CN210626706U - Waveguide structure - Google Patents
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- CN210626706U CN210626706U CN201921956524.2U CN201921956524U CN210626706U CN 210626706 U CN210626706 U CN 210626706U CN 201921956524 U CN201921956524 U CN 201921956524U CN 210626706 U CN210626706 U CN 210626706U
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Abstract
The present application provides a waveguide structure comprising: the number of the annular waveguides is more than two; the first linear waveguide is in a linear shape, and an incident end and a first connecting end are respectively arranged at two ends of the first linear waveguide; the second linear waveguide is in a linear shape, and an emergent end and a second connecting end are respectively arranged at two ends of the second linear waveguide; and a U-shaped waveguide connecting the first connection end and the second connection end, wherein a center connecting line of adjacent annular waveguides is parallel to the first linear waveguide and the second linear waveguide.
Description
Technical Field
The application relates to the technical field of semiconductors, in particular to a waveguide structure.
Background
Silicon photonics, a new generation of technology for optical device development and integration based on silicon and silicon-based substrate materials (e.g., SiGe/Si, SOI, etc.) using existing Complementary Metal Oxide Semiconductor (CMOS) processes, combines the characteristics of ultra-large scale, ultra-high precision fabrication of integrated circuit technology with the advantages of photonics, ultra-high speed, ultra-low power consumption. Silicon photonics has urgent application requirements in the fields of optical communication and optical interconnection at the present stage, and is a potential technology for realizing on-chip optical interconnection and optical computers in the future.
Waveguide structures are important devices in silicon photonic devices. A micro-ring resonator structure is known in the prior art, for example, a micro-ring is disposed between two parallel straight waveguides, light enters one straight waveguide, light in the straight waveguide is coupled into the micro-ring, and is coupled from the micro-ring into the other straight waveguide and exits from the other straight waveguide.
The micro-ring resonant cavity structure is used as a basic optical component, the optical transmission direction of the micro-ring resonant cavity structure is controllable, and the resonance of the micro-ring resonant cavity structure does not need a cavity surface or a grating to provide optical feedback, so that the micro-ring resonant cavity structure is favorable for the monolithic integration with other optoelectronic components.
It should be noted that the above background description is only for the convenience of clear and complete description of the technical solutions of the present application and for the understanding of those skilled in the art. Such solutions are not considered to be known to the person skilled in the art merely because they have been set forth in the background section of the present application.
Disclosure of Invention
In a conventional microring structure, a large Free Spectral Range (FSR) can be achieved by reducing the microring radius and connecting a plurality of microrings of different sizes in series between two parallel straight waveguides, wherein the series connection of microrings means: and the connecting line of the centers of two adjacent microrings is vertical to the extending direction of the two straight waveguides. In addition, in the conventional micro-ring structure, the number of micro-rings can be increased to improve the smoothness of the output spectrum.
The inventor of the present application finds that, in the conventional micro-ring structure, a plurality of micro-rings with different sizes need to be designed, so that the layout design is complicated, and the extension direction of the linear waveguide is perpendicular to the arrangement direction of the plurality of ring waveguides, which occupies a large area on the surface of the chip.
The embodiment of the application provides a waveguide structure and a manufacturing method thereof, in the waveguide structure, a U-shaped waveguide is used for connecting two linear waveguides, so that resonant light and non-resonant light are subjected to constructive interference at the same port, and more than two annular waveguides are connected in parallel between the two parallel linear waveguides, so that smoothness of the top of an output spectrum is improved, a Free Spectral Range (FSR) is doubled, and the design of a layout is simple, and the area occupied by the surface of a chip is small.
According to an aspect of an embodiment of the present application, there is provided a waveguide structure including:
the number of the annular waveguides is more than two;
the first linear waveguide is in a linear shape, and an incident end and a first connecting end are respectively arranged at two ends of the first linear waveguide;
the second linear waveguide is in a linear shape, and an emergent end and a second connecting end are respectively arranged at two ends of the second linear waveguide; and
and the U-shaped waveguide is connected with the first connecting end and the second connecting end, wherein the central connecting line of the adjacent annular waveguides is parallel to the first linear waveguide and the second linear waveguide.
According to another aspect of an embodiment of the present application, wherein the radii of each of the annular waveguides are the same.
According to another aspect of the embodiments of the present application, the number of the ring waveguides is three or more, and the center distances (Ls) of two adjacent ring waveguides are equal.
According to another aspect of the embodiments of the present application, wherein the distance (Ls) between the centers of two adjacent ring waveguides is one time the circumference of the ring waveguides.
According to another aspect of the embodiments of the present application, wherein the length (Lu) of the U-shaped waveguide is an even multiple of the half perimeter of the ring waveguide.
According to another aspect of an embodiment of the present application, wherein the waveguide structure is formed of a first material on a substrate formed of a second material, the first material having a higher refractive index than the second material.
According to another aspect of the embodiments of the present application, wherein the first material is germanium (Ge) and the second material is silicon (Si).
According to another aspect of embodiments of the present application, there is provided a method of manufacturing a waveguide structure, the method including:
epitaxially growing a first material layer on a substrate;
etching the first material layer to obtain a waveguide structure formed by the first material,
wherein the waveguide structure comprises:
the number of the annular waveguides is more than two;
the first linear waveguide is in a linear shape, and an incident end and a first connecting end are respectively arranged at two ends of the first linear waveguide;
the second linear waveguide is in a linear shape, and an emergent end and a second connecting end are respectively arranged at two ends of the second linear waveguide; and
and the U-shaped waveguide is connected with the first connecting end and the second connecting end, wherein the central connecting line of the adjacent annular waveguides is parallel to the first linear waveguide and the second linear waveguide.
The beneficial effect of this application lies in: in the waveguide structure, the U-shaped waveguide is used for connecting two linear waveguides, so that resonant light and non-resonant light are constructively interfered at the same port, and more than two annular waveguides are connected in parallel between the two parallel linear waveguides, so that the smoothness of the top of an output spectrum is improved, the Free Spectral Range (FSR) is doubled, the design of a layout is simple, and the occupied area of a chip surface is small.
Specific embodiments of the present application are disclosed in detail with reference to the following description and drawings, indicating the manner in which the principles of the application may be employed. It should be understood that the embodiments of the present application are not so limited in scope. The embodiments of the application include many variations, modifications and equivalents within the spirit and scope of the appended claims.
Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments, in combination with or instead of the features of the other embodiments.
It should be emphasized that the term "comprises/comprising" when used herein, is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps or components.
Drawings
The accompanying drawings, which are included to provide a further understanding of the embodiments of the application, are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application. It is obvious that the drawings in the following description are only some embodiments of the application, and that for a person skilled in the art, other drawings can be derived from them without inventive effort. In the drawings:
fig. 1 is a schematic view of a waveguide structure of embodiment 1 of the present application in a lateral direction;
FIG. 2 is a schematic diagram of an output end spectrum of a ring waveguide disposed in parallel between a first linear waveguide and a second linear waveguide;
FIG. 3 is a schematic diagram of an output end spectrum of a ring waveguide disposed in parallel between a first linear waveguide and a second linear waveguide in the case of a U-shaped waveguide;
fig. 4 is a schematic view of a manufacturing method of a waveguide structure of embodiment 2 of the present application.
Detailed Description
The foregoing and other features of the present application will become apparent from the following description, taken in conjunction with the accompanying drawings. In the description and drawings, particular embodiments of the application are disclosed in detail as being indicative of some of the embodiments in which the principles of the application may be employed, it being understood that the application is not limited to the described embodiments, but, on the contrary, is intended to cover all modifications, variations, and equivalents falling within the scope of the appended claims.
In the description of the embodiments of the present application, for convenience of description, a direction parallel to the surface of the substrate is referred to as "lateral direction", and a direction perpendicular to the surface of the substrate is referred to as "longitudinal direction", in which the "thickness" of each component means the dimension of the component in the "longitudinal direction", a direction directed from the substrate to the waveguide structure is referred to as "upper" direction, and a direction opposite to the "upper" direction is referred to as "lower" direction.
Example 1
The embodiment of the application provides a waveguide structure.
Fig. 1 is a schematic view of a waveguide structure of embodiment 1 of the present application in a lateral direction.
As shown in fig. 1, the waveguide structure 1 includes: a ring waveguide 11, a first linear waveguide 12, a second linear waveguide 13, and a U-shaped waveguide 14.
In the present embodiment, as shown in fig. 1, the number of the ring waveguides 11 is two or more, for example, two, three, or more than three. Wherein the center connecting line of the adjacent ring waveguides 11 is parallel to the first and second linear waveguides 12 and 13, i.e., more than two ring waveguides are parallel between the first and second linear waveguides 12 and 13.
As shown in fig. 1, the first linear waveguide 12 is in a linear shape, and two ends of the first linear waveguide 12 are an incident end 121 and a first connection end 122, respectively.
As shown in fig. 1, the second linear waveguide 13 has a linear shape, and the two ends of the second linear waveguide 13 are an exit end 131 and a second connection end 132.
As shown in fig. 1, the U-shaped waveguide 14 connects the first connection end 122 and the second connection end 132.
As shown in fig. 1, the ring waveguide 11 closest to the U-shaped waveguide 14 is a ring waveguide 111, and a line connecting the first connection end 122 and the second connection end 132 passes through the center C of the ring waveguide 111. The line connecting the first connection end 122 and the second connection end 132 is perpendicular to the first linear waveguide 12 and the second linear waveguide 13.
In the present embodiment, as shown in fig. 1, the incident light can enter the first linear waveguide 12 from the incident end 121, on one hand, the light waves meeting the resonance condition of the annular waveguide can be sequentially coupled into the two or more annular waveguides 11, and coupled from the annular waveguides 11 into the second linear waveguide 13, and output from the exit end 131; on the other hand, light waves (i.e., non-resonant light) that do not satisfy the resonance condition of the annular waveguide among the incident light propagate through the U-shaped waveguide 14 to the second straight waveguide 13, and are also output from the output end 131.
According to the present embodiment, in the waveguide structure 1, two linear waveguides are connected using a U-shaped waveguide so that resonant light and non-resonant light constructively interfere at the same port, and two or more ring waveguides are connected in parallel between the two parallel linear waveguides, whereby the smoothness of the top of the output spectrum is improved and the Free Spectral Range (FSR) is doubled; in addition, in the embodiment, more than two annular waveguides are connected in parallel between the two linear waveguides, and the extending direction of the linear waveguides is consistent with the arrangement direction of the plurality of annular waveguides, so that the layout is simple in design, and the occupied area of the chip surface is small.
In the present embodiment, the radii of the ring waveguides 11 may be the same, and thus, it is not necessary to provide a plurality of microrings having different radii in the layout used in the process of manufacturing the waveguide structure 1, and thus the layout is simple.
As shown in fig. 1, the adjacent ring waveguides 11 have a center distance Ls. When the number of the ring waveguides is three or more, the center distances (Ls) of two adjacent ring waveguides are equal to each other.
In a specific embodiment, the distance (Ls) between the centers of two adjacent ring waveguides 11 is twice the circumference of the ring waveguide 11, i.e., twice the half circumference of the ring waveguide 11, thereby enabling the bragg resonance to coincide with the resonance of the ring waveguide.
As shown in fig. 1, the U-shaped waveguide 14 has a length Lu. In a particular embodiment, Lu may be equal to an integer multiple of the circumference of the annular waveguide 11, i.e., Lu may be equal to an even multiple of the half circumference of the annular waveguide 11, thereby doubling the Free Spectral Range (FSR).
In this embodiment, by adjusting Ls, superposition of bragg resonance and resonance in the annular waveguide 11 can be realized, so that smoothness of the top of the spectrum of the exit end 131 is increased, that is, a box-type spectrum is obtained; further, by adjusting Lu, the Free Spectral Range (FSR) of the spectrum of the emission end 131 can be doubled. Thus, in the present embodiment, by adjusting Ls and Lu, the purpose of doubling the Free Spectral Range (FSR) and box-type spectra can be achieved simultaneously in the waveguide structure 1. Compared with the conventional micro-ring resonator, the waveguide structure 1 of the present embodiment has a doubled Free Spectral Range (FSR) and a box spectrum, and thus can be used in the field of silicon-based optoelectronics such as wavelength division multiplexing (wdm) and filters.
Fig. 2 is a schematic diagram of an output end spectrum of a ring waveguide disposed in parallel between a first linear waveguide and a second linear waveguide. As shown in fig. 2, 201, 202, and 203 are diagrams of output end spectra in the case where 1 ring waveguide is provided between a first linear waveguide and a second linear waveguide, 2 ring waveguides are connected in parallel, and 3 ring waveguides are connected in parallel, respectively. As shown in fig. 2, the greater the number of parallel ring waveguides, the smoother the top of the spectrum.
In fig. 2, the Free Spectral Range (FSR) is the spectral range 204.
Fig. 3 is a schematic diagram of an output end spectrum of a ring waveguide disposed in parallel between a first linear waveguide and a second linear waveguide in the case of a U-shaped waveguide. As shown in fig. 3, 301, 302, 303 are diagrams of output end spectra in the case where there are 1 ring waveguide between the first linear waveguide and the second linear waveguide, 2 ring waveguides are connected in parallel, and 3 ring waveguides are connected in parallel, respectively. The Free Spectral Range (FSR) is the spectral range 304.
As shown in fig. 2 and 3, the spectral range 304 is twice the spectral range 204, and it can be seen that the Free Spectral Range (FSR) can be doubled by adding a U-shaped waveguide.
Further, in fig. 3, the greater the number of parallel ring waveguides, the smoother the top of the spectrum. For example, for the top of the spectrum shown by dashed circle 305 in fig. 3, the smoothness at the top of spectrum 303 is higher than the smoothness at the top of spectrum 302, and the smoothness at the top of spectrum 302 is higher than the smoothness at the top of spectrum 301.
In this embodiment, the waveguide structure 11 may be formed of a first material, and the waveguide structure 11 may be located on a substrate (not shown in fig. 1), which may be formed of a second material.
In this embodiment, the refractive index of the first material may be higher than the refractive index of the second material, so that the light wave can form total reflection in the waveguide structure 11, avoiding incidence on the substrate. For example, the first material is germanium (Ge) and the second material is silicon (Si). The first material may be silicon or silicon nitride, and the second material may have a refractive index smaller than that of silicon or silicon nitride.
The first material is selected from germanium or silicon materials, and the following advantages can be obtained: germanium or silicon has transparency in the spectral range up to mid-infrared wavelengths, and thus, the use of germanium or silicon to form a waveguide structure enables lower losses over a large wavelength range.
According to the present embodiment, in the waveguide structure 1, two linear waveguides are connected using a U-shaped waveguide so that resonant light and non-resonant light constructively interfere at the same port, and two or more ring waveguides are connected in parallel between the two parallel linear waveguides, whereby the smoothness of the top of the output spectrum is improved and the Free Spectral Range (FSR) is doubled; in addition, in the embodiment, more than two annular waveguides are connected in parallel between the two linear waveguides, and the extending direction of the linear waveguides is consistent with the arrangement direction of the plurality of annular waveguides, so that the layout is simple in design, and the occupied area of the chip surface is small.
Example 2
Embodiment 2 provides a method of manufacturing a waveguide structure, for manufacturing the waveguide structure described in embodiment 1.
Fig. 4 is a schematic view of a manufacturing method of the waveguide structure of the present embodiment. As shown in fig. 4, in the present embodiment, the manufacturing method may include:
In step 401, the method for extending the first material layer on the substrate may be vapor deposition or chemical deposition.
In step 402, the waveguide structure can be obtained by: and coating photoresist on the surface of the first material layer, exposing and developing the photoresist to obtain a photoresist pattern, and etching the first material layer by taking the photoresist pattern as a mask, thereby obtaining the waveguide structure formed by the first material.
Through step 402, the waveguide structure 1 shown in fig. 1 can be obtained.
In one embodiment, the substrate may be a silicon material and the first material layer may be a germanium material layer that is epitaxially grown on the surface of the silicon substrate.
According to the present embodiment, in the manufactured waveguide structure 1, two linear waveguides are connected using a U-shaped waveguide so that resonant light and non-resonant light constructively interfere at the same port, and two or more ring waveguides are connected in parallel between the two parallel linear waveguides, whereby the smoothness of the top of the output spectrum is improved and the Free Spectral Range (FSR) is doubled; in addition, in the embodiment, more than two annular waveguides are connected in parallel between the two linear waveguides, and the extending direction of the linear waveguides is consistent with the arrangement direction of the plurality of annular waveguides, so that the layout is simple in design, and the occupied area of the chip surface is small.
The present application has been described in conjunction with specific embodiments, but it should be understood by those skilled in the art that these descriptions are intended to be illustrative, and not limiting. Various modifications and adaptations of the present application may occur to those skilled in the art based on the spirit and principles of the application and are within the scope of the application.
Claims (7)
1. A waveguide structure, comprising:
the number of the annular waveguides is more than two;
the first linear waveguide is in a linear shape, and an incident end and a first connecting end are respectively arranged at two ends of the first linear waveguide;
the second linear waveguide is in a linear shape, and an emergent end and a second connecting end are respectively arranged at two ends of the second linear waveguide; and
a U-shaped waveguide connecting the first connection end and the second connection end,
wherein the central connecting line of the adjacent annular waveguides is parallel to the first linear waveguide and the second linear waveguide.
2. The waveguide structure of claim 1,
the radii of the annular waveguides are the same.
3. The waveguide structure of claim 1,
the number of the annular waveguides is more than three, and the central distances (Ls) of two adjacent annular waveguides are equal.
4. The waveguide structure of claim 1,
the distance (Ls) between the centers of two adjacent annular waveguides is one time of the perimeter of the annular waveguides.
5. The waveguide structure of claim 1,
the length (Lu) of the U-shaped waveguide is an even multiple of the half perimeter of the annular waveguide.
6. The waveguide structure of claim 1,
the waveguide structure is formed of a first material, on a substrate formed of a second material,
the refractive index of the first material is higher than the refractive index of the second material.
7. The waveguide structure of claim 6,
the first material is germanium (Ge),
the second material is silicon (Si).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921956524.2U CN210626706U (en) | 2019-11-13 | 2019-11-13 | Waveguide structure |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921956524.2U CN210626706U (en) | 2019-11-13 | 2019-11-13 | Waveguide structure |
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| CN210626706U true CN210626706U (en) | 2020-05-26 |
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| CN201921956524.2U Active CN210626706U (en) | 2019-11-13 | 2019-11-13 | Waveguide structure |
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