CN112180501A - Silicon-based optical coupling structure, silicon-based monolithic integrated optical device and manufacturing method thereof - Google Patents

Abstract

The present application provides a silicon-based optical coupling structure, a silicon-based monolithic integrated optical device, and a manufacturing method thereof. The silicon-based optical coupling structure includes: a first groove portion formed in the substrate silicon of a silicon-on-insulator (SOI) substrate; and a first optical waveguide structure formed in the silicon-on-insulator (SOI) substrate In the top layer silicon of the substrate; a second optical waveguide structure, which is connected to the first optical waveguide structure in the lateral direction and extends in a first direction in the lateral direction, and the second optical waveguide structure is located in the first optical waveguide structure above the groove portion; and through grooves, which are formed on both sides of the second optical waveguide structure in a lateral second direction, the second direction is perpendicular to the first direction, and the through grooves are parallel to the first direction. A groove portion is connected, wherein the refractive index of the material of the second optical waveguide structure is lower than the refractive index of the material of the first optical waveguide structure. The present application can improve the coupling efficiency of the light field.

Description

Silicon-based optical coupling structure, silicon-based monolithic integrated optical device and manufacturing method thereof

technical field

The present application relates to the field of semiconductor technology, and in particular, to a silicon-based optical coupling structure and a manufacturing method thereof, as well as a silicon-based monolithic integrated optical device and a manufacturing method thereof.

Background technique

A major technical difficulty in the practical application of silicon photonics is the light source. Since silicon is an indirect band gap material, it has low luminous efficiency and low band-edge absorption coefficient, making it difficult to realize silicon light-emitting devices.

Using a coupler to introduce light from an external light source into the chip and using a III-V group hybrid integrated laser are currently the most mainstream methods for introducing light sources.

In addition to the above methods, the all-silicon Raman lasers led by Intel and the monolithic integrated lasers of germanium on silicon and III-V quantum dots led by the Massachusetts Institute of Technology and the University of California have also achieved one in recent years. With a series of breakthroughs, the laser performance has gradually reached practical requirements, providing technical reserves for the realization of silicon-based optical interconnects that are fully compatible with CMOS processes in the future.

It should be noted that the above description of the technical background is only for the convenience of clearly and completely describing the technical solutions of the present application and facilitating the understanding of those skilled in the art. It should not be assumed that the above-mentioned technical solutions are known to those skilled in the art simply because these solutions are described in the background section of this application.

SUMMARY OF THE INVENTION

Silicon-based monolithic integrated lasers require epitaxial growth of germanium, III-V and other direct bandgap materials on silicon or silicon-on-insulator. Due to the difference in material systems and material heights, it is extremely challenging to achieve efficient optical field coupling between lasers and silicon photonic chips. , is one of the important challenges facing the practical application of silicon-based monolithic integrated lasers.

Embodiments of the present application provide a silicon-based optical coupling structure and a manufacturing method thereof, as well as a silicon-based monolithic integrated optical device and a manufacturing method thereof. The silicon-based optical coupling structure has a suspended structure, thereby achieving high efficiency of the optical field. coupling.

According to an aspect of the embodiments of the present application, a silicon-based optical coupling structure is provided, including:

a first groove portion formed in the substrate silicon of a silicon-on-insulator (SOI) substrate;

a first optical waveguide structure formed in the top layer silicon of the silicon-on-insulator (SOI) substrate;

a second optical waveguide structure connected to the first optical waveguide structure in the lateral direction and extending in a first direction in the lateral direction, and the second optical waveguide structure is located above the first groove portion; and

a through groove is formed on both sides of the second optical waveguide structure in a lateral second direction, the second direction is perpendicular to the first direction, and the through groove communicates with the first groove portion, Wherein, the refractive index of the material of the second optical waveguide structure is lower than the refractive index of the material of the first optical waveguide structure.

According to another aspect of the embodiments of the present application, the silicon-based light coupling structure further has:

A support structure, formed in the through groove, has the same size as the through groove in a second direction, and supports the second optical waveguide structure from the second direction.

According to another aspect of the embodiments of the present application, wherein the second optical waveguide structure has:

a rectangular waveguide, which is rectangular in the lateral direction and extends along the first direction;

A tapered waveguide, which is tapered in the lateral direction, extends along the first direction, and has different widths at both ends in the first direction, wherein the rectangular waveguide is different from the first direction in the first direction. The wider ends of the tapered waveguide are connected.

According to another aspect of the embodiments of the present application, the material of the second optical waveguide structure is silicon oxide.

According to another aspect of the embodiments of the present application, the first optical waveguide structure has an inverse tapered structure on a side close to the second optical waveguide structure.

According to another aspect of the embodiments of the present application, wherein,

At least a portion of the first optical waveguide structure is located above the first groove portion.

According to another aspect of the embodiments of the present application, a silicon-based monolithic integrated optical device is provided, which has:

The silicon-based light coupling structure of any of the above aspects; and

A laser formed on the bottom surface of the second groove portion of the substrate silicon of the silicon-on-insulator (SOI) substrate, and/or the top layer silicon of the silicon-on-insulator (SOI) substrate silicon photonics chips in

in,

The light-emitting layer of the laser is at the same position in the longitudinal direction as the first optical waveguide structure, and faces the second optical waveguide structure in the lateral direction,

The light-receiving part of the silicon photonic chip faces the first optical waveguide structure in the lateral direction, and the light-receiving part is covered by the outer cladding.

According to another aspect of the embodiments of the present application, a method for manufacturing a silicon-based optical coupling structure is provided, including:

forming a first optical waveguide structure in the top layer silicon of a silicon-on-insulator (SOI) substrate, and forming an outer cladding longitudinally and laterally covering the first optical waveguide structure;

The substrate silicon of the silicon-on-insulator substrate is etched from the outer cladding to form a second optical waveguide structure laterally connected to the first optical waveguide structure, the second optical waveguide structure in the extending in the first lateral direction, and forming through grooves on both sides of the second optical waveguide structure in the lateral second direction; and

The second optical waveguide structure and the substrate silicon under at least a part of the first optical waveguide structure are etched through the through groove to form a first groove portion in the substrate silicon,

Wherein, the refractive index of the material of the second optical waveguide structure is lower than the refractive index of the material of the first optical waveguide structure.

According to another aspect of the embodiments of the present application, wherein the silicon substrate is etched through the through groove to form a first groove portion, comprising:

The silicon substrate is etched using an isotropic etching method, so that the second optical waveguide structure and at least part of the first optical waveguide structure are suspended.

According to another aspect of the embodiments of the present application, a method for manufacturing a silicon-based monolithic integrated optical device is provided, the method comprising:

forming a first optical waveguide structure in the top layer silicon of a silicon-on-insulator (SOI) substrate, and forming an outer cladding longitudinally and laterally covering the first optical waveguide structure;

A trench region is defined in the silicon-on-insulator (SOI) substrate, and the trench region is etched until the substrate under the trench region is etched to a predetermined thickness to form a second groove portion ;

A laser is formed on the bottom surface of the second groove portion, and the light-emitting layer of the laser is at the same longitudinal position as the first optical waveguide structure;

The substrate silicon of the silicon-on-insulator substrate is etched from the outer cladding between the laser and the first optical waveguide structure to form a lateral connection to the first optical waveguide a second optical waveguide structure between the structure and the laser, the second optical waveguide structure extends in the first lateral direction, and is formed on both sides of the second optical waveguide structure in the lateral second direction through grooves; and

The second optical waveguide structure and the substrate silicon under at least a part of the first optical waveguide structure are etched through the through groove to form a first groove portion in the substrate silicon,

Wherein, the refractive index of the material of the second optical waveguide structure is lower than the refractive index of the material of the first optical waveguide structure.

The beneficial effect of the present application is that the silicon-based light coupling structure has a suspended structure, thereby enabling efficient coupling of light fields.

With reference to the following description and drawings, specific embodiments of the present application are disclosed in detail, indicating the manner in which the principles of the present application may be employed. It should be understood that the embodiments of the present application are not thereby limited in scope. Embodiments of the present application include many changes, modifications and equivalents within the spirit and scope of the appended claims.

Features described and/or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, in combination with, or instead of features in other embodiments .

It should be emphasized that the term "comprising/comprising" when used herein refers to the presence of a feature, integer, step or component, but does not exclude the presence or addition of one or more other features, integers, steps or components.

Description of drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the present application, constitute a part of the specification, are used to illustrate the embodiments of the present application, and together with the written description, serve to explain the principles of the present application. Obviously, the drawings in the following description are only some embodiments of the present application, and for those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative effort. In the attached image:

1 is a schematic cross-sectional view of a silicon-based monolithic integrated optical device having a silicon-based optical coupling structure according to Embodiment 1 of the present application;

2a is a perspective view of the silicon-based optical coupling structure of Embodiment 1 of the present application;

2b is a plan view of the first optical waveguide structure and the second optical waveguide structure in Embodiment 1 of the present application;

3 is a schematic diagram of a method for manufacturing a silicon-based optical coupling structure according to Embodiment 2 of the present application;

FIG. 4 is a schematic diagram of the manufacturing method of the silicon-based monolithic integrated optical device according to the second embodiment of the present application.

Detailed ways

The foregoing and other features of the present application will become apparent from the following description with reference to the accompanying drawings. In the specification and drawings, specific embodiments of the present application are specifically disclosed, which are indicative of some embodiments in which the principles of the present application may be employed, it being understood that the present application is not limited to the described embodiments, on the contrary, the present The application includes all modifications, variations and equivalents falling within the scope of the appended claims.

In the description of the various embodiments of the present application, for the convenience of description, the direction parallel to the surface of the substrate is referred to as the "transverse direction", and the direction perpendicular to the surface of the substrate is referred to as the "longitudinal direction". Thickness" refers to the dimension of the component in the "longitudinal" direction, in which the direction from the substrate silicon of the substrate to the top layer silicon is called the "upper" direction, and the opposite of the "upper" direction is the "down" direction .

Example 1

Embodiments of the present application provide a silicon-based optical coupling structure.

FIG. 1 is a schematic cross-sectional view of a silicon-based monolithic integrated optical device having the silicon-based optical coupling structure of the present embodiment, and FIG. 2a is a schematic perspective view of the silicon-based optical coupling structure.

As shown in FIG. 1 and FIG. 2a, the silicon-based optical coupling structure 1 includes: a first groove part 11, a first optical waveguide structure 12, a second optical waveguide structure 13, and a through groove 14 (not shown in FIG. 1, FIG. 2a shows).

In the present embodiment, the first groove portion 11 is formed in the substrate silicon 101 of the silicon-on-insulator (SOI) substrate 10 .

In the present embodiment, as shown in FIGS. 1 and 2a, the first optical waveguide structure 12 is formed in the top layer silicon 102 of the silicon-on-insulator (SOI) substrate 10, and at least a portion of the first optical waveguide structure 12 may be located in Above the first groove portion 11 .

In this embodiment, as shown in FIGS. 1 and 2 a , the second optical waveguide structure 13 is connected to the first optical waveguide structure 12 in the lateral direction, and the second optical waveguide structure 13 extends in the first direction L1 in the lateral direction , and the second optical waveguide structure 13 is located above the first groove portion 11 . In addition, as shown in FIG. 2a, the second optical waveguide structure 13 may also surround a part of the first optical waveguide structure 12 in a second lateral direction L2, wherein the second direction L2 is perpendicular to the first direction L1.

In this embodiment, as shown in FIG. 2 a , the through grooves 14 may be formed on both sides of the second optical waveguide structure 13 in the second lateral direction L2 , and the through grooves 14 communicate with the first groove portion 11 .

According to the present embodiment, the first optical waveguide structure 12 and the second optical waveguide structure 13 can be formed as suspended structures, so as to avoid light leakage from the substrate and improve the efficiency of optical field coupling; in addition, the second optical waveguide structure 13 Through grooves 14 are formed on both sides, which can prevent light from leaking from the side surfaces of the second optical waveguide structure 13 .

In this embodiment, the refractive index of the material of the second optical waveguide structure 13 may be lower than the refractive index of the material of the first optical waveguide structure 12 , so that the second optical waveguide structure 13 surrounds the first optical waveguide structure 13 from the second direction. In the portion of the optical waveguide structure 12 , light can be efficiently coupled from the second optical waveguide structure 13 into the first optical waveguide structure 12 . In this embodiment, the first optical waveguide structure 12 is formed by using the top layer silicon 102 of the SOI substrate 10 , and its material is silicon; and the second optical waveguide structure 13 can be formed by the buried oxide layer 103 of the SOI substrate 10 and the covering The outer layer 15 of the first optical waveguide structure 12 is formed, and the material of the second optical waveguide structure 13 may be silicon oxide, such as silicon dioxide (SiO ₂ ).

In this embodiment, as shown in FIG. 1 , the outer layer 15 may cover the first optical waveguide structure 12 in the lateral and longitudinal directions. In addition, the lower part of the first optical waveguide structure 12 may be covered by the buried oxide layer 103 of the SOI substrate 10 . Thus, the first optical waveguide structure 12 is surrounded by the lower refractive index material in the entire circumferential direction around the first direction L1 , reducing the leakage of light from the first optical waveguide structure 12 .

In this embodiment, as shown in FIG. 2a , the silicon-based light coupling structure 1 may further have a support structure 16 , the support structure 16 is formed in the through groove 14 and has the same size as the through groove 14 in the second direction L2 . The support structure 16 is fixedly connected between the two walls of the through groove 14 in the second direction L2, thereby, the second optical waveguide structure 13 can be supported from the second direction L2, and the structural stability of the second optical waveguide structure 13 can be improved .

In this embodiment, as shown in FIG. 2 a , the second optical waveguide structure 13 has: a first rectangular waveguide 131 and a tapered waveguide 132 . Wherein, the first rectangular waveguide 131 is rectangular in the lateral direction and extends along the first direction L1; the tapered waveguide 132 is tapered in the lateral direction and extends along the first direction L1, and the two ends in the first direction are The widths are different, wherein, in the first direction L1 , the wider end 132 a of the tapered waveguide 132 is connected to the first rectangular waveguide 131 . In addition, the second optical waveguide structure 13 also has a second rectangular waveguide 133 having a narrower width, and the second rectangular waveguide 133 is connected to the narrower end of the tapered waveguide 132 .

FIG. 2 b is a schematic plan view of the first optical waveguide structure 12 and the second optical waveguide structure 13 in a plane parallel to the surface of the substrate 10 in Embodiment 1 of the present application.

In this embodiment, as shown in FIG. 2b , the first optical waveguide structure 12 has an inverse tapered structure 121 in the L1 direction, wherein the inverse tapered structure 121 is located close to the first optical waveguide structure 12 in the L1 direction One side of the second optical waveguide structure 13 .

As shown in FIG. 2 b , the reverse tapered structure 121 may be encapsulated in the second optical waveguide structure 13 in the lateral direction, for example, the reverse tapered structure 121 may be encapsulated in the tapered waveguide 132 and the second rectangular waveguide 133 . The width of the inverse tapered structure 121 in the second direction L2 may be as follows: the width of the end of the inverse tapered structure 121 facing the first rectangular waveguide 131 is the narrowest, and the width of the position along the L1 direction farther away from the first rectangular waveguide 131 gradually increase.

When light enters the silicon waveguide from the SiO2 waveguide, the mode fields of the SiO2 waveguide and the silicon waveguide are quite different, which will increase the coupling loss. In the present application, since the first optical waveguide structure 12 has an inverse-tapered structure 121 , the reversed-tapered structure 121 can increase the mode field in the first optical waveguide structure 12 , and thus, light is transmitted from the second optical waveguide structure 13 When entering the first optical waveguide structure 12 , the mode field can be matched and the coupling loss can be reduced.

In addition, in this embodiment, as shown in FIG. 2b , the first optical waveguide structure 12 may further have a rectangular structure 122 in the L1 direction, wherein the rectangular structure 122 is further away from the first optical waveguide structure 121 in the L1 direction than the inverse tapered structure 121 One side of a rectangular waveguide 131 .

In addition, in this embodiment, the thickness of the first optical waveguide structure 12 may be kept the same or different everywhere in the L1 direction.

As shown in FIG. 1 , the silicon-based monolithic integrated optical device 100 may have: a silicon-based optical coupling structure 1 , a laser 2 , and a silicon optical chip 3 .

As shown in FIG. 1 , the laser 2 can be formed on the surface of the second groove portion 17 of the substrate silicon 101 of the silicon-on-insulator (SOI) substrate 10 , and the silicon photonic chip 3 can be formed on the silicon-on-insulator (SOI) in the top layer silicon 102 of the substrate 10 .

In this embodiment, the laser 2 may be, for example, an edge-emitting laser, wherein the laser 2 may be fabricated by stacking direct bandgap materials such as epitaxy III-V, Ge(Sn), or the like. The height of the light emitting layer 21 of the laser 2 is the same as that of the first optical waveguide structure 12 , that is, the light emitting layer 21 of the laser 2 and the first optical waveguide structure 12 are at the same position in the longitudinal direction. In addition, the light-emitting layer 21 of the laser 2 faces the second optical waveguide structure 13 in the lateral direction, and the light-emitting layer 21 can be covered by the outer layer 15 in the lateral direction, whereby the light emitted by the light-emitting layer 21 can be coupled to the outer layer 15 via the outer layer 15 . in the second optical waveguide structure 13 .

In this embodiment, the light-receiving part (not shown) of the silicon photonic chip 3 may face the first optical waveguide structure 12 in the lateral direction, and the upper surface of the light-receiving part may be covered by the outer layer 15 . Thereby, light coupled into the first optical waveguide structure 12 can be coupled into the silicon photonic chip 3 .

As shown in FIG. 1 , in this embodiment, the light emitted by the light emitting layer 21 of the laser 2 is coupled to the second optical waveguide structure 13 and transmitted to the first optical waveguide structure 12 , and then guided into the silicon photonic chip 3 . It can be seen that although the thickness of the laser 2 is relatively thick, the laser 2 is formed on the surface of the second groove portion 17 of the silicon substrate 101 of the SOI substrate 10 in the present application, so that the laser 2 can be a sinking laser, so that in the longitudinal direction The upper surface can be aligned with the first optical waveguide structure 12 , which can effectively reduce the height difference between the light emitting layer 21 of the laser 2 and the silicon photonic chip 3 and reduce the coupling difficulty.

It should be noted that, in FIG. 1 , the silicon-based monolithic integrated optical device 100 has both the laser 2 and the silicon photonics chip 3 , and this embodiment may not be limited to this. In addition to the silicon-based optical coupling structure 1 , only one of the laser 2 and the silicon optical chip 3 may be provided. In addition, in this embodiment, the laser 2 and the silicon photonic chip 3 are only examples, and the embodiment may not be limited thereto. For example, the laser 2 and the silicon photonic chip 3 may be other optical devices.

Example 2

Embodiment 2 provides a method for manufacturing a silicon-based optical coupling structure, which is used to manufacture the silicon-based optical coupling structure described in Embodiment 1.

FIG. 3 is a schematic diagram of a manufacturing method of a silicon-based optical coupling structure in this embodiment. As shown in FIG. 3 , in this embodiment, the manufacturing method may include:

Step 301, forming the first optical waveguide structure 12 in the top layer silicon 102 of the silicon-on-insulator (SOI) substrate 10, for example, by photolithography and etching to form the first optical waveguide structure 12; Covering the outer cladding 15 of the first optical waveguide structure, for example, depositing SiO2 material to form the outer cladding 15;

Step 302, etching from the outer layer 15 to the silicon substrate 101 of the silicon-on-insulator substrate 10 to form a second optical waveguide structure 13 connected to the first optical waveguide structure 12 in the lateral direction, the second optical waveguide structure 13 extends in the lateral first direction, and through grooves 14 are formed on both sides of the second optical waveguide structure 13 in the lateral second direction, and the surface of the substrate silicon 101 is exposed to the through grooves 14, for example, by photolithography and Etching process, starting from the outer layer 15 to etch downwards to form through-troughs 14, until the substrate silicon 101 is exposed, and the etching is stopped; and

Step 303 , etching the second optical waveguide structure 13 and at least part of the silicon substrate 101 under the first optical waveguide structure 12 through the through groove 14 to form the first groove portion 11 in the silicon substrate 10 .

In this embodiment, the refractive index of the material of the second optical waveguide structure 13 is lower than the refractive index of the material of the first optical waveguide structure 12 .

In this embodiment, step 303 may include the following steps:

Step 3031 , etching the substrate silicon 101 by isotropic etching, so that the second optical waveguide structure 13 and at least part of the first optical waveguide structure 12 are suspended.

The isotropic etching method in step 3031 is, for example, isotropic dry etching, and sulfur hexafluoride (SF6) can be used as the etching gas.

In addition, in this embodiment, step 303 may further include the following steps after step 3031:

Step 3032 , continue to etch the silicon substrate 101 using anisotropic etching to increase the depth of the first groove portion 11 .

The anisotropic etching method in step 3032 is, for example, anisotropic dry etching, and a mixed gas of sulfur hexafluoride (SF6) and octafluorocyclobutane (C4F8) may be used as the etching gas. In addition, the step 3032 Dicos depth may be, for example, 100 microns.

In this embodiment, the manufacturing method of the silicon-based optical coupling structure shown in FIG. 3 can be included in the manufacturing method of the silicon-based monolithic integrated optical device for manufacturing the silicon-based monolithic integrated optical device described in Embodiment 1 Device 100 .

FIG. 4 is a schematic diagram of the manufacturing method of the silicon-based monolithic integrated optical device of the present embodiment. As shown in FIG. 4, in this embodiment, the manufacturing method may include:

Step 401 , forming the first optical waveguide structure 12 in the top layer silicon 102 of the silicon-on-insulator (SOI) substrate 10 , and forming the outer layer 15 covering the first optical waveguide structure 12 in the longitudinal and lateral directions, in this step 401 , Refer to the above step 301;

Step 402: Define a trench region in the silicon-on-insulator (SOI) substrate 10, and etch the trench region until the substrate silicon under the trench region is etched to a predetermined thickness, for example, 2 microns, to forming a second groove portion 17;

Step 403 , forming the laser 2 on the bottom surface of the second groove portion 17 , the light emitting layer 21 of the laser 2 and the first optical waveguide structure 12 are in the same position in the longitudinal direction, for example, on the silicon on the bottom surface of the second groove portion 17 Epitaxy III-V group materials and active region materials such as Ge(Sn) are stacked, and laser 2 is prepared;

Step 404: Etch down from the outer layer 15 between the laser 2 and the first optical waveguide structure 12 to the substrate silicon 101 of the silicon substrate 10 on the insulator to form a lateral connection to the first optical waveguide structure 12 The second optical waveguide structure 13 between the laser 2 and the second optical waveguide structure 13 extends in the first lateral direction, and through grooves 14 are formed on both sides of the second optical waveguide structure 13 in the lateral second direction , the specific implementation of step 404 can refer to step 302; and

Step 405 , etching the second optical waveguide structure 13 and at least part of the silicon substrate 101 under the first optical waveguide structure 12 through the through groove 14 to form the first groove portion 11 in the silicon substrate 101 . The details of step 404 are: Embodiments may refer to step 303 .

In the embodiment of FIG. 4 , the refractive index of the material of the second optical waveguide structure 13 is lower than the refractive index of the material of the first optical waveguide structure 12 .

In addition, in this embodiment, after the laser 2 is formed in step 403 , the outer cladding 15 may be additionally deposited, so that the laser is covered in the outer cladding 15 , and filling is filled between the laser 3 and the first optical waveguide structure 12 The outer layer 15 is convenient for forming the second optical waveguide structure 13 in step 404.

In addition, in this embodiment, before forming the first optical waveguide structure 12 , the silicon photonics chip 3 can also be formed first, and the silicon photonics chip can be covered with the outer layer 15 .

According to the present embodiment, according to the present embodiment, the first optical waveguide structure 12 and the second optical waveguide structure 13 can be formed as suspended structures, thereby avoiding light leakage from the substrate and improving the efficiency of optical field coupling; Through grooves 14 are formed on both sides of the optical waveguide structure 13 to prevent light from leaking from the sides of the second optical waveguide structure 13 ; in addition, the laser 2 is formed in the second groove portion 17 of the silicon substrate 101 of the SOI substrate 10 On the surface, the laser 2 can be a sunken laser, so that it can be aligned with the first optical waveguide structure 12 in the longitudinal direction, which can effectively reduce the height difference between the light-emitting layer 21 of the laser 2 and the silicon photonic chip 3 and reduce the coupling difficulty.

The present application has been described above with reference to the specific embodiments, but those skilled in the art should understand that these descriptions are all exemplary and do not limit the protection scope of the present application. Those skilled in the art can make various variations and modifications to the present application according to the spirit and principles of the present application, and these variations and modifications are also within the scope of the present application.

Claims (10)

1. A silicon-based optical coupling structure, comprising: a first groove portion formed in the substrate silicon of a silicon-on-insulator (SOI) substrate; a first optical waveguide structure formed in the top layer silicon of the silicon-on-insulator (SOI) substrate; a second optical waveguide structure connected to the first optical waveguide structure in the lateral direction and extending in a first direction in the lateral direction, and the second optical waveguide structure is located above the first groove portion; and a through groove is formed on both sides of the second optical waveguide structure in a lateral second direction, the second direction is perpendicular to the first direction, and the through groove communicates with the first groove portion, Wherein, the refractive index of the material of the second optical waveguide structure is lower than the refractive index of the material of the first optical waveguide structure. 2. The silicon-based light coupling structure of claim 1, wherein the silicon-based light coupling structure further comprises: A support structure, formed in the through groove, has the same size as the through groove in a second direction, and supports the second optical waveguide structure from the second direction. 3. The silicon-based optical coupling structure of claim 1, wherein the second optical waveguide structure has: a rectangular waveguide, which is rectangular in the lateral direction and extends along the first direction; A tapered waveguide, which is tapered in the lateral direction, extends along the first direction, and has different widths at both ends in the first direction, wherein the rectangular waveguide is different from the first direction in the first direction. The wider ends of the tapered waveguide are connected. 4. The silicon-based light coupling structure of claim 1, wherein, The material of the second optical waveguide structure is silicon oxide. 5. The silicon-based light coupling structure of claim 1, wherein, The first optical waveguide structure has an inverse tapered structure on a side close to the second optical waveguide structure. 6. The silicon-based light coupling structure of claim 1, wherein, At least a portion of the first optical waveguide structure is located above the first groove portion. 7. A silicon-based monolithic integrated optical device, comprising: The silicon-based light coupling structure of any one of claims 1 to 6; and A laser formed on the bottom surface of the second groove portion of the substrate silicon of the silicon-on-insulator (SOI) substrate, and/or the top layer silicon of the silicon-on-insulator (SOI) substrate silicon photonics chips in in, The light-emitting layer of the laser is at the same position in the longitudinal direction as the first optical waveguide structure, and faces the second optical waveguide structure in the lateral direction, The light-receiving part of the silicon photonic chip faces the first optical waveguide structure in the lateral direction, and the light-receiving part is covered by the outer cladding. 8. A method for manufacturing a silicon-based optical coupling structure, comprising: forming a first optical waveguide structure in the top layer silicon of a silicon-on-insulator (SOI) substrate, and forming an outer cladding longitudinally and laterally covering the first optical waveguide structure; The substrate silicon of the silicon-on-insulator substrate is etched from the outer cladding to form a second optical waveguide structure laterally connected to the first optical waveguide structure, the second optical waveguide structure in the extending in the first lateral direction, and forming through grooves on both sides of the second optical waveguide structure in the lateral second direction; and The second optical waveguide structure and the substrate silicon under at least a part of the first optical waveguide structure are etched through the through groove to form a first groove portion in the substrate silicon, Wherein, the refractive index of the material of the second optical waveguide structure is lower than the refractive index of the material of the first optical waveguide structure. 9 . The method for manufacturing a silicon-based light coupling structure according to claim 8 , wherein etching the substrate silicon through the through groove to form the first groove portion comprises: 10 . The silicon substrate is etched using an isotropic etching method, so that the second optical waveguide structure and at least part of the first optical waveguide structure are suspended. 10. A method for manufacturing a silicon-based monolithic integrated optical device, the method comprising: forming a first optical waveguide structure in the top layer silicon of a silicon-on-insulator (SOI) substrate, and forming an outer cladding longitudinally and laterally covering the first optical waveguide structure; A trench region is defined in the silicon-on-insulator (SOI) substrate, and the trench region is etched until the substrate under the trench region is etched to a predetermined thickness to form a second groove portion ; A laser is formed on the bottom surface of the second groove portion, and the light-emitting layer of the laser is at the same longitudinal position as the first optical waveguide structure; The substrate silicon of the silicon-on-insulator substrate is etched from the outer cladding between the laser and the first optical waveguide structure to form a lateral connection to the first optical waveguide a second optical waveguide structure between the structure and the laser, the second optical waveguide structure extends in the first lateral direction, and is formed on both sides of the second optical waveguide structure in the lateral second direction through grooves; and The second optical waveguide structure and the substrate silicon under at least a part of the first optical waveguide structure are etched through the through groove to form a first groove portion in the substrate silicon, Wherein, the refractive index of the material of the second optical waveguide structure is lower than the refractive index of the material of the first optical waveguide structure.

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