Traveling wave electrode structure, electro-optic modulator, and quantum computer

Abstract

The present disclosure provides a kind of traveling wave electrode structure, electro-optic modulator and quantum computer, wherein the traveling wave electrode structure includes signal electrode and ground electrode.Signal electrode is provided with two, and each signal electrode is bent to form the folding structure of multiple layers, two signal electrodes are arranged along the first direction, and two signal electrodes are symmetrically arranged.Signal electrode is provided with layout space on both sides in extension direction.Ground electrode is provided with multiple, and multiple ground electrodes are arranged in layout space, and layout gap is left between adjacent signal electrode and ground electrode.By setting the extension of optical waveguide along two signal electrodes, the extension path of two optical waveguides also presents symmetrical state, avoids the problem that two side-by-side signal electrodes, optical waveguide exist bending section with different curvature, avoids the problem that different degrees of delay of photoelectric signal are caused due to different curvature, and the synchronism of signal transmission, modulation is improved.

Description

Technical Field

[0001] This disclosure relates to the technical field of electro-optic modulation, specifically to a traveling wave electrode structure, an electro-optic modulator, and a quantum computer. Background Technology

[0002] Thin-film lithium niobate electro-optic modulators are core devices in optical communication, optical sensing, and microwave photonics, and their performance directly affects the bandwidth, power consumption, and integration density of optical communication systems. Traditional lithium niobate modulators are typically based on bulk lithium niobate, which suffers from problems such as high driving voltage, large device size, and difficulty in compatibility with CMOS processes. With the development of thin-film lithium niobate technology, thin-film lithium niobate electro-optic modulators have gradually become a research hotspot due to their superior optical field confinement capabilities and higher electro-optic coefficients.

[0003] To achieve a lower half-wave voltage, traditional thin-film lithium niobate electro-optic modulators often require increasing the modulation length (i.e., the interaction length between the electrode and the optical waveguide) to enhance the electro-optic effect, typically employing a folded modulation region design. For the GSGSG electrode structure, folding the electrode results in the signal line needing to pass through two bends, one large and one small. These bends create photoelectric delay, affecting the synchronization of signal modulation and causing optical loss. Summary of the Invention

[0004] In view of this, the present disclosure aims to provide a traveling wave electrode structure, an electro-optic modulator, and a quantum computer to solve the problems of asynchronous signal modulation and large optical loss caused by photoelectric delay introduced by folding the electrodes.

[0005] In a first aspect, this disclosure provides a traveling wave electrode structure, including signal electrodes and ground electrodes. Two signal electrodes are provided, each bent to form a multi-layered folded structure. The two signal electrodes are arranged symmetrically along a first direction. Arrangement spaces are provided on both sides of the signal electrodes in the extending direction. Multiple ground electrodes are provided, arranged within the arrangement spaces, with arrangement gaps between them and adjacent signal electrodes.

[0006] In the above technical solution, by setting the optical waveguide to extend along the two signal electrodes, and the extension paths of the two optical waveguides are also symmetrical, the problem of two side-by-side signal electrodes and optical waveguides having bends with different curvatures is avoided, and the problem of different degrees of delay in photoelectric signals caused by different curvatures is avoided, thereby improving the synchronization of signal transmission and modulation.

[0007] In one specific implementation, the two signal electrodes are planar symmetrical about a first plane. The first plane is perpendicular to a first direction.

[0008] In one specific implementation, the signal electrode includes a first straight segment, a second straight segment, a third straight segment, a first bent segment, and a second bent segment. The first, second, and third straight segments are arranged sequentially at intervals along a first direction and are parallel to each other. The first and second straight segments are connected by the first bent segment, and the second and third straight segments are connected by the second bent segment. A first space is formed between the first and second straight segments. A second space is formed between the second and third straight segments. The openings of the first spaces formed by the two signal electrodes face the same direction, and the openings of the second spaces formed by the two signal electrodes also face the same direction.

[0009] In one specific implementation, the grounding electrode includes two first grounding electrodes and two second grounding electrodes. A portion of the first grounding electrode is located within a first space, and another portion extends along a second bent section and a third straight section on the side opposite to the second space. A portion of the second grounding electrode is located within the second space, and another portion extends along a first bent section and a first straight section on the side opposite to the first space.

[0010] In one specific implementation, the width of the portion of the first grounding electrode located within the first space is D1, and the width of the portion located outside the first space is D2. D1 and D2 satisfy: D1 > D2.

[0011] In one specific implementation, the portion of the two second ground electrodes located between the two signal electrodes is a shared segment, and the two second ground electrodes form an integral structure through the shared segment.

[0012] In one specific implementation, the traveling-wave electrode structure further includes two optical waveguides, each corresponding to one of the two signal electrodes. The optical waveguides are located between the first, second, and third straight sections and a ground electrode on the side facing away from the middle region of the two signal electrodes. Alternatively, the optical waveguides are located between the first, second, and third straight sections and a ground electrode on the side facing the middle region of the two signal electrodes.

[0013] In one specific implementation, the vertical projections of the two signal electrodes on the second plane are centrally symmetrical about the set point.

[0014] In one specific implementation, the signal electrode includes a first straight segment, a second straight segment, a third straight segment, a first bent segment, and a second bent segment. The first, second, and third straight segments are arranged sequentially at intervals along a first direction and are parallel to each other. The first and second straight segments are connected by the first bent segment, and the second and third straight segments are connected by the second bent segment. A first space is formed between the first and second straight segments, and a second space is formed between the second and third straight segments. The openings of the first spaces formed by the two signal electrodes face opposite directions, and the openings of the second spaces formed by the two signal electrodes also face opposite directions.

[0015] In a second aspect, this disclosure provides an electro-optic modulator including a traveling-wave electrode structure as described in any of the preceding claims.

[0016] Thirdly, this disclosure provides an optical quantum computer, including a single-photon source, an optical quantum chip, and a single-photon detector. The optical quantum chip includes an electro-optic modulator as described above. The single-photon source is used to generate single photons. The optical quantum chip is used to control the single photons. The single-photon detector is used to measure the single photons and output the calculation results. Attached Figure Description

[0017] Figure 1 The diagram shown is a schematic diagram of the structure of a traveling wave electrode provided in an embodiment of this disclosure.

[0018] Figure 2 The diagram shows a first space and a second space of a traveling wave electrode provided in an embodiment of this disclosure.

[0019] Figure 3 The diagram shown is a schematic diagram of the interaction between an optical waveguide, a signal electrode, and a ground electrode provided in an embodiment of this disclosure.

[0020] Figure 4 The diagram shown is a schematic diagram of the structure of a traveling wave electrode provided in another embodiment of this disclosure.

[0021] The attached figures are labeled as follows:

[0022] 1. Signal electrode; 11. First straight section; 12. Second straight section; 13. Third straight section; 14. First bent section; 15. Second bent section; 101. First space; 102. Second space;

[0023] 2. Grounding electrode; 21. First grounding electrode; 22. Second grounding electrode; 23. Common segment;

[0024] 3. Optical waveguide. Detailed Implementation

[0025] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure are within the scope of protection of this disclosure.

[0026] To facilitate understanding of the traveling-wave electrode structure provided in the embodiments of this disclosure, a brief description of the relevant content is provided first. Thin-film lithium niobate electro-optic modulators are core devices in fields such as optical communication, optical sensing, and microwave photonics, and their performance directly affects the bandwidth, power consumption, and integration density of optical communication systems. Traditional lithium niobate modulators are typically based on bulk lithium niobate, which suffers from problems such as high driving voltage, large device size, and difficulty in compatibility with CMOS processes. With the development of thin-film lithium niobate technology, thin-film lithium niobate electro-optic modulators have gradually become a research hotspot due to their superior optical field confinement capabilities and higher electro-optic coefficients.

[0027] To achieve a lower half-wave voltage, traditional thin-film lithium niobate electro-optic modulators often require increasing the modulation length (i.e., the interaction length between the electrode and the optical waveguide) to enhance the electro-optic effect, typically employing a folded modulation region design. For the GSGSG electrode structure, folding the electrode results in the signal line needing to pass through two bends, one large and one small. These bends create photoelectric delay, affecting the synchronization of signal modulation and causing optical loss.

[0028] To overcome the above problems, this disclosure provides a traveling wave electrode structure. By improving the layout of the signal electrodes, it avoids the phenomenon of inconsistent travel caused by different sizes of bending structures in the signal lines, reduces photoelectric delay and optical loss, and improves the synchronization of signal modulation. The following detailed description is provided in conjunction with specific accompanying drawings and embodiments.

[0029] refer to Figure 1 The main components of the traveling wave electrode structure provided in this embodiment are shown. The traveling wave electrode structure includes a signal electrode 1 and a ground electrode 2. There are two signal electrodes 1, namely S+ electrode and S- electrode; there are multiple ground electrodes 2, which together with the signal electrodes 1 form a GGSSG electrode structure.

[0030] In this embodiment, the signal electrode 1 is formed into a multi-layered folded structure by bending. In this embodiment, a three-layered folded structure is used as an example. In other embodiments, the signal electrode 1 can also be configured to form a folded structure with different numbers of layers, such as two, four, or five layers.

[0031] Two signal electrodes 1 are arranged along a first direction and are symmetrically positioned. The signal electrodes 1 have placement spaces on both sides of their extension direction. Multiple ground electrodes 2 are placed within these placement spaces, with gaps between the ground electrodes 2 and adjacent signal electrodes 1. These gaps are used for laying optical waveguides. In other words, multiple ground electrodes 2 are arranged along the extension direction of the signal electrodes 1, on both sides of the signal electrodes 1, and are positioned in the same extension direction as the signal electrodes 1.

[0032] In the embodiments of this disclosure, two signal electrodes 1 are symmetrically arranged, and the signal electrodes 1 are folded stacked structures. Since they are symmetrical structures, although their extension and bending directions differ, the two signal electrodes 1 have the same extension trend. Correspondingly, the arrangement space on both sides of the signal electrodes 1, the width of the arrangement gap, and the extension trend can all remain the same. The optical waveguides are respectively arranged in the arrangement gaps corresponding to the two signal electrodes 1, ensuring that the optical waveguides extend in the same direction.

[0033] In the prior art, two signal electrodes 1 are arranged side by side and bent in the same direction to form a stacked structure. This will cause the two signal electrodes 1 to have bends of different sizes at the bends. Taking the bend of the signal electrode 1 as an example, the two signal electrodes 1 will have bends of different radii at the bends. The optical waveguide will also have bends of different curvatures at the bends. Different curvatures will cause different degrees of delay in the optical signal. The higher the curvature, that is, the tighter the bend, the more the photoelectric delay time will increase significantly. The lower the curvature, the gentler the bend, and the smaller the photoelectric delay compared to the high curvature part.

[0034] In this embodiment, an optical waveguide is provided to extend along two signal electrodes 1, and the extension paths of the two optical waveguides are also symmetrical. This avoids the problem of two side-by-side signal electrodes 1 and optical waveguides having bends with different curvatures, thus avoiding different degrees of delay in photoelectric signals due to different curvatures and improving the synchronization of signal transmission and modulation.

[0035] In this embodiment of the disclosure, the two signal electrodes 1 are the S+ signal electrode and the S- signal electrode, respectively. For ease of explanation, they are referred to as signal electrode 1 only in this embodiment of the disclosure.

[0036] Furthermore, in actual design, the symmetrical layout of the two signal electrodes 1 can be adjusted according to actual needs. For example, the two signal electrodes 1 can be set to be symmetrical about a specific plane or to be centrally symmetrical about a point.

[0037] For example, the two signal electrodes 1 are planar symmetrical about a first plane, wherein the first plane is perpendicular to a first direction.

[0038] refer to Figure 1 and Figure 2 The signal electrode 1 includes a first straight segment 11, a second straight segment 12, a third straight segment 13, a first bent segment 14, and a second bent segment 15. The first straight segment 11, the second straight segment 12, and the third straight segment 13 are arranged at intervals along a first direction and are parallel to each other. The first straight segment 11 and the second straight segment 12 are connected by the first bent segment 14, and the second straight segment 12 and the third straight segment 13 are connected by the second bent segment 15, so that the signal electrode 1 forms an integral structure consisting of the first straight segment 11, the first bent segment 14, the second straight segment 12, the second bent segment 15, and the third straight segment 13 in sequence.

[0039] exist Figure 1 In the diagram, for a signal electrode 1 located on the upper side, the first straight segment 11, the second straight segment 12, and the third straight segment 13 are arranged sequentially from bottom to top; for a signal electrode 1 located on the lower side, the first straight segment 11, the second straight segment 12, and the third straight segment 13 are arranged sequentially from top to bottom. Therefore, the first direction is... Figure 1 The up and down directions are shown in the diagram.

[0040] The first plane is perpendicular to the first direction and located between the two signal electrodes 1, such that the two signal electrodes 1 form a face-symmetrical structure about the first plane. It should be understood that the first plane is not a plane predetermined in space, but rather the plane of symmetry between the two signal electrodes 1, where they form a face-symmetrical structure. For example, the first plane is... Figure 1 AA in the middle.

[0041] A first space 101 is formed between the first straight segment 11 and the second straight segment 12, and a second space 102 is formed between the second straight segment 12 and the third straight segment 13. A first bent segment 14 blocks one end of the opening of the first space 101, and a second bent segment 15 blocks one end of the opening of the second space 102, so that the openings of the first space 101 and the second space 102 are opposite.

[0042] Accordingly, with the two signal electrodes 1 symmetrical about the first plane, the openings of the first space 101 formed by the two signal electrodes 1 face the same direction, and the openings of the second openings 102 formed by the two signal electrodes 1 also face the same direction. Thus, in practical use, the deployed optical waveguide enters from the starting end of the two signal electrodes 1, that is, at the end where the opening of the first space 101 formed by the two signal electrodes 1 is located. In this embodiment, the openings of the two first spaces 101 are located at the same end, which facilitates the connection between the optical waveguide and the input signal during actual deployment. Correspondingly, it also facilitates the concentrated output of the modulated signal, shortens the wiring path, and simplifies the overall structure.

[0043] The grounding electrode 2 is provided in two sets, which are respectively set to correspond to the two signal electrodes 1. Each set of grounding electrodes 2 includes a first grounding electrode 21 and a second grounding electrode 22.

[0044] A portion of the first ground electrode 21 is located within the first space 101, with one end facing the opening of the first space 101 extending along the second bent end 15 and the third straight section 13 on the side away from the second space 102. A portion of the second ground electrode 22 is located within the second space 102, with one end facing the opening of the second space 102 extending along the first bent end 14 and the first straight section 11 on the side away from the first space 101. Thus, the first ground electrode 21 and the second ground electrode 22 form a sandwich, within which the signal electrode 1 is located, and a gap for laying optical waveguides is formed between the signal electrode 1 and the first and second ground electrodes 21.

[0045] With the above arrangement, each of the two second ground electrodes 22 has a portion located between the two signal electrodes 1. The portion of the two second ground electrodes 22 located between the two signal electrodes 1 is a common segment 23, so that the two second ground electrodes 22 form an integral structure through the common segment 23.

[0046] The shared segment 23 enables the two second grounding electrodes 22 to form an integrated structure, improving the overall compactness of the traveling wave electrode. The shared segment 23 and the first straight segment 11 of the two signal electrodes 1 are simultaneously arranged with a gap, saving the material used for the grounding electrodes 2.

[0047] For example, the width of the above-mentioned layout gap is H, and the cross-sectional size of the laid optical waveguide is h, where H and h satisfy: 1.2≤H / h≤2.

[0048] Limiting H / h to no less than 1.2 avoids excessive concentration of electric field at the electrode edge due to excessively small spacing, uneven distribution of field strength in the waveguide core area, and some areas being in electric field blind zones, thus improving electric field uniformity. In addition, it can also reduce the problem of electrode short circuits and leakage caused by etching deviations due to excessively small electrode spacing.

[0049] Furthermore, limiting the H / h value to no more than 2 avoids the problem of reduced electric field concentration in the waveguide core region due to excessively large gaps, thus increasing the concentration of the electric field in the waveguide core region. Limiting the gap size also increases the effective refractive index and reduces electrode resistance. In addition, it avoids the problem of reduced space utilization caused by excessively large electrode gaps, thereby improving the space utilization of this traveling wave electrode structure.

[0050] Further, refer to Figure 1 and Figure 2The width of the portion of the first grounding electrode 21 located within the first space 101 is D1, and the width of the portion located outside the first space 101 is D2. D1 and D2 satisfy: D1 > D2.

[0051] The width of the first grounding electrode 21 between the first straight section 11 and the second straight section 12 is larger. Both sides of this portion of the first grounding electrode 21 have layout gaps. In some practical designs, optical waveguides can be placed in both layout gaps on both sides of this portion of the first grounding electrode 21 as needed. In this case, the two optical waveguides share a section of the first grounding electrode 2. In this embodiment, the width of this portion of the first grounding electrode 21 is larger, which can accommodate a greater number of optical waveguides.

[0052] Furthermore, the width of the first grounding electrode 21 located within the first space 101 needs to be set according to the interval between the first straight section 11 and the second straight section 12, so that there is enough space for the first grounding electrode 21 to be laid out between it and the first straight section 11 and the second straight section 12. The width of the first grounding electrode 21 outside the first space 101 can be determined according to design requirements.

[0053] Correspondingly, the width of the portion of the second grounding electrode 22 located within the second space 102 is also greater than the width of the portion outside the second space 102.

[0054] Furthermore, in one embodiment, reference is made to Figure 2 The opening of the first space 101 faces left. In another embodiment, the opening of the first space 101 may also face right.

[0055] refer to Figure 3 The traveling wave electrode structure also includes an optical waveguide 3, of which two optical waveguides 3 are provided, each corresponding to one of the two signal electrodes 1. For example, the optical waveguide 3 is located in the gap between the first straight section 11, the second straight section 12, the third straight section 13 and the ground electrode 2 on the side facing away from the middle region of the two signal electrodes 1, i.e., in the gap between the ground electrode 2 on the side facing away from the first plane, ensuring that the optical signal within the optical waveguide 3 is consistently subjected to the same direction of the electric field in its extension direction.

[0056] In another embodiment, the optical waveguide 3 can also be positioned in the layout gap between the first straight section 11, the second straight section 12, the third straight section 13 and the ground electrode 2 facing the middle region of the two signal electrodes 1.

[0057] In other embodiments, the wiring method of the optical waveguide 3 in the traveling wave electrode structure can be adjusted according to actual needs. The specific design can be carried out based on the common knowledge of those skilled in the art, and will not be described in detail in the embodiments disclosed herein.

[0058] refer to Figure 4 In another embodiment, the two signal electrodes 1 are centrally symmetrical about a set point. Similarly, the signal electrode 1 includes a first straight segment 11, a second straight segment 12, a third straight segment 13, a first bent segment 14, and a second bent segment 15.

[0059] The designated point is the center point of the shared segment 23, such as... Figure 4 Point O in the diagram. It should be understood that in this embodiment, the two signal electrodes 1 are centrally symmetrical about a set point. It is not that a point is selected in space and then the signal electrodes 1 are arranged around that point. Rather, after the signal electrodes 1 are arranged, they are centrally symmetrical about a point, which is the aforementioned set point.

[0060] The first straight segment 11, the second straight segment 12, and the third straight segment 13 are arranged at intervals along the first direction and are parallel to each other. The first straight segment 11 and the second straight segment 12 are connected by the first bent segment 14, and the second straight segment 12 and the third straight segment 13 are connected by the second bent segment 15, so that the signal electrode 1 forms an integral structure consisting of the first straight segment 11, the first bent segment 14, the second straight segment 12, the second bent segment 15, and the third straight segment 13 in sequence.

[0061] A first space 101 is formed between the first straight segment 11 and the second straight segment 12, and a second space 102 is formed between the second straight segment 12 and the third straight segment 13. A first bent segment 14 blocks one end of the opening of the first space 101, and a second bent segment 15 blocks one end of the opening of the second space 102, so that the openings of the first space 101 and the second space 102 are opposite.

[0062] Accordingly, when the two signal electrodes 1 are centrally symmetrical about the set point, the openings of the first space 101 formed by the two signal electrodes 1 are oriented in opposite directions, and the openings of the second opening 102 formed by the two signal electrodes 1 are also oriented in opposite directions.

[0063] Thus, in practical use, the entry points of the two optical waveguides 3 into the gap between the signal electrode 1 and the ground electrode 2 are located on opposite sides of the traveling wave electrode structure. Compared to the case where the two optical waveguides 3 enter the gap from the same side of the traveling wave electrode structure, this facilitates selection based on different input optical signals during practical use, allowing the traveling wave electrode structure of this embodiment to adapt to various different input optical signal conditions.

[0064] This disclosure also provides an electro-optic modulator, including the traveling wave electrode structure described above.

[0065] In addition, this disclosure also provides an optical quantum computer, including a single-photon source, an optical quantum chip, and a single-photon detector. The optical quantum chip includes the aforementioned electro-optic modulator. The single-photon source is used to generate single photons, the optical quantum chip is used to control the single photons, and the single-photon detector is used to measure the single photons and output the calculation results.

[0066] In practical applications, the electro-optic modulator provided in this application can be implemented based on basic materials such as lithium niobate and integrated into an optical quantum computer. An optical quantum computer is a quantum computing device that uses photons (light particles) as qubits for information processing. An optical quantum computer mainly includes a single-photon source, an optical quantum chip, and a detection system. The single-photon source generates high-quality single photons as qubit carriers by exciting quantum dots with lasers or by spontaneous parametric down-conversion (SPDC). The optical quantum processor consists of optical components such as optical fibers, waveguides, beam splitters, phase modulators, and mirrors to achieve optical transmission and logical operations (such as Hadamard gates and CNOT gates). The detection system can measure the final state of the photons (such as polarization or path) and output the calculation results. For details on the specific processing procedures of an optical quantum computer, please refer to the specific descriptions of related technologies; they will not be elaborated upon here.

[0067] The above description is merely a preferred embodiment of this disclosure and is not intended to limit this disclosure. Any modifications or equivalent substitutions made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A traveling wave electrode structure, characterized in that, Includes signal electrodes and ground electrodes; The signal electrode is provided in two parts, each of which is bent to form a multi-layered folded structure. The two signal electrodes are arranged along a first direction and are symmetrically arranged about a first plane, which is perpendicular to the first direction. The signal electrodes have arrangement spaces on both sides in the extension direction; Multiple grounding electrodes are provided, and the multiple grounding electrodes are arranged in the layout space, with a layout gap left between them and the adjacent signal electrodes. The signal electrode includes a first straight segment, a second straight segment, and a third straight segment arranged at intervals along the first direction; The signal electrode further includes a first bent section and a second bent section, the first straight section and the second straight section are connected through the first bent section, and the second straight section and the third straight section are connected through the second bent section; A first space is formed between the first straight segment and the second straight segment; A second space is formed between the second straight segment and the third straight segment; The openings of the first space formed by the two signal electrodes face the same direction, and the openings of the second space formed by the two signal electrodes face the same direction. The grounding electrode includes two first grounding electrodes and two second grounding electrodes; A portion of the first grounding electrode is located within the first space, and another portion extends along the second bent section and the third straight section on the side away from the second space. A portion of the second grounding electrode is located within the second space, and another portion extends along the side of the first bent section and the first straight section away from the first space.

2. The traveling wave electrode structure according to claim 1, characterized in that, The width of the portion of the first grounding electrode located within the first space is D1, and the width of the portion located outside the first space is D2. The condition D1 and D2 satisfy: D1 > D2.

3. The traveling wave electrode structure according to claim 1, characterized in that, The portion of the two second ground electrodes located between the two signal electrodes is a shared segment, and the two second ground electrodes form an integral structure through the shared segment.

4. The traveling wave electrode structure according to claim 1, characterized in that, The traveling wave electrode structure also includes an optical waveguide, and two optical waveguides are provided, each corresponding to one of the two signal electrodes; The optical waveguide is located between the first straight section, the second straight section, the third straight section, and the ground electrode on the side facing away from the middle region of the two signal electrodes; or The optical waveguide is located between the first straight section, the second straight section, the third straight section, and the ground electrode facing the middle region of the two signal electrodes.

5. An electro-optic modulator, characterized in that, Including the traveling wave electrode structure as described in any one of claims 1-4.

6. An optical quantum computer, characterized in that, It includes a single-photon source, a quantum chip, and a single-photon detector. The quantum chip includes the electro-optic modulator as described in claim 5. The single-photon source is used to generate single photons. The quantum chip is used to control the single photons. The single-photon detector is used to measure the single photons and output the calculation results.

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