Electro-optic modulator and optical quantum computer

Abstract

The embodiment of the present disclosure provides an electro-optical modulator and an optical quantum computer. The electro-optical modulator comprises an electrode assembly and an optical waveguide assembly. The electrode assembly comprises a positive signal electrode, a negative signal electrode, a first ground electrode and a second ground electrode, and the positive signal electrode and the negative signal electrode are arranged between the first ground electrode and the second ground electrode. The optical waveguide assembly is configured to carry an optical signal, and comprises a first optical waveguide and a second optical waveguide. The first optical waveguide is located between the positive signal electrode and the negative signal electrode and is used to carry a first optical signal. The second optical waveguide is located between the first ground electrode and the positive signal electrode or between the second ground electrode and the negative signal electrode and is used to carry a second optical signal. The application of equal-amplitude voltage signals with opposite phases to the closely coupled positive signal electrode and the negative signal electrode helps to improve the modulation efficiency and reduce common-mode noise.

Description

Technical Field

[0001] This disclosure relates to the field of optical modulators, and in particular to an electro-optic modulator and an optical quantum computer. Background Technology

[0002] An optical modulator is a key optoelectronic device whose core function is to modulate electrical signals onto an optical carrier wave, thereby controlling characteristics such as amplitude, phase, and frequency. Depending on the modulation mechanism employed, optical modulators mainly include electro-optic modulators and acousto-optic modulators.

[0003] Electro-optic modulators utilize the electro-optic effect of crystals to modulate electrical signals onto optical carriers, enabling precise control over the intensity, phase, or frequency of light waves. This modulation technique allows for efficient information transmission in optical fibers, thus overcoming the bandwidth limitations of traditional electrical communications.

[0004] However, since common electro-optic modulators are driven by a single signal, their overall modulation efficiency is low. Moreover, in the case of multi-channel integration, the electrode spacing between adjacent modulation units is extremely small, which will generate significant capacitive and inductive coupling. Especially at high frequencies, the induced current caused by the external transmission line will be superimposed on the original signal line, resulting in a deterioration in signal transmission quality. Utility Model Content

[0005] In view of this, one embodiment of the present disclosure provides an electro-optic modulator and an optical quantum computer, which aims to solve the problems of low modulation efficiency and poor signal transmission quality when traditional electro-optic modulators are integrated with multiple channels.

[0006] On one hand, an embodiment of this disclosure provides an electro-optic modulator including an electrode assembly and an optical waveguide assembly. The electrode assembly includes a positive signal electrode, a negative signal electrode, a first ground electrode, and a second ground electrode, the positive and negative signal electrodes being disposed between the first and second ground electrodes. The optical waveguide assembly is configured to carry optical signals, including a first optical waveguide and a second optical waveguide. The first optical waveguide is located between the positive and negative signal electrodes and is used to carry a first optical signal. The second optical waveguide is located between the first ground electrode and the positive signal electrode, or between the second ground electrode and the negative signal electrode, and is used to carry a second optical signal.

[0007] As one possible implementation, the electro-optic modulator also includes a plurality of first protrusions and a plurality of second protrusions, with the plurality of first protrusions located on the positive signal electrode and the plurality of second protrusions located on the negative signal electrode, and the first protrusions and the second protrusions being periodically distributed.

[0008] As one possible implementation, multiple first protrusions and multiple second protrusions are arranged opposite to each other or back to back.

[0009] As one possible implementation, the electro-optic modulator also includes a plurality of first protrusions and a plurality of second protrusions, the plurality of first protrusions being located on a first ground electrode and the plurality of second protrusions being located on a second ground electrode, the first protrusions and the second protrusions being periodically distributed, and the plurality of first protrusions and the plurality of second protrusions being arranged opposite to each other.

[0010] As one possible implementation, multiple first protrusions and multiple second protrusions are symmetrically arranged.

[0011] As one possible implementation, multiple first protrusions and multiple second protrusions are arranged in an alternating manner.

[0012] As one possible implementation, the first protrusion and the second protrusion include a bent portion on the side away from the electrode and a connecting portion connecting the bent portion and the electrode. The width of the bent portion is less than 4 micrometers, the length of the bent portion is less than 300 micrometers, and the connecting portion is less than 20 micrometers.

[0013] As one possible implementation, each of the first and second protrusions is arranged in a similar T-shape or L-shape.

[0014] As one possible implementation, the electro-optic modulator also includes a third optical waveguide. The third optical waveguide assembly is located in the modulation region of the electro-optic modulator. When the second optical waveguide is located between the first ground electrode and the positive signal electrode, the third optical waveguide is located between the second ground electrode and the negative signal electrode. When the second optical waveguide is located between the second ground electrode and the negative signal electrode, the third optical waveguide is located between the first ground electrode and the positive signal electrode.

[0015] On the other hand, one embodiment of this disclosure provides an optical quantum computer, which includes a single-photon source, an optical quantum chip, and a single-photon detector. One or more of the single-photon source, the optical quantum chip, and the single-photon detector include the electro-optic modulator described above.

[0016] By dividing the signal electrodes into positive and negative signal electrodes, and respectively connecting them to a first and a second ground electrode, a differential driving structure is formed. In this way, the tightly coupled positive and negative signal electrodes are applied with voltages of equal amplitude and opposite values. Under the same driving voltage amplitude, the electric field strength inside the differential electrode pair is approximately twice that of the single-ended electrode pair. This means that when optical signals in different electric fields produce the same phase change, the optical signal between the positive and negative signal electrodes requires a smaller voltage, thus contributing to improved modulation efficiency.

[0017] Furthermore, since the external noise of the signal electrodes is typically common-mode noise, this symmetrical distribution of positive and negative signal electrodes filters out common-mode noise at the receiving end. Additionally, this symmetrical structure ensures that the electric fields generated by the positive and negative signal electrodes are in opposite directions away from them, and the currents on the positive and negative signal electrodes are also in opposite directions, helping to reduce capacitive and inductive coupling to external lines. In the differential traveling wave electrode structure, each signal electrode (positive or negative) is adjacent to the ground electrode, forming a local "signal-ground" unit. This symmetrical layout not only helps limit the lateral spread of the electromagnetic field but also reduces the coupling of electric and magnetic fields to adjacent channels. Moreover, because the positive and negative signal currents are in opposite directions, the generated electric and magnetic fields cancel each other out in the far-field region, further suppressing crosstalk between multiple channels. Compared to traditional single-ended transmission structures, differential structures are advantageous for improving multi-channel transmission quality and ensuring signal integrity. Attached Figure Description

[0018] It should be understood that the following figures only illustrate certain embodiments of this disclosure and should not be construed as limiting the scope.

[0019] It should be understood that the same or similar reference numerals are used in the accompanying drawings to denote the same or similar elements.

[0020] It should be understood that the accompanying drawings are only schematic, and the dimensions and scales of the elements in the drawings are not necessarily precise.

[0021] Figure 1 This is a schematic diagram of the structure of an electro-optic modulator provided in one embodiment of the present disclosure.

[0022] Figure 2 This is a schematic diagram of the structure of an electro-optic modulator provided in another embodiment of the present disclosure.

[0023] Figure 3 This is a schematic diagram of the structure of an electro-optic modulator provided in yet another embodiment of the present disclosure.

[0024] Figure 4 for Figure 3 A cross-sectional view of the modulation region of the electro-optic modulator.

[0025] Figure 5 This is a schematic diagram of the structure of an electro-optic modulator provided in yet another embodiment of the present disclosure.

[0026] Figure 6 for Figure 5 A cross-sectional view of the modulation region of the electro-optic modulator.

[0027] Figure 7 for Figure 5 A schematic diagram of the structure of a local area of ​​the electro-optic modulator.

[0028] Figure 8 This is a schematic diagram of the structure of an electro-optic modulator provided in yet another embodiment of the present disclosure.

[0029] Figure 9 This is a schematic diagram of the structure of an electro-optic modulator provided in yet another embodiment of the present disclosure.

[0030] Figure 10 This is a schematic diagram of the structure of an electro-optic modulator provided in yet another embodiment of the present disclosure.

[0031] Figure 11 This is a schematic diagram of the structure of an electro-optic modulator provided in yet another embodiment of the present disclosure.

[0032] Figure 12 This is a schematic diagram of the structure of an electro-optic modulator provided in yet another embodiment of the present disclosure.

[0033] Figure 13 A simulation comparison diagram showing the microwave refractive index of an electro-optic modulator provided in one embodiment of this disclosure and a common electro-optic modulator. Detailed Implementation

[0034] The embodiments of this disclosure are described below with reference to the accompanying drawings. It should be understood that there are various implementations of this disclosure, and it should not be construed as being limited to the embodiments set forth herein. The embodiments set forth herein are merely for a more thorough and clear understanding of this disclosure.

[0035] The emergence of electro-optic modulators (such as Mach-Zehnder interferometer structures) is a revolutionary breakthrough in the optical communication industry. It makes precise control of optical carriers by electrical signals a reality, which not only exponentially increases communication capacity, but also helps to achieve lossless transmission over ultra-long distances.

[0036] Commercial electro-optic modulators typically employ a GSG (Ground-Signal-Ground) structure, consisting of three electrodes: a ground electrode, a signal electrode, and another ground electrode. In this single-ended signal electrode structure, the two ground electrodes are positioned on either side of the signal electrode, forming a symmetrical shielding environment. However, this single-ended signal-driven method not only has low modulation efficiency but also generates a large current value per unit time, thus lacking strong suppression capabilities against potential electromagnetic interference such as ground bounce and track collapse, as well as potential fluctuations, resulting in relatively weak anti-interference capabilities. Furthermore, when other transmission lines are present near the single-ended signal-driven electrodes, i.e., in multi-channel integration, significant capacitive and inductive coupling may occur, especially at high frequencies. The induced current caused by external transmission lines can be superimposed on the original signal line, degrading signal transmission quality. Therefore, this disclosure provides an embodiment of an electro-optic modulator 100. Compared to traditional electro-optic modulators, the electro-optic modulator 100 provided in this disclosure can more effectively improve the modulation efficiency of the electro-optic modulator, and in the case of multi-channel integration, it reduces crosstalk between signals to improve the quality of signal retransmission, thereby potentially having better performance in terms of modulation efficiency and reliability.

[0037] To facilitate understanding, the overall structure of the electro-optic modulator 100 will be illustrated below with an example. It should be understood that the overall structure of the electro-optic modulator 100 is not limited to the description below. For example, one or more elements mentioned below may be omitted or replaced, and their layout relationships may be changed.

[0038] refer to Figure 1 and Figure 2 The electro-optic modulator 100 includes an electrode assembly 10 and an optical waveguide assembly 20. The electrode assembly 10 may include a first ground electrode 11, a second ground electrode 12, a positive signal electrode 13, and a negative signal electrode 14, with the positive signal electrode 13 and negative signal electrode 14 disposed between the first and second ground electrodes. In other words, compared to the common GSG structure, the signal electrode located in the middle is divided into a positive signal electrode and a negative signal electrode, forming a differential signal drive.

[0039] Continue to refer to Figure 1 and Figure 2The optical waveguide assembly 20 is configured to carry an optical signal S. The optical waveguide assembly 20 includes a first optical waveguide 24 (e.g., a lithium niobate waveguide) and a second optical waveguide 22 (e.g., a lithium niobate waveguide). The first optical waveguide 24 is located between the positive signal electrode 13 and the negative signal electrode 14, and is used to carry the first optical signal S1. The second optical waveguide 22 is located between the first ground electrode 11 and the positive signal electrode 13. Alternatively, the second optical waveguide 22 can be located between the second ground electrode 12 and the negative signal electrode 14, and is used to carry the second optical signal S2. The optical waveguide assembly 20 is used to guide the optical signal (e.g., a light wave) through a specific path (the optical waveguide). The refractive index n of the electro-optic material (e.g., lithium niobate LiNbO3, silicon, indium phosphide InP, etc.) in its modulation region (i.e., the optical mode field distribution region) varies with the external electric field. Due to the characteristics of lithium niobate material (e.g., electro-optic coefficient, refractive index, etc.), it has advantages such as ultra-low loss, ultra-high bandwidth, ultra-linearity, and high integration, and therefore has been widely used.

[0040] For ease of explanation, the optical waveguide component in this disclosure will be illustrated using lithium niobate (LiNbO3) as an example.

[0041] By dividing the signal electrodes into positive and negative signal electrodes, and respectively coordinating them with a first ground electrode and a second ground electrode, a differential driving structure is formed. In this way, the tightly coupled positive and negative signal electrodes are applied with voltages of equal amplitude and opposite values. Under the same driving voltage amplitude, the electric field strength inside the differential electrode pair is approximately twice that of the single-ended electrode pair. This means that when optical signals in different electric fields produce the same phase change, the optical signal between the positive and negative signal electrodes requires less voltage, increasing the phase change per unit voltage to approximately twice the value. The overall modulation efficiency of the electro-optic modulator is increased to approximately 1.5 times, thus contributing to improved modulation efficiency.

[0042] In differential drive structures, external electromagnetic interference often couples simultaneously to both positive and negative signal electrodes in common-mode form. Therefore, differential structures naturally suppress common-mode noise. Furthermore, this symmetrical structure ensures that the electric fields generated by the positive and negative signal electrodes are in opposite directions away from them, and the currents on the positive and negative signal electrodes also flow in opposite directions, helping to reduce capacitive and inductive coupling to external lines. In differential traveling-wave electrode structures, each signal electrode (positive or negative) is adjacent to a ground electrode, forming a local "signal-ground" unit. This symmetrical layout not only helps limit the lateral spread of the electromagnetic field but also reduces the coupling of electric and magnetic fields to adjacent channels. Moreover, because the positive and negative signal currents flow in opposite directions, the generated electric and magnetic fields cancel each other out in the far-field region, further suppressing crosstalk between multiple channels. Compared to traditional single-ended transmission structures, differential structures are advantageous for improving multi-channel transmission quality and ensuring signal integrity.

[0043] It's understandable that signal electrodes can also be divided into positive and negative signal electrodes with unequal amplitudes, and different driving voltages can be set accordingly. For example, when the ratio of the absolute value of the driving voltage of the positive signal electrode to the absolute value of the driving voltage of the negative signal electrode is equal to 2, the driving voltages of the positive and negative signal electrodes need to be adaptively adjusted, but compared to the GSG structure, this is beneficial for improving modulation efficiency. In some examples, the ratio of the absolute value of the driving voltage of the positive signal electrode to the absolute value of the driving voltage of the negative signal electrode is less than 5 and greater than or equal to 1. It's understandable that when the ratio = 1, compared to unequal amplitude driving voltages, this not only helps reduce power consumption but also further improves modulation efficiency.

[0044] It should be noted that the electro-optic modulator 100 may further include an input optical waveguide 62 and a beam splitter 42. The beam splitter 42 is located at one end outside the electrode assembly 10 and is used to split the input optical signal S0 in the input optical waveguide 62 into a first optical signal S1 and a second optical signal S2. The second optical waveguide 24 located in the modulation region carries the first optical signal S1, and the second optical waveguide 22 located in the modulation region carries the second optical signal S2. There are many types of beam splitters, such as those that split light according to power. For example, the splitting ratio of the beam splitter can be 1:1, where the input optical signal S0 is split into a second optical signal S2 with the same power as the first optical signal S1. Different splitting ratios can be selected according to actual working needs. For example, the beam splitter can be a Y-branch, an optical fiber beam splitter, etc., and no specific limitation is made here.

[0045] Combination Figure 2 The electro-optic modulator 100 may further include a plurality of first protrusions 32 (e.g., including but not limited to metallic materials such as gold, copper, aluminum, and copper-aluminum alloys) and a plurality of second protrusions 34 (e.g., including but not limited to metallic materials such as gold, copper, aluminum, and copper-aluminum alloys). The plurality of first protrusions 32 may be located on the positive signal electrode 13, and the plurality of second protrusions 34 may be located on the negative signal electrode 14. Both the plurality of first protrusions 32 and the plurality of second protrusions 34 are periodically distributed. Periodic distribution can be understood as the plurality of first protrusions 32 and the plurality of second protrusions 34 appearing repeatedly on the positive signal electrode 13 and the negative signal electrode 14, respectively.

[0046] The periodically distributed first and second protrusions help improve impedance matching and velocity matching, thereby increasing the electro-optic bandwidth of the electro-optic modulator. Simulations show (see reference) Figure 13The mutual configuration of the first protrusion, the second protrusion, the first optical waveguide located between the positive signal electrode and the negative signal electrode, and the second optical waveguide located between the positive signal electrode and the first ground electrode or between the negative signal electrode and the second ground electrode in this disclosure, and the fact that the refractive index of the optical waveguide group in this application is significantly less than that of the optical waveguide group in ordinary differential electro-optic modulation, helps to match the phase velocity of the light wave and the microwave, thereby helping to improve the electro-optic bandwidth.

[0047] As an example, see reference Figure 3 Multiple first protrusions 32 can be provided on the positive signal electrode 13, and multiple second protrusions 34 can be provided on the negative signal electrode 14. The multiple first protrusions 32 and multiple second protrusions 34 are arranged opposite to each other. A second optical waveguide 22 is located between the multiple first protrusions 32 and multiple second protrusions 34, and a first optical waveguide 24 can be located between the first ground electrode 11 and the positive signal electrode 13. Of course, the second optical waveguide 22 can also be located between the first ground electrode 11 and the positive signal electrode 13. The multiple first protrusions 32 and multiple second protrusions 34 are arranged adjacent to each other, and the multiple first protrusions 32 distributed on the positive signal electrode 13 and the multiple second protrusions 34 distributed on the negative signal electrode 14 are arranged symmetrically.

[0048] As another example, see Figure 8 Multiple first protrusions 32 can be provided on the positive signal electrode 13, and multiple second protrusions 34 can be provided on the negative signal electrode 14. The multiple first protrusions 32 and multiple second protrusions 34 are arranged opposite to each other. That is, the multiple first protrusions 32 are located on the side of the positive signal electrode 13 facing the first ground electrode 11, and the multiple second protrusions 34 are located on the side of the negative signal electrode 14 facing the second ground electrode 12. The first optical waveguide 24 is located between the positive signal electrode 13 and the negative signal electrode 14, and the second optical waveguide 22 is located between the first ground electrode 11 and the positive signal electrode 13. Of course, the second optical waveguide 22 can also be located between the second ground electrode 12 and the negative signal electrode 14. The multiple first protrusions 32 and multiple second protrusions 34 are arranged adjacent to each other, and the multiple first protrusions 32 distributed on the positive signal electrode 13 and the multiple second protrusions 34 distributed on the negative signal electrode 14 are arranged symmetrically.

[0049] In one example, reference Figure 5Multiple first protrusions 32 are located on the first ground electrode 11, and multiple second protrusions 34 are located on the second ground electrode 12. A first optical waveguide 24 is located between the positive signal electrode 13 and the negative signal electrode 14, and a second optical waveguide 22 is located between the first ground electrode 11 and the positive signal electrode 13. Alternatively, the second optical waveguide 22 can also be located between the second ground electrode 12 and the negative signal electrode 14. The multiple first protrusions 32 and the multiple second protrusions 34 are periodically distributed and are arranged opposite to each other.

[0050] refer to Figure 2 , Figure 3 , Figure 5 and Figure 8 Multiple first protrusions 32 and multiple second protrusions 34 are symmetrically arranged.

[0051] In one example, a plurality of first protrusions 32 may be provided on the positive signal electrode 13, and a plurality of second protrusions 34 may be provided on the negative signal electrode 14, with the plurality of first protrusions 32 and the plurality of second protrusions 34 arranged opposite to each other. Furthermore, the plurality of first protrusions 32 and the plurality of second protrusions 34 are arranged symmetrically. A first optical waveguide 24 may be located between the positive signal electrode and the negative signal electrode, and a second optical waveguide 22 may be located between the first ground electrode 11 and the positive signal electrode 13. Alternatively, the second optical waveguide 22 may also be located between the second ground electrode 12 and the negative signal electrode 14.

[0052] In another example, refer to Figure 3 and Figure 10 Multiple first protrusions 32 are located on the first ground electrode 11, and multiple second protrusions 34 are located on the second ground electrode 14, with the first protrusions 32 and the second protrusions 34 arranged opposite to each other. Furthermore, the multiple first protrusions 32 and the multiple second protrusions 34 are arranged symmetrically. A first optical waveguide 24 is located between the positive signal electrode 13 and the negative signal electrode 14, and a second optical waveguide 22 can be located between the first ground electrode 11 and the positive signal electrode 13. Alternatively, the second optical waveguide 22 can also be located between the second ground electrode 12 and the negative signal electrode 14.

[0053] refer to Figure 9 and Figure 12 Multiple first protrusions 32 and multiple second protrusions 34 are arranged alternately.

[0054] In one example, the positive signal electrode 13 has multiple first protrusions 32, and the negative signal electrode 14 has multiple second protrusions 34, which are arranged opposite to each other and interleaved. A first optical waveguide 24 is located between the positive signal electrode 13 and the negative signal electrode 14, and a second optical waveguide 22 can be located between the first ground electrode 11 and the positive signal electrode 13. Alternatively, the second optical waveguide 22 can also be located between the second ground electrode 12 and the negative signal electrode 14.

[0055] In another example, a plurality of first protrusions 32 are located on the first ground electrode 11, and a plurality of second protrusions 34 are located on the second ground electrode 12, with the first protrusions 32 and the second protrusions 34 arranged opposite to each other. Furthermore, the first protrusions 32 and the second protrusions 34 are arranged alternately. The first optical waveguide 24 can be located between the positive signal electrode 13 and the negative signal electrode 14, and the second optical waveguide 22 can be located between the first ground electrode 11 and the positive signal electrode 13. Alternatively, the second optical waveguide 22 can also be located between the second ground electrode 12 and the negative signal electrode 14.

[0056] refer to Figure 7 Each first protrusion 32 and each second protrusion 34 may include a bend 321 on the side away from the electrode and a connecting portion 323 connecting the bend 321 and the electrode. The width 'a' of the bend 321 is less than 4 micrometers (e.g., the width 'a' can be 1 micrometer, 1.5 micrometers, 2 micrometers, 2.5 micrometers, 3 micrometers, and 3.5 micrometers). Preferably, the width 'a' of the bend 321 is 1 micrometer, but it can also be slightly greater or slightly less than 1 micrometer. The length 'b' of the bend 321 can be greater than 10 micrometers and less than 300 micrometers (e.g., the length 'b' can be 40 micrometers, 50 micrometers, 60 micrometers, 70 micrometers, 80 micrometers, 90 micrometers, 100 micrometers, 200 micrometers, 250 micrometers, etc.). Preferably, the length 'b' of the bend 321 can be greater than 50 micrometers and less than or equal to 200 micrometers; for example, the length 'b' can be 65 micrometers, 75 micrometers, 85 micrometers, 95 micrometers, 105 micrometers, etc. The length c of the connecting portion 323 can be less than 20 micrometers (e.g., length c can be 1 micrometer, 4 micrometers, 5 micrometers, 7 micrometers, 10 micrometers, 12 micrometers, 18 micrometers, etc.). Preferably, the length c of the connecting portion 323 can be 2 micrometers or 3 micrometers. In another embodiment, the length c of the connecting portion 323 can be 15 micrometers. Different shaped protrusions correspond to different preferred values ​​of length c, which can be selected according to actual needs.

[0057] It is understandable that the shapes of the first protrusion 32 and the second protrusion 34 can be varied, such as T-shaped or L-shaped, as long as they can form a protruding shape that helps improve impedance matching and speed matching; no specific limitations are imposed. (Reference) Figures 2 to 9 Each of the plurality of first protrusions 32 and the plurality of second protrusions 34 is arranged in a similar T-shape.

[0058] In one example, reference Figure 3 and Figure 9 Multiple T-shaped electrodes 22 are disposed on the positive signal electrode 13, and multiple T-shaped electrodes 24 are disposed on the negative signal electrode 14. The multiple T-shaped electrodes 22 and 24 are arranged opposite to each other and symmetrically. The first optical waveguide 24 is located between the positive signal electrode 13 and the negative signal electrode 14, and the second optical waveguide 22 is located between the first ground electrode 11 and the positive signal electrode 13. Of course, the second optical waveguide 22 can also be located between the second ground electrode and the negative signal electrode.

[0059] In another example, refer to Figure 9 Multiple T-shaped electrodes 22 are disposed on the positive signal electrode 13, and multiple T-shaped electrodes 24 are disposed on the negative signal electrode 14. The multiple T-shaped electrodes 22 and 24 are arranged opposite to each other, and are staggered. The first optical waveguide 24 is located between the positive signal electrode 13 and the negative signal electrode 14, and the second optical waveguide 22 is located between the first ground electrode 11 and the positive signal electrode 13. Of course, the second optical waveguide 22 can also be located between the second ground electrode 12 and the negative signal electrode 14.

[0060] refer to Figures 10 to 12 Each of the plurality of first protrusions 32 and the plurality of second protrusions 34 is arranged in a similar L-shape.

[0061] In one example, reference Figure 10 Multiple L-shaped electrodes 32 are located on the first ground electrode 11, and multiple L-shaped electrodes 34 are located on the second ground electrode 12, with the L-shaped electrodes 32 and 34 arranged opposite to each other and symmetrically. A first optical waveguide 24 is located between the positive signal electrode 13 and the negative signal electrode 14, and a second optical waveguide 22 is located between the first ground electrode 13 and the positive signal electrode 14. Alternatively, the second optical waveguide 22 can also be located between the second ground electrode 12 and the negative signal electrode 14.

[0062] In another example, refer to Figure 11Multiple L-shaped electrodes 32 are disposed on the positive signal electrode 13, and multiple L-shaped electrodes 34 are disposed on the negative signal electrode 14. The multiple L-shaped electrodes 32 and 34 are arranged opposite to each other and symmetrically. The first optical waveguide 24 is located between the positive signal electrode 13 and the negative signal electrode 14, and the second optical waveguide 22 is located between the first ground electrode 11 and the positive signal electrode 13. Of course, the second optical waveguide 22 can also be located between the second ground electrode 12 and the negative signal electrode 14.

[0063] In another example, refer to Figure 12 Multiple L-shaped electrodes 32 are disposed on the positive signal electrode 13, and multiple L-shaped electrodes 34 are disposed on the negative signal electrode 14. The multiple L-shaped electrodes 32 and 34 are arranged opposite to each other, and are staggered. The first optical waveguide 24 is located between the positive signal electrode 13 and the negative signal electrode 14, and the second optical waveguide 22 is located between the first ground electrode 11 and the positive signal electrode 13. Of course, the second optical waveguide 22 can also be located between the second ground electrode 12 and the negative signal electrode 14.

[0064] The T-shaped and L-shaped structures not only help reduce the manufacturing difficulty and cost of electro-optic modulators, but also help achieve speed matching and impedance matching, thereby helping to improve the electro-optic bandwidth of electro-optic modulators.

[0065] refer to Figures 3 to 12 The electro-optic modulator 100 may further include a third optical waveguide 26 (e.g., a lithium niobate optical waveguide), the third optical waveguide assembly being located in the modulation region of the electro-optic modulator. When the second optical waveguide 22 is located between the first ground electrode 11 and the positive signal electrode 13, the third optical waveguide 26 is located between the second ground electrode 12 and the negative signal electrode 14; when the second optical waveguide 26 is located between the second ground electrode 12 and the negative signal electrode 14, the third optical waveguide 26 is located between the first ground electrode 11 and the positive signal electrode 13.

[0066] It should be noted that the third optical waveguide is not used for transmitting optical signals. Three electric fields are formed between the positive signal electrode 13, the negative signal electrode 14, the first ground electrode 11, and the second ground electrode 12 in the electro-optic modulator 100: between the positive signal electrode 13 and the negative signal electrode 14, between the positive signal electrode 13 and the first ground electrode 11, and between the negative signal electrode 14 and the second ground electrode 12. The first optical waveguide 24 is located between the positive and negative signal electrodes. The second optical waveguide 22 and the third optical waveguide 26 can be located either between the positive signal electrode 13 and the first ground electrode 11, or between the negative signal electrode 14 and the second ground electrode 12, respectively. Alternatively, they can be located between the positive signal electrode 13 and the first ground electrode 11, or between the negative signal electrode 14 and the second ground electrode 12, respectively. Thus, the three electric fields in the electro-optic modulator 100 are distributed with different optical waveguides. This design facilitates further improvement in impedance matching and speed matching, maintaining consistency with the modulation region, thereby contributing to further increases in electro-optic bandwidth.

[0067] It should also be noted that the third optical waveguide 26 is symmetrically arranged with the second optical waveguide 22. The third optical waveguide 26 is located in the modulation region. For example, within the modulation region, the length of the third optical waveguide 26 is greater than or equal to that of the second optical waveguide 22. Specifically, the length of the third optical waveguide 26 is greater than or equal to 95% of the length of the second optical waveguide, in order to achieve a symmetrical distribution between the third optical waveguide 26 and the second optical waveguide 22, thereby improving modulation efficiency. Furthermore, the width of the third optical waveguide 26 is less than 10 micrometers, for example, 9 micrometers, 8 micrometers, 7 micrometers, 6 micrometers, 5 micrometers, 4 micrometers, etc., preferably 5 micrometers.

[0068] refer to Figure 2 The electro-optic modulator 100 may further include a combiner 44 and an output optical waveguide 64. The combiner 44 may be located outside the electrode assembly 10. The first optical signal S1 and the second optical signal S2, after being modulated, result in a third optical signal S3 and a fourth optical signal S4, which are then combined by the combiner 44 to form an output optical signal S5. The output optical waveguide 64 is used to carry the output optical signal S5. There are many types of combiners, such as waveguide combiners and fiber optic couplers, etc., and no specific type is limited.

[0069] Continue to refer to Figure 5 The electro-optic modulator 100 may further include a thermally adjustable electrode 51, located between the electrode assembly 10 and the beam combiner 44. The thermally adjustable electrode 51 is used to adjust the bias operating point of the electro-optic modulator 100 during operation, so that the output optical signal after passing through the beam combiner 44 has a specific phase difference. Of course, the thermally adjustable electrode 51 can... Figures 3 to 12 The first optical waveguide 24 or the second optical waveguide 22 on any of the electro-optic modulators.

[0070] It is worth noting that, for reference Figure 4 and Figure 6 Below the optical waveguide component 20, an oxide layer 70 (e.g., including but not limited to silicon dioxide and silicon nitride) and a substrate 80 (e.g., including but not limited to silicon and quartz) are stacked in sequence.

[0071] One embodiment of this disclosure also provides an optical device including an electro-optic modulator 100 and a driver, the driver being electrically connected to the electro-optic modulator and configured to apply a modulation voltage to the electro-optic modulator. The electro-optic modulator 100 includes the electro-optic modulator provided in any embodiment of this disclosure.

[0072] In differential drive structures, external electromagnetic interference often couples simultaneously to both positive and negative signal electrodes in common-mode form. Therefore, differential structures naturally suppress common-mode noise. Furthermore, this symmetrical structure ensures that the electric fields generated by the positive and negative signal electrodes are in opposite directions away from them, and the currents on the positive and negative signal electrodes also flow in opposite directions, helping to reduce capacitive and inductive coupling to external lines. In differential traveling-wave electrode structures, each signal electrode (positive or negative) is adjacent to a ground electrode, forming a local "signal-ground" unit. This symmetrical layout not only helps limit the lateral spread of the electromagnetic field but also reduces the coupling of electric and magnetic fields to adjacent channels. Moreover, because the positive and negative signal currents flow in opposite directions, the generated electric and magnetic fields cancel each other out in the far-field region, further suppressing crosstalk between multiple channels. Compared to traditional single-ended transmission structures, differential structures are advantageous for improving multi-channel transmission quality and ensuring signal integrity.

[0073] In practical applications, the electro-optic modulator provided in this application can be implemented based on basic materials such as lithium niobate (LiNbO3) 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.

[0074] A quantum computer primarily consists of a single-photon source, a quantum chip, and a detection system. The single-photon source generates high-quality single photons, which serve as the carriers of qubits, through laser excitation of quantum dots or spontaneous parametric down-conversion (SPDC). The quantum processor is composed of optical components such as optical fibers, waveguides, beam splitters, phase modulators, and mirrors to achieve optical transmission and logical operations (e.g., Hadamard gates, CNOT gates). The detection system measures the final state of the photons (e.g., polarization or path) and outputs the calculation results. For detailed descriptions of the specific processing procedures of a quantum computer, please refer to the relevant technical descriptions; they will not be elaborated upon here.

[0075] In practical applications, the electro-optic modulator provided in this application can be used in various components of the aforementioned optical quantum computer. That is, one or more of the single-photon source, optical quantum chip, and single-photon detector in the optical quantum computer include the electro-optic modulator provided in this application.

[0076] For example, single-photon sources can use electro-optic modulators when active modulation of quantum states is required. Electro-optic modulators play the role of quantum state programming engines in optical quantum chips, dynamically manipulating optical quantum states through high-speed electro-optic effects to realize core functions of quantum computing, communication, and sensing.

[0077] Therefore, the aforementioned electro-optic modulators or optical quantum computers are also within the scope of protection of this application.

[0078] It is understood that in this disclosure, directional descriptions such as "upper," "lower," "inner," and "outer" are relative rather than absolute. These directional terms may apply when the electro-optic modulator provided in this disclosure is positioned according to the orientation and location shown in the accompanying drawings.

[0079] It should be understood that although terms such as "first" or "second" may be used in this disclosure to describe various elements (such as a first optical waveguide and a second optical waveguide), these elements are not defined by these terms, which are only used to distinguish one element from another.

[0080] The basic principles of this disclosure have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this disclosure are merely examples and not limitations, and should not be considered as essential features of each embodiment of this disclosure. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the scope of this disclosure to the necessity of employing the aforementioned specific details for implementation.

[0081] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this disclosure to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations therein.

[0082] The components and devices described in this disclosure are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the accompanying drawings. As those skilled in the art will recognize, these components and devices can be connected, arranged, and configured in any manner.

[0083] The above are merely specific embodiments of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. An electro-optic modulator, characterized in that, include: An electrode assembly includes a positive signal electrode, a negative signal electrode, a first ground electrode, and a second ground electrode, wherein the positive signal electrode and the negative signal electrode are disposed between the first ground electrode and the second ground electrode; An optical waveguide assembly is configured to carry an optical signal. The optical waveguide assembly includes a first optical waveguide and a second optical waveguide. The first optical waveguide is located between the positive signal electrode and the negative signal electrode and is used to carry a first optical signal. The second optical waveguide is located between the first ground electrode and the positive signal electrode or between the second ground electrode and the negative signal electrode and is used to carry a second optical signal.

2. The electro-optic modulator according to claim 1, characterized in that, The electro-optic modulator also includes a plurality of first protrusions and a plurality of second protrusions, the plurality of first protrusions being located on the positive signal electrode and the plurality of second protrusions being located on the negative signal electrode, and the first protrusions and the second protrusions being periodically distributed.

3. The electro-optic modulator according to claim 2, characterized in that, The plurality of first protrusions and the plurality of second protrusions are arranged opposite to each other or back to back.

4. The electro-optic modulator according to claim 1, characterized in that, The electro-optic modulator further includes a plurality of first protrusions and a plurality of second protrusions, the plurality of first protrusions being located on the first ground electrode and the plurality of second protrusions being located on the second ground electrode, the first protrusions and the second protrusions being periodically distributed and arranged opposite to each other.

5. The electro-optic modulator according to any one of claims 2 to 4, characterized in that, Multiple first protrusions and multiple second protrusions are symmetrically arranged.

6. The electro-optic modulator according to any one of claims 2 to 4, characterized in that, The plurality of first protrusions and the plurality of second protrusions are arranged alternately.

7. The electro-optic modulator according to claim 2, characterized in that, The first protrusion and the second protrusion include a bent portion on the side away from the electrode and a connecting portion connecting the bent portion and the electrode. The width of the bent portion is less than 4 micrometers, the length of the bent portion is less than 300 micrometers, and the length of the connecting portion is less than 20 micrometers.

8. The electro-optic modulator according to claim 2, characterized in that, Each of the first and second protrusions is arranged in a similar T-shape or L-shape.

9. The electro-optic modulator according to claim 1, characterized in that, The electro-optic modulator further includes a third optical waveguide, which is located in the modulation region of the electro-optic modulator. When the second optical waveguide is located between the first ground electrode and the positive signal electrode, the third optical waveguide is located between the second ground electrode and the negative signal electrode. When the second optical waveguide is located between the second ground electrode and the negative signal electrode, the third optical waveguide is located between the first ground electrode and the positive signal electrode.

10. An optical quantum computer, characterized in that, The optical quantum computer includes a single-photon source, an optical quantum chip, and a single-photon detector, wherein one or more of the single-photon source, the optical quantum chip, and the single-photon detector include an electro-optic modulator as described in any one of claims 1 to 9.

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