Multi-mode interferometer
By using separate inlet and outlet waveguide components in a multi-mode interferometer, using the differences in refractive index and overlapping settings of different materials, the problems of excessive length and too small waveguide spacing caused by wide width are solved, and a compact optimized design is achieved, reducing crosstalk and maintaining performance.
Patent Information
- Application Number
- CN202311801938.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-25
- Publication Date
- 2025-07-04
AI Technical Summary
The existing multimode interferometers have longer lengths when the width is wider, resulting in an increase in device area. When the width is narrower, the waveguide spacing is too small, resulting in crosstalk problems, affecting performance.
The first and second inlet waveguides and outlet waveguide components are used to separate the refractive index differences and overlapping settings of different materials to realize the transfer and constraint of light, reduce the waveguide spacing and optimize the design.
The multimode interferometer is achieved with a narrower width and shorter length, reducing crosstalk, optimizing device structure and maintaining performance.
Smart Images
Figure CN120255068A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of silicon-based optoelectronic devices, and particularly to a compact multimode interferometer. Background Art
[0002] A multimode interferometer is a passive device in silicon-based optoelectronics. The multimode interferometer has one or more input waveguide ports and output waveguide ports at the same time. For a multimode interferometer with fixed m input waveguide ports and n output waveguide ports, its length is proportional to the square of the width. Therefore, the length of a wider multimode interferometer will be correspondingly longer, resulting in an increase in the device area. For a narrower multimode interferometer, when the spacing between its multiple input waveguide ports or the spacing between its multiple output waveguide ports is too small, crosstalk problems between waveguides will occur, thus affecting the performance of the multimode interferometer. Summary of the Invention
[0003] An object of the present invention is to overcome the above-mentioned defects existing in the prior art and provide a multimode interferometer.
[0004] To achieve the above object, the technical solution of the present invention is as follows:
[0005] The present invention provides a multimode interferometer, including:
[0006] A body waveguide, an input waveguide component, and an output waveguide component encapsulated in a dielectric layer;
[0007] The input waveguide component includes a first input waveguide and a second input waveguide separated from each other, and the output waveguide component includes a first output waveguide and a second output waveguide separated from each other;
[0008] The first input waveguide and the first output waveguide are respectively connected to opposite ends of the body waveguide; the second input waveguide and the second output waveguide are separated from each other, and a part of the second input waveguide overlaps with the first input waveguide, and a part of the second output waveguide overlaps with the first output waveguide;
[0009] Wherein, the light conducted to the second input waveguide is transferred to the first input waveguide and then conducted to the body waveguide, and the light conducted to the first output waveguide through the body waveguide is transferred to the second output waveguide and conducted outwards.
[0010] Further, the first light incident waveguide and the first light output waveguide are respectively connected to opposite ends of the body waveguide along a first direction. The first ends of the second light incident waveguide and the second light output waveguide are disposed on opposite endsides of the body waveguide along the first direction and are separated from the body waveguide. Moreover, the first end of the second light incident waveguide is overlapped with the first light incident waveguide in a second direction perpendicular to the first direction, and the first end of the second light output waveguide is overlapped with the first light output waveguide in the second direction.
[0011] Further, the widths of the first light incident waveguide and the first light output waveguide in a third direction perpendicular to the first direction and the second direction gradually decrease in the first direction away from the body waveguide. The widths of the first ends of the second light incident waveguide and the second light output waveguide in the overlapping region gradually decrease in the first direction approaching the body waveguide in the third direction.
[0012] Further, the length of the first light incident waveguide in the first direction corresponds to the length of the first end of the second light incident waveguide in the first direction, and / or the length of the first light output waveguide in the first direction corresponds to the length of the first end of the second light output waveguide in the first direction.
[0013] Further, the second light incident waveguide and the second light output waveguide are located on the same side or both sides of the body waveguide in the second direction.
[0014] Further, the dielectric layer material has a first refractive index, the body waveguide, the first light incident waveguide, and the first light output waveguide materials have a second refractive index, and the second light incident waveguide and the second light output waveguide materials have a third refractive index, and the first refractive index, the second refractive index, and the third refractive index increase in sequence.
[0015] Further, the dielectric layer material is a first material, the body waveguide, the first light incident waveguide, and the first light output waveguide materials are a second material, and the second light incident waveguide and the second light output waveguide materials are a third material, and the first material, the second material, and the third material are all different.
[0016] Further, the first material includes silicon dioxide, and / or the second material includes silicon nitride, and / or the third material includes silicon.
[0017] Further, the light incident waveguide assembly and the light output waveguide assembly are one to multiple groups.
[0018] Further, the light incident port waveguide assembly is also reused to export light. At this time, the light output port waveguide assembly is reused to import light. Among them, the light conducted to the second light output port waveguide is transferred to the first light output port waveguide and then conducted to the body waveguide. The light conducted to the first light incident port waveguide through the body waveguide is transferred to the second light incident port waveguide and conducted outwards.
[0019] As can be seen from the above technical solutions, in the present invention, an incident port waveguide assembly including a first incident port waveguide and a second incident port waveguide, and an output port waveguide assembly including a first output port waveguide and a second output port waveguide are respectively provided at the incident port and the output port of the multimode interferometer body waveguide located in the dielectric layer. By utilizing the difference in material refractive index between the dielectric layer, the first incident port waveguide and the first output port waveguide, and the second incident port waveguide and the second output port waveguide, the light conducted to the second incident port waveguide can be transferred to the first incident port waveguide and then conducted to the body waveguide. The light conducted to the first output port waveguide through the body waveguide is transferred to the second output port waveguide and conducted outwards. At the same time, by utilizing the fact that the refractive indices of the second incident port waveguide and the second output port waveguide are greater than those of the first incident port waveguide and the first output port waveguide, the characteristic that the confinement of light by the materials of the second incident port waveguide and the second output port waveguide is stronger than that by the materials of the first incident port waveguide and the first output port waveguide, the distances at which crosstalk occurs between multiple second incident port waveguides or multiple second output port waveguides are respectively smaller than the distances at which crosstalk occurs between multiple first incident port waveguides or multiple first output port waveguides, realizing a compact optimized design with a narrower width and a shorter length than the traditional multimode interferometer. Description of the Drawings
[0020] Figure 1 It is a schematic structural diagram of a multimode interferometer according to a preferred embodiment of the present invention.
[0021] Figure 2 It is a schematic side view structural diagram of a multimode interferometer according to a preferred embodiment of the present invention.
[0022] Figure 3 It is Figure 2 the cross-sectional structural diagram taken along the A-A direction in
[0023] Figure 4 It is Figure 2 the cross-sectional structural diagram taken along the B-B direction in Detailed Embodiments
[0024] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be described clearly and completely below. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts shall fall within the protection scope of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein shall have the ordinary meanings as understood by those of ordinary skill in the art to which the present invention pertains. The words such as "including" used herein are intended to mean that the elements or items appearing before this word cover the elements or items listed after this word and their equivalents, without excluding other elements or items.
[0025] The following further elaborates on the specific embodiments of the present invention with reference to the accompanying drawings.
[0026] Reference Figure 1 A multimode interferometer of the present invention includes: a body waveguide 15 coated in a dielectric layer 11, a light input port waveguide assembly 12, and a light output port waveguide assembly 16.
[0027] Among them, the light input port waveguide assembly 12 includes a first light input port waveguide 14 and a second light input port waveguide 13 that are separated from each other; the light output port waveguide assembly 16 includes a first light output port waveguide 17 and a second light output port waveguide 18 that are separated from each other.
[0028] The first light input port waveguide 14 and the first light output port waveguide 17 are respectively connected to opposite ends of the body waveguide 15. For example, the body waveguide 15 has two opposite ends in the Figure 1 shown first direction. The first light input port waveguide 14 is connected to the left end of the body waveguide 15 as shown in the first direction, and the first light output port waveguide 17 is connected to the right end of the body waveguide 15 as shown in the first direction. It can be understood that the connection positions of the first light input port waveguide 14 and the first light output port waveguide 17 at the left and right ends of the body waveguide 15 can be interchanged.
[0029] The second light incident waveguide 13 and the second light output waveguide 18 are respectively arranged on the left and right ends of the body waveguide 15, and correspond to the first light incident waveguide 14 and the first light output waveguide 17 in their respective positions. Among them, the second light incident waveguide 13 and the second light output waveguide 18 are separated from each other. A part of the second light incident waveguide 13 is arranged overlapping with the first light incident waveguide 14; a part of the second light output waveguide 18 is arranged overlapping with the first light output waveguide 17. For example, the second light incident waveguide 13 intersects with the first light incident waveguide 14 through its first end (illustrated as its right end); the second light output waveguide 18 intersects with the first light output waveguide 17 through its first end (illustrated as its left end). The second end (illustrated as its left end) of the second light incident waveguide 13 and the second end (illustrated as its right end) of the second light output waveguide 18 are respectively led out to the outside, so that the multimode interferometer cooperates with external devices.
[0030] Reference Figure 1 - Figure 2 。In some embodiments, the first end of the second light incident waveguide 13 is arranged on the left end side of the body waveguide 15 along the first direction, and is separated from the body waveguide 15 and the first light incident waveguide 14 in the second direction (perpendicular to the first direction, in Figure 1 , the second direction is perpendicular to the drawing plane, in Figure 2 , the first direction is perpendicular to the drawing plane); the first end of the second light output waveguide 18 is arranged on the right end side of the body waveguide 15 along the first direction, and is separated from the body waveguide 15 and the first light output waveguide 17 in the second direction. And, the first end of the second light incident waveguide 13 is arranged overlapping with the first light incident waveguide 14 in the second direction; the first end of the second light output waveguide 18 is arranged overlapping with the first light output waveguide 17 in the second direction.
[0031] Furthermore, along the first direction, the center line of the first end of the second light incident waveguide 13 coincides with the center line of the first light incident waveguide 14; the center line of the first end of the second light output waveguide 18 coincides with the center line of the first light output waveguide 17.
[0032] Reference Figure 1 。In some embodiments, the width of the first light incident waveguide 14 in the third direction perpendicular to the first direction and the second direction gradually decreases in the first direction away from the left end of the body waveguide 15, and the width of the first end of the second light incident waveguide 13 in the overlapping area gradually decreases in the first direction towards the left end of the body waveguide 15. Similarly, the width of the first light output waveguide 17 in the third direction perpendicular to the first direction and the second direction gradually decreases in the first direction away from the right end of the body waveguide 15, and the width of the first end of the second light output waveguide 18 in the overlapping area gradually decreases in the first direction towards the right end of the body waveguide 15. To more clearly reflect the structure in Figure 1 Figure 3 shows the cross-sectional structure of the body waveguide 15, the first light input waveguide 14, and the first light output waveguide 17 along the A-A direction in Figure 2 in the second direction, Figure 4 shows the cross-sectional structure of the second light input waveguide 13 and the second light output waveguide 18 along the B-B direction in Figure 2 in the second direction.
[0033] In some embodiments, the length of the first light input waveguide 14 in the first direction corresponds to the length of the first end portion of the second light input waveguide 13 in the first direction.
[0034] The length of the first light output waveguide 17 in the first direction corresponds to the length of the first end portion of the second light output waveguide 18 in the first direction.
[0035] Refer to Figure 2 . In some embodiments, the second light input waveguide 13 and the second light output waveguide 18 are located on the same side of the body waveguide 15 in the second direction. For example, the second light input waveguide 13 and the second light output waveguide 18 are both located on the lower side of the illustrated body waveguide 15 in the second direction. Similarly, the second light input waveguide 13 and the second light output waveguide 18 can also be both located on the upper side of the body waveguide 15 in the second direction.
[0036] In other embodiments, the second light input waveguide 13 and the second light output waveguide 18 can also be located on both sides of the body waveguide 15 in the second direction.
[0037] In some embodiments, the light input waveguide assembly 12 and the light output waveguide assembly 16 are one or more groups. For example, a group of light input waveguide assemblies 12 (i.e., including a corresponding first light input waveguide 14 and a second light input waveguide 13) can be provided at one end of the body waveguide 15, and at the same time, a group of light output waveguide assemblies 16 (i.e., including a corresponding first light output waveguide 17 and a second light output waveguide 18) can be provided at the other end of the body waveguide 15. Or, multiple groups of light input waveguide assemblies 12 can be provided at one end of the body waveguide 15, and at the same time, a group of light output waveguide assemblies 16 can be provided at the other end of the body waveguide 15. Or, a group of light input waveguide assemblies 12 can be provided at one end of the body waveguide 15, and at the same time, multiple groups of light output waveguide assemblies 16 can be provided at the other end of the body waveguide 15. Or, multiple groups of light input waveguide assemblies 12 can be provided at one end of the body waveguide 15, and at the same time, multiple groups of light output waveguide assemblies 16 can also be provided at the other end of the body waveguide 15. Further, the number of groups of the multiple groups of light input waveguide assemblies 12 and the multiple groups of light output waveguide assemblies 16 can be the same or different. Figure 1 to Figure 4 Schematically shows a multimode interferometer structure of the present invention having three groups of light input waveguide assemblies 12 and light output waveguide assemblies 16. As can be seen from the foregoing, the number (number of groups) of the light input waveguide assemblies 12 and the number of the light output waveguide assemblies 16 are both adjustable.
[0038] In some embodiments, the material of the dielectric layer 11 has a first refractive index (low refractive index); the materials of the body waveguide 15, the first light input waveguide 14, and the first light output waveguide 17 have a second refractive index (medium refractive index); the materials of the second light input waveguide 13 and the second light output waveguide 18 have a third refractive index (high refractive index). And the first refractive index, the second refractive index, and the third refractive index increase in sequence.
[0039] In some embodiments, the dielectric layer 11 is made of a first material; the materials of the body waveguide 15, the first light input waveguide 14, and the first light output waveguide 17 are made of the same second material; the second light input waveguide 13 and the second light output waveguide 18 are made of the same third material. Among them, the first material, the second material, and the third material are different from each other. Among them, the dielectric layer 11 serves as a cladding layer to cover the body waveguide 15, the light input waveguide assemblies 12, and the light output waveguide assemblies 16. The body waveguide 15, the light input waveguide assemblies 12, and the light output waveguide assemblies 16 serve as core layers and together with the dielectric layer 11 form a multimode interference device.
[0040] In some embodiments, the first material includes silicon dioxide; the second material includes silicon nitride; the third material includes silicon. That is, the dielectric layer 11 can be made of silicon dioxide material; the materials of the body waveguide 15, the first light input waveguide 14, and the first light output waveguide 17 can be made of silicon nitride material; the second light input waveguide 13 and the second light output waveguide 18 can be made of silicon material. Since the refractive indices of the materials of silicon dioxide, silicon nitride, and silicon increase in sequence, the refractive indices between the dielectric layer 11, the first light input waveguide 14 (the first light output waveguide 17), and the second light input waveguide 13 (the second light output waveguide 18) also increase in sequence.
[0041] When the above multi-mode interferometer of the present invention operates, the light conducted to the second light inlet waveguide 13 of the high refractive index silicon material, when conducted from the second end to the first end, due to the gradually narrowing width of the first end, the constraint of the second light inlet waveguide 13 on the light gradually weakens at the first end; while the width of the first light outlet waveguide 17 of the medium refractive index silicon nitride material overlapping with the second light inlet waveguide 13 gradually increases in the same direction, and the constraint on the light gradually strengthens. Therefore, the light conducted to the first end of the second light inlet waveguide 13 can be transferred to the first light inlet waveguide 14 in the overlapping area and further conducted into the body waveguide 15 of the medium refractive index silicon nitride material. The light conducted to the first light outlet waveguide 17 of the medium refractive index silicon nitride material through the body waveguide 15 is affected by the gradually narrowing width of the first light outlet waveguide 17 in the same direction, resulting in a gradually weakened constraint on the light, and the gradually increasing width of the first end of the second light outlet waveguide 18 of the high refractive index silicon material located in the overlapping area, with a gradually strengthening constraint on the light, and is transferred to the second light outlet waveguide 18, so that the light can be transmitted by conducting to the second end of the second light outlet waveguide 18, and the function of the multi-mode interferometer is realized.
[0042] Among them, an optical adapter structure is respectively formed between the first light inlet waveguide 14 and the second light inlet waveguide 13, and between the first light outlet waveguide 17 and the second light outlet waveguide 18.
[0043] Since the constraint of the second light inlet waveguide 13 and the second light outlet waveguide 18 of the high refractive index material on the light is stronger than that of the first light inlet waveguide 14 and the first light outlet waveguide 17 of the medium refractive index material, the minimum distance for crosstalk to occur between multiple second light inlet waveguides 13 is correspondingly smaller than the minimum distance for crosstalk to occur between multiple first light inlet waveguides 14, and the minimum distance for crosstalk to occur between multiple second light outlet waveguides 18 is also correspondingly smaller than the minimum distance for crosstalk to occur between multiple first light outlet waveguides 17. Therefore, compared with the traditional multi-mode interferometer, the multi-mode interferometer proposed by the present invention can be designed to be narrower in width and shorter in length. Thus, while ensuring the device performance, the structure of the multi-mode interferometer is optimized, and it has a smaller size than the usual multi-mode interferometer.
[0044] In some embodiments, the light inlet waveguide assembly 12 is also reused to export light. At this time, the light outlet waveguide assembly 16 is reused to import light. That is, the light inlet waveguide assembly 12 can also function as the light outlet waveguide assembly 16 in function, and the light outlet waveguide assembly 16 can simultaneously function as the light inlet waveguide assembly 12. In this usage state, the light conducted to the second light outlet waveguide 18 is transferred to the first light outlet waveguide 17 and then conducted into the body waveguide 15; the light conducted to the first light inlet waveguide 14 through the body waveguide 15 is transferred to the second light inlet waveguide 13 and conducted outwards.
[0045] In summary, in the present invention, an incident light waveguide assembly 12 including a first incident light waveguide 14 and a second incident light waveguide 13 is respectively provided at the incident light port and the output light port of the multimode interferometer body waveguide 15 located in the dielectric layer 11, and an output light waveguide assembly 16 including a first output light waveguide 17 and a second output light waveguide 18. By utilizing the difference in material refractive index between the dielectric layer 11, the first incident light waveguide 14 and the first output light waveguide 17, and the second incident light waveguide 13 and the second output light waveguide 18, and the adapter structures respectively formed by the first incident light waveguide 14 and the second incident light waveguide 13, and the first output light waveguide 17 and the second output light waveguide 18, the light conducted to the second incident light waveguide 13 can be transferred to the first incident light waveguide 14 and then conducted to the body waveguide 15, and the light conducted to the first output light waveguide 17 through the body waveguide 15 can be transferred to the second output light waveguide 18 and conducted outwards. At the same time, since the refractive indices of the second incident light waveguide 13 and the second output light waveguide 18 are greater than those of the first incident light waveguide 14 and the first output light waveguide 17, the characteristic that the confinement of light by the materials of the second incident light waveguide 13 and the second output light waveguide 18 is stronger than that by the materials of the first incident light waveguide 14 and the first output light waveguide 17 is utilized, so that the crosstalk spacing between multiple second incident light waveguides 13 or between multiple second output light waveguides 18 is respectively smaller than the crosstalk spacing between multiple first incident light waveguides 14 or between multiple first output light waveguides 17, realizing a compact optimized design with a narrower width and a shorter length than the traditional multimode interferometer.
[0046] Although the embodiments of the present invention have been described in detail above, it is obvious to those skilled in the art that various modifications and changes can be made to these embodiments. However, it should be understood that such modifications and changes are all within the scope and spirit of the present invention described in the claims. Moreover, the present invention described herein can have other embodiments and can be implemented or realized in various ways.
Claims
1. A multimode interferometer, characterized in that, Comprising: A body waveguide, an incident light port waveguide assembly, and an output light port waveguide assembly encapsulated in a dielectric layer; The incident light port waveguide assembly includes a first incident light port waveguide and a second incident light port waveguide that are separated from each other, and the output light port waveguide assembly includes a first output light port waveguide and a second output light port waveguide that are separated from each other; The first incident light port waveguide and the first output light port waveguide are respectively connected to opposite ends of the body waveguide; the second incident light port waveguide and the second output light port waveguide are separated from each other, and a part of the second incident light port waveguide overlaps with the first incident light port waveguide, and a part of the second output light port waveguide overlaps with the first output light port waveguide; Wherein, the light conducted to the second incident light port waveguide is conducted to the body waveguide by transferring to the first incident light port waveguide, and the light conducted to the first output light port waveguide through the body waveguide is conducted outwards by transferring to the second output light port waveguide.
2. The multimode interferometer according to claim 1, wherein The first incident light port waveguide and the first output light port waveguide are respectively connected to opposite ends of the body waveguide along a first direction, and the first ends of the second incident light port waveguide and the second output light port waveguide are arranged on opposite endsides of the body waveguide along the first direction and are separated from the body waveguide, and the first end of the second incident light port waveguide overlaps with the first incident light port waveguide in a second direction perpendicular to the first direction, and the first end of the second output light port waveguide overlaps with the first output light port waveguide in the second direction.
3. The multimode interferometer according to claim 2, characterized in that, The widths of the first incident light port waveguide and the first output light port waveguide in a third direction perpendicular to the first direction and the second direction gradually decrease in the first direction away from the body waveguide, and the widths of the first ends of the second incident light port waveguide and the second output light port waveguide in the overlapping region gradually decrease in the first direction close to the body waveguide in the third direction.
4. The multimode interferometer according to claim 2, wherein, The length of the first incident light port waveguide in the first direction corresponds to the length of the first end of the second incident light port waveguide in the first direction, and / or, the length of the first output light port waveguide in the first direction corresponds to the length of the first end of the second output light port waveguide in the first direction.
5. The multimode interferometer according to claim 2, wherein The second incident light port waveguide and the second output light port waveguide are located on the same side or both sides of the body waveguide in the second direction.
6. The multimode interferometer according to claim 1, characterized in that, The dielectric layer material has a first refractive index, the body waveguide, the first incident light port waveguide, and the first output light port waveguide materials have a second refractive index, the second incident light port waveguide and the second output light port waveguide materials have a third refractive index, and the first refractive index, the second refractive index, and the third refractive index increase in sequence.
7. The multimode interferometer according to claim 1, characterized in that, The dielectric layer material is a first material, the body waveguide, the first incident light port waveguide, and the first output light port waveguide materials are a second material, the second incident light port waveguide and the second output light port waveguide materials are a third material, and the first material, the second material, and the third material are all different.
8. The multimode interferometer according to claim 7, wherein The first material includes silicon dioxide, and / or the second material includes silicon nitride, and / or the third material includes silicon.
9. The multimode interferometer according to claim 1, wherein, The light incident port waveguide assembly and the light output port waveguide assembly are one to multiple groups.
10. The multimode interferometer according to claim 1, characterized in that, The light incident port waveguide assembly is also reused to output light. At this time, the light output port waveguide assembly is reused to input light; among them, the light conducted to the second light output port waveguide is transferred to the first light output port waveguide and then conducted to the body waveguide, and the light conducted to the first light incident port waveguide through the body waveguide is transferred to the second light incident port waveguide and conducted outward.