxygen layer and converting the modulated light signal into an electrical signal.

2. The method of manufacturing an optical transceiver according to claim 1, wherein The etching of the lithium niobate layer in the light modulation region to form a thin-film lithium niobate waveguide comprises: etching the lithium niobate layer in the light modulation region in a direction perpendicular to the substrate to form a thin-film lithium niobate waveguide; wherein the depth of etching the lithium niobate layer is less than the thickness of the lithium niobate layer; After the etching of the lithium niobate layer in the light modulation region to form a thin-film lithium niobate waveguide, the manufacturing method further comprises: forming a plurality of first metal electrodes on the lithium niobate layer.

3. The method of manufacturing an optical transceiver according to claim 1, wherein The etching of the lithium niobate layer in the light modulation region to form a thin-film lithium niobate waveguide comprises: etching the lithium niobate layer in the light modulation region in a direction perpendicular to the substrate to form a thin-film lithium niobate waveguide and expose the buried oxygen layer; wherein the depth of etching the lithium niobate layer is the same as the thickness of the lithium niobate layer; After the etching of the lithium niobate layer in the light modulation region to form a thin-film lithium niobate waveguide, the manufacturing method further comprises: forming a plurality of first metal electrodes on the buried oxygen layer.

4. The method of manufacturing an optical transceiver of claim 1, wherein The substrate further comprises a light coupling region, the light coupling region being located between the light modulation region and the light detection region; removing the lithium niobate layer and part of the substrate in the light coupling region to form an air cavity between the remaining substrate and the buried oxygen layer; wherein the buried oxygen layer in the light coupling region forms a suspended waveguide; the suspended waveguide is used for coupling the modulated light signal to the light absorption layer.

5. The method of manufacturing an optical transceiver according to claim 4, wherein The removing of the lithium niobate layer and part of the buried oxygen layer in the light detection region to form a groove comprises: removing the lithium niobate layer in the light detection region to expose the buried oxygen layer; etching the buried oxygen layer in the light detection region in a direction perpendicular to the substrate to form a groove; wherein the depth of the groove is the same as the thickness of the buried oxygen layer.

6. The method of manufacturing an optical transceiver according to claim 5, wherein After the removing of the lithium niobate layer and part of the buried oxygen layer in the light detection region to form a groove, the manufacturing method further comprises: doping the substrate on both sides of the bottom of the groove in a direction perpendicular to the transmission direction of the light signal to form a first doped region and a second doped region, respectively; After the forming of the light absorption layer in the groove, the manufacturing method further comprises: removing the buried oxygen layer in the light detection region to expose the surfaces of the first doped region and the second doped region; A second metal electrode and a third metal electrode are formed on the first doped region and the second doped region, respectively.

7. The method of claim 1, wherein the substrate comprises silicon. The material of the substrate comprises silicon. The material of the light absorption layer comprises germanium or a group III-V material.

8. An optical transceiver, comprising: The optical transceiver comprises a lithium niobate modulator, an optical coupling structure and a photodetector on a substrate, the optical coupling structure being between the lithium niobate modulator and the photodetector; the substrate comprises a substrate, a buried oxide layer and a lithium niobate layer stacked in sequence; The lithium niobate modulator comprises the substrate, a buried oxide layer on the substrate and a thin film lithium niobate waveguide on the buried oxide layer; the thin film lithium niobate waveguide is formed by etching the lithium niobate layer; The optical coupling structure comprises a silicon layer, a suspended waveguide and an air cavity between the silicon layer and the suspended waveguide; the silicon layer is formed by etching part of the substrate; the suspended waveguide is formed by the buried oxide layer; The photodetector comprises the substrate and a light absorption layer on the substrate; wherein the thin film lithium niobate waveguide is used for modulating an optical signal and outputting the modulated optical signal to the suspended waveguide; the suspended waveguide is used for coupling the modulated optical signal to the light absorption layer; the light absorption layer is used for detecting the modulated optical signal from the suspended waveguide and converting the modulated optical signal into an electrical signal.

9. The optical transceiver of claim 8, wherein, The lithium niobate modulator further comprises: A first metal electrode, the first metal electrode being in contact with the thin film lithium niobate waveguide or the first metal electrode being in contact with the buried oxide layer.

10. The optical transceiver of claim 8, wherein, The photodetector further comprises: A first doped region and a second doped region, the first doped region and the second doped region being formed by doping the substrate; the light absorption layer being between the first doped region and the second doped region; A second metal electrode and a third metal electrode, the second metal electrode and the third metal electrode being on the first doped region and the second doped region, respectively.

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