Electro-optic modulator and optical quantum computer

Abstract

The present disclosure provides an electro-optical modulator and an optical quantum computer. The electro-optical modulator comprises an electro-optical modulation structure and a waveguide transmission structure. The electro-optical modulation structure is used to modulate input light. The waveguide transmission structure is coupled to the electro-optical modulation structure and is used to modulate the mode field of the light input and / or output from the electro-optical modulation structure. The waveguide transmission structure comprises a first optical waveguide, a second optical waveguide, a third optical waveguide and two curved optical waveguides. The first optical waveguide and the second optical waveguide are connected by one curved optical waveguide, and the second optical waveguide and the third optical waveguide are connected by one curved optical waveguide. In the direction of propagation of the light, the width of the second optical waveguide increases, and the width of the first optical waveguide and / or the third optical waveguide increases. Alternatively, in the direction of propagation of the light, the width of the second optical waveguide decreases, and the width of the first optical waveguide and / or the third optical waveguide decreases. By the above technical solution, the generation of high-order modes is reduced, and the modulation efficiency is improved.

Description

Technical Field

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

[0002] Existing lithium niobate electro-optic modulators all have waveguide widths located on the same side of the waveguide mode hybridization width, making it impossible to achieve a zero-loss transition of the TEO mode from the left to the right side of the mode hybridization region. If the waveguide width were to change from the left to the right side of the waveguide mode hybridization, it would excite higher-order modes, leading to a decrease in the total power of the TEO mode and the generation of multiple modes in the modulation efficiency region, thus resulting in a decrease in modulation efficiency. Summary of the Invention

[0003] In view of this, the present disclosure aims to provide an electro-optic modulator and an optical quantum computer to solve the problem that the total power of the TEO mode decreases when the waveguide width variation range includes the hybrid width, thereby causing a decrease in modulation efficiency.

[0004] In a first aspect, this disclosure provides an electro-optic modulator, including an electro-optic modulation structure and a waveguide transmission structure. The electro-optic modulation structure is used to modulate input light. The waveguide transmission structure is coupled to the electro-optic modulation structure and is used to modulate the mode field of the light input to and / or output to the electro-optic modulation structure. The waveguide transmission structure is made of an orthorhombic crystal material and includes a first optical waveguide, a second optical waveguide, a third optical waveguide, and two bent optical waveguides. The first optical waveguide has a first input terminal and a first output terminal arranged opposite each other along a first direction. The second optical waveguide has a second input terminal and a second output terminal arranged opposite each other along a second direction. The third optical waveguide has a third input terminal and a third output terminal arranged opposite each other along the first direction. The first output terminal and the second input terminal are connected by a bent optical waveguide, and the second output terminal and the third input terminal are connected by a bent optical waveguide. Along the direction of light propagation, the width of the second optical waveguide increases, and the widths of the first optical waveguide and / or the third optical waveguide increase. Alternatively, along the direction of light propagation, the width of the second optical waveguide decreases, and the widths of the first optical waveguide and / or the third optical waveguide decrease. The first and second directions are two crystal orientations that are perpendicular to each other.

[0005] In the above technical solution, the waveguide transmission structure provided in this embodiment can increase the width range of the input light waveguide, and the second optical waveguide can avoid the hybrid width of the input light in the first direction. This allows the input light to steadily and gradually transition from the left side of the hybrid width to the right side in the first direction, avoiding the problem of reduced TEO fundamental mode components due to mode switching of the input light when the width of the optical waveguide is the hybrid width. This increases the proportion of TEO fundamental mode in the light transmitted to the electro-optic modulation structure, reduces the generation of higher-order modes, increases the total power of the TEO mode transmitted to the electro-optic modulation structure, and improves modulation efficiency.

[0006] In one specific implementation, the width of the first output terminal is the same as the width of the second input terminal. The width of the second output terminal is the same as the width of the third input terminal.

[0007] In one specific implementation, the width of the curved optical waveguide is the same in the direction of extension of the curved optical waveguide.

[0008] In one specific feasible implementation, the curved optical waveguide is a quarter circle.

[0009] In a specific feasible implementation, the width of the second input terminal is D1, and the width of the second output terminal is D2. Light propagates along the first direction, and the waveguide width corresponding to the mode conversion caused by the TE0 mode is E. D1, D2, and E satisfy: D1 < E < D2. Alternatively, D1, D2, and E satisfy: D2 < E < D1.

[0010] In one specific feasible implementation, the first direction is the Y direction of the orthorhombic crystal system material, and the second direction is the Z direction of the orthorhombic crystal system material.

[0011] In one specific feasible implementation, the orthorhombic crystal system material is lithium niobate.

[0012] In one specific implementation, the electro-optic modulation structure includes a modulation arm, a signal electrode, a ground electrode, and a matching resistor. There are two modulation arms, extending along a first direction and arranged along a second direction, with the ends of the modulation arms used to connect to a waveguide transmission structure. The signal electrode is disposed between the two modulation arms. There are two ground electrodes, each located on a side of the two modulation arms opposite to the signal electrode along the second direction. The matching resistor is connected to the signal electrode.

[0013] In one specific implementation, the electro-optic modulation structure further includes two heating units. The two heating units are located at the ends of the two modulation arms furthest from the light source, and are thermally connected to the modulation arms.

[0014] Secondly, 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, and the single-photon detector is used to measure the single photons and output the calculation results. Attached Figure Description

[0015] Figure 1 The diagram shown is an overall schematic diagram of an electro-optic modulator provided in an embodiment of this disclosure.

[0016] Figure 2 The diagram shown is a schematic diagram of a waveguide transmission structure provided in an embodiment of this disclosure.

[0017] Figure 3 The diagram shown is a schematic diagram of a waveguide transmission structure provided in another embodiment of this disclosure.

[0018] Figure 4 The diagram shown is a schematic diagram of the waveguide transmission structure provided in the third embodiment of this disclosure.

[0019] Figure 5 The figure shows the effect of the X-cut Y-transmission waveguide width variation on the effective refractive index.

[0020] Figure 6 The figure shows the effect of the X-cut Z-transmission waveguide width variation on the effective refractive index.

[0021] The attached figures are labeled as follows:

[0022] 1. Electro-optic modulation structure; 11. Modulation arm; 12. Signal electrode; 13. Ground electrode; 14. Matching resistor; 15. Heating unit.

[0023] 2. Waveguide transmission structure, 21. First optical waveguide, 211. First input terminal, 212. First output terminal, 22. Second optical waveguide, 221. Second input terminal, 222. Second output terminal, 23. Third optical waveguide, 231. Third input terminal, 232. Third output terminal, 24. Curved optical waveguide. Detailed Implementation

[0024] 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.

[0025] To facilitate understanding of the electro-optic modulator provided in this disclosure, a brief description is provided first. In existing lithium niobate electro-optic modulators, the waveguide width is always located on the same side of the waveguide mode hybridization width; that is, the waveguide width is either smaller than or larger than the hybridization width, to prevent mode hybridization during light transmission. However, it is impossible to achieve a zero-loss transition of the TEO mode from the left side of the mode hybridization width to the right side. If the waveguide width changes from the left to the right side of the waveguide mode hybridization width, it will excite higher-order modes, leading to a decrease in the total power of the TEO mode and the generation of multiple modes in the modulation efficiency region, thus resulting in a decrease in modulation efficiency.

[0026] Specifically, to ensure a smooth transition between the mode field of the input light and the mode field of the modulator's main waveguide, and to reduce coupling loss, optical signal reflection, mode distortion, and other problems, mode matching is achieved through a waveguide with a gradually varying width. When light propagates in a waveguide with a gradually varying width, a mode conversion occurs when the waveguide width reaches a certain value; this corresponding waveguide width is called the hybridization width.

[0027] Taking the input light in TE0 mode as an example, when the waveguide width gradually increases or decreases to the left of the hybrid width (i.e., less than the hybrid width), the input light can remain stable in TE0 mode. Similarly, when the waveguide width gradually increases or decreases to the right of the hybrid width (i.e., greater than the hybrid width), the input light can also remain stable in TE0 mode. However, when the waveguide width of the input light passes through the hybrid width, a mode transition occurs at the corresponding point, exciting the TE0 fundamental mode to transition to TM1 mode. This leads to a decrease in the TE0 component of the target mode and an increase in TE0 loss, thereby reducing modulation efficiency.

[0028] To overcome the above problems, this disclosure provides an electro-optic modulator. By improving the design of the waveguide transmission structure connected to the electro-optic modulation structure, the limitation of the input light being confined to the left or right side of the hybrid width during waveguide width changes is reduced, the range of waveguide width variation is increased, and mode conversion problems during waveguide width changes are avoided, thus ensuring modulation efficiency. The following detailed description, in conjunction with specific figures and embodiments, further illustrates this feature.

[0029] refer to Figure 1 The main components of the electro-optic modulator provided in this embodiment are shown, including an electro-optic modulation structure 1 and a waveguide transmission structure 2. The electro-optic modulation structure 1 is the main structure for achieving modulation, and the waveguide transmission structure 2 is used for width adjustment so that light can achieve a smooth transition between different transmission media.

[0030] The electro-optic modulation structure 1 includes a modulation arm 11, a signal electrode 12, and a ground electrode 13. Two modulation arms 11 are provided, each extending along a first direction and arranged along a second direction, which are perpendicular to each other. The signal electrode 12 is located between the two modulation arms 11. Two ground electrodes 13 are provided, each located on the side of the two modulation arms 11 facing away from the signal electrode 12 along the second direction. The sequence along the second direction is: ground electrode 13, modulation arm 11, signal electrode 12, modulation arm 11, and ground electrode 13.

[0031] The ends of the two modulation arms 11 extend along the first direction to the outside of the signal electrode 12 and the ground electrode 13, and are connected to the waveguide transmission structure through the Y-branch structure.

[0032] In addition, the electro-optic modulation structure 1 also includes a matching resistor 14 and a heating unit 15. The matching resistor 14 is connected to the signal electrode 12 to match the impedance of the signal source and the load in the circuit, reduce signal reflection, and improve transmission efficiency.

[0033] Two heating units 15 are provided, each located on one end of the two modulation arms 11 away from the incident light, and on the outer side of the signal electrode 12 and the ground electrode 13 along the first direction. The heating units 15 and the modulation arms 11 are thermally connected, and the phase difference between the two modulation arms 11 is adjusted through the thermo-optic effect, thereby realizing the adjustment of the bias point.

[0034] Specifically, the heating unit 15 is a heating resistor. When the heating resistor is energized, Joule heat is generated. The heating resistor and the modulation arm 11 transfer heat to achieve temperature regulation of the modulation arm 11, thereby changing the light refractive index and achieving phase difference regulation.

[0035] Furthermore, it should be noted that the electro-optic modulation structure 1 described above is an exemplary structure. In other embodiments, the electro-optic modulation structure 1 may also be an electro-optic modulator designed with a T-type electrode, or other electro-optic modulation structures 1 commonly found in the art. These will not be described in detail in this disclosure.

[0036] refer to Figure 1 Two waveguide transmission structures 2 are provided, one at each end of the electro-optic modulation structure 1 and the other connected to the end of the modulation arm 11. By providing waveguide transmission structures 2 at both ends, the unmodulated input light and the modulated output light can be adjusted separately. Of course, in some embodiments, the waveguide transmission structure 2 can be provided at only one end according to actual needs.

[0037] refer to Figure 2 The waveguide transmission structure 2 is made of an orthorhombic crystal material and includes a first optical waveguide 21, a second optical waveguide 22, a third optical waveguide 23, and two bent optical waveguides 24. The first optical waveguide 21 and the third optical waveguide 23 extend along a first direction, and the second optical waveguide 22 extends along a second direction. The first optical waveguide 21 has a first input terminal 211 and a first output terminal 212 arranged opposite each other along the first direction, with the first input terminal 211 connected to an input light source. The second optical waveguide 22 has a second input terminal 221 and a second output terminal 222 arranged opposite each other along the second direction. The third optical waveguide 23 has a third input terminal 231 and a third output terminal 232 arranged opposite each other along the first direction.

[0038] Along the direction of light propagation, the width of the second optical waveguide 22 increases, and the width of the first optical waveguide 21 and / or the third optical waveguide 23 increases. Alternatively, along the direction of light propagation, the width of the second optical waveguide 22 decreases, and the width of the first optical waveguide 21 and / or the third optical waveguide 23 decreases.

[0039] Specifically, the width variations of the first optical waveguide 21, the second optical waveguide 22, and the third optical waveguide 23 mentioned above include various different forms, as detailed below:

[0040] Firstly, along the direction of light propagation, the width of the second optical waveguide 22 increases, the width of the first optical waveguide 21 increases, and the width of the third optical waveguide 23 remains unchanged.

[0041] Secondly, along the direction of light propagation, the width of the second optical waveguide 22 increases, the width of the first optical waveguide 21 remains unchanged, and the width of the third optical waveguide 23 increases.

[0042] Thirdly, along the direction of light propagation, the width of the second optical waveguide 22 increases, the width of the first optical waveguide 21 increases, and the width of the third optical waveguide 23 also increases.

[0043] Fourth, along the direction of light propagation, the width of the second optical waveguide 22 decreases, the width of the first optical waveguide 21 decreases, and the width of the third optical waveguide 23 remains unchanged.

[0044] Fifth, along the direction of light propagation, the width of the second optical waveguide 22 decreases, the width of the first optical waveguide 21 remains unchanged, and the width of the third optical waveguide 23 decreases.

[0045] Sixth, along the direction of light propagation, the width of the second optical waveguide 22 decreases, the width of the first optical waveguide 21 decreases, and the width of the third optical waveguide 23 also decreases.

[0046] Taking the example of the width of the second optical waveguide 22 increasing in the direction of light propagation, at least one of the first optical waveguide 21 and the third optical waveguide 23 is also set to increase in the direction of light propagation. The specific range of adjustment of the optical waveguide width is designed according to the actual needs.

[0047] For example, refer to Figure 2 The overall width of the optical waveguide needs to be adjusted from 400nm to 800nm, and the hybrid width of light in the first direction is 690nm. Therefore, the widths of the first optical waveguide 21 and the second optical waveguide 22 are designed to increase in the direction of light propagation. The width of the first optical waveguide 21 increases from 400nm to 600nm, and the width of the second optical waveguide 22 increases from 600nm to 800nm.

[0048] Accordingly, refer to Figure 3 If the overall width of the optical waveguide needs to be adjusted from 600nm to 1000nm, and the hybrid width of light in the first direction is 690nm, then the widths of the second optical waveguide 22 and the third optical waveguide 23 are designed to increase in the direction of light propagation. The width of the second optical waveguide 22 increases from 600nm to 800nm, and the width of the third optical waveguide 23 increases from 800nm ​​to 1000nm.

[0049] Additionally, refer to Figure 4 If the overall width of the optical waveguide needs to be adjusted from 400nm to 1000nm, and the hybrid width of light in the first direction is 690nm, then the widths of the first optical waveguide 21, the second optical waveguide 22, and the third optical waveguide 23 are designed to increase in the direction of light propagation. The width of the first optical waveguide 21 increases from 400nm to 600nm, the width of the second optical waveguide 22 increases from 600nm to 800nm, and the width of the third optical waveguide 23 increases from 800nm ​​to 1000nm.

[0050] It should be noted that the above values ​​and ranges are merely illustrative examples and should not be construed as limiting the scope of protection of this disclosure. When the width of the second optical waveguide 22 decreases in the direction of light propagation, the corresponding design can be made according to the above illustrative description, and will not be repeated in the embodiments of this disclosure.

[0051] Two curved optical waveguides 24 are used to connect the first optical waveguide 21, the second optical waveguide 22, and the third optical waveguide 23, achieving a smooth transition connection among the three. Specifically, the first output terminal 212 and the second input terminal 221 are connected through a curved optical waveguide 24, and the second output terminal 222 and the third input terminal 231 are connected through a curved optical waveguide 24.

[0052] Among them, the first direction and the second direction are two crystal orientations that are perpendicular to each other.

[0053] Taking the incident light as TEO mode as an example, the optical waveguide extends along the first direction. In the first direction, the width of the optical waveguide increases. If the aforementioned width-increasing interval includes the hybrid width, the incident light will undergo mode conversion at the location where the width of the optical waveguide is equal to the hybrid width, resulting in a decrease in the proportion of the incident light in TEO mode, which will subsequently lead to a decrease in modulation efficiency.

[0054] In this embodiment, the optical waveguide extending along the first direction is divided into three parts: a first optical waveguide 21 and a third optical waveguide 23 extending along the first direction, and a second optical waveguide 22 extending along the second direction. These three parts are smoothly connected by two curved optical waveguides 24. The widths of the first optical waveguide 21, the second optical waveguide 22, and the third optical waveguide 23 increase progressively in their respective extending directions, achieving the same width variation as the overall optical waveguide extending along the first direction.

[0055] Due to the anisotropy of orthorhombic materials, the hybrid width of the optical waveguide in the first direction differs from that in the second direction. The width of the second input terminal 221 is positioned to the left of the hybrid width of the input light in the first direction, and the width of the second output terminal 222 is positioned to the right of the hybrid width of the input light in the first direction. This allows the width of the optical waveguide in the first direction to avoid the hybrid width of the input light in that direction. The optical waveguide corresponding to this hybrid width is the second optical waveguide 22, which extends along the second direction. Due to the anisotropy of orthorhombic materials, when the width of the second optical waveguide 22 is the same as the hybrid width of the input light in the first direction, no mode conversion occurs within the second optical waveguide 22.

[0056] Thus, the waveguide transmission structure 2 provided in this embodiment can increase the width range of the input light waveguide, and the second optical waveguide 22 can avoid the hybrid width of the input light in the first direction. This allows the input light to steadily and gradually transition from the left side of the hybrid width to the right side in the first direction, avoiding the problem of reduced TEO fundamental mode components due to mode switching of the input light when the width of the optical waveguide is the hybrid width. This increases the proportion of TEO fundamental mode in the light transmitted to the electro-optic modulation structure 1, reduces the generation of higher-order modes, increases the total power of the TEO mode in the light transmitted to the electro-optic modulation structure 1, and improves modulation efficiency.

[0057] For example, the first direction is the Y-direction of the orthorhombic crystal material, and the second reverse direction is the Z-direction of the orthorhombic crystal material. The orthorhombic crystal material is lithium niobate, lithium tantalate, or potassium dihydrogen phosphate. In this embodiment, lithium niobate is used as an example to illustrate the orthorhombic crystal material used to fabricate the waveguide transmission structure 2.

[0058] In the first optical waveguide 21 and the third optical waveguide 23, the direction of light propagation is X-cutting Y-propagation, and in the second optical waveguide 22, the direction of light propagation is X-cutting Z-propagation.

[0059] refer to Figure 5 , Figure 5 This figure illustrates the effect of varying X-axis and Y-axis waveguide widths on the effective refractive index. In the figure, Neff for different waveguide widths (530.0 nm) represents the effective refractive index corresponding to light with a wavelength of 530.0 nm at different waveguide widths. The vertical axis, Neff, represents the effective refractive index, and the horizontal axis, width of waveguide, represents the waveguide width, both in micrometers. The figure shows that as the waveguide width increases from 500 nm to 690 nm, a transition occurs from the TE0 fundamental mode to the TM1 mode.

[0060] refer to Figure 6 , Figure 6This diagram illustrates the effect of varying X-axis and Y-axis waveguide widths on the effective refractive index. In the figure, Neff for different waveguide widths (530.0 nm) represents the effective refractive index corresponding to light with a wavelength of 530.0 nm at different waveguide widths. The vertical axis, Neff, represents the effective refractive index, and the horizontal axis, width of waveguide, represents the waveguide width, both in micrometers. When the waveguide width is 690 nm, and within a certain range around 690 nm, the input light can stably remain in the TE0 fundamental mode without mode conversion.

[0061] Specifically, refer to Figure 2 The width of the first output terminal 212 is the same as the width of the second input terminal 221, and the width of the second output terminal 222 is the same as the width of the third input terminal 231. This ensures a smooth transition between the first optical waveguide 21, the second optical waveguide 22, and the third optical waveguide 23 as much as possible.

[0062] Furthermore, by setting the widths of the two curved optical waveguides 24 to be the same in their extension directions, the risk of mode conversion of the input light in the curved optical waveguide 24 due to the change in the width of the curved optical waveguide 24 can be reduced to the greatest extent, thereby increasing the power of the TEO fundamental mode in the light after passing through the waveguide transmission structure 2 and improving the modulation efficiency.

[0063] Specifically, the curved optical waveguide 24 is a quarter circle.

[0064] For example, when light is transmitted along an optical waveguide set in the first direction, the waveguide width corresponding to the mode conversion from TEO mode is E. This waveguide width E may be a specific point value, such as 690nm, or it may correspond to a range of waveguide widths, such as 650nm~700nm.

[0065] The width of the second input terminal 221 is D1, and the width of the second output terminal is D2. D1, D2, and E satisfy: D1 < E < D2.

[0066] For example, when E is 690nm, then D1 < 690nm < D2. When E is in the range of 650nm to 700nm, then D1 < 650nm < 700nm < D2.

[0067] In some other embodiments, when the widths of the first optical waveguide 21, the second optical waveguide 22, and the third optical waveguide 23 decrease along the direction of light propagation, then D1, D2, and E satisfy: D2 < E < D1.

[0068] By limiting the width at both ends of the second optical waveguide 22 and increasing the width of the second optical waveguide 22 in the second direction, it is possible to ensure that the hybrid width of the input light in the first direction is avoided by the second optical waveguide 22, so as to ensure the power of the TEO fundamental mode transmitted to the electro-optic modulation structure 1.

[0069] 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, perform measurements, and output calculation results.

[0070] 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.

[0071] 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. An electro-optic modulator, characterized in that, include: An electro-optic modulation structure is used to modulate the input light; A waveguide transmission structure, coupled to the electro-optic modulation structure, is used to modulate the mode field of the light input to and / or output to the electro-optic modulation structure; The waveguide transmission structure is made of an orthorhombic crystal material, including: A first optical waveguide is provided with a first input terminal and a first output terminal arranged opposite to each other along a first direction; The second optical waveguide is provided with a second input terminal and a second output terminal arranged opposite to each other along a second direction; The third optical waveguide is provided with a third input terminal and a third output terminal arranged opposite to each other along the first direction; Two curved optical waveguides are provided. The first output terminal and the second input terminal are connected through one of the curved optical waveguides. The second output terminal and the third input terminal are connected through another curved optical waveguide. The first optical waveguide, the second optical waveguide, and the third optical waveguide are smoothly connected through the two curved optical waveguides. The first optical waveguide and the third optical waveguide extend along the first direction, and the second optical waveguide extends along the second direction. Along the direction of light propagation, the width of the second optical waveguide increases, and the widths of the first optical waveguide and / or the third optical waveguide also increase; or, Along the direction of light propagation, the width of the second optical waveguide decreases, and the width of the first optical waveguide and / or the third optical waveguide decreases. The hybrid width during mode conversion of light propagating along the first direction is located within the width range of the second optical waveguide; and The first direction and the second direction are two crystal orientations that are perpendicular to each other.

2. The electro-optic modulator according to claim 1, characterized in that, The width of the first output terminal is the same as the width of the second input terminal; The width of the second output terminal is the same as the width of the third input terminal.

3. The electro-optic modulator according to claim 2, characterized in that, The width of the curved optical waveguide is the same in the direction of its extension.

4. The electro-optic modulator according to claim 1, characterized in that, The curved optical waveguide is 1 / 4 circle.

5. The electro-optic modulator according to claim 1, characterized in that, The width of the second input terminal is D1, and the width of the second output terminal is D2; When light propagates along the first direction, the hybridization width corresponding to the mode transition from TE0 mode is E; D1, D2, and E satisfy: D1 < E < D2; or D1, D2, and E satisfy the condition: D2 < E < D1.

6. The electro-optic modulator according to any one of claims 1-5, characterized in that, The first direction is the Y-direction of the orthorhombic crystal system material, and the second direction is the Z-direction of the orthorhombic crystal system material.

7. The electro-optic modulator according to claim 6, characterized in that, The orthorhombic crystal system material is lithium niobate.

8. The electro-optic modulator according to claim 1, characterized in that, The electro-optic modulation structure includes: Two modulation arms extend along the first direction and are arranged along the second direction, with the ends of the modulation arms used to connect to the waveguide transmission structure. A signal electrode is disposed between the two modulation arms; Two ground electrodes are respectively located on the side of the two modulation arms away from the signal electrodes along the second direction; A matching resistor is connected to the signal electrode.

9. The electro-optic modulator according to claim 8, characterized in that, The electro-optic modulation structure also includes two heating units; Two heating units are located at the ends of the two modulation arms furthest from the light source, and the heating units are thermally connected to the modulation arms.

10. An optical quantum computer, characterized in that, The device includes a single-photon source, a quantum chip, and a single-photon detector. The quantum chip includes an electro-optic modulator as described in any one of claims 1-9. 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 calculation results.

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