Waveguide with multiple sets of layers

Abstract

A waveguide includes a plurality of layer sets arranged in stack. Each layer set includes a first layer including at least tantalum and oxygen, and a second layer including at least silicon and oxygen. The waveguide is configured to propagate light associated with a particular wavelength in a first direction, the first direction being orthogonal to a second direction in which the plurality of layer sets are stacked. The number of the plurality of layer sets is greater than or equal to 15. The respective thicknesses of the first layer and the second layer in the second direction are less than or equal to one fifteenth of the specific wavelength.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims priority to U.S. Patent Application No. 63 / 599,264, filed on November 15, 2023, entitled “WAVEGUIDE WITH TUNEDEFFECTIVE REFRACTIVE INDEX” and U.S. Patent Application No. 63 / 599,231, filed on November 15, 2023, entitled “MULTI-LAYERED MATERIALS FOR USE IN WAVEGUIDES”. The disclosures of these prior applications are considered part of and incorporated by reference into this patent application. Background Art

[0003] Waveguides confine and guide light (eg, by achieving multiple internal reflections of the light), which allows the light to propagate within the waveguide (eg, from an input end of the waveguide to an output end of the waveguide). Waveguides can be used in a variety of applications, such as optical fibers and integrated optical circuits. Summary of the invention

[0004] In some implementations, a waveguide includes a substrate; and a plurality of layer sets stacked on the substrate, wherein each layer set includes: a first layer including at least tantalum and oxygen; and a second layer including at least silicon and oxygen, wherein: the waveguide is configured to propagate light associated with a specific wavelength in a first direction, the first direction is orthogonal to the second direction, the plurality of layer sets are stacked on the substrate in the second direction, and respective thicknesses of the first layer and the second layer in the second direction are less than or equal to one-fifteenth of the specific wavelength.

[0005] In some implementations, a waveguide includes a plurality of layer sets arranged in a stack, wherein each layer set includes: a first layer including at least tantalum and oxygen; and a second layer including at least silicon and oxygen, wherein: the waveguide is configured to propagate light associated with a specific wavelength in a first direction, the first direction is orthogonal to the second direction, the plurality of layer sets are arranged in a stack in the second direction, and the number of the plurality of layer sets is greater than or equal to 15.

[0006] In some implementations, a waveguide includes a plurality of layer sets arranged in a stack, wherein each layer set includes: a first layer including at least a first material; and a second layer including at least a second material, wherein: the waveguide is configured to propagate light associated with a specific wavelength in a first direction, the first direction is orthogonal to the second direction, the plurality of layer sets are arranged in a stack in the second direction, and the number of the plurality of layer sets is greater than or equal to 15. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1A-1B is a diagram of an example waveguide; and

[0008] Figure 2A-2B is a diagram of an example waveguide with respect to multiple light modes propagating through the waveguide. DETAILED DESCRIPTION

[0009] The following detailed description of example implementations refers to the accompanying drawings.The same reference numbers in different drawings may identify the same or similar elements.

[0010] The waveguide dimensions may be based on the refractive index of the material from which the waveguide is made. For example, to achieve mode coupling (or other applications), the waveguide may have specific dimensions related to one or more refractive indices of the one or more materials from which the waveguide is made. An optically transparent material may have a discrete refractive index for a particular wavelength. For example, a tantalum oxide material (Ta2O5) may have a refractive index of 2.09 at 850 nanometers (nm). However, in some use cases, it may be desirable to use such a material but may be desirable to have a different refractive index (e.g., to enable the use of different dimensions for the waveguide). For example, in some use cases, it may be desirable to have a refractive index of 2.05 while using a tantalum oxide material.

[0011] Furthermore, in some scenarios, different production processes may result in different refractive indices. For example, a magnetron sputtering process used to manufacture a waveguide using a tantalum oxide material may result in a tantalum oxide material having a refractive index of 2.125. This may be the result of many factors, such as whether the structure being manufactured is polycrystalline, nano-polycrystalline, or amorphous; the density of the material being manufactured; the stoichiometry of the material being manufactured; or other factors. Therefore, it may be desirable to adjust the refractive index of the manufacturing material from a first refractive index (e.g., an actual value of 2.125) to a second refractive index selected for a particular use case (e.g., a desired value of 2.09).

[0012] One technique for achieving a desired refractive index is to change the configuration of the deposition process used to make the waveguide. For example, a process controller can change the gas flow rate, process pressure, power applied to the target, or another parameter to adjust the resulting refractive index. However, adjusting the configuration of the deposition process may have a negative impact on the performance of the waveguide, such as by increasing absorption losses (e.g., in the case of substoichiometric compounds) or scattering losses (e.g., due to an increase in roughness). Another technique for achieving a desired refractive index is to dope or mix a specific material (e.g., a tantalum oxide material) with a second material (e.g., a silicon oxide material (SiO2)) to achieve the desired refractive index. However, doping or mixing with different materials may lead to manufacturing difficulties. For example, in order to achieve the desired refractive index, it may be difficult to achieve a very precise target composition for each individual refractive index. In addition, some material sets cannot be mixed well to form a uniform composite target, which leads to undesirable changes in the refractive index. For example, it has been observed that silicon (Si) and germanium (Ge) cannot be mixed well.

[0013] Some implementations described herein include a waveguide having a plurality of layer sets arranged in a stack. Each set includes a first layer and a second layer, wherein the thickness of each layer is thin relative to the wavelength of light for which the waveguide is configured (e.g., the thickness is at least one-fifteenth of the wavelength). In addition, the number of layer sets can be greater than or equal to a threshold number (e.g., 15 or more). In this manner, the plurality of layer sets include a form birefringent (FB) stack, and thereby the waveguide has an ordinary refractive index (n) associated with a first direction (e.g., a propagation direction of light within the waveguide). o ), and an extraordinary refractive index (n) associated with a second direction (eg, a stacking direction of the plurality of layer sets) e In addition, the number of layer sets and / or the thickness of each layer in the layer set can be selected so that the waveguide has a specific ordinary refractive index (n o ) and / or specific anomalous refractive index (n e ).

[0014] In this way, multiple layer sets can be used to adjust the ordinary refractive index (n o ) and / or the extraordinary refractive index (n e ) can be fine-tuned, thereby enabling precise refractive indices to be achieved for different use cases. By achieving precise refractive indices, some implementations increase the flexibility of waveguide design. In addition, the number of multiple layer sets and / or the thickness of each layer in the layer set can be selected so that the waveguide provides an optimal number of multiple light modes propagating through the waveguide (e.g., a preferred number of modes) and / or prevents or minimizes light losses associated with the propagation of multiple modes. This further enables the waveguide to be used in different use cases where waveguides with greater losses are not practical.

[0015] Figure 1A-1B is a diagram of an example waveguide 100. In some implementations, the waveguide 100 may include a substrate 105 and a substrate disposed on the substrate (eg, on a top surface of the substrate 105, such as Figure 1A-1B The plurality of layer sets 110 (eg, two or more layer sets 110) may be arranged in a stacked manner (eg, the plurality of layer sets 110 may be disposed in a stacked manner on a substrate). Figure 1A-1B An example stack of waveguides 100 is shown.

[0016] The waveguide 100 may be configured to propagate light in a first direction. For example, the waveguide 100 may be configured to propagate light in a first direction parallel to the Figure 1A-1B In other words, the waveguide 100 can be configured to propagate light in a first direction that is orthogonal to a second direction (e.g., parallel to the y-axis) in which the plurality of layer sets 110 are stacked (e.g., on the substrate 105). That is, Figure 1A-1B A view of an end (eg, an input end or an output end) of the waveguide 100 is shown, and through which light may propagate into or out of the waveguide 100 .

[0017] The waveguide 100 may be configured to propagate light associated with a spectral range, such as light associated with wavelengths from 350 nm to 5000 nm (e.g., greater than or equal to 350 nm and less than or equal to 5000 nm), from 420 nm to 1600 nm, or other ranges. As another example, the spectral range may include one or more sub-ranges of light associated with ultraviolet light to infrared light, such as one or more portions of ultraviolet light (e.g., one or more portions of light associated with wavelengths from 200 nm to 399 nm), one or more portions of visible light (e.g., one or more portions of light associated with wavelengths from 400 nm to 799 nm), and / or one or more portions of infrared light (e.g., one or more portions of light associated with wavelengths from 800 nm to 5000 nm). In some implementations, the waveguide 100 may be configured to propagate light associated with a particular wavelength, such as light associated with a spectral range centered around a particular wavelength. For example, the waveguide 100 may be configured to propagate light associated with a spectral range centered around 785 nm (eg, a spectral range from 770 nm to 800 nm centered around 785 nm).

[0018] The substrate 105 may include a glass substrate, a polymer substrate, a polycarbonate substrate, a silicon (Si) substrate, a germanium (Ge) substrate, or an active device wafer (e.g., including a photodiode (PD), a PD array, an avalanche photodiode (APD), an APD array, a charge coupled device (CCD) sensor, and / or a complementary metal oxide semiconductor (CMOS) sensor, etc.). In some implementations, the thickness of the substrate 105 may be greater than or equal to 10 micrometers (μm), 50 μm, and / or 500 μm. Additionally or alternatively, the thickness of the substrate 105 may be less than or equal to a specific thickness threshold. For example, the specific thickness threshold may be less than or equal to 10 millimeters (mm) or 5 mm.

[0019] Each layer set 110 in the one or more layer sets 110 may include a first layer 115 and a second layer 120. The second layer 120 may be disposed on (e.g., directly or indirectly on) the first layer 115 (e.g., disposed in a stacked manner, such as in a second direction). Figure 1A-1BAs shown, a first surface (e.g., bottom surface) of the second layer 120 can be disposed on (e.g., directly on) a surface (e.g., top surface) of the first layer 115. In some implementations, one or more other layers can be disposed between the first layer 115 and the second layer 120. That is, in some implementations, each layer set 110 can include two or more layers.

[0020] The first layer 115 may include a first material. The first layer material may include at least a first oxide, such as a tantalum pentoxide (Ta2O5) material, a silicon dioxide (SiO2) material, a niobium pentoxide (Nb2O5), a niobium titanium oxide (NbTiO x ) materials, niobium tantalum pentoxide (Nb 2-x Ta x O5) material, titanium dioxide (TiO2) material, aluminum oxide (Al2O3) material, zirconium oxide (ZrO2) material, yttrium oxide (Y2O3) material or hafnium oxide (HfO2) material, etc. Additionally or alternatively, the first material may include at least one of the following: tantalum and oxygen; niobium, titanium and oxygen; hydrogen and germanium; hydrogen and silicon; silicon and germanium; hydrogen, silicon and germanium; silicon; or germanium. For example, the first material may include at least one of the following: tantalum pentoxide (Ta2O5) material, niobium titanium oxide (NbTiO x ) material, germanium (Ge) material, hydrogenated germanium (Ge:H) material, silicon germanium (SiGe) material, hydrogenated silicon germanium (SiGe:H) material, silicon (Si) material, amorphous silicon (a Si) material, silicon and hydrogen (SiH) material, hydrogenated silicon (Si:H) material, or germanium (Ge) material, and in some implementations, may include one or more other elements or materials. In some implementations, the first material may include at least tantalum and oxygen. For example, the first material may include tantalum pentoxide (Ta2O5) material, and in some implementations, may include one or more other elements or materials (e.g., tantalum, oxygen, hydrogen, silicon, aluminum, nitrogen, silicon dioxide (SiO2) material and / or aluminum nitride (AlN) material).

[0021] Thus, for light associated with a spectral range (eg, from 400 nm to 799 nm, or another spectral range), the first layer 115 can have a refractive index from 1.9 to 2.5 (eg, greater than or equal to 1.9 and less than or equal to 2.5).

[0022] The second layer 120 may include a second material. The second material may include at least a second oxide (such as at least a silicon dioxide (SiO2) material), and / or one or more other elements or materials (e.g., silicon; oxygen; silicon oxide (SiO x) material, where x is less than 2; silicon nitride (SiN) material; aluminum silicon (AlSi) material; and / or another material). In some implementations, the second material may include at least one of the following: silicon and oxygen, aluminum and oxygen, or magnesium and fluorine. For example, the second material may include at least one of a silicon dioxide (SiO2) material, an aluminum oxide (Al2O3) material, or a magnesium fluoride (MgF) material, and in some implementations, may include one or more other elements or materials. Therefore, for light associated with a spectral range (e.g., from 400nm to 799nm, or another spectral range), the second layer 120 may have a refractive index from 1.3 to 1.8 (e.g., greater than or equal to 1.3 and less than or equal to 1.8).

[0023] In some implementations, each layer in layer set 110 is associated with a particular thickness (eg, in the second direction parallel to Figure 1A-1B y-axis shown). For example, each of the first layer 115 and the second layer 120 can have a respective thickness in a range from 1 nm to 20 nm (e.g., a thickness greater than or equal to 1 nm and less than or equal to 20 nm). In some implementations, each of the first layer 115 and the second layer 120 can have a thickness in a range from 1 nm to a thickness threshold (e.g., a thickness greater than or equal to 1 nm and less than or equal to the thickness threshold). The thickness threshold can, for example, be associated with the light that the waveguide 100 is configured to propagate. For example, when the waveguide 100 is configured to propagate light associated with a particular wavelength (e.g., as described above), the thickness threshold can be one-fifteenth, one-twentieth, one-twenty-fifth, or one-thirtieth, etc., of the particular wavelength. In this manner, each of the first layer 115 and the second layer 120 can be referred to as a “thin” layer.

[0024] In some implementations, the layers in the first layer set 110 can have the same thickness or different thicknesses as the corresponding layers in the second layer set 110. For example, the first layer 115 and the second layer 120 in the first layer set 110 can have respective thicknesses that are the same (e.g., equal or within a threshold value, the threshold value being less than or equal to 1 nm) as the respective thicknesses of the first layer 115 and the second layer 120 in the second layer set 110. Alternatively, the first layer 115 and the second layer 120 in the first layer set can have respective thicknesses that are different from the first layer 115 and the second layer 120 in the second layer set 110. Thus, each layer set 110 in the plurality of layer sets 110 can have a thickness profile that is the same as or different from the thickness profile of another layer set 110 in the plurality of layer sets 110.

[0025] In some implementations, the number of the plurality of layer sets 110 may satisfy (e.g., be greater than or equal to) a number threshold. The number threshold may be, for example, greater than or equal to 15, 16, 17, 18, 19, 20, etc. That is, when arranged in a stack (e.g., on the substrate 105), the number of the plurality of layer sets 110 may be greater than or equal to the number threshold.

[0026] Thus, the layer thickness of each layer in the layer set 110 and / or the number of the plurality of layers 110 may be selected such that the plurality of layer sets 110 comprises a form-ordered birefringence (FB) stack. For example, for a particular wavelength of light that the waveguide 100 is configured to propagate, the plurality of layer sets 110 may be such that the waveguide 100 has a first direction (e.g., a propagation direction of light that is parallel to the first direction) and a second direction (e.g., a propagation direction of light that is parallel to the first direction) of the waveguide 100. Figure 1A-1B The ordinary refractive index (n o ), and a second direction (eg, a stacking direction of the plurality of layers 110, which is parallel to Figure 1A-1B The anomalous refractive index (n e ), which are different from each other (i.e., n o ≠n e ).

[0027] As a specific example, when the layer thickness (d H ) and the layer thickness (d L ) is substantially less than a certain wavelength (e.g., less than or equal to a thickness threshold), and the number of the plurality of layers 110 is substantially high (e.g., greater than or equal to a number threshold), the ordinary refractive index (n) of the waveguide 100 o ) and the extraordinary refractive index (n e ) can be described by the following function associated with the effective medium theory (EMT):

[0028]

[0029] as well as

[0030]

[0031] Where n H is the refractive index of the first layer 115 (eg, for a particular wavelength), n L is the refractive index of the second layer 120 (eg, for a particular wavelength), and n H Greater than n L Thus, the layer thickness of each layer in the layer set 110 and / or the number of the plurality of layers 110 may be selected so that the waveguide 100 has a specific ordinary refractive index (n o ) and / or specific anomalous refractive index (n eIn some implementations, the specific anomalous refractive index (n e ) may be smaller than the refractive index (n H ) and is greater than the refractive index of the second layer 120 (n L ).

[0032] like Figure 1B As shown, the waveguide 100 may include a first other layer 125 disposed between the plurality of layer sets 110 and the substrate 105, and / or may include a second other layer 130 disposed on the plurality of layer sets 110. Each of the first other layer 125 and / or the second other layer 130 may be configured as a cladding, a passivation layer, a protective layer, and / or another type of layer. Each of the first other layer 125 and / or the second other layer 130 may include at least an oxide. For example, each of the first other layer 125 and / or the second other layer 130 may include an oxide material (e.g., a silicon dioxide (SiO2) material), and in some implementations, may include one or more other elements or materials (e.g., silicon, oxygen, and / or other materials). Additionally or alternatively, each of the first other layer 125 and / or the second other layer 130 may include at least a polymer material (e.g., at least a siloxane polymer material or another polymer material) or at least an air cladding, etc.

[0033] As mentioned above, Figure 1A-1B Provided as an example. Other examples can be found with Figure 1A-1B In practice, Figure 1A-1B The waveguide 100 can include more layers, components, and / or structures than shown; fewer layers, components, and / or structures; different layers, components, and / or structures; or differently arranged layers, components, and / or structures. For example, within the layer set 110, the first layer 115 can be disposed above (e.g., directly or indirectly on) the second layer 120.

[0034] Figure 2A-2B 2 is a diagram 200 of an example waveguide 100 with respect to multiple modes 205 of light propagating through the waveguide 100. Figure 2A-2B As shown, the modes 205 in the plurality of modes 205 may propagate within the respective layer sets 110. That is, light may enter the waveguide 100 via the input end of the waveguide 100 and may propagate as the plurality of modes 205 within the plurality of layer sets 110, respectively.

[0035] In some implementations, the number of the plurality of layer sets 110 and / or the thickness of each layer in the layer sets 110 can be selected to provide an optimal number (e.g., a preferred number of modes) of the plurality of modes 205 and / or to prevent or minimize optical losses associated with propagation of the plurality of modes. For example, the number of the plurality of layers 110 and / or the layer thickness of each layer in the layer sets 110 can be selected to enable the plurality of modes 205 to propagate within the waveguide 100 without interference (or with minimal interference).

[0036] Thus, the waveguide 100 may be associated with a propagation loss parameter (α) that satisfies a propagation loss parameter threshold. That is, the waveguide 100 (e.g., due to the "effective" aggregation of the corresponding propagation loss parameters of the first layer 115 and the second layer 120 in each layer set 110) may have a propagation loss parameter that is less than or equal to the propagation loss parameter threshold. The propagation loss parameter threshold may be less than or equal to 0.08 decibels per centimeter and / or In some implementations, the waveguide 100 may have a value greater than or equal to and is less than or equal to The propagation loss parameters.

[0037] Furthermore, the waveguide 100 may be associated with a propagation loss parameter that is less than at least one of: a propagation loss parameter associated with the first layer 115 in each layer set 110, or a propagation loss parameter associated with the second layer 120 in each layer set 110. That is, the waveguide 100 may have a propagation loss parameter that is less than a propagation parameter of at least one individual layer in each layer set 110 (e.g., due to an "effective" aggregation of the respective propagation loss parameters of the first layer 115 and the second layer 120 in each layer set 110).

[0038] As mentioned above, Figure 2A-2B Other examples can be found in the Figure 2A-2B In practice, Figure 2A-2B Compared to what is shown, multiple modes 205 can propagate within more layers, components, and / or structures; fewer layers, components, and / or structures; different layers, components, and / or structures; or differently arranged layers, components, and / or structures.

[0039] The above disclosure provides illustration and description, but is not intended to be exhaustive or to limit the implementation to the precise form disclosed. Modifications and variations may be made in light of the above disclosure or may be acquired from practice of the implementation.

[0040] As used herein, the term "component" is intended to be broadly interpreted as hardware, firmware, or a combination of hardware and software. It is apparent that the systems and / or methods described herein can be implemented in different forms of hardware, firmware, and / or a combination of hardware and software. The actual dedicated control hardware or software code used to implement these systems and / or methods does not limit these implementations. Therefore, the operation and behavior of these systems and / or methods are described herein without reference to specific software codes, and it should be understood that, based on the description herein, these systems and / or methods can be implemented using software and hardware.

[0041] As used herein, satisfying a threshold may refer to a value being greater than a threshold, greater than or equal to a threshold, less than a threshold, less than or equal to a threshold, equal to a threshold, not equal to a threshold, etc., depending on the context.

[0042] Even if specific feature combinations are listed in the claims and / or disclosed in the specification, these combinations are not intended to limit the disclosure of various implementations. In fact, many of these features can be combined in ways that are not specifically listed in the claims and / or disclosed in the specification. Although each dependent claim listed below may directly depend on only one claim, the disclosure of various implementations includes each dependent claim combined with each other claim in the claim set. As used herein, a phrase referring to "at least one" in a list of items refers to any combination of these items, including single members. For example, "at least one of a, b, or c" is intended to cover a, b, c, ab, ac, bc, and abc, as well as any combination with multiple identical items.

[0043] Unless explicitly stated, any element, behavior or instruction used in this article should not be interpreted as critical or necessary. In addition, as used in this article, the articles "a" and "an" are intended to include one or more projects and can be used interchangeably with "one or more". In addition, as used in this article, the article "the" is intended to include one or more projects quoted in combination with the article "the", and can be used interchangeably with "one or more". In addition, as used in this article, the term "set" is intended to include two or more projects (for example, a combination of related projects, unrelated projects, or related projects and unrelated projects), and can be used interchangeably with "one or more". If only one project is intended to be used, the phrase "only one" or similar language is used. In addition, as used in this article, the terms "have", "have", "contain" etc. are intended to be open terms. In addition, unless otherwise explicitly stated, the word "based on" means "at least partially based on". In addition, as used in this article, the term "or" is inclusive when used in a series, and can be used interchangeably with "and / or", unless otherwise explicitly stated (for example, if used in combination with "any one" or "only one").

[0044] As used herein, the term "X material" (where X is a chemical composition such as Ta2O5, SiO2, or Si:H) means that the X material includes at least a threshold percentage of X. The threshold percentage may be, for example, greater than or equal to 1%, 5%, 10%, 25%, 50%, 75%, 85%, 90%, 95%, and / or 99%. In addition, when a material is represented by a specific chemical name or chemical formula, the material may include non-stoichiometric variations of the stoichiometrically exact chemical formula identified by the chemical name. For example, the silicon dioxide (SiO2) material described herein may include SiO x , where x is in the range from 0.8 to 1.2.

Claims

1. A waveguide comprising: substrate; as well as A plurality of layer sets are stacked and arranged on the substrate, wherein each layer set comprises: a first layer comprising at least tantalum and oxygen; and The second layer comprises at least silicon and oxygen, wherein: The waveguide is configured to propagate light associated with a specific wavelength in a first direction, the first direction being orthogonal to a second direction in which the plurality of layer sets are stacked on the substrate, and The respective thicknesses of the first layer and the second layer in the second direction are less than or equal to one fifteenth of the specific wavelength.

2. The waveguide according to claim 1, wherein: The first layer comprises at least tantalum pentoxide (Ta2O5) material; and The second layer includes at least silicon dioxide (SiO2) material.

3. The waveguide according to claim 1, wherein: The respective thicknesses of the first layer and the second layer in the first direction are greater than or equal to 1 nanometer and less than or equal to 20 nanometers.

4. The waveguide according to claim 1, wherein: The number of the plurality of layer sets is greater than or equal to 15.

5. The waveguide according to claim 1, wherein: The plurality of layer sets comprises a form-ordered birefringent (FB) stack.

6. The waveguide according to claim 1, wherein: The specific wavelength is associated with a spectral range from 400 nanometers to 799 nanometers.

7. The waveguide according to claim 1, wherein: The plurality of layer sets causes the waveguide to have, for the particular wavelength, an ordinary refractive index associated with the first direction and an extraordinary refractive index associated with the second direction.

8. The waveguide according to claim 7, wherein: For the specific wavelength, the extraordinary refractive index is smaller than a refractive index of the first layer and larger than a refractive index of the second layer.

9. The waveguide of claim 1, wherein: The waveguide is associated with a propagation loss parameter that is less than at least one of: a propagation loss parameter associated with the first layer, or a propagation loss parameter associated with the second layer.

10. A waveguide comprising: A plurality of layer sets are arranged in a stacked manner, wherein each layer set comprises: a first layer comprising at least tantalum and oxygen; and The second layer comprises at least silicon and oxygen, wherein: The waveguide is configured to propagate light associated with a specific wavelength in a first direction, the first direction being orthogonal to a second direction in which the plurality of layer sets are stacked, and The number of the plurality of layer sets is greater than or equal to 15.

11. The waveguide according to claim 10, wherein: The first layer comprises at least tantalum pentoxide (Ta2O5) material; and The second layer includes at least silicon dioxide (SiO2) material.

12. The waveguide of claim 10, wherein: The respective thicknesses of the first layer and the second layer in the first direction are greater than or equal to 1 nanometer and less than or equal to 20 nanometers.

13. The waveguide of claim 10, wherein: The plurality of layer sets causes the waveguide to have, for the particular wavelength, an ordinary refractive index associated with the first direction and an extraordinary refractive index associated with the second direction.

14. The waveguide of claim 13, wherein: For the specific wavelength, the extraordinary refractive index is smaller than a refractive index of the first layer and larger than a refractive index of the second layer.

15. The waveguide of claim 10, wherein: The waveguide is associated with a propagation loss parameter that is less than at least one of: a propagation loss parameter associated with the first layer, or a propagation loss parameter associated with the second layer.

16. A waveguide comprising: A plurality of layer sets are arranged in a stacked manner, wherein each layer set comprises: A first layer comprising at least a first material; and The second layer comprises at least a second material, wherein: The waveguide is configured to propagate light associated with a specific wavelength in a first direction, the first direction being orthogonal to a second direction in which the plurality of layer sets are stacked, and The number of the plurality of layer sets is greater than or equal to 15.

17. A waveguide according to claim 16, wherein: The waveguide is associated with a propagation loss parameter that is less than at least one of: a propagation loss parameter associated with the first layer, or a propagation loss parameter associated with the second layer.

18. The waveguide of claim 16, wherein: The respective thicknesses of the first layer and the second layer in the first direction are greater than or equal to 1 nanometer and less than or equal to 20 nanometers.

19. The waveguide of claim 16, wherein: The plurality of layer sets causes the waveguide to have an extraordinary refractive index associated with the second direction for the particular wavelength.

20. The waveguide of claim 19, wherein: For the specific wavelength, the extraordinary refractive index is smaller than a refractive index of the first layer and larger than a refractive index of the second layer.

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