Optical components and optical chips based on slit waveguides

Abstract

Embodiments of the present application relate to slot waveguide-based optical components and optical chips. According to some embodiments of the present application, a slot waveguide-based optical component includes: a first waveguide; a slot waveguide located within the first waveguide; and an optical device located within the slot waveguide. Another embodiment of the present application provides an optical chip including one or more of the aforementioned optical components. The slot waveguide-based optical components and optical chips provided by the embodiments of the present application can effectively address issues encountered in conventional technologies.

Description

Technical Field

[0001] The present application belongs to the field of optical communication technology, and specifically relates to an optical component and an optical chip based on a slot waveguide. Background Art

[0002] Optical devices are often used to analyze quantum states in fields such as optical quantum computing. However, existing optical devices are typically integrated with waveguides, and their advantages, such as high efficiency and low temporal jitter, have led to widespread application in fields such as optical quantum computing.

[0003] However, when integrating waveguides with optical devices, the optical devices are typically placed on the surface of the waveguide and extend along its length. Placing the optical device on the waveguide surface requires light detection by absorbing the evanescent waves of the waveguide's mode field. To achieve high light absorption efficiency, the optical device must be very long. However, as the length of the optical device increases, its inductance increases, increasing the decay time of the electrical pulse generated by the optical device detecting a single photon. This results in the optical device being unable to respond to the next single photon in a timely manner, reducing the detection efficiency of the optical device across the entire waveguide and preventing the optical device from achieving a high detection rate.

[0004] Therefore, the present application proposes an optical component and an optical chip based on a slot waveguide. Summary of the Invention

[0005] The present application is made to solve the above-mentioned problems, and one of its purposes is to provide an optical component and an optical chip based on a slot waveguide.

[0006] The present application provides an optical component based on a slot waveguide, which includes: a first waveguide; a slot waveguide located inside the first waveguide; and an optical device located inside the slot waveguide.

[0007] In the above optical component, the optical device includes a superconducting nanowire single photon detector (SNSPD).

[0008] In the above optical component, the refractive index of the slot waveguide is lower than the refractive indexes of the first waveguide and the optical device.

[0009] The above optical component, wherein the slot waveguide comprises a silica waveguide.

[0010] The optical component described above, wherein the first waveguide comprises at least one of a silicon nitride waveguide, a silicon dioxide waveguide, and a niobium nitride waveguide.

[0011] In the above optical component, the thickness of at least one end of the slot waveguide gradually decreases.

[0012] In the above optical component, at least a portion of the optical device is located inside at least one end of the slot waveguide.

[0013] In the above optical component, the distance between the optical device and the bottom surface of the slot waveguide gradually decreases.

[0014] In the above optical component, the shape of the optical device is the same as that of the slot waveguide, and the optical device and the slot waveguide are arranged to substantially overlap.

[0015] The present application also provides an optical chip, which includes any of the aforementioned optical components based on a slit waveguide.

[0016] The function and effect of the technical solution applied for

[0017] The present invention provides a slot waveguide-based optical component comprising: a first waveguide; a slot waveguide located within the first waveguide; and an optical device located within the slot waveguide. Because the optical device is located within the slot waveguide, where light intensity is high, the optical device's light absorption efficiency is improved, significantly shortening the length of the optical device while still achieving near-100% light absorption efficiency, thereby enhancing the optical device's detection efficiency and detection rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the cross-sectional structure of an optical component based on a slot waveguide according to an embodiment of the present application.

[0019] Figure 2 It is a cross-sectional side view of the optical component of an embodiment of the present application.

[0020] Figure 3 yes Figure 2 Schematic diagram of the cross-sectional structure of the CC′ section.

[0021] Figure 4 yes Figure 2 Schematic diagram of the cross-sectional structure of the DD′ section.

[0022] Figure 5 It is a schematic diagram of the planar structure of the optical device 30.

[0023] Figure 6 This is another structural diagram of the optical device terminal.

[0024] Figure 7 、 Figure 8 FIG. 4 is a top view of an optical component in another embodiment.

[0025] Figure 9 yes Figure 7 Schematic diagram of the cross-sectional structure of the BB′ section.

[0026] Figure 10 is a schematic cross-sectional view of an optical component in another embodiment.

[0027] Figure 11 FIG. 4 is a top view of an optical component in yet another embodiment.

[0028] Figure 12 yes Figure 11 Schematic diagram of the cross section of section AA′.

[0029] Figure 13 2 is a schematic structural diagram of an optical component in yet another embodiment.

[0030] Figure 14 2 is a schematic structural diagram of another optical component in yet another embodiment. DETAILED DESCRIPTION

[0031] In order to make the technical means, creative features, objectives and effects achieved by this application easier to understand, the following detailed description of the optical components and optical chips based on slot waveguides provided by this application is given in conjunction with the embodiments and drawings.

[0032] The embodiments of the present application will be described in detail below. Throughout this specification, identical or similar components and components having identical or similar functions are represented by similar reference numerals. The embodiments described herein with respect to the accompanying drawings are illustrative and diagrammatic and are intended to provide a basic understanding of the present application. The embodiments of the present application should not be construed as limiting the present application.

[0033] As used herein, the terms "substantially," "approximately," "substantially," "about," and "approximately" are used to describe and illustrate small variations. When used in conjunction with an event or circumstance, the terms may refer to instances where the event or circumstance occurred precisely as well as instances where the event or circumstance occurred very approximately. For example, when used in conjunction with a numerical value, the terms may refer to a range of variation of less than or equal to ±10% of the numerical value, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%. For example, two values ​​may be considered “substantially” the same if the difference between them is less than or equal to ±10% of the mean of the values ​​(e.g., less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%).

[0034] In this specification, unless otherwise specified or limited, relative terms such as "vertical," "lateral," "upper," "lower," and their derivatives (e.g., "upper surface," etc.) should be interpreted as referring to directions described in the discussion or illustrated in the drawings. These relative terms are used for convenience of description only and do not require that the present application be constructed or operated in a specific orientation.

[0035] In addition, amounts, ratios, and other numerical values ​​are sometimes presented herein in a range format. It should be understood that such a range format is used for convenience and brevity and should be interpreted flexibly to include not only the values ​​explicitly specified as limits of the range, but also all individual values ​​or sub-ranges encompassed within the range, as if each value and sub-range were explicitly specified.

[0036] Furthermore, for ease of description, “first,” “second,” etc. may be used herein to distinguish different operations of one component or a series of components. “First,” “second,” etc. are not intended to describe the corresponding components.

[0037] Figure 1 Schematic diagram of the cross-sectional structure of the optical component 100 based on the slot waveguide according to an embodiment of the present application.

[0038] See also Figure 1 The slot waveguide-based optical component 100 provided in this embodiment includes: a first waveguide 10 ; a slot waveguide 20 located inside the first waveguide 10 ; and an optical device 30 located inside the slot waveguide 20 .

[0039] like Figure 1 As shown, when light is incident on the optical component 100 in a direction perpendicular to the paper, since the refractive index of the slot waveguide 20 is lower than the refractive index of the waveguides on both sides thereof and its width is narrow, the light mainly propagates in the slot waveguide 20, so that the light intensity in the slot waveguide is significantly stronger than the light intensity in other areas (such as the high refractive index areas on both sides thereof, i.e., the first waveguide). The optical device is located inside the slot waveguide, which can significantly enhance the light intensity inside and near the optical device. Therefore, the use of the slot waveguide can enhance the light absorption efficiency of the optical device.

[0040] The “optical devices” in this application include active devices and passive devices, both of which require light to pass through and can control light, such as routing, modulating, generating or absorbing light, etc.

[0041] Figure 1 In the optical component 100 provided in the embodiment, the refractive index of the first waveguide 10 is relatively large. For example, the first waveguide 10 may include a silicon nitride waveguide. In other embodiments, the first waveguide 10 may also include other high-refractive-index waveguides, such as silicon, lithium niobate, etc.

[0042] In other embodiments, the first waveguide 10 may include waveguides made of various materials, such as Figure 1 The waveguides on the left and right sides of the slot waveguide 20 can be made of different materials.

[0043] The slot waveguide 20 is located within the first waveguide 10. The slot waveguide 20 may have a lower refractive index than the first waveguide 10. For example, the slot waveguide 20 may comprise a silica waveguide. In other embodiments, the slot waveguide 20 may comprise other low-refractive-index waveguides, such as a silicon oxynitride waveguide, or a waveguide with an upper portion of air and a lower portion of a dielectric such as silica. Placing the slot waveguide 20 within the first waveguide 10 can effectively increase the light intensity within the slot waveguide 20. Figure 1 The optical device 30 provided in the embodiment is located inside the slot waveguide 20, wherein the optical device 30 may include a superconducting nanowire single photon detector SNSPD. In other embodiments, the optical device 30 may also include other optical devices, such as a general photodetector PD. When light enters the optical component 100 (e.g. Figure 1 The light is incident perpendicular to the paper surface), and the light intensity at the slit waveguide is the largest, thereby enhancing the efficiency of the optical device in absorbing light.

[0044] Integrated quantum photonic chips used in applications such as optical quantum computing require optical devices, such as single-photon detectors (SPDs), to analyze the quantum states of light. Compared to traditional perpendicular-incidence superconducting nanowire single-photon detectors (SNSPDs), waveguide-integrated SNSPDs (WI-SNSPDs), which integrate SNSPDs with waveguides, have attracted considerable research in recent years due to their high efficiency and low temporal jitter.

[0045] Currently, in the WI-SNSPD structure, a nanowire (SNSPD) is placed on top of a waveguide and extends along the waveguide direction, detecting incident photons by absorbing the evanescent wave of the waveguide mode field. The longer the nanowire, the higher the proportion of light absorbed, and thus the higher the on-chip detection efficiency. However, as the length of the nanowire increases, its inductance also increases accordingly, causing the decay time of the electric pulse formed by detecting a single photon to become longer. During the pulse decay time after a detection (absorbing a photon to generate an electric pulse), the detector cannot respond to the next absorbed photon, so the maximum detection rate is limited by the length of the nanowire.

[0046] Therefore, the embodiment of the present application proposes an optical component based on a slot waveguide, placing the SNSPD inside the slot waveguide to enhance the light absorption of the SNSPD, thereby achieving a light absorption efficiency close to 100% and a high-speed detection rate of GHz using a shorter SNSPD.

[0047] Figure 1In the embodiment, the refractive index of the slot waveguide 20 is lower than the refractive index of the first waveguide 10 and the optical device 30. Placing the optical device 30 in the slot waveguide 20 with a low refractive index can improve the absorption efficiency of the optical device 30.

[0048] Figure 2 1 is a cross-sectional side view of the optical component 100 according to an embodiment of the present application.

[0049] See also Figure 2 The optical component 100 in which the thickness of at least one end 40 of the slot waveguide 20 decreases gradually. Figure 2 The slot waveguide 20 in the embodiment has a thickness gradually decreasing from a larger area to a smaller area. At least a portion 31 of the optical device 30 is located inside at least one end 40 of the slot waveguide 20 .

[0050] See also Figure 2 In the optical assembly 100, the distance between the optical device 30 and the bottom of the slot waveguide 20 can be varied to increase the light coupling efficiency. Figure 2 As shown, the distance H2 between at least a portion 31 of the optical device 30 and the bottom of the slot waveguide 20 gradually decreases, as shown in FIG. Figure 2 As shown, the height of other parts of the optical device 30 remains unchanged, for example Figure 2 The height H1 in the figure is a fixed value. In other embodiments, the height H2 of the end of at least a portion 31 of the optical device 30 may also be zero. Figure 2 In the figure, light is incident from the left side (a). Due to the gradual increase in the thickness of the slot waveguide 20 or the gradual increase in the distance between the optical device 30 and the bottom of the slot waveguide 20, the light transmission undergoes an adiabatic approximate change at this location, thereby greatly reducing the scattering loss of the optical device 30.

[0051] Figure 3 yes Figure 2 Schematic diagram of the cross-sectional structure of the CC′ section.

[0052] See also Figure 3 , Figure 3 for Figure 2 The optical device 30 (the optical device 30 is Figure 5 The cross-sectional structure diagram of the U-shaped structure in FIG2 is shown when the distance from the bottom of the slot waveguide 20 to the bottom of the slot waveguide 20 is H1. Figure 3 As shown, the optical device 30 is disposed inside the slot waveguide 20 , and the slot waveguide 20 is located inside the first waveguide 10 .

[0053] Figure 4 yes Figure 2 Schematic diagram of the cross-sectional structure of the DD′ section.

[0054] See also Figure 4 , Figure 4 for Figure 2Schematic diagram of the cross-sectional structure when the distance between at least a portion 31 of the optical device 30 and the bottom surface of the slot waveguide 20 is H2.

[0055] Figure 5 The optical device 30 (eg Figure 2-4 Schematic diagram of the planar structure of the optical device in FIG.

[0056] See also Figure 5 In the embodiment, the two terminals of the optical device 30 may be arranged on the same side, for example Figure 5 In other embodiments, the two terminals of the optical device 30 can also be set at the left end,

[0057] The slot waveguide may cover the upper and lower surfaces of the optical device 30. Figure 3 and Figure 4 Then Figure 5 The structure of the optical device and the cross-sectional view of the slot waveguide and the first waveguide when viewed from the out end.

[0058] Figure 6 FIG. 5 is a schematic diagram of a planar structure of another optical device 50 .

[0059] See also Figure 6 In the embodiment, the two terminals of the optical device 50 are located on its left and right sides, respectively. Light enters the first waveguide 10 from direction a and exits from the other end. While maintaining the total length of the other optical device 50, by locating the other optical device 50 at the center of the first waveguide 10, the proportion of the other optical device 50 in the middle of the first waveguide 10 (where absorption is maximum) can be increased.

[0060] Figure 7 and Figure 8 is a top view of the optical component 200 in some other embodiments.

[0061] Figure 9 yes Figure 7 Schematic diagram of the cross-sectional structure of section BB′.

[0062] See also Figure 7-9 In the embodiment, the optical device 203 and the slot waveguide 202 are substantially overlapped and arranged, and the optical device 203 and the slot waveguide 202 may have the same shape, for example, both are U-shaped. Figure 8 In the embodiment, the optical device 203 has a larger width and a smaller thickness.

[0063] See also Figure 8In the embodiment, the optical device 203 is arranged to overlap the slot waveguide (not shown in the figure), and the right end 203a of the optical device 203 forms an angle with the propagation direction of the light in the first waveguide 201 (along the b direction). Figure 7 Compared with the structure of the optical device in Figure 8 When the intermediate light is transmitted from direction b, the cross-section of the first waveguide 201 changes slowly, so that the light loss is reduced when the light is transmitted from the right end 203a to the left end 203b of the optical device 203 along direction b, thereby enabling the optical device 203 to absorb more light energy. The optical device 203 and the slit waveguide 202 are overlapped, which also ensures the feasibility of the preparation.

[0064] See also Figure 9 In the optical component 200 provided by the embodiment, the slot waveguide 202 is longitudinally arranged in the first waveguide 201, and the optical device 203 is located inside the slot waveguide 202 and overlapped with the slot waveguide 202.

[0065] Figure 10 FIG. 2 is a schematic cross-sectional view of an optical component 200 in another embodiment.

[0066] See also Figure 10 In the optical component 200 provided by the embodiment, the first waveguide 201 may be a ridge waveguide, the slot waveguide 202 is longitudinally arranged in the first waveguide 201 , and the optical device 203 is arranged inside the slot waveguide 202 .

[0067] Figure 11 FIG. 4 is a top view of an optical component 300 in yet another embodiment.

[0068] See also Figure 11 In the embodiment, the optical device 303 is U-shaped and is located inside the slot waveguide 302. Optionally, two terminals of the optical device 303 extend out of the slot waveguide 302 for electrical connection with the outside. Figure 12 In the embodiment, the optical device 303 is located inside the slot waveguide 302, which can enhance the absorption efficiency of the optical device 303 for TM polarized light.

[0069] Figure 12 yes Figure 11 Schematic cross-sectional view of section AA′ of the optical component 300 in FIG.

[0070] See also Figure 12 In the optical device 300 provided in the embodiment, the slot waveguide 302 is laterally arranged in the first waveguide 301 , and the optical device 303 is located inside the slot waveguide 302 . Figure 12 The first waveguide 301 in the embodiment can be a planar waveguide or a ridge waveguide.

[0071] Figure 13FIG. 3 is a schematic structural diagram of an optical component 300 in yet another embodiment.

[0072] See also Figure 13 In the embodiment, Figure 13 In the embodiment of the optical component 300 , the first waveguide 301 may be a ridge waveguide, the slot waveguide 302 is located inside the narrower upper portion of the ridge waveguide, and the optical device 303 is located inside the slot waveguide 302 . Figure 13 In the embodiment, the thickness of the optical device 303 may be greater than 10 nanometers and the width may be less than 10 nanometers. Figure 13 The upper waveguide and the lower waveguide (the lower portion of the ridge waveguide) of the middle slot waveguide 302 may also be made of different materials. Figure 13 The slot waveguide 302 may also be located inside the lower portion of the ridge waveguide where the width is wider.

[0073] Figure 14 FIG. 3 is a schematic structural diagram of an optical component 300 in yet another embodiment.

[0074] See also Figure 14 An embodiment of Figure 14 The first waveguide 301 of the optical component 300 is a ridge waveguide, the slot waveguide 302 is located inside the lower portion of the ridge waveguide where the width is relatively wide, and the optical device 303 is located inside the slot waveguide 302 . Figure 14 The slot waveguide 302 is located outside the lower portion of the ridge waveguide. Figure 13 and Figure 14 When etching a ridge waveguide in the embodiment of the present invention, the etching may pass through the slot waveguide 302 or may not pass through the slot waveguide 302, thereby forming a ridge waveguide or a stripe waveguide.

[0075] This embodiment also provides an optical chip, which includes the optical component in any of the above embodiments.

[0076] The above description and accompanying drawings provide exemplary embodiments of specific structures of the specific embodiments. The above application provides existing preferred embodiments, but these contents are not intended to be limiting. Various changes and modifications will undoubtedly become apparent to those skilled in the art after reading the above description. Therefore, the appended claims should be construed as covering all changes and modifications within the true intent and scope of this application. Any and all equivalents within the scope of the claims should be considered to still be within the intent and scope of this application.

Claims

1. An optical component based on a slot waveguide, comprising: First Waveguide; a slot waveguide located inside the first waveguide; as well as an optical device located inside the slot waveguide; wherein the refractive index of the slot waveguide is lower than the refractive indexes of the first waveguide and the optical device; wherein the thickness of at least one end of the slot waveguide gradually decreases; wherein at least a portion of the optical device is located inside the at least one end of the slot waveguide; The distance between the at least a portion of the optical device and the bottom surface of the slot waveguide gradually decreases. 2 . The optical assembly according to claim 1 , wherein the optical device comprises a superconducting nanowire single photon detector (SNSPD).

3. The optical assembly of claim 1, wherein the slot waveguide comprises a silica waveguide.

4. The optical component of claim 1, wherein the first waveguide comprises at least one of a silicon nitride waveguide, a silicon dioxide waveguide, and a niobium nitride waveguide. 5 . The optical component according to claim 1 , wherein a surface shape of the optical device is the same as a cross-sectional shape of the slot waveguide, and at least a portion of the optical device and the slot waveguide are overlapped.

6. An optical chip comprising the optical component according to any one of claims 1 to 5.

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