Optical coupling structure and integrated photonic chip thereof

Abstract

The application provides an optical coupling structure and an integrated photonic chip. The optical coupling structure comprises a first silicon-based photonic platform and a second silicon-based photonic platform. The first silicon-based photonic platform comprises a first optical waveguide structure and a support limiting structure, and the second silicon-based photonic platform comprises a second optical waveguide structure and a positioning structure. The second silicon-based photonic platform is coupled to the support limiting structure through the positioning structure and is arranged on the first silicon-based photonic platform. The second optical waveguide structure is located in the waveguide extension direction of the first optical waveguide structure. The silicon layer thicknesses of the first silicon-based photonic platform and the second silicon-based photonic platform are different, the advantages of thick silicon and thin silicon platforms are complementary, the low loss and the mature and stable characteristics of the thick silicon platform are retained, the high integration advantage of the thin silicon platform is considered, the continuity of optical signal transmission is guaranteed through structural positioning, the integration and performance of the silicon-based photonic device are improved, and the optical transmission platform with high integration and low transmission loss is formed.

Description

Technical Field

[0001] This application relates to the field of silicon photonics design technology, and more specifically, to an optical coupling structure and its integrated photonic chip. Background Technology

[0002] Silicon-based photonics platforms utilize the optical properties of silicon (such as high refractive index and infrared transparency) to fabricate optical devices such as optical waveguides and optical modulators on silicon wafers, thereby realizing an integrated platform for the generation, transmission, modulation, and detection of optical signals.

[0003] Thick silicon platforms and thin silicon platforms are two core technology platforms in the fields of silicon photonics, which are classified based on the thickness of the silicon layer above the insulating layer and the differences in supporting processes. Thick silicon platforms usually refer to technology platforms that use silicon-on-insulator (SOI) substrates and have a large silicon layer thickness; thin silicon platforms refer to silicon photonics technology platforms built on SOI substrates with a thickness of less than 1 micrometer.

[0004] However, due to their larger device size, thick silicon platforms are difficult to integrate as densely as thin silicon platforms. Thin silicon platforms are more susceptible to process errors. Since both thick and thin silicon platforms have their own advantages and disadvantages, combining the advantages and disadvantages of thick and thin silicon platforms is of great significance for the development of silicon-based photonics platforms. Summary of the Invention

[0005] The purpose of this application is to provide an optical coupling structure and its integrated photonic chip. By integrating and coupling a thick silicon platform and a thin silicon platform to form an optical coupling structure, the advantages of the thick silicon platform and the thin silicon platform are complemented, thereby improving the integration and performance of silicon-based photonic devices and forming a high-integration, low-transmission-loss, high-performance integrated optical transmission platform.

[0006] In a first aspect, this application provides an optical coupling structure, comprising: a first silicon-based photonic platform and a second silicon-based photonic platform; the first silicon-based photonic platform includes a first optical waveguide structure and a support and limiting structure, and the second silicon-based photonic platform includes a second optical waveguide structure and a positioning structure; the second silicon-based photonic platform is coupled to the support and limiting structure through the positioning structure and is disposed on the first silicon-based photonic platform; wherein, the second optical waveguide structure is located in the waveguide extension direction of the first optical waveguide structure, and the silicon layer thicknesses of the first silicon-based photonic platform and the second silicon-based photonic platform are different.

[0007] The optical coupling structure designed above utilizes first and second silicon-based photonic platforms with different silicon layer thicknesses. The coupling between these platforms is achieved through the cooperation of the support and limiting structure of the first platform and the positioning structure of the second platform. Furthermore, the second optical waveguide structure is located along the waveguide extension direction of the first waveguide structure, thus realizing the physical connection between the thick and thin silicon platforms and aligning the optical signal transmission path. This optical coupling structure breaks through the limitations of a single platform, achieving complementary advantages between thick and thin silicon platforms. It retains the low loss and mature, stable device library characteristics of the thick silicon platform while also taking into account the high integration advantages of the thin silicon platform. Simultaneously, structural positioning ensures the continuity of optical signal transmission, reduces coupling alignment errors, and improves the integration and performance of silicon-based photonic devices, ultimately forming a high-integration, low-transmission-loss, high-performance integrated optical transmission platform.

[0008] In an optional embodiment of the first aspect, the first silicon-based photonic platform further includes a first substrate layer and a first insulating layer; the first insulating layer and the support and limiting structure are both disposed on the first substrate layer; the first substrate layer includes a first region and a second region; the first insulating layer is located in the first region and the support and limiting structure is located in the second region; a first optical waveguide structure is disposed through the first insulating layer; wherein, the waveguide end of the first optical waveguide structure is located at the contact plane between the first region and the second region.

[0009] In the above-described implementation, this solution clearly defines the layered structure of the first silicon-based photonic platform and the positions of each component. Specifically, the first insulating layer and the support and limiting structure are respectively disposed on different regions of the first substrate layer. The first optical waveguide structure penetrates the first insulating layer and its end is located on the contact plane of the two regions. In this way, the first optical waveguide structure is stably supported and guided for signal transmission. The division of the two regions ensures that the support and limiting structure and the first optical waveguide structure do not interfere with each other. At the same time, the design of the waveguide end position provides a precise docking reference for subsequent coupling with the second optical waveguide, reducing the leakage of optical signals at the coupling interface.

[0010] In an optional embodiment of the first aspect, the second silicon-based photonic platform includes, from bottom to top, a first silicon layer, a second insulating layer, and a second substrate layer; the second insulating layer includes a first insulating region and a second insulating region, the first silicon layer is located in the first insulating region, and the second insulating region is located above the first insulating layer of the first silicon-based photonic platform; the first silicon layer is etched with a second optical waveguide structure and a positioning structure; wherein the positioning structure is contact-coupled with the support and limiting structure, and the limiting second optical waveguide structure is located in the waveguide extension direction of the first optical waveguide structure.

[0011] In the above-described embodiment, this solution defines a layered structure for the second silicon-based photonic platform. The second insulating layer is arranged in sections, and the first silicon layer is etched to form a second optical waveguide structure and a positioning structure. The positioning structure is coupled and positioned to the support and limiting structure. Thus, the layered structure design ensures the structural stability of the second silicon-based photonic platform, and the cooperation between the positioning structure and the support and limiting structure achieves precise alignment between the second and first optical waveguide structures, ensuring efficient transmission of optical signals along the waveguide extension direction and avoiding coupling losses caused by misalignment.

[0012] In an optional embodiment of the first aspect, the support and limiting structure includes a first limiting support block and a second limiting support block; the first limiting support block and the second limiting support block are spaced apart, and the first limiting support block and the second limiting support block are at the same vertical distance relative to the first substrate layer; the waveguide extension direction of the first optical waveguide structure is located in the spaced area between the first limiting support block and the second limiting support block; the positioning structure includes a first positioning component and a second positioning component, and the second optical waveguide structure is disposed between the first positioning component and the second positioning component; wherein, the first positioning component is attached to and abuts against the first limiting support block, and the second positioning component is attached to and abuts against the second limiting support block.

[0013] In the above-described implementation, the supporting and limiting structure is designed as spaced first and second limiting support blocks, and the positioning structure is a first and second positioning component that fits and abuts against each other. The second optical waveguide structure is located between the two positioning components. In this way, the symmetrical structure of the double support blocks and the double positioning components forms a bidirectional limiting, which improves the stability of the second silicon-based photonic platform after coupling. The spaced area provides space for the extension of the first optical waveguide structure, ensuring the precise alignment of the second optical waveguide structure and the first optical waveguide structure in the extension direction and reducing horizontal alignment error.

[0014] In an optional embodiment of the first aspect, the first positioning component includes a first contact platform and a first positioning protrusion connected to the first contact platform, and the second positioning component includes a second contact platform and a second positioning protrusion connected to the second contact platform; wherein the first positioning protrusion and the second positioning protrusion are at the same vertical distance relative to the second insulating layer, and the vertical distance between the first contact platform and the second contact platform relative to the first positioning protrusion is the same as the etching depth of the second optical waveguide structure; the first contact platform is attached to the upper surface of the first limiting support block, and the first positioning protrusion abuts against the first sidewall of the first limiting support block; the second contact platform is attached to the upper surface of the second limiting support block, and the second positioning protrusion abuts against the first sidewall of the second limiting support block; wherein the first sidewall of the first limiting support block and the first sidewall of the second limiting support block are opposite to each other.

[0015] In the above-described implementation, this solution refines the positioning component structure, including a contact platform and a positioning protrusion. It clarifies the relationship between the vertical distance and etching depth of each component and the fitting and contacting method. In this way, the contact platform fits against the upper surface of the support block to ensure vertical positioning accuracy, the positioning protrusion abuts against the side wall of the support block to achieve horizontal limiting, and the matching of the vertical distance and etching depth ensures that the second optical waveguide structure and the first optical waveguide structure are at the same optical transmission height, further reducing vertical coupling loss and improving coupling efficiency.

[0016] In an optional embodiment of the first aspect, the first sidewall of the first limiting support block and the first sidewall of the second limiting support block are both inclined toward the direction of the first optical waveguide structure.

[0017] In the above-described implementation, the first sidewalls of the limiting support block are all inclined toward the first optical waveguide structure. This inclined sidewalls act as guides when the positioning component is coupled with the support block, facilitating precise alignment during assembly. At the same time, the inclined structure increases the contact area, improves the structural stability after coupling, and reduces the impact of assembly errors on the optical coupling effect.

[0018] In an optional embodiment of the first aspect, the first sidewall of the first limiting support block and the first sidewall of the second limiting support block are both arranged parallel to the waveguide extension direction of the first optical waveguide structure.

[0019] In the above implementation, the first sidewall of the limiting support block is designed to be parallel to the waveguide extension direction of the first optical waveguide structure. This parallel sidewall makes the contact surface between the positioning protrusion and the sidewall planar, further improving the horizontal positioning accuracy and ensuring that the second optical waveguide structure and the first optical waveguide structure are strictly parallel in the extension direction. This avoids waveguide direction deviation caused by the tilt of the sidewall and is suitable for scenarios with extremely high coupling accuracy requirements.

[0020] In an alternative embodiment of the first aspect, the first optical waveguide structure is disposed parallel to the first substrate layer, and the second optical waveguide structure is directly opposite the first optical waveguide structure.

[0021] In the above implementation scheme, the first optical waveguide structure is designed to be parallel to the first substrate layer, and the second optical waveguide structure is directly opposite to the first optical waveguide structure. This ensures the linearity of the optical signal transmission direction by setting the waveguides in parallel, and the directly opposite structure allows the optical signal to directly enter the second optical waveguide structure from the first optical waveguide structure, reducing the mode conversion loss of the optical signal during the coupling process and improving the optical transmission efficiency.

[0022] In an optional embodiment of the first aspect, the second optical waveguide structure has the same etching depth as the first positioning protrusion and the second positioning protrusion, wherein the vertical distance of the first optical waveguide structure relative to the first substrate is equal to the difference between the vertical distance of the first limiting support block relative to the first substrate and the etching depth of the second optical waveguide structure; the horizontal distance of the first optical waveguide structure along the waveguide direction to the first limiting support block is equal to the horizontal distance of the second optical waveguide structure to the first limiting support block.

[0023] In the above implementation, this solution clearly defines the distance relationship between the first optical waveguide structure and the second optical waveguide structure in the vertical and horizontal directions. By matching the vertical distance, it ensures that the two optical waveguide structures are in the same optical transmission plane, avoiding mode field mismatch in the vertical direction. The equal horizontal distance makes the spacing between the two waveguides at the coupling interface uniform, reducing optical signal leakage, further reducing coupling loss, and improving the stability and consistency of coupling.

[0024] In an alternative embodiment of the first aspect, the etching depth of the second optical waveguide structure is between 1 μm and 2 μm.

[0025] In the above implementation, the etching depth of the second optical waveguide structure is between 1µm and 2µm. This etching depth range ensures the ability of the second optical waveguide structure to confine the optical signal and avoids optical signal leakage, while also preventing damage to the silicon layer due to excessive etching. At the same time, it adapts to the silicon layer thickness characteristics of the thick silicon platform and achieves efficient mode field matching with the first waveguide.

[0026] In an alternative embodiment of the first aspect, the silicon layer thickness of the first silicon-based photonic platform is between 100 nm and 400 nm, and the silicon layer thickness of the second silicon-based photonic platform is between 2 μm and 5 μm.

[0027] In the above implementation, this solution limits the silicon layer thickness of the first silicon-based photonic platform to 100nm-400nm (thin silicon) and the silicon layer thickness of the second silicon-based photonic platform to 2um-5um (thick silicon). This clearly defines the thickness range of the two platforms, enabling the first platform to have the advantage of high integration and the second platform to have the advantage of low transmission loss. Through coupling, the functional division of thin silicon integration and thick silicon transmission is realized, meeting the device performance requirements of different application scenarios.

[0028] In a second aspect, this application provides an integrated photonic chip, which includes an optical coupling structure according to any optional embodiment of the first aspect.

[0029] The integrated photonic chip designed above, because it includes the optical coupling structure described above, can achieve coupling between first and second silicon-based photonic platforms with different silicon layer thicknesses by using the cooperation of support and positioning structures. Furthermore, the second optical waveguide structure is located in the waveguide extension direction of the first optical waveguide structure, realizing the physical connection and optical signal transmission path alignment between the thick and thin silicon platforms. In this way, the optical coupling structure designed in this scheme breaks the limitation of a single platform, realizing the complementary advantages of thick and thin silicon platforms. It retains the low-loss characteristics of the thick silicon platform while taking into account the high integration advantages of the thin silicon platform. At the same time, the structural positioning ensures the continuity of optical signal transmission and reduces coupling alignment errors. This allows the integrated photonic chip to have the advantages of both thick and thin silicon platforms, improving the chip's integration, transmission performance, and reliability, and expanding the chip's application range in optical communication, optical sensing, and other fields.

[0030] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the first overall structure of the optical coupling structure provided in the embodiments of this application;

[0033] Figure 2 This is a schematic diagram of the second overall structure of the optical coupling structure provided in the embodiments of this application;

[0034] Figure 3 A schematic diagram of the structure of the first silicon-based photonic platform provided in the embodiments of this application;

[0035] Figure 4 This is a schematic diagram of the structure of the second silicon-based photonic platform provided in an embodiment of this application.

[0036] Reference numerals: 1-First silicon-based photonic platform; 11-First optical waveguide structure; 12-Supporting and limiting structure; 121-First limiting support block; 122-Second limiting support block; 13-First substrate layer; 131-First region; 132-Second region; 14-First insulating layer; 2-Second silicon-based photonic platform; 21-Second optical waveguide structure; 22-Positioning structure; 221-First positioning component; 2210-First contact platform; 2211-First positioning protrusion; 222-Second positioning component; 2220-Second contact platform; 2221-Second positioning protrusion; 23-First silicon layer; 24-Second insulating layer; 241-First insulating region; 242-Second insulating region; 25-Second substrate layer. Detailed Implementation

[0037] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0039] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0040] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0041] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0042] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0043] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0044] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0045] Silicon-based photonics platforms utilize the optical properties of silicon (such as high refractive index and infrared transparency) to fabricate optical devices such as optical waveguides and optical modulators on silicon wafers, thereby realizing an integrated platform for the generation, transmission, modulation, and detection of optical signals.

[0046] Thick silicon platforms and thin silicon platforms are two core technology platforms in silicon photonics and other fields, classified based on the thickness of the silicon layer above the insulating layer and the differences in supporting processes. Thick silicon platforms usually refer to technology platforms that use silicon-on-insulator (SOI) substrates with a large silicon layer thickness. Typical thick silicon waveguides in the industry can reach a thickness of 3 micrometers. Thin silicon platforms refer to silicon photonics technology platforms built on SOI substrates with a thickness of less than 1 micrometer. For example, the mainstream platforms are built on SOI substrates with thicknesses of 220 nanometers and 310 nanometers.

[0047] However, due to their larger device size, thick silicon platforms are difficult to integrate as densely as thin silicon platforms. Thin silicon platforms are more susceptible to process errors. Since both thick and thin silicon platforms have their own advantages and disadvantages, combining the advantages and disadvantages of thick and thin silicon platforms is of great significance for the development of silicon-based photonics platforms.

[0048] To address the aforementioned issues, this application first provides an optical coupling structure and its integrated photonic chip. By setting up first and second silicon-based photonic platforms with different silicon layer thicknesses, coupling between the two is achieved through the cooperation of the support and limiting structure of the first silicon-based photonic platform and the positioning structure of the second silicon-based photonic platform. Furthermore, the second optical waveguide is located in the extension direction of the first optical waveguide, realizing the physical connection between the thick silicon and thin silicon platforms and the alignment of the optical signal transmission path. In this way, the optical coupling structure designed by this scheme breaks the limitations of a single platform, realizing the complementary advantages of thick silicon and thin silicon platforms. It retains the low-loss characteristics of the thick silicon platform while taking into account the high integration advantages of the thin silicon platform. At the same time, the structural positioning ensures the continuity of optical signal transmission, reduces coupling alignment errors, and improves the integration and performance of silicon-based photonic devices, thereby forming a high-integration, low-transmission-loss, high-performance integrated optical transmission platform.

[0049] Based on the above ideas, this application first provides an optical coupling structure, such as... Figures 1 to 2 As shown, the optical coupling structure includes a first silicon-based photonic platform 1 and a second silicon-based photonic platform 2. The first silicon-based photonic platform 1 includes a first optical waveguide structure 11 and a support and limiting structure 12. The second silicon-based photonic platform 2 includes a second optical waveguide structure 21 and a positioning structure 22. The second silicon-based photonic platform 2 is coupled to the support and limiting structure 12 through the positioning structure 22 and is disposed on the first silicon-based photonic platform 1. The second optical waveguide structure 21 in the second silicon-based photonic platform 2 is located in the waveguide extension direction of the first optical waveguide structure 11.

[0050] The first silicon-based photonic platform and the second silicon-based photonic platform have different silicon layer thicknesses. Specifically, one of the first silicon-based photonic platform 1 and the second silicon-based photonic platform 2 is the thin silicon platform described above, and the other is the thick silicon platform described above. In particular, as a possible implementation, assuming the first silicon-based photonic platform 1 is the thin silicon platform described above, the silicon layer thickness of the first silicon-based photonic platform can be set between 100nm and 400nm. Specifically, the silicon layer thickness of the first silicon-based photonic platform can be any one of 100nm, 150nm, 200nm, 220nm, 250nm, 300nm, 310nm, 350nm, and 400nm, preferably 220nm and 310nm. Assuming the second silicon-based photonic platform 2 is the thick silicon platform described above, the silicon layer thickness of the second silicon-based photonic platform 2 can be set between 2µm and 5µm. Specifically, the silicon layer thickness of the second silicon-based photonic platform can be any one of 2µm, 2.5µm, 3µm, 3.2µm, 3.5µm, 3.8µm, 4µm, 4.2µm, 4.4µm, 4.6µm, 4.8µm, and 5µm, with 3µm being the preferred thickness.

[0051] In the above-designed optical coupling structure, input light can be input through the second optical waveguide structure 21 of the second silicon-based photonic platform 2 and transmitted through it. Since the second optical waveguide structure 21 in the second silicon-based photonic platform 2 is located in the waveguide extension direction of the first optical waveguide structure 11, the transmission direction of the second optical waveguide structure 21 is directly opposite to the first optical waveguide structure 11. This allows the second optical waveguide structure 21 to accurately transmit the transmitted light beam to the corresponding first optical waveguide structure 11 of the first silicon-based photonic platform 1, thereby achieving further optical transmission through the first optical waveguide structure 11 and thus realizing stable transmission of the optical signal. It should be noted that this scheme only describes the optical signal transmission of the optical coupling structure. Other functions on the first silicon-based photonic platform 1 and the second silicon-based photonic platform 2 designed in this scheme can be adaptively configured according to actual needs. For example, various optical devices can be integrated on a thin silicon platform to realize optical signal data acquisition and optical signal polarization, and optical signal modulation or detection devices can be integrated on a thick silicon platform.

[0052] The optical coupling structure designed above utilizes first and second silicon-based photonic platforms with different silicon layer thicknesses. The coupling between these platforms is achieved through the cooperation of the support and limiting structure of the first platform and the positioning structure of the second platform. Furthermore, the second optical waveguide is located along the extension direction of the first waveguide, thus realizing the physical connection between the thick and thin silicon platforms and aligning the optical signal transmission path. This optical coupling structure breaks through the limitations of a single platform, achieving complementary advantages between thick and thin silicon platforms. It retains the low-loss characteristics of the thick silicon platform while also taking into account the high integration advantages of the thin silicon platform. Simultaneously, structural positioning ensures the continuity of optical signal transmission, reduces coupling alignment errors, and improves the integration and performance of silicon-based photonic devices, ultimately forming a high-integration, low-transmission-loss, high-performance integrated optical transmission platform.

[0053] In an optional implementation of this embodiment, such as Figure 3 As shown, the first silicon-based photonic platform 1 designed in this scheme also includes a first substrate layer 13 and a first insulating layer 14; the first insulating layer 14 and the support and limiting structure 12 are both disposed on the first substrate layer 13; the first substrate layer 13 includes a first region 131 and a second region 132; the first insulating layer 14 is located in the first region 131, and the support and limiting structure 12 is located in the second region 132; the first optical waveguide structure 11 is disposed through the first insulating layer 14; wherein, the waveguide end of the first optical waveguide structure 11 is located at the contact plane between the first region 131 and the second region 132.

[0054] In the above-described embodiment, this solution clearly defines the layered structure of the first silicon-based photonic platform and the positions of each component. Specifically, it is designed with a bottommost first substrate layer 13, which can be made of materials such as silicon dioxide or silicon oxide. The first substrate layer 13 is divided into two regions: a first region 131 and a second region 132. A first insulating layer 14 is located within the first region 131, and a support and limiting structure 12 is located within the second region 132. Furthermore, the first optical waveguide structure 11 designed in this solution is disposed within the first insulating layer 14 and penetrates through the first insulating layer 14, so that the two waveguide ends of the first optical waveguide structure 11 protrude from the first insulating layer 14. The waveguide ends of the first optical waveguide structure 11 are located at the contact plane between the first region 131 and the second region 132, thereby preparing for alignment with the second optical waveguide structure 21.

[0055] In the above-described implementation, this solution clearly defines the layered structure of the first silicon-based photonic platform and the positions of each component. Specifically, the first insulating layer and the support and limiting structure are respectively disposed on different regions of the first substrate layer. The first optical waveguide penetrates the first insulating layer and its end is located on the contact plane of the two regions. In this way, the stable support and signal transmission guidance of the first optical waveguide structure are achieved. The division of the two regions ensures that the support and limiting structure and the first optical waveguide structure do not interfere with each other. At the same time, the design of the waveguide end position provides a precise docking reference for subsequent coupling with the second optical waveguide, reducing the leakage of optical signals at the coupling interface.

[0056] In an optional implementation of this embodiment, such as Figure 4 As shown, the second silicon-based photonic platform 2 designed in this scheme, when coupled with the first silicon-based photonic platform 1, includes a first silicon layer 23, a second insulating layer 24, and a second substrate layer 25 from bottom to top; the second insulating layer 24 includes a first insulating region 241 and a second insulating region 242, the first silicon layer 23 is located in the first insulating region 241, and the second insulating region 242 is located above the first insulating layer 14 of the first silicon-based photonic platform 1; the first silicon layer 23 is etched with a second optical waveguide structure 21 and a positioning structure 22; wherein, the positioning structure 22 is contact-coupled with the support limiting structure 12, and the second optical waveguide structure 21 is limited to the waveguide extension direction of the first optical waveguide structure 11.

[0057] In the above embodiment, the second silicon-based photonic platform 2, consisting of a second substrate layer 25, a second insulating layer 24, and a first silicon layer 23 from bottom to top, is inverted to form a first silicon layer 23, a second insulating layer 24, and a second substrate layer 25 from bottom to top. In this way, the second silicon-based photonic platform is mounted on the first silicon-based photonic platform 1, so that the positioning structure 22 etched on the first silicon layer 23 is in contact with and coupled to the support and limiting structure 12 of the first silicon-based photonic platform 1, thereby limiting the second optical waveguide structure 21 to be located in the waveguide extension direction of the first optical waveguide structure 11.

[0058] In the above-described embodiment, this solution defines a layered structure for the second silicon-based photonic platform. The second insulating layer is arranged in sections, and the first silicon layer is etched to form the second optical waveguide and the positioning structure. The positioning structure is coupled and positioned to the support and limiting structure. Thus, the layered structure design ensures the structural stability of the second silicon-based photonic platform, and the cooperation between the positioning structure and the support and limiting structure achieves precise alignment between the second and first optical waveguides, ensuring efficient transmission of optical signals along the waveguide extension direction and avoiding coupling losses caused by misalignment.

[0059] Furthermore, such as Figure 3 and Figure 4 As shown, the support and limiting structure 12 designed in this scheme includes a first limiting support block 121 and a second limiting support block 122. The first limiting support block 121 and the second limiting support block 122 are spaced apart, and the first limiting support block 121 and the second limiting support block 122 are at the same vertical distance relative to the first substrate layer 13, that is, the first limiting support block 121 and the second limiting support block 122 have the same height. The waveguide extension direction of the first optical waveguide structure 11 is located in the interval area between the first limiting support block 121 and the second limiting support block 122, that is, the waveguide extension direction of the first optical waveguide structure 11 is located between the interval between the first limiting support block 121 and the second limiting support block 122, so that the waveguide extension direction can be unobstructed. The first limiting support block 121 and the second limiting support block 122 can be obtained by deposition on the second region 132 of the first substrate layer 13. The materials of the first limiting support block 121 and the second limiting support block 122 can be, but are not limited to, SiO, SiN, SiNO, etc.

[0060] Based on the above, the positioning structure 22 designed in this scheme includes a first positioning component 221 and a second positioning component 222. The second optical waveguide structure 21 is disposed between the first positioning component 221 and the second positioning component 222. In the case of contact coupling, the first positioning component 221 is attached to and abuts against the first limiting support block 121, and the second positioning component 222 is attached to and abuts against the second limiting support block 122. Since the etched position of the second optical waveguide structure 21 is located between the first positioning component 221 and the second positioning component 222, and through the contact abutment between the first positioning component 221 and the second positioning component 222 and the first limiting support block 121 and the second limiting support block 122, the second optical waveguide structure 21 is restricted between the first limiting support block 121 and the second limiting support block 122, thereby accurately positioning the second optical waveguide structure 21 in the waveguide extension direction of the first optical waveguide structure 11.

[0061] In the above-described implementation, the supporting and limiting structure is designed as spaced first and second limiting support blocks, and the positioning structure is a first and second positioning component that fits and abuts against each other. The second waveguide is located between the two positioning components. In this way, the symmetrical structure of the double support blocks and the double positioning components forms a bidirectional limiting, which improves the stability of the second silicon-based photonic platform after coupling. The spaced area provides space for the extension of the first optical waveguide, ensuring the precise alignment of the second optical waveguide structure and the first optical waveguide structure in the extension direction and reducing horizontal alignment error.

[0062] Furthermore, please continue to refer to Figure 4 The first positioning component 221 of this design includes a first contact platform 2210 and a first positioning protrusion 2211 connected to the first contact platform 2210. The second positioning component 222 includes a second contact platform 2220 and a second positioning protrusion 2221 connected to the second contact platform 2220. The first positioning protrusion 2211 and the second positioning protrusion 2221 are at the same vertical distance relative to the second insulating layer 24, that is, the first positioning protrusion 2211 and the second positioning protrusion 2221 have the same height. The vertical distance between the first contact platform 2210 and the second contact platform 2220 and the first positioning protrusion 2211 is the same as the etching depth of the second optical waveguide structure 21, that is, the height of the second optical waveguide structure 21 is the same as the height of the first positioning protrusion 2211 and the second positioning protrusion 2221.

[0063] Based on the above design, when the second silicon-based photonic platform 2 is mounted on the first silicon-based photonic platform 1, the first contact platform 2210 is attached to the upper surface of the first limiting support block 121, and the first positioning protrusion 2211 abuts against the first sidewall of the first limiting support block 121; the second contact platform 2220 is attached to the upper surface of the second limiting support block 122, and the second positioning protrusion 2221 abuts against the first sidewall of the second limiting support block 122, wherein the first sidewall of the first limiting support block 121 and the first sidewall of the second limiting support block 122 are opposite to each other.

[0064] In the above implementation, this solution ensures vertical positioning accuracy by having the contact platform adhere to the upper surface of the support limiting block, and then achieves horizontal limiting by having the positioning protrusion abut against the side wall of the support limiting block. The matching of the vertical distance and the etching depth ensures that the second optical waveguide structure and the first optical waveguide structure are on the same optical transmission path, further reducing vertical coupling loss and improving coupling efficiency.

[0065] In an optional embodiment of this scheme, as one possible implementation, the first sidewall of the first limiting support block 121 and the first sidewall of the second limiting support block 122 are both inclined towards the first optical waveguide structure 11. That is, the first sidewalls of the first limiting support block 121 and the second limiting support block 122 are both inclined. In this way, the inclined sidewalls play a guiding role when the positioning structure 22 and the supporting limiting structure 12 are coupled, which facilitates precise alignment during the assembly process. At the same time, the inclined structure can increase the contact area, improve the structural stability after coupling, and reduce the impact of assembly errors on the optical coupling effect. In addition, the inclined sidewalls make the positioning protrusion contact and abut against the sidewall, but cannot be fully pushed in. This keeps the second optical waveguide structure 21 and the first optical waveguide structure 11 at a certain distance, so that they do not contact each other, thereby reducing the contact damage caused by the contact between the second optical waveguide structure 21 and the first optical waveguide structure 11.

[0066] In an optional embodiment of this example, as another possible implementation, in order to reduce the distance between the second optical waveguide structure 21 and the first optical waveguide structure 11, thereby reducing the loss of optical signal transmission, the first sidewall of the first limiting support block 121 and the first sidewall of the second limiting support block 122 can also be arranged parallel to the waveguide extension direction of the first optical waveguide structure 11. That is, the first sidewall of the first limiting support block 121 and the first sidewall of the second limiting support block 122 are parallel to each other. This allows the positioning protrusion to be pushed into the supporting limiting structure, thereby reducing the distance between the second optical waveguide structure 21 and the first optical waveguide structure 11, and thus reducing the loss of optical signal transmission.

[0067] In an optional embodiment of this example, in order to ensure the linearity of the optical signal transmission direction and reduce the mode conversion loss of the optical signal during the coupling process, thereby improving the optical transmission efficiency, the first optical waveguide structure 11 designed in this scheme can be arranged parallel to the first substrate layer 13, and the second optical waveguide structure 21 is directly opposite to the first optical waveguide structure 11.

[0068] The relative height difference between the first silicon-based photonic platform 1 and the second silicon-based photonic platform 2 in this design is determined by the etching depth of the second optical waveguide structure 21 and the height of the support and limiting structure 12. The left-right position difference is determined by the alignment accuracy of the etching process of the first silicon-based photonic platform 1 and the second silicon-based photonic platform 2. Therefore, in this design, the second optical waveguide structure 21 has the same etching depth as the first positioning protrusion 2211 and the second positioning protrusion 2221. The vertical distance of the first optical waveguide structure 11 relative to the first substrate layer 13 is equal to that of the first limiting support block. The difference between the vertical distance of 121 relative to the first substrate layer 13 and the etching depth of the second optical waveguide structure 21 makes the first optical waveguide structure 11 and the second optical waveguide structure 21 have the same height; at the same time, the horizontal distance between the first optical waveguide structure 11 and the first limiting support block 121 along the waveguide direction is equal to the horizontal distance between the second optical waveguide structure 21 and the first limiting support block 121, making the first optical waveguide structure 11 and the second optical waveguide structure 21 have the same horizontal position, and thus making the second optical waveguide structure 21 face the first optical waveguide structure 11.

[0069] In the above implementation, this solution clearly defines the distance relationship between the first optical waveguide structure and the second optical waveguide structure in the vertical and horizontal directions. In this way, the matching of vertical distances ensures that the two waveguides are in the same optical transmission plane, avoiding mode field mismatch in the vertical direction; the equality of horizontal distances makes the spacing between the two waveguides at the coupling interface uniform, reducing optical signal leakage, further reducing coupling loss, and improving the stability and consistency of coupling.

[0070] This solution can be illustrated through the following specific embodiments:

[0071] Example 1: The substrate thickness of the first silicon-based photonic platform (thin silicon platform) is 220nm. The first optical waveguide structure is parallel to the first substrate layer, and its vertical distance from the first substrate layer is 1µm. The support and limiting structure consists of first and second limiting support blocks, with sidewalls parallel to the waveguide extension direction of the first optical waveguide structure. The spacing region is 5µm wide. The distances between the first optical waveguide structure and the nearest edges of the first and second limiting support blocks are 2.5µm and 2.5µm respectively. The vertical distance between the first and second limiting support blocks and the first substrate layer is 2.5µm.

[0072] The second silicon-based photonic platform (thick silicon platform) has a substrate thickness of 3µm and a first silicon layer thickness of 3µm. The etching depths of the second optical waveguide structure, the first positioning protrusion, and the second positioning protrusion are all 1.5µm. The distances from the second optical waveguide structure to the nearest edges of the first and second positioning protrusions are 2.5µm each. The first and second positioning components of the positioning structure are respectively attached and abutted against the support limiting blocks. At this time, the difference between the vertical distance of the first limiting support block relative to the first substrate layer and the etching depth of the second optical waveguide structure is 2.5µm - 1.5µm = 1µm, which is equal to the vertical distance between the first optical waveguide structure and the first substrate layer. Therefore, this matching of vertical distances ensures that the two waveguides are in the same optical transmission plane. Since the distance between the second optical waveguide structure and the positioning structure is equal to the distance between the first optical waveguide structure and the two side support limiting structures, the two are also aligned in the horizontal direction, thus achieving their direct alignment.

[0073] The first silicon-based photonic platform (thin silicon) integrates a high-density optical modulator and a germanium-based photodetector to achieve electro-optical and optical-electrical signal conversion. The second silicon-based photonic platform (thick silicon) uses a second optical waveguide structure as a long-distance transmission channel to transmit the modulated optical signal to the optical module interface. Thus, the high integration of the thin silicon platform allows for a smaller optical module size and the integration of more functional devices. The transmission loss of the second optical waveguide on the thick silicon platform is lower than that of the single thin silicon platform, meeting the requirements of data center optical modules for long-distance, low-loss transmission. Simultaneously, the parallel sidewalls of the supporting limiting block and positioning component ensure precise alignment between the second and first optical waveguide structures. Equal horizontal distances reduce optical signal leakage at the coupling interface and lower coupling loss; vertical distance matching avoids mode field mismatch, further improving transmission efficiency.

[0074] Example 2: The first silicon-based photonic platform (thin silicon platform) has a silicon layer thickness of 310 nm, and the end of the first optical waveguide is located at the contact plane between the first and second regions; the sidewalls of the first and second limiting support blocks of the supporting and limiting structure are inclined at 3° towards the first optical waveguide. The second silicon-based photonic platform (thick silicon platform) has a silicon layer thickness of 5 μm, the second optical waveguide has an etching depth of 2 μm, the positioning protrusion of the positioning structure abuts against the inclined sidewall of the support block, and the second waveguide is directly opposite the first waveguide.

[0075] The second optical waveguide structure of the second silicon-based photonic platform (thick silicon) in the above-described structural design serves as the sensing area, utilizing the high Q-value of the thick silicon waveguide to sense weak light signals. The first silicon-based photonic platform (thin silicon) integrates signal processing circuitry, converting the sensing signal into an electrical signal and outputting it. Thus, the high Q-value of the thick silicon platform enhances the sensor's detection sensitivity, enabling precise detection of trace substances; the thin silicon platform's high integration of the signal processing circuitry reduces the size of the sensor chip. Simultaneously, the inclined sidewalls of the support block facilitate rapid alignment and assembly of the positioning components, reducing the manufacturing difficulty of the sensor chip; the 2µm etching depth of the second waveguide enhances the confinement of the light signal, increasing the light field intensity of the sensing area and thus improving detection sensitivity; the first and second waveguides are aligned to ensure efficient transmission of the sensing signal to the processing circuitry, reducing signal attenuation.

[0076] This application also provides an integrated photonic chip, which includes the optical coupling structure of any of the optional embodiments described above.

[0077] The integrated photonic chip designed above, because it includes the optical coupling structure described above, can achieve coupling between first and second silicon-based photonic platforms with different silicon layer thicknesses by using the cooperation of support and positioning structures. Furthermore, the second optical waveguide is located in the extension direction of the first optical waveguide, realizing the physical connection and optical signal transmission path alignment between the thick and thin silicon platforms. Thus, the optical coupling structure designed in this scheme breaks the limitations of a single platform, achieving complementary advantages between thick and thin silicon platforms. It retains the low-loss characteristics of the thick silicon platform while also taking into account the high integration advantages of the thin silicon platform. Simultaneously, structural positioning ensures the continuity of optical signal transmission and reduces coupling alignment errors, enabling the integrated photonic chip to possess the advantages of both thick and thin silicon platforms. This improves the chip's integration, transmission performance, and reliability, expanding its application range in optical communication, optical sensing, and other fields.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. An optical coupling structure, characterized by, The light coupling structure comprises a first silicon-based photonic platform and a second silicon-based photonic platform; the first silicon-based photonic platform comprises a first optical waveguide structure and a support limiting structure, and the second silicon-based photonic platform comprises a second optical waveguide structure and a positioning structure; The second silicon-based photonic platform is coupled to the support limiting structure through the positioning structure and is arranged on the first silicon-based photonic platform; The second optical waveguide structure is located in the waveguide extension direction of the first optical waveguide structure, and the silicon layer thicknesses of the first silicon-based photonic platform and the second silicon-based photonic platform are different.

2. The light coupling structure of claim 1, wherein, The first silicon-based photonic platform further comprises a first substrate layer and a first insulating layer; the first insulating layer and the support limiting structure are arranged on the first substrate layer; The first substrate layer comprises a first region and a second region; the first insulating layer is located in the first region, and the support limiting structure is located in the second region; The first optical waveguide structure is arranged through the first insulating layer; wherein the waveguide end of the first optical waveguide structure is located at the contact plane of the first region and the second region.

3. The light coupling structure of claim 2, wherein, The second silicon-based photonic platform comprises a first silicon layer, a second insulating layer and a second substrate layer from bottom to top; The second insulating layer comprises a first insulating region and a second insulating region, the first silicon layer is located in the first insulating region, and the second insulating region is located above the first insulating layer of the first silicon-based photonic platform; The first silicon layer is etched with the second optical waveguide structure and the positioning structure; wherein the positioning structure is in contact with the support limiting structure and limits the second optical waveguide structure in the waveguide extension direction of the first optical waveguide structure.

4. The light coupling structure of claim 3, wherein, The support limiting structure comprises a first limiting support block and a second limiting support block; The first limiting support block and the second limiting support block are arranged at the same vertical distance relative to the first substrate layer, and the waveguide extension direction of the first optical waveguide structure is located in the interval region of the first limiting support block and the second limiting support block; The positioning structure comprises a first positioning component and a second positioning component, and the second optical waveguide structure is arranged between the first positioning component and the second positioning component; The first positioning component is attached to the first limiting support block and abuts against the first limiting support block, and the second positioning component is attached to the second limiting support block and abuts against the second limiting support block.

5. The light coupling structure of claim 4, wherein, The first positioning component comprises a first contact platform and a first positioning protrusion connected to the first contact platform, and the second positioning component comprises a second contact platform and a second positioning protrusion connected to the second contact platform; The first positioning protrusion and the second positioning protrusion are at the same vertical distance relative to the second insulating layer, and the vertical distance of the first contact platform and the second contact platform relative to the first positioning protrusion is the same as the etching depth of the second optical waveguide structure. The first contact platform is attached to the upper surface of the first limiting support block, and the first positioning protrusion is in abutment with the first side wall of the first limiting support block; the second contact platform is attached to the upper surface of the second limiting support block, and the second positioning protrusion is in abutment with the first side wall of the second limiting support block; wherein the first side wall of the first limiting support block is opposite to the first side wall of the second limiting support block.

6. The light coupling structure of claim 5, wherein, Wherein, The first side wall of the first limiting support block and the first side wall of the second limiting support block are both inclined to the direction of the first optical waveguide structure.

7. The light coupling structure of claim 5, wherein, Wherein, The first side wall of the first limiting support block and the first side wall of the second limiting support block are both parallel to the waveguide extension direction of the first optical waveguide structure.

8. The light coupling structure of claim 5, wherein, Wherein, The first optical waveguide structure is parallel to the first substrate layer, and the second optical waveguide structure is opposite to the first optical waveguide structure.

9. The light coupling structure of claim 8, wherein, The etching depth of the second optical waveguide structure is the same as that of the first positioning protrusion and the second positioning protrusion, wherein the vertical distance of the first optical waveguide structure relative to the first substrate layer is equal to the difference between the vertical distance of the first limiting support block relative to the first substrate layer and the etching depth of the second optical waveguide structure; The horizontal distance of the first optical waveguide structure along the waveguide extension direction to the first limiting support block is equal to the horizontal distance of the second optical waveguide structure to the first limiting support block.

10. The light coupling structure of claim 3, wherein, The etching depth of the second optical waveguide structure is between 1um and 2um.

11. The light coupling structure of claim 1, wherein, The thickness of the silicon layer of the first silicon-based photon platform is between 100nm and 400nm, and the thickness of the silicon layer of the second silicon-based photon platform is between 2um and 5um.

12. An integrated photonic chip, characterized in that, The integrated photon chip comprises the optical coupling structure of any one of claims 1-11.

Images