A mode conversion and multiplexer based on zirconia waveguide

Abstract

The application relates to a mode conversion and multiplexer based on a zirconium oxide waveguide, which comprises a zirconium oxide waveguide layer, the zirconium oxide waveguide layer comprising a first waveguide, a second waveguide and a third waveguide, the first waveguide comprising a first input waveguide, a first coupling waveguide, a first straight waveguide, a second coupling waveguide and a first output waveguide; the second waveguide comprising a second input waveguide and a third coupling waveguide; the third waveguide comprising a third input waveguide and a fourth coupling waveguide; a coupling area formed by the first coupling waveguide and the third coupling waveguide converts fundamental mode light in the third coupling waveguide into second-order mode light, and the first straight waveguide transmits the second-order mode light and the fundamental mode light; a coupling area formed by the second coupling waveguide and the fourth coupling waveguide converts fundamental mode light in the fourth coupling waveguide into third-order mode light, and the first output waveguide transmits the third-order mode light, the fundamental mode light and the second-order mode light. The application can solve the problem of a relatively large size of a mode division multiplexer based on a polymer in the related art.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of integrated optics of optical communication, and in particular to a mode conversion and multiplexer based on zirconium oxide waveguide. BACKGROUND

[0002] In recent years, as one of the methods for improving the capacity of fiber communication system, mode division multiplexing technology is popular because it can provide new degrees of freedom for optical fiber and optical network on chip. As a key device in mode division multiplexing technology, mode division multiplexers have been proposed, such as free space optical mode division multiplexer, fused fiber mode division multiplexer and waveguide mode division multiplexer. Among the waveguide mode division multiplexers, there are mode division multiplexers based on silicon and mode division multiplexers based on polymers.

[0003] At a wavelength of 1550nm, the refractive index of polymer is generally around 1.5, which is close to the refractive index of fiber material, so it is easy to design low-loss fiber coupling devices.

[0004] However, the size of the mode division multiplexer is related to the refractive index of the material, and the larger the refractive index, the smaller the size can be designed. Because the refractive index of polymer is small, the mode division multiplexer based on polymer usually has a large size, which needs to be further optimized in size. SUMMARY

[0005] The embodiment of the present application provides a mode conversion and multiplexer based on zirconium oxide waveguide to solve the problem of large size of mode division multiplexer based on polymer in the related art.

[0006] The embodiment of the present application provides a mode conversion and multiplexer based on zirconium oxide waveguide, which comprises a zirconium oxide waveguide layer, and the zirconium oxide waveguide layer comprises:

[0007] A first waveguide comprising a first input waveguide, a first coupling waveguide, a first straight waveguide, a second coupling waveguide and a first output waveguide connected in sequence;

[0008] A second waveguide comprising a second input waveguide and a third coupling waveguide connected in sequence;

[0009] A third waveguide comprising a third input waveguide and a fourth coupling waveguide connected in sequence;

[0010] The coupling region formed by the first coupling waveguide and the third coupling waveguide is used to convert the light with a mode of fundamental mode in the third coupling waveguide into light with a mode of second-order mode, and the first straight waveguide is used to transmit the light with the second-order mode and the light with the mode of fundamental mode in the first coupling waveguide to the second coupling waveguide.

[0011] The coupling region formed by the second coupling waveguide and the fourth coupling waveguide is used for converting light in the fourth coupling waveguide in a fundamental mode into light in a third-order mode, the first output waveguide is used for transmitting the light in the third-order mode, and the light in the second coupling waveguide is in a fundamental mode and a second-order mode.

[0012] In some embodiments, the first coupling waveguide is a tapered waveguide, the width of which increases from W1 to W2, the width of W1 ranges from 1800 nm to 2200 nm, and the width of W2 ranges from 3000 nm to 3200 nm.

[0013] In some embodiments, the third coupling waveguide is a tapered waveguide, the width of which decreases from W3 to W4, the width of W3 ranges from 1100 nm to 1400 nm, and the width of W4 ranges from 800 nm to 1100 nm.

[0014] In some embodiments, the second coupling waveguide is a tapered waveguide, the width of which increases from W5 to W6, the width of W5 ranges from 3100 nm to 4400 nm, and the width of W6 ranges from 4800 nm to 5000 nm.

[0015] In some embodiments, the fourth coupling waveguide is a tapered waveguide, the width of which decreases from W7 to W8, the width of W7 ranges from 1100 nm to 1300 nm, and the width of W8 ranges from 800 nm to 1100 nm.

[0016] In some embodiments, the coupling region formed by the first coupling waveguide and the third coupling waveguide has a length L1 of 450 μm to 500 μm, and the distance gap1 between the first coupling waveguide and the third coupling waveguide is 0.8 μm to 1 μm.

[0017] In some embodiments, the coupling region formed by the second coupling waveguide and the fourth coupling waveguide has a length L2 of 500 μm to 530 μm, and the distance gap2 between the second coupling waveguide and the fourth coupling waveguide is 0.8 μm to 1 μm.

[0018] In some embodiments, the second waveguide further comprises a first curved waveguide connected to the second input waveguide and the third coupling waveguide at two ends, respectively.

[0019] In some embodiments, the second waveguide further comprises a second curved waveguide connected to the third coupling waveguide, and the tail end of the second curved waveguide is provided with an inclined surface.

[0020] In some embodiments, the third waveguide further comprises a third curved waveguide connected to the third input waveguide and the fourth coupling waveguide at two ends, respectively.

[0021] In some embodiments, the third waveguide further comprises a fourth curved waveguide connected to the fourth coupling waveguide, and the tail end of the fourth curved waveguide is provided with an inclined surface.

[0022] In some embodiments, the first input waveguide is configured to couple light from outside the chip into light in the fundamental mode, and has a width of 800-1600 nm, a thickness of 150-300 nm, and a refractive index of 1.9-2.0.

[0023] In some embodiments, the second input waveguide is configured to couple light from outside the chip into light in the fundamental mode, and has a width of 800-1600 nm, a thickness of 150-300 nm, and a refractive index of 1.9-2.0.

[0024] In some embodiments, the third input waveguide is configured to couple light from outside the chip into light in the fundamental mode, and has a width of 800-1600 nm, a thickness of 150-300 nm, and a refractive index of 1.9-2.0.

[0025] In some embodiments, the first straight waveguide has a width of 3000-3200 nm.

[0026] In some embodiments, the first output waveguide has a width of 4800-5000 nm.

[0027] In some embodiments, the mode conversion and multiplexer further comprises a substrate and an upper cladding layer, the zirconium oxide waveguide layer is deposited on the substrate, and the upper cladding layer is deposited on the zirconium oxide waveguide layer.

[0028] In some embodiments, the substrate has a thickness of 2 μm and a refractive index of 1.4-2.0.

[0029] In some embodiments, the upper cladding layer has a thickness of 2 μm and a refractive index of 1.4-1.6.

[0030] The technical scheme provided in the application has the following beneficial effects:

[0031] The mode conversion and multiplexer based on a zirconium oxide waveguide provided in the embodiments of the application uses zirconium oxide ZrO2 as a core layer material, and has a refractive index of about 1.94 in the TE mode and about 1.92 in the TM mode at a wavelength of 1550 nm. The zirconium oxide material is basically transparent in the near-infrared band, and has a higher refractive index than a polymer. Therefore, the zirconium oxide material is more suitable for processing small-size devices than the polymer material.

[0032] The processing steps of the zirconium oxide waveguide are relatively simple. After a photoresist is used to process a pattern, a layer of zirconium oxide is evaporated, and then the zirconium oxide waveguide can be obtained by lift-off. The cross-sectional size of the waveguide can be adjusted as needed, and the zirconium oxide does not need to be etched.

[0033] Zirconia material itself is cheaper than pure silicon, and zirconia waveguide can be processed on polymer platform, which is relatively low cost and easy to integrate with polymer. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0035] Figure 1 The mode conversion and multiplexer based on zirconia waveguide provided by the embodiments of the present application are shown in the schematic diagram.

[0036] Figure 2 The mode conversion and multiplexer based on zirconia waveguide provided by the embodiments of the present application are shown in the cross-sectional view.

[0037] Figure 3 The simulation diagram of mode conversion from E11 in the third coupling waveguide to E21 in the first coupling waveguide provided by the embodiments of the present application is shown in the simulation diagram.

[0038] Figure 4 The simulation diagram of E11 in the first coupling waveguide keeping E11 provided by the embodiments of the present application is shown in the simulation diagram.

[0039] Figure 5 The simulation diagram of mode conversion from E11 in the fourth coupling waveguide to E31 in the second coupling waveguide provided by the embodiments of the present application is shown in the simulation diagram.

[0040] In the figure: 1, substrate; 2, zirconia waveguide layer; 3, upper cladding layer;

[0041] 1011, first input waveguide; 1012, first coupling waveguide; 1013, first straight waveguide; 1014, second coupling waveguide; 1015, first output waveguide;

[0042] 1021, second input waveguide; 1022, first bending waveguide; 1023, third coupling waveguide; 1024, second bending waveguide;

[0043] 1031, third input waveguide; 1032, third bending waveguide; 1033, fourth coupling waveguide; 1034, fourth bending waveguide. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of the present application.

[0045] Referring to Figure 1 and Figure 2 , the embodiments of the present application provide a mode conversion and multiplexer based on a zirconium oxide waveguide, which comprises a zirconium oxide waveguide layer 2, and further comprises a substrate 1 and an upper cladding layer 3, the zirconium oxide waveguide layer 2 is deposited on the substrate 1, and the upper cladding layer 3 is deposited on the zirconium oxide waveguide layer 2, wherein the substrate 1 can adopt silica, and the upper cladding layer 3 can adopt a polymer or silica, such as Figure 1 , the substrate 1 and the upper cladding layer 3 both adopt silica, so that the zirconium oxide waveguide layer 2 is wrapped in silica, the thickness of the substrate 1 is set according to actual needs, such as 2 μm as an example, and the refractive index is 1.4-2.0; the thickness of the upper cladding layer 3 is set according to actual needs, such as 2 μm as an example, and the refractive index is 1.4-1.6. The zirconium oxide waveguide layer 2 comprises a first waveguide, a second waveguide and a third waveguide, and the three waveguides are arranged at intervals.

[0046] The first waveguide comprises a first input waveguide 1011, a first coupling waveguide 1012, a first straight waveguide 1013, a second coupling waveguide 1014 and a first output waveguide 1015 connected in sequence.

[0047] The second waveguide comprises a second input waveguide 1021 and a third coupling waveguide 1023 connected in sequence.

[0048] The third waveguide comprises a third input waveguide 1031 and a fourth coupling waveguide 1033 connected in sequence.

[0049] The first coupling waveguide 1012 and the third coupling waveguide 1023 form a coupling region, and the coupling region has the effect of converting light in the third coupling waveguide 1023 with a mode of a fundamental mode E 11 into light with a mode of a second-order mode E 21 ; the first straight waveguide 1013 has the effect of transmitting the light with the second-order mode E 21 together with light in the first coupling waveguide 1012 with a mode of a fundamental mode E 11 to the second coupling waveguide 1014.

[0050] The second coupling waveguide 1014 and the fourth coupling waveguide 1033 form a coupling region. The function of this coupling region is to convert the fundamental mode E in the fourth coupling waveguide 1033 into a coupling region. 11 The light is converted into a third-order mode E. 31 The first output waveguide 1015 is used to transmit the third-order mode E. 31 The light, and the fundamental mode E in the second coupled waveguide 1014. 11 and second-order module E 21 The light.

[0051] The principle of this application is as follows:

[0052] According to coupled-mode theory, when two dielectric waveguides are very close together, energy exchange occurs between them due to the evanescent field; that is, light energy is transferred from one waveguide to the other. The two waveguides involved in the coupling can be of the same type or different types. When the structures of the two waveguides are very different, the energy exchange is often unequal, typically with light from one waveguide coupling to the other. Figure 1 As shown in the first coupling region, light undergoes mode conversion in the coupling region formed by the first coupling waveguide 1012 and the third coupling waveguide 1023. The first coupling waveguide 1012 and the third coupling waveguide 1023 have different structures; the fundamental mode light E present in the third coupling waveguide 1023... 11 Transformed into E through mode coupling 21 The second-order mode, while the fundamental mode light E exists in the first coupled waveguide 1012. 11 Still E 11 , and the converted E 21 They are transmitted together to the first direct waveguide 1013. For example... Figure 3 As shown, the fundamental mode light E in the third coupled waveguide 1023 11 Transformed into E through mode coupling 21 Second-order module; and Figure 4 The fundamental mode light E existing in the first coupled waveguide 1012 11 Still E 11 No mode conversion occurs; while Figure 5 The fundamental mode light E exists in the fourth coupled waveguide 1033 11 Transformed into E through mode coupling 31 Third-order module.

[0053] The mode converter and multiplexer provided in this application uses zirconia (ZrO2) as the core material. At a wavelength of 1550 nm, its measured refractive index is approximately 1.94 at TE and approximately 1.92 at TM. It is essentially transparent in the near-infrared band. Compared to polymers, zirconia has a higher refractive index, making it more suitable for fabricating small-sized devices. The substrate layer can be SiO2, and the upper cladding layer can be a polymer or silicon dioxide with a refractive index of 1.4–1.6.

[0054] The fabrication process for zirconia waveguides is relatively simple. After creating a pattern with photoresist, a layer of zirconia is deposited by vapor deposition, and then the waveguide is removed using a lift-off process. The cross-sectional dimensions of the waveguide can be adjusted as needed, and no etching of the zirconia is required.

[0055] Zirconia is cheaper than pure silicon, and zirconia waveguides can be fabricated on polymer processing platforms, making them relatively low-cost and easy to integrate with polymers.

[0056] See Figure 1 As shown, the first coupling waveguide 1012 is a tapered waveguide with a width increasing from W1 to W2. The width of W1 ranges from 1800nm ​​to 2200nm, and the width of W2 ranges from 3000nm to 3200nm. The third coupling waveguide 1023 is a tapered waveguide with a width decreasing from W3 to W4. The width of W3 ranges from 1100nm to 1400nm, and the width of W4 ranges from 800nm ​​to 1100nm.

[0057] See Figure 1 As shown, the second coupling waveguide 1014 is a tapered waveguide with a width that increases from W5 to W6. The width of W5 ranges from 3100nm to 4400nm, and the width of W6 ranges from 4800nm ​​to 5000nm. The fourth coupling waveguide 1033 is a tapered waveguide with a width that decreases from W7 to W8. The width of W7 ranges from 1100nm to 1300nm, and the width of W8 ranges from 800nm ​​to 1100nm.

[0058] See Figure 1 As shown, the coupling region formed by the first coupling waveguide 1012 and the third coupling waveguide 1023 has a length L1 of 450μm to 500μm, and the gap1 between the first coupling waveguide 1012 and the third coupling waveguide 1023 is 0.8μm to 1μm.

[0059] See Figure 1 As shown, the coupling region formed by the second coupling waveguide 1014 and the fourth coupling waveguide 1033 has a length L2 of 500μm to 530μm, and the spacing gap2 between the second coupling waveguide 1014 and the fourth coupling waveguide 1033 is 0.8μm to 1μm.

[0060] Referring to Figure 1 and Figure 2 , the first input waveguide 1011 is used to couple light from outside the chip into light with mode fundamental mode E 11 , the waveguide supports one mode, i.e. the fundamental mode E 11 , and its width W b is 800nm-1600nm, thickness H b is 150-300nm, and refractive index is 1.9-2.0.

[0061] Referring to Figure 1 and Figure 2 , the second input waveguide 1021 is used to couple light from outside the chip into light with mode fundamental mode E 11 , the waveguide supports one mode, i.e. the fundamental mode E 11 , and its width W a is 800nm-1600nm, thickness H a is 150-300nm, and refractive index is 1.9-2.0.

[0062] Referring to Figure 1 and Figure 2 , the third input waveguide 1031 is used to couple light from outside the chip into light with mode fundamental mode E 11 , the waveguide supports one mode, i.e. the fundamental mode E 11 , and its width W c is 800nm-1600nm, thickness H c is 150-300nm, and refractive index is 1.9-2.0.

[0063] Referring to Figure 1 , the first straight waveguide 1013 is used to transmit light with mode second-order mode E 21 together with light with mode fundamental mode E 11 in the first coupling waveguide 1012 to the second coupling waveguide 1014, the waveguide supports two modes, i.e. the fundamental mode E 11 and the second-order mode E 21 , and the width of the first straight waveguide 1013 is 3000nm-3200nm.

[0064] Referring to Figure 1 , the first output waveguide 1015 is used to transmit light with mode third-order mode E 31 , and light with mode fundamental mode E 11 and second-order mode E 21 in the second coupling waveguide 1014, the waveguide supports three modes, i.e. the fundamental mode E 11 , the second-order mode E 21 and the third-order mode E 31The width of the first output waveguide 1015 is 4800nm ​​to 5000nm.

[0065] All parameters of the mode converter and multiplexer in this application, including W1, W2, W3, W4, W5, W6, W7, W8, L1, L2, gap1, gap2, etc., are within the optimal solution parameter range for realizing the mode conversion and coupling process, and have been obtained through extensive experimental verification. Figure 3 As shown, within the parameter range of this application, it is possible to realize the transformation from the fundamental model E 11 Convert to E 21 Furthermore, the conversion efficiency reaches over 80%.

[0066] Similarly, such as Figure 5 As shown, within the parameter range of this application, it is possible to realize the transformation from the fundamental model E 11 Convert to E 31 Furthermore, the conversion efficiency reaches over 80%.

[0067] See Figure 1 As shown, the second waveguide also includes a first curved waveguide 1022 whose two ends are respectively connected to the second input waveguide 1021 and the third coupling waveguide 1023; the function of the first curved waveguide 1022 is to transmit the light transmitted from the second input waveguide 1021 to the third coupling waveguide 1023.

[0068] The second waveguide also includes a second curved waveguide 1024 connected to the third coupled waveguide 1023, the tail end of which has a bevel. The function of the second curved waveguide 1024 is to output the remaining energy from the mode conversion of the third coupled waveguide 1023 from the beveled tail end of the second curved waveguide 1024, thereby reducing reflection.

[0069] See Figure 1 As shown, the third waveguide also includes a third curved waveguide 1032 with its two ends connected to the third input waveguide 1031 and the fourth coupling waveguide 1033, respectively; the function of the third curved waveguide 1032 is to transmit the light transmitted from the third input waveguide 1031 to the fourth coupling waveguide 1033.

[0070] The third waveguide also includes a fourth curved waveguide 1034 connected to the fourth coupled waveguide 1033, the fourth curved waveguide 1034 having a beveled end. The function of the fourth curved waveguide 1034 is to output the remaining energy from the mode conversion of the fourth coupled waveguide 1033 from the beveled end of the fourth curved waveguide 1034, thereby reducing reflection.

[0071] In the description of the present application, it should be noted that the terms "upper", "lower", and the like are used for indicating the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. Unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be interpreted broadly, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0072] It should be noted that in the present application, relational terms such as "first" and "second", and the like are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus including a series of elements includes not only those elements, but also other elements not explicitly listed, or other elements inherent in such a process, method, article or apparatus. Without more limitations, the element defined by the statement "comprising a" does not exclude the presence of other identical elements in the process, method, article or apparatus including the element.

[0073] The above is only a specific embodiment of the present application, which enables those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features applied herein.

Claims

1. A mode conversion and multiplexer based on a zirconium oxide waveguide, characterized in that, It comprises a zirconium oxide waveguide layer (2) comprising: The first waveguide comprises a first input waveguide (1011), a first coupling waveguide (1012), a first straight waveguide (1013), a second coupling waveguide (1014) and a first output waveguide (1015) connected in sequence; The second waveguide comprises a second input waveguide (1021) and a third coupling waveguide (1023) connected in sequence; The third waveguide comprises a third input waveguide (1031) and a fourth coupling waveguide (1033) connected in sequence; The coupling region formed by the first coupling waveguide (1012) and the third coupling waveguide (1023) is used to convert the light in the third coupling waveguide (1023) with a mode of a fundamental mode into light with a mode of a second-order mode, and the first straight waveguide (1013) is used to transmit the light with the second-order mode together with the light in the first coupling waveguide (1012) with a mode of a fundamental mode to the second coupling waveguide (1014); The coupling region formed by the second coupling waveguide (1014) and the fourth coupling waveguide (1033) is used to convert the light in the fourth coupling waveguide (1033) with a mode of a fundamental mode into light with a mode of a third-order mode, the first output waveguide (1015) is used to transmit the light with the third-order mode, and the light in the second coupling waveguide (1014) with a mode of a fundamental mode and a second-order mode; The first coupling waveguide (1012) is a tapered waveguide with a width increasing from W1 to W2, the width of W1 ranges from 1800nm to 2200nm, and the width of W2 ranges from 3000nm to 3200nm; The third coupling waveguide (1023) is a tapered waveguide with a width decreasing from W3 to W4, the width of W3 ranges from 1100nm to 1400nm, and the width of W4 ranges from 800nm to 1100nm; The second coupling waveguide (1014) is a tapered waveguide with a width increasing from W5 to W6, the width of W5 ranges from 3100nm to 4400nm, and the width of W6 ranges from 4800nm to 5000nm; The fourth coupling waveguide (1033) is a tapered waveguide with a width decreasing from W7 to W8, the width of W7 ranges from 1100nm to 1300nm, and the width of W8 ranges from 800nm to 1100nm; The coupling region formed by the first coupling waveguide (1012) and the third coupling waveguide (1023) has a length L1 of 450μm to 500μm, and the distance gap1 between the first coupling waveguide (1012) and the third coupling waveguide (1023) is 0.8μm to 1μm; The coupling region formed by the second coupling waveguide (1014) and the fourth coupling waveguide (1033) has a length L2 of 500μm to 530μm, and the distance gap2 between the second coupling waveguide (1014) and the fourth coupling waveguide (1033) is 0.8μm to 1μm; The first input waveguide (1011) is used for coupling the light outside the chip into the light with the fundamental mode, and has a width of 800nm-1600nm, a thickness of 150-300nm, and a refractive index of 1.9-2.0; The second input waveguide (1021) is used for coupling the light outside the chip into the light with the fundamental mode, and has a width of 800nm-1600nm, a thickness of 150-300nm, and a refractive index of 1.9-2.0; The third input waveguide (1031) is used for coupling the light outside the chip into the light with the fundamental mode, and has a width of 800nm-1600nm, a thickness of 150-300nm, and a refractive index of 1.9-2.0; The first straight waveguide (1013) has a width of 3000nm-3200nm; The first output waveguide (1015) has a width of 4800nm-5000nm.

2. The mode conversion and multiplexer based on the zirconium oxide waveguide according to claim 1, wherein: the second waveguide further comprises a first curved waveguide (1022) connected with the second input waveguide (1021) and the third coupling waveguide (1023) respectively at two ends; and / or, the second waveguide further comprises a second curved waveguide (1024) connected with the third coupling waveguide (1023), and the tail end of the second curved waveguide (1024) has a bevel.

3. The mode conversion and multiplexer based on the zirconium oxide waveguide according to claim 1, wherein: the third waveguide further comprises a third curved waveguide (1032) connected with the third input waveguide (1031) and the fourth coupling waveguide (1033) respectively at two ends; and / or, the third waveguide further comprises a fourth curved waveguide (1034) connected with the fourth coupling waveguide (1033), and the tail end of the fourth curved waveguide (1034) has a bevel. The mode conversion and multiplexer further comprises a substrate (1) and an upper cladding layer (3), the zirconium oxide waveguide layer (2) is deposited on the substrate (1), and the upper cladding layer (3) is deposited on the zirconium oxide waveguide layer (2).

5. The mode conversion and multiplexer based on the zirconium oxide waveguide according to claim 4, wherein: the substrate (1) has a thickness of 2μm and a refractive index of 1.4-2.0; 4. The zirconia-oxide waveguide based mode conversion and multiplexer of claim 1, wherein: and / or, the upper cladding layer (3) has a thickness of 2μm and a refractive index of 1.4-1.

6. ​ ​ ​

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