Bent waveguide structure and manufacturing method thereof

Abstract

The invention provides a bent waveguide structure and a manufacturing method thereof, which can effectively reduce the offset of the transmission energy of a bent waveguide in a bending mode to the outer side of the bending direction, and further reduce the bending mismatch loss caused by the offset. The curved waveguide structure includes: a substrate; a first waveguide formed on the substrate so as to be bent in a predetermined bending direction; the second waveguide is formed on one side, close to the bending direction, of the top of the first waveguide, and the width of the second waveguide is smaller than that of the first waveguide.

Description

Technical Field

[0001] The present disclosure relates to the field of semiconductor optoelectronic technology, and in particular to a curved waveguide structure and a manufacturing method thereof. Background Art

[0002] A waveguide is a structure used to guide electromagnetic waves in a certain direction. In electromagnetics and communications engineering, a waveguide can refer to any linear structure that transmits electromagnetic waves between its endpoints. It is primarily used as a transmission line at microwave frequencies, connecting microwave transmitters and receivers to their antennas in microwave ovens, radar, communications satellites, and microwave radio link equipment.

[0003] Common waveguide structures include parallel twin conductors, coaxial lines, parallel planar waveguides, rectangular waveguides, circular waveguides, microstrip lines, planar dielectric waveguides, and optical fibers. From the perspective of guiding electromagnetic waves, these waveguide structures can be divided into an inner region and an outer region, with electromagnetic waves confined to the inner region (requiring transverse resonance within the waveguide cross-section).

[0004] A curved waveguide is a special waveguide structure that can be used to transmit electromagnetic waves. Its operating principle is based on the propagation characteristics of electromagnetic waves in a waveguide. When an electromagnetic wave enters a curved waveguide, it is reflected on both the inside and outside of the waveguide, forming a complex electromagnetic field distribution. By varying the waveguide's bending radius and direction, the transmission path and pattern of the electromagnetic wave can be controlled.

[0005] In the field of optics, curved waveguides are widely used in optical communications and optical sensing. By guiding light waves through curved waveguides, functions such as optical signal transmission, modulation, beam splitting, and beam combining can be achieved. As the basic building block of optical waveguide devices, curved waveguides can serve as connecting structures between different devices or as an integral component of the device itself. Curved waveguides can be used to construct structures such as microring resonators, arrayed waveguide filters, and delay lines, which have a wide range of applications in optical communications and optical sensing.

[0006] In the microwave and millimeter wave fields, curved waveguides are also used to transmit and control electromagnetic waves. By varying the waveguide's bending radius and direction, parameters such as the electromagnetic wave's transmission path, phase, and amplitude can be controlled, enabling functions such as modulation, frequency conversion, and power synthesis of microwave and millimeter wave signals.

[0007] Furthermore, curved waveguides can be used to construct optical switches and optical transmission systems. By manipulating the optical path within a curved waveguide, optical signals can be controlled and distributed, which has important implications for fields such as optical communications and optical computing. Furthermore, curved waveguides can serve as the base material for optical sensors, extending their sensing range and accuracy.

[0008] There are two main types of bending modes for curved waveguides: E-plane bending and H-plane bending. The bending types include arc bending waveguides and angled bending waveguides.

[0009] The curved portion of a chamfered waveguide is chamfered to reduce the bend radius and bending loss. Key features of chamfered waveguides include: The chamfered portion reduces the bend radius, thereby reducing bending loss; chamfered waveguides are typically made of metal materials, such as copper and aluminum, which offer excellent electrical conductivity and mechanical strength; Parameters such as length, flange, material, and surface treatment can be customized to meet specific needs; and chamfered waveguides have a wide range of applications, including a variety of electronic and optical systems.

[0010] Circular-arc waveguides have a small bending radius and therefore exhibit high bending losses. The key features of circular-arc waveguides include: determining the waveguide's radius and bending angle to determine the waveguide's curvature and bending losses; considering the waveguide's material and transmission wavelength to determine the waveguide's refractive index and transmission mode; selecting an appropriate bending mode based on actual conditions to minimize bending losses and optimize waveguide performance; and, in actual processing, paying attention to waveguide machining accuracy and surface quality to ensure waveguide performance and stability.

[0011] To reduce the bending radius to minimize device size and increase integration while minimizing bending losses, appropriate bending patterns can be employed. Compact curved waveguides are key to increasing the capacity density of integrated chips. However, conventional curved waveguides currently in use exhibit corresponding losses. Curved waveguide losses include radiation loss and bend mismatch loss. Bend mismatch loss is caused by the deviation of the bending pattern from the center, resulting in a mismatch with the straight waveguide pattern. Bend mismatch loss is caused by the following: In a bending pattern, the curved waveguide bends in the bending direction, and its transmitted energy is offset to the outside of the bending direction, resulting in energy loss.

[0012] Figure 1 This is a light field diagram showing the phenomenon that the transmission energy of the curved waveguide in the bending mode in the prior art is offset to the outside of the bending direction. Figure 1 As can be seen from the light field diagram in the figure, when the energy is transmitted by the curved waveguide, the energy will be biased to the other side of the bending direction (for example, Figure 1 The offset (shown on the right) causes bend mismatch loss. Summary of the Invention

[0013] The present disclosure is completed to solve the above-mentioned problems in the prior art. Its purpose is to provide a curved waveguide structure and a manufacturing method thereof, which can effectively reduce the offset of the transmission energy of the curved waveguide in the bending mode toward the outside of the bending direction, thereby reducing the bending mismatch loss caused by the offset.

[0014] According to an exemplary embodiment of the present disclosure, there is provided a curved waveguide structure including a substrate, a first waveguide formed on the substrate in a manner of being curved toward a predetermined curved direction, and a second waveguide formed on a top of the first waveguide near one side of the curved direction and having a width smaller than the first waveguide.

[0015] Optionally, in the curved waveguide structure described above, a plurality of the second waveguides are formed, and the plurality of the second waveguides are spaced apart from each other by a distance.

[0016] Optionally, in the curved waveguide structure described above, a number and a position of the second waveguide are determined based on at least one of a shape and an area of the top of the first waveguide.

[0017] Optionally, in the curved waveguide structure described above, the plurality of the second waveguides are identical to each other.

[0018] Optionally, in the curved waveguide structure described above, the plurality of the second waveguides are equal to each other in the distance.

[0019] Optionally, in the curved waveguide structure described above, a width of the second waveguide is determined based on a width of an optical field, and the wider the width of the optical field, the greater the maximum width allowed by the second waveguide.

[0020] Optionally, in the curved waveguide structure described above, the width of the second waveguide is between 0.3 μm and 0.5 μm.

[0021] Optionally, in the curved waveguide structure described above, a ratio of a height of the second waveguide to a height of the first waveguide is between 0.1 and 2.

[0022] Optionally, in the curved waveguide structure described above, a material of the second waveguide is the same as a material of the first waveguide.

[0023] Optionally, in the curved waveguide structure described above, a cross-sectional shape of the first waveguide and the second waveguide is rectangular.

[0024] Optionally, in the curved waveguide structure described above, the substrate includes a flat plate etching portion including a first dielectric layer having one surface in contact with the first waveguide and a second dielectric layer in contact with another surface of the first dielectric layer, and a refractive index of the second dielectric layer is lower than that of the first dielectric layer.

[0025] According to another exemplary embodiment of the present disclosure, a method for manufacturing a curved waveguide structure is provided, comprising the steps of: providing a substrate; forming a first waveguide on the substrate that is curved in a predetermined bending direction; and forming a second waveguide having a width smaller than that of the first waveguide on a top side of the first waveguide close to the bending direction.

[0026] Optionally, in the above-mentioned method for manufacturing a curved waveguide structure, in the step of forming the second waveguide, a plurality of second waveguides are formed, and the plurality of second waveguides are spaced apart from each other.

[0027] Optionally, in the above-mentioned method for manufacturing a curved waveguide structure, the number and position of the second waveguides are determined based on at least any one of a shape and an area of ​​a top of the first waveguide.

[0028] Optionally, in the above-mentioned method for manufacturing a curved waveguide structure, the plurality of second waveguides are identical to each other.

[0029] Optionally, in the above-mentioned method for manufacturing a curved waveguide structure, the plurality of second waveguides are spaced equally apart from each other.

[0030] Optionally, in the above-mentioned method for manufacturing a curved waveguide structure, the second waveguide is formed by any one of chemical vapor deposition, laser direct writing, micromachining, and femtosecond laser processing.

[0031] According to the curved waveguide structure and manufacturing method thereof involved in the present disclosure, the offset of the transmission energy of the curved waveguide in the bending mode toward the outside of the bending direction can be effectively reduced, thereby reducing the bending mismatch loss caused by the offset. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present disclosure may be better understood by describing exemplary embodiments of the present disclosure in conjunction with the accompanying drawings, in which:

[0033] Figure 1 A light field diagram illustrating a phenomenon in which the transmission energy of a curved waveguide in a curved mode is offset toward the outside of the bending direction in the prior art;

[0034] Figure 2 is a schematic cross-sectional view of a curved waveguide structure according to one embodiment of the present disclosure;

[0035] Figure 3 is a schematic top view of a curved waveguide structure according to one embodiment of the present disclosure;

[0036] Figure 4 is a schematic cross-sectional view of a curved waveguide structure according to another embodiment of the present disclosure;

[0037] Figure 5 FIG. 4 is a flow chart of a method for manufacturing a curved waveguide structure according to one embodiment of the present disclosure. DETAILED DESCRIPTION

[0038] The specific embodiments of the present disclosure will be described below. It should be noted that in the specific description of these embodiments, in order to provide a concise description, this specification cannot provide a detailed description of all the features of the actual embodiments. It should be understood that in the actual implementation of any embodiment, just as in the process of any engineering project or design project, in order to achieve the specific goals of the developer and to meet system-related or business-related restrictions, various specific decisions are often made, and this will also change from one embodiment to another. In addition, it is also understandable that although the efforts made in this development process may be complex and lengthy, for ordinary technicians in the field related to the content of this disclosure, some changes in design, manufacturing or production based on the technical content disclosed in this disclosure are just conventional technical means and should not be understood as the content of this disclosure being insufficient.

[0039] Unless otherwise defined, the technical or scientific terms used in the claims and description shall have the usual meaning understood by persons of ordinary skill in the technical field to which the present disclosure belongs. The words "first", "second" and similar terms used in the patent application description and claims of the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "one" or "a" do not indicate a quantity limitation, but rather indicate the existence of at least one. Words such as "include" or "comprising" mean that the elements or objects appearing before "include" or "comprising" cover the elements or objects listed after "include" or "comprising" and their equivalents, and do not exclude other elements or objects. Words such as "connected" or "connected" and similar terms are not limited to physical or mechanical connections, nor are they limited to direct or indirect connections.

[0040] In the present disclosure, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature includes the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0041] In the present disclosure, unless otherwise specified, all embodiments and preferred embodiments mentioned herein can be combined with each other to form new technical solutions. In the present disclosure, unless otherwise specified, all technical features and preferred features mentioned herein can be combined with each other to form new technical solutions.

[0042] In the curved waveguide structure and manufacturing method disclosed herein, a second waveguide, which is a narrow waveguide and has a smaller width than the first waveguide, is formed on the top side of the curved waveguide, near the bending direction. This effectively reduces the amount by which the transmission energy of the curved waveguide in a bending mode is offset outward in the bending direction, thereby reducing the bending mismatch loss caused by the offset.

[0043] The second waveguide, which is a narrow waveguide, is used to adjust the bending mode. Since the bending mode will shift toward the outside of the bend, a narrow waveguide is provided on the top of the waveguide on the inner side of the bend to reduce the amount of the bending mode shifting toward the outside, thereby reducing the mode mismatch loss.

[0044] The embodiments of the present disclosure are described below in conjunction with the accompanying drawings. It should be understood that the embodiments described herein are only used to illustrate and explain the present disclosure, and are not used to limit the present disclosure.

[0045] Figure 2 is a schematic cross-sectional view of a curved waveguide structure according to one embodiment of the present disclosure, Figure 3 FIG. 1 is a schematic top view of a curved waveguide structure according to an embodiment of the present disclosure. Figure 2 As shown, the curved waveguide structure 10 may include a substrate 11 , a first waveguide 12 and a second waveguide 13 .

[0046] The substrate 11 is used to form a waveguide material thereon. For example, the substrate 11 may be an SOI (Silicon-On-Insulator) substrate. The substrate 11 may include a flat plate etched portion 111. The flat plate etched portion 111 may include a first dielectric layer 1111, one surface of which contacts the first waveguide 12, and a second dielectric layer 1112, which contacts the other surface of the first dielectric layer 1111. The first dielectric layer 1111 is a light propagation medium, such as silicon, silicon nitride, or silicon oxide. The second dielectric layer 1113 has a lower refractive index than the first dielectric layer 1111, and may be, for example, a wrapping layer or capping layer in an SOI structure.

[0047] The first waveguide 12 is formed on the substrate 11 in a manner of bending towards a predetermined bending direction R. The transmission characteristics of the first waveguide 12 as a bent waveguide are related to multiple factors, including the material, size, shape, transmission mode, etc. of the bent waveguide. In some embodiments, the transmission frequency of the bent waveguide is related to the length and width of the bent waveguide. In some embodiments of the present disclosure, the width of the first waveguide 12 can be between 1 μm and 6 μm.

[0048] The second waveguide 13 is formed on the top of the first waveguide 12 near the side of the bending direction R, and the width is smaller than that of the first waveguide 12. Here, the width refers to the cross-sectional width obtained by cutting in the vertical plane perpendicular to the surface of the substrate 11.

[0049] In some embodiments of the present disclosure, the second waveguide 13 can be formed in a position not more than half the width of the first waveguide 12 on the top of the first waveguide 12 near the side of the bending direction R. For example, as shown in FIG. 1B, the second waveguide 13 can be formed at the end position of the top of the first waveguide 12 near the side of the bending direction R. Figure 2

[0050] The wider the width of the second waveguide 13, the better the adjustment effect on the bending mode. However, as the width of the second waveguide 13 increases, the light field will enter the second waveguide 13, causing new mode mismatch loss. Therefore, in some embodiments of the present disclosure, considering the loss problem caused by the width, the width of the second waveguide 13 can be determined based on the width of the light field. The wider the width of the light field, the greater the maximum width allowed by the second waveguide 13.

[0051] For example, the width of the second waveguide 13 can be set as a standard that cannot be too wide to cause the light field energy to enter the second waveguide 13. In some embodiments of the present disclosure, the width of the second waveguide 13 can be between 0.3 μm and 0.5 μm.

[0052] The height of the second waveguide 13 can be set according to the actual architecture of the chip. Here, the height refers to the up-down height in the direction perpendicular to the surface of the substrate 11. In some embodiments of the present disclosure, the ratio of the height of the second waveguide 13 to the height of the first waveguide 12 can be between 0.1 and 2. For example, in some embodiments of the present disclosure, the height of the first waveguide 12 can be between 2 μm and 8 μm, and the height of the second waveguide 13 can be between 0.2 μm and 16 μm.

[0053] In some embodiments of the present disclosure, the second waveguide 13 can be formed with multiple second waveguides 13, and the multiple second waveguides 13 are arranged at a distance from each other. The more the number of second waveguides 13, the better the adjustment effect on the bending mode, and the more effective the reduction of mismatch loss.

[0054] For example, as shown in FIG. 1C, the second waveguide 13 can be formed with multiple second waveguides 13, and the multiple second waveguides 13 are arranged at a distance from each other. Figure 2 ​As shown, a second waveguide 13 may be formed at the end of the top of the first waveguide 12 close to the bending direction R, and two other second waveguides 13 may be provided toward the center of the first waveguide 12. Of course, the present disclosure is not limited to the above example, and the number and position of the second waveguides 13 may be reasonably determined based on at least any one of the shape and area of ​​the top of the first waveguide 12.

[0055] In some embodiments of the present disclosure, the plurality of second waveguides 13 may be identical to each other. Figure 2 As shown, the spacing between the plurality of second waveguides 13 can be set equal. In some embodiments, the spacing can be between 0.1 μm and 0.5 μm.

[0056] By arranging a plurality of identical second waveguides at equal distances, force adjustment can be performed uniformly, and the adjustment effect of the second waveguide on the bending mode can be optimized, thereby optimizing the transmission performance of the curved waveguide structure.

[0057] In addition, in some embodiments of the present disclosure, the material of the second waveguide 13 may be the same as that of the first waveguide 12. Of course, the present disclosure is not limited thereto, and the material of the second waveguide 13 may be different from that of the first waveguide 12.

[0058] The materials of the first waveguide 12 and the second waveguide 13 can be conventional materials or metamaterials. Conventional materials can include copper, aluminum, etc., which have good electrical conductivity and mechanical strength and are suitable for a variety of electronic and optical systems. In addition, copper and aluminum can be surface-treated, such as silver plating, gold plating, nickel plating, passivation, conductive oxidation, etc., to improve their oxidation resistance and corrosion resistance. Metamaterials can include InP, SiO2, and polymers. Each of these materials has its own characteristics and advantages. For example, InP has a high refractive index and good thermal stability, SiO2 has excellent optical properties and chemical stability, and polymers have a low dielectric constant and good mechanical properties.

[0059] The shapes of the first waveguide 12 and the second waveguide 13 can generally be determined based on the application scenario and transmission characteristics. In some embodiments of the present disclosure, the first waveguide 12 and the second waveguide 13 are configured as rectangular parallelepipeds with a length extending along the direction of travel of the waveguides, which can further reduce signal loss and radiation.

[0060] Furthermore, light waves in the optical field are input through the signal input port, transmitted through the waveguide structure disclosed herein, and then output through the signal output port. The shape and size of the signal input and output ports also affect the transmission characteristics of the curved waveguide structure. Therefore, to achieve optimal transmission performance, the shape and size of the signal input and output ports can be designed based on the appropriate application scenario and transmission frequency range for different types of photonic devices. For example, simulation and optimization can be performed through experiments and simulation software to achieve optimal transmission performance.

[0061] Figure 3 FIG shows an example of a specific waveguide travel direction D and a corresponding position structure of a signal input port IN and a signal output port OUT. Figure 3 As shown, the waveguide travel direction D is along the bending direction of the arc segment, and the signal input port IN and the signal output port OUT are respectively arranged at the two ends of the arc segment.

[0062] The above example provides a plurality of identical second waveguides. However, the present disclosure is not limited thereto, and a plurality of different second waveguides may also be provided. For example, the second waveguides may be different in shape, size, material, etc.

[0063] In addition, based on considerations of optical performance, the spacing between the plurality of second waveguides may also be set to be different to achieve a wider range of adjustment.

[0064] Figure 4 FIG is a cross-sectional schematic diagram of a curved waveguide structure according to another embodiment of the present disclosure. Figure 4 As shown, the width, height and other dimensions of the three second waveguides 13 are different from each other, and the spacing between them is also different.

[0065] According to the curved waveguide structure involved in the present disclosure, the offset of the transmission energy of the curved waveguide in the bending mode toward the outside of the bending direction can be effectively reduced, thereby reducing the bending mismatch loss caused by the offset.

[0066] Furthermore, the curved waveguide structure disclosed herein eliminates the need for complex structural adjustments to the bending mode; instead, it requires only a few additional components to the existing curved waveguide structure, resulting in a lower device cost. Furthermore, the second waveguide is vertically coupled to the first waveguide, maintaining the same lateral footprint and preventing interference with other device designs within the chip.

[0067] According to the curved waveguide structure disclosed in the present invention, the offset of the transmission energy toward the outside of the bending direction is smaller than that in the prior art.

[0068] Figure 5Flowchart of a manufacturing method of a curved waveguide structure according to one embodiment of the present disclosure. The manufacturing method 100 of the curved waveguide structure of the present embodiment includes the following steps.

[0069] First, in step 101, a substrate is provided. The substrate is used to form a waveguide material thereon. The substrate may, for example, be an SOI substrate. The SOI substrate may, for example, include a bottom layer of silicon, a buried oxide layer, and a top layer of silicon.

[0070] Next, in step 102, a first waveguide is formed on the substrate to be curved in a predetermined curved direction. Specifically, the first waveguide is formed by etching the substrate as described above. The etching process for manufacturing the curved waveguide can be obtained by using techniques well known to those skilled in the art, and the specific parameters and actual settings thereof are not specifically limited herein.

[0071] Then, in step 103, a second waveguide with a width smaller than that of the first waveguide is formed on the top of the first waveguide near one side of the curved direction. The wider the width of the second waveguide, the better the adjustment effect on the curved mode. However, as the width of the second waveguide increases, the optical field will enter the second waveguide, causing new mode mismatch loss. Therefore, in some embodiments of the present disclosure, considering the loss problem caused by the width, the width of the second waveguide can be determined based on the width of the optical field, and the wider the width of the optical field, the greater the maximum width allowed by the second waveguide.

[0072] In some embodiments of the present disclosure, the second waveguide can be formed by any one of a chemical vapor deposition method, a laser direct writing method, a microfabrication method, and a femtosecond laser machining method.

[0073] In the chemical vapor deposition (CVD) method, a technique for generating materials on the substrate of the curved waveguide through a chemical reaction can achieve high-precision fabrication of narrow waveguides. This method can produce narrow waveguides with high quality, high uniformity, and high stability, and can also achieve mass production.

[0074] In the laser direct writing method, a laser is focused and scanned on the surface of the material of the curved waveguide, and a narrow waveguide structure is formed on the surface of the material through the interaction between the laser and the material. This method has the advantages of high precision, high speed, and high flexibility, but the narrow waveguide structure produced may have a problem of high surface roughness.

[0075] In the microfabrication method, a microfabrication technique is used to process a narrow waveguide structure on the substrate of the curved waveguide. This method can produce narrow waveguides with complex shapes and sizes, but the processing precision and surface quality may be limited.

[0076] Femtosecond laser processing utilizes the ultrashort pulses and high peak power of femtosecond lasers to perform micro-nanofacture on the surface of curved waveguide materials. This method enables the fabrication of narrow waveguides with high precision, speed, and flexibility, while also avoiding issues such as thermal damage and heat-affected zones.

[0077] Furthermore, in step 103 of forming the second waveguide, it is preferred to form a plurality of second waveguides, each spaced apart from the other. A greater number of second waveguides improves the bending mode adjustment effect and more effectively reduces mismatch loss. The number and position of the second waveguides can be determined based on at least one of the shape and area of ​​the top of the first waveguide.

[0078] Furthermore, multiple second waveguides can be identical to one another. The spacing between multiple second waveguides can be equal. By equidistantly arranging multiple identical second waveguides, force adjustment can be uniformly performed, optimizing the second waveguide's adjustment effect on the bending mode, thereby optimizing the transmission performance of the curved waveguide structure.

[0079] Of course, the present disclosure is not limited to this, and multiple second waveguides may be provided that are different from one another. For example, the second waveguides may differ in shape, size, material, etc. Furthermore, based on optical performance considerations, the spacing between the multiple second waveguides may also be varied to achieve a wider range of adjustment.

[0080] According to the manufacturing method of the curved waveguide structure involved in the present disclosure, the offset of the transmission energy of the curved waveguide in the bending mode toward the outside of the bending direction can be effectively reduced, thereby reducing the bending mismatch loss caused by the offset.

[0081] In addition, according to the manufacturing method of the curved waveguide structure involved in the present disclosure, the manufacturing process is simple and diversified, the manufacturing difficulty is low, and it is easy to manufacture and mass produce.

[0082] It should be understood that the above description is illustrative and not restrictive. For example, the above embodiments (and / or aspects thereof) can be used in combination with each other. In addition, without departing from the scope of the present disclosure, many modifications can be made to adapt specific conditions or materials to the teachings of the various embodiments of the present disclosure. Although the sizes and types of materials described herein are used to define the parameters of the various embodiments of the present disclosure, the various embodiments are not meant to be restrictive, but rather exemplary embodiments. Upon reading the above description, many other embodiments will be apparent to those skilled in the art. Therefore, the scope of the various embodiments of the present disclosure should be determined with reference to the appended claims, and the full range of equivalents to which these claims are intended to protect.

Claims

1. A curved waveguide structure, characterized in that: The curved waveguide structure comprises: substrate; a first waveguide formed on the substrate in a manner bent in a predetermined bending direction; and The second waveguide is formed on a top side of the first waveguide close to the bending direction and has a width smaller than that of the first waveguide.

2. The curved waveguide structure according to claim 1, wherein A plurality of the second waveguides are formed, and the plurality of the second waveguides are spaced apart from each other.

3. The curved waveguide structure according to claim 2, wherein: The number and positions of the second waveguides are determined based on at least any one of a shape and an area of ​​a top portion of the first waveguide.

4. The curved waveguide structure according to claim 2, wherein: The plurality of second waveguides are identical to each other.

5. The curved waveguide structure according to claim 2, wherein: The plurality of second waveguides are spaced equally apart from each other.

6. The curved waveguide structure according to any one of claims 1 to 5, wherein: The width of the second waveguide is determined based on the width of the light field, The wider the width of the light field is, the larger the maximum width allowed by the second waveguide is.

7. The curved waveguide structure according to any one of claims 1 to 5, wherein: The width of the second waveguide is between 0.3 μm and 0.5 μm.

8. The curved waveguide structure according to any one of claims 1 to 5, wherein: The ratio of the height of the second waveguide to the height of the first waveguide is between 0.1 and 2.

9. The curved waveguide structure according to any one of claims 1 to 5, wherein: The material of the second waveguide is the same as that of the first waveguide.

10. The curved waveguide structure according to any one of claims 1 to 5, wherein: The cross-sectional shapes of the first waveguide and the second waveguide are rectangular.

11. The curved waveguide structure according to any one of claims 1 to 5, wherein: The substrate includes a flat etching portion, The plate etching portion includes a first dielectric layer having one surface in contact with the first waveguide and a second dielectric layer in contact with the other surface of the first dielectric layer. The refractive index of the second dielectric layer is lower than that of the first dielectric layer.

12. A method for manufacturing a curved waveguide structure, characterized in that: The steps include: providing a substrate; forming a first waveguide on a substrate so as to bend in a predetermined bending direction; and The step of forming a second waveguide having a width smaller than that of the first waveguide on a top side of the first waveguide close to the bending direction.

13. The method for manufacturing a curved waveguide structure according to claim 12, wherein: In the step of forming the second waveguide, a plurality of the second waveguides are formed, and the plurality of the second waveguides are spaced apart from each other.

14. The method for manufacturing a curved waveguide structure according to claim 13, wherein: The number and positions of the second waveguides are determined based on at least any one of a shape and an area of ​​a top portion of the first waveguide.

15. The method for manufacturing a curved waveguide structure according to claim 13, wherein: The plurality of second waveguides are identical to each other.

16. The method for manufacturing a curved waveguide structure according to any one of claims 12 to 15, wherein: The plurality of second waveguides are spaced equally apart from each other.

17. The method for manufacturing a curved waveguide structure according to any one of claims 12 to 15, wherein: The second waveguide is formed by any one of chemical vapor deposition, laser direct writing, micromachining, and femtosecond laser processing.

Images