Waveguide components, waveguide component control methods, optical chips and optical quantum computers

Abstract

This invention provides a waveguide assembly, a control method for the waveguide assembly, an optical chip, and an optical quantum computer. The waveguide assembly includes: a waveguide body having a preset polarization period in the direction of optical signal propagation; multiple heating devices for heating different regions of the waveguide body; and a controller for controlling the multiple heating devices to heat corresponding regions of the waveguide body to different temperatures, enabling the waveguide body to undergo spontaneous parametric switching at different frequencies, generating quantum entangled light sources in different bands. This waveguide assembly, while meeting the requirements for generating broadband quantum entangled light sources, reduces dependence on waveguide process parameters, thereby reducing the difficulty of waveguide manufacturing.

Description

Technical Field

[0001] This invention relates to the field of quantum communication technology, specifically to a waveguide component, a control method for the waveguide component, an optical chip, and an optical quantum computer. Background Technology

[0002] In quantum optics, spontaneous parametric down-conversion (SPDC) via waveguides is a common and widely used method for generating quantum entangled light sources. Among these, broadband quantum entangled light sources with high bandwidth are of great significance in quantum optics applications.

[0003] In related technologies, in order to generate broadband quantum entangled light sources, chirped polarization or dispersion-designed waveguides can be used. However, these two designs are very sensitive to waveguide process errors, which increases the difficulty of waveguide manufacturing. Summary of the Invention

[0004] In view of this, embodiments of the present invention aim to provide a waveguide component, a control method for the waveguide component, an optical chip, and an optical quantum computer, so that the waveguide component can meet the requirements for generating broadband quantum entangled light sources while reducing its dependence on waveguide process parameters, thereby reducing the difficulty of waveguide process manufacturing.

[0005] The first aspect of the present invention provides a waveguide assembly comprising:

[0006] A waveguide body having a preset polarization period in the direction of optical signal propagation;

[0007] Multiple heating devices are used to heat different regions of the waveguide body;

[0008] The controller is used to control the multiple heating devices to heat the waveguide body in the corresponding area to different temperatures, so that the waveguide body can spontaneously parametrically switch at different frequencies to generate quantum entangled light sources in different bands.

[0009] In some embodiments, the plurality of heating devices are spaced apart on the waveguide body along the direction of optical signal propagation.

[0010] In some embodiments, the heating device includes a heating resistor, and the current connected to the heating resistor varies in different heating devices.

[0011] In some implementations, the controller is further configured to:

[0012] Based on the rated current of each heating resistor, the current connected to the corresponding heating resistor is controlled so that the waveguide body in the region corresponding to the different heating resistors performs spontaneous parametric down-conversion on the passing optical signal, generating quantum entangled light sources in different bands.

[0013] In some implementations, the controller is further configured to:

[0014] The control light source output device outputs pump photons to the optical signal input terminal of the waveguide body;

[0015] Different currents are applied to the target heating resistor until the intensity of the optical signal output from the optical signal output terminal of the waveguide body, corresponding to the target band of the target heating resistor, reaches a preset intensity threshold. Based on the current applied to the target heating resistor when the preset intensity threshold is reached, the rated current of the target heating resistor is determined.

[0016] From the remaining heating resistors with undetermined rated currents, determine a new target heating resistor and return to the step: control the target heating resistor to be connected to different currents until the intensity of the optical signal output terminal of the waveguide body corresponding to the target band of the target heating resistor reaches a preset intensity threshold. Based on the current connected to the target heating resistor when the preset intensity threshold is reached, determine the rated current of the target heating resistor.

[0017] In some implementations, the controller is further configured to:

[0018] The current connected to the heating resistor with a known rated current is kept constant. A new target heating resistor is determined from the remaining heating resistors with undetermined rated currents. The process returns to the step of controlling the target heating resistor to be connected to different currents until the intensity of the optical signal output terminal of the waveguide body corresponding to the target heating resistor reaches a preset intensity threshold. Based on the current connected to the target heating resistor when the preset intensity threshold is reached, the rated current of the target heating resistor is determined.

[0019] In some embodiments, when determining the rated current of the target heating resistor, the optical signal output terminal of the waveguide body is connected to the signal input terminal of the target bandpass filter corresponding to the target heating resistor, the signal output terminal of the target bandpass filter is connected to a power meter, the transmission wavelength of the target bandpass filter is the center wavelength of the target band, and the wavelength bandwidth of the transmission wavelength of the target bandpass filter is less than or equal to the wavelength bandwidth of the target band.

[0020] The controller is also used to determine the intensity of the optical signal in the target band corresponding to the target heating resistor based on the data collected by the power meter.

[0021] In some embodiments, the heating device further includes a positive electrode and a negative electrode connected to the heating resistor.

[0022] A second aspect of the present invention provides a control method for a waveguide assembly, the method being applied to the waveguide assembly described in the first aspect, wherein the heating device includes a heating resistor, and the method includes:

[0023] The control light source output device outputs pump photons to the optical signal input terminal of the waveguide body;

[0024] Obtain the rated current corresponding to each of the heating resistors;

[0025] Based on the rated current of each heating resistor, the current connected to the corresponding heating resistor is controlled so that the waveguide body in the region corresponding to the different heating resistors performs spontaneous parametric down-conversion on the passing optical signal, generating quantum entangled light sources in different bands.

[0026] A third aspect of the present invention provides an optical chip comprising the waveguide component described in the first aspect.

[0027] A fourth aspect of the present invention provides an optical quantum computer comprising the optical chip described in the third aspect.

[0028] Compared with related technologies, the waveguide component, waveguide component control method, optical chip, and optical quantum computer provided by the present invention have the following advantages:

[0029] A controller and heating device are installed on a periodically polarized waveguide body. The heating device can change the temperature of a local waveguide, thereby altering the effective refractive index of the local waveguide through a thermo-optical effect. At a suitable temperature, the local waveguide in the region corresponding to the heating device can undergo spontaneous parametric down-switching at a specific frequency to achieve quasi-phase matching within a specific wavelength band, generating a quantum entangled light source in that band. Furthermore, by further installing multiple heating devices, the corresponding regions of the waveguide body can be heated to different temperatures under the control of the controller, enabling the waveguide assembly to achieve quasi-phase matching in multiple wavelength bands, thereby generating a broadband quantum entangled light source. Moreover, since the waveguide assembly in this embodiment does not achieve broadband phase matching during the design phase, but rather tunes the waveguide refractive index to achieve broadband phase matching by heating after sample preparation, the influence of process errors can be overcome, thereby reducing the difficulty of waveguide manufacturing. Attached Figure Description

[0030] Figure 1 The diagram shown is a structural schematic of a waveguide component provided in an embodiment of the present invention.

[0031] Figure 2The diagram shown is a structural schematic of another waveguide component provided in an embodiment of the present invention.

[0032] Figure 3 The diagram shown is a comparison of effects provided by an embodiment of the present invention.

[0033] Figure 4 The diagram shows a flowchart of a debugging method for a semiconductor testing device according to an embodiment of the present invention. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Spontaneous parametric downconversion refers to the process where, when a pump photon passes through a second-order nonlinear crystal, it transforms into an entangled photon pair during its interaction with the crystal. The two photons in this pair are called the idler photon and the signal photon. During spontaneous parametric downconversion, the frequencies of the idler and signal photons are not random; they must simultaneously satisfy the conservation of momentum and energy. Energy conservation refers to… That is, the frequency of the signal photon With the frequency of idle photons The sum must equal the frequency of the pump photon. The conservation of momentum refers to... That is, the wave vector of the signal photon wave vector of idle frequency photons The sum must equal the wave vector of the pump photon. The momentum conservation condition, also known as the phase matching condition, is only possible for photon pairs that simultaneously satisfy both energy and momentum conservation conditions to be generated during spontaneous parametric conversion.

[0036] Phase matching is generally very difficult to achieve for photon pairs that satisfy energy conservation (due to dispersion). Therefore, a common method is to achieve quasi-phase matching using periodically polarized lithium niobate (PPLN) waveguides. Lithium niobate waveguides have very high second-order nonlinear coefficients, making them an ideal platform for generating spontaneous parametric down-conversion.

[0037] In lithium niobate waveguides, a periodically applied high-voltage electric field can cause periodic polarization reversal in the direction of optical signal propagation, thereby compensating for the effects of phase mismatch and achieving quasi-phase matching. To accurately compensate for phase mismatch, the polarization period of the periodically polarized lithium niobate must satisfy certain conditions. , The polarization period is indicated. Although based on periodically polarized lithium niobate, we can select a specific polarization period to make idler and signal photons of a certain frequency simultaneously satisfy phase matching and energy conservation, for most photon pair combinations, it is still impossible to make them simultaneously satisfy these two conditions. Therefore, the conditions for spontaneous parametric conversion can only be met at specific frequencies, and it is difficult to generate broadband quantum entangled light sources.

[0038] To generate broadband quantum entangled light sources, chirped polarization and dispersion design are commonly used methods. For conventional periodically polarized lithium niobate waveguides, since the polarization period is fixed throughout the waveguide, only a few photon pairs can achieve quasi-phase matching. However, if we gradually change the polarization period along the propagation direction of the optical signal within the waveguide, it becomes possible to achieve quasi-phase matching for multiple photon pairs. This involves dividing the entire waveguide into many small blocks, each with a polarization period that allows a small subset of photon pairs to achieve quasi-phase matching. These blocks are then combined to form a complete waveguide, enabling multiple photon pairs to achieve quasi-phase matching over a broadband range, thus realizing a broadband quantum entangled light source. This method is called chirped polarization.

[0039] Another commonly used method for achieving broadband quasi-phase matching is dispersion design. Even if a pair of photons satisfies both energy conservation and quasi-phase matching through periodically polarized lithium niobate waveguides, the phase matching condition is still not met for most photon pairs that satisfy energy conservation. This is because the modes exhibit dispersion, meaning the effective refractive index of the mode changes with frequency. However, the dispersion curve can be altered by adjusting the waveguide's structural parameters. By selecting appropriate structural parameters, the waveguide's dispersion in the target wavelength band can be made close to zero, thus enabling photon pairs in the target wavelength band to simultaneously satisfy energy conservation and phase matching, achieving a broadband entangled light source.

[0040] For waveguides based on chirped polarization, the quasi-phase matching condition is highly sensitive to the refractive index. During micro / nano fabrication, unavoidable process errors cause the actual fabricated sample's structural dimensions to deviate from the design expectations to some extent. These dimensional deviations lead to deviations in the effective refractive index, ultimately preventing the quasi-phase matching condition from being met as intended.

[0041] For waveguides based on dispersion design improvements, in practical applications, parameters such as wafer thickness, etching depth, and cladding material cannot be arbitrarily chosen but are limited by the overall system design. With these parameters constrained, it is often impossible to achieve zero dispersion in the target wavelength band, regardless of how the remaining adjustable parameters are adjusted. Furthermore, sometimes pursuing zero dispersion requires selecting structural parameters with lower conversion efficiency under spontaneous parameters, leading to a decrease in the brightness of the entangled light source.

[0042] It is evident that the two designs mentioned above share a common problem: they are highly sensitive to waveguide process errors, which increases the difficulty of waveguide manufacturing. Furthermore, the actual samples produced often fail to achieve the expected broadband effect. In addition, the dispersion design method can only be applied to systems with certain specific parameters.

[0043] In view of the above problems, this application aims to provide a waveguide component, a control method for the waveguide component, an optical chip, and an optical quantum computer. Wherein, as... Figure 1 As shown, the waveguide assembly may include a waveguide body 110, multiple heating devices 120, and a controller (not shown in the figure).

[0044] The waveguide body has a preset polarization period in the direction of optical signal propagation. That is, the waveguide body in this embodiment can be a periodically polarized waveguide. By periodically applying a high voltage electric field, the waveguide can periodically reverse polarization in the direction of optical signal propagation, thereby having the ability to compensate for phase mismatch.

[0045] In this embodiment of the present disclosure, when using waveguide components to generate broadband quantum entangled light sources, the controller can control the light source output device to output pump photons to the optical signal input terminal of the waveguide body. In addition, the controller can also control multiple heating devices to operate, so as to heat the waveguide body in the corresponding area to different temperatures, thereby enabling the waveguide body to undergo spontaneous parametric down-conversion at different frequencies, and obtain quantum entangled light sources of different bands by pump photon conversion.

[0046] The waveguide assembly using the embodiments of this disclosure includes a controller and a heating device on a periodically polarized waveguide body. The heating device can change the temperature of a local waveguide, thereby changing the effective refractive index of the local waveguide through thermo-optical effects. At a suitable temperature, the local waveguide in the region corresponding to the heating device can undergo spontaneous parametric down-conversion at a specific frequency to achieve quasi-phase matching in a specific band and generate a quantum entangled light source in that band. Furthermore, by further providing multiple heating devices, the corresponding regions of the waveguide body can be heated to different temperatures under the control of the controller, enabling the waveguide assembly to achieve quasi-phase matching in multiple bands to generate a broadband quantum entangled light source.

[0047] Furthermore, since the waveguide component of this embodiment does not achieve broadband phase matching during the design phase, but tunes the waveguide refractive index by heating it after sample preparation to meet broadband phase matching, the influence of process errors can be overcome, thereby reducing the difficulty of waveguide manufacturing.

[0048] In some implementations, continue as Figure 1 As shown, multiple heating devices 120 are spaced apart on the waveguide body 110 along the direction of optical signal propagation.

[0049] In this embodiment of the disclosure, by arranging multiple heating devices at intervals along the direction of optical signal propagation on the waveguide body, the area where the heating devices heat the waveguide body can be separated, thereby reducing the impact of heat diffusion during heating by each heating device, improving the heating accuracy of each heating device, and thus ensuring the generation capability of quantum entangled light source in a specified band.

[0050] In some implementations, such as Figure 2 As shown, the heating device 120 includes a heating resistor 121, and the current connected to the heating resistor 121 in different heating devices 120 is different.

[0051] In this embodiment, the waveguide body can be heated electrically using heating resistors. These multiple heating resistors can be resistors of the same specifications. In this case, by applying different currents to the heating resistors in different heating devices, the waveguide body in corresponding areas can be heated to different temperatures using multiple heating devices. After the target heating resistor heats the waveguide body, the heated waveguide body can undergo spontaneous parametric down-conversion within a wavelength band, generating a quantum entangled light source corresponding to that band.

[0052] In some implementations, continue as Figure 2 As shown, the heating device 120 may further include a positive electrode 122 and a negative electrode 123 connected to the heating resistor 121. The heating resistor 121, the positive electrode 122, and the negative electrode 123 together form a thermoelectric electrode, which heats the waveguide body 110, continuing as shown. Figure 2 As shown, the negative terminal 123 connected to each heating resistor 121 is the same negative terminal 123, that is, all heating resistors 121 share a common negative terminal.

[0053] In some embodiments, where the heating device includes a heating resistor, the controller is also used to:

[0054] Based on the rated current of each heating resistor, the current connected to the corresponding heating resistor is controlled so that the waveguide body in the region corresponding to different heating resistors performs spontaneous parametric down-conversion on the passing optical signal, generating quantum entangled light sources in different bands.

[0055] The rated current corresponding to the heating resistor refers to the current that heats the waveguide body in the corresponding area to a specified temperature through the heating resistor. At the specified temperature, the waveguide body can spontaneously parametrically downconvert the passing optical signal (pump photon) to generate a quantum entangled light source.

[0056] In this embodiment of the disclosure, the rated current corresponding to each heating resistor can be pre-calibrated during the testing phase. Subsequently, when applying the waveguide component, the controller can directly control the heating resistor to connect to the corresponding rated current so that the waveguide body in the corresponding area is heated to different specified temperatures through the heating resistor. This allows the waveguide body in the area corresponding to different heating resistors to perform spontaneous parametric down-conversion on the passing optical signal, generating quantum entangled light sources in different bands.

[0057] In some implementations, the controller is also used for:

[0058] The light source output device controls the output of pump photons to the optical signal input terminal of the waveguide body;

[0059] Different currents are connected to the target heating resistor until the intensity of the optical signal output terminal of the waveguide body corresponding to the target heating resistor reaches a preset intensity threshold. Based on the current connected to the target heating resistor when the preset intensity threshold is reached, the rated current of the target heating resistor is determined.

[0060] From the remaining heating resistors with undetermined rated current, determine a new target heating resistor and return to the step: control the target heating resistor to be connected to different currents until the intensity of the optical signal output terminal of the waveguide body corresponding to the target band of the target heating resistor reaches a preset intensity threshold. Based on the current connected to the target heating resistor when the preset intensity threshold is reached, determine the rated current of the target heating resistor.

[0061] In this embodiment, each heating resistor can be calibrated individually to obtain the rated current corresponding to each heating resistor. The heating resistor currently being calibrated can be understood as the target heating resistor. Furthermore, the controller can also be used for control during the rated current calibration phase.

[0062] During the rated current calibration phase, the controller can control the light source output device to output pump photons to the optical signal input terminal of the waveguide body. Furthermore, for the target heating resistor being calibrated, the controller can gradually control the current connected to the target heating resistor and obtain the intensity of the optical signal in the target band corresponding to the target heating resistor under different currents, and determine whether the intensity reaches a preset intensity threshold. If the intensity of the optical signal in the target band reaches the preset intensity threshold under a certain current, it indicates that the waveguide body can achieve quasi-phase matching within the target band under that current, generating a large number of quantum entangled light sources in the target band. This current can then be saved as the rated current of the target heating resistor being calibrated. After obtaining the rated current of one heating resistor, a new target heating resistor can be determined from the remaining heating resistors with undetermined rated currents, and processed using the same method to complete the calibration of the rated current of all uncalibrated heating resistors, obtaining the rated current corresponding to each heating resistor.

[0063] It is understood that in this embodiment, the waveguide body can be considered as multiple waveguide regions, each heated by a heating resistor. Furthermore, the broadband band containing the quantum entangled light source is divided into multiple smaller bands, each corresponding to a waveguide region. Thus, heating the corresponding waveguide region with the heating resistor achieves quasi-phase matching within the corresponding band, generating a quantum entangled light source corresponding to that band. Consequently, multiple waveguide regions can generate quantum entangled light sources in multiple bands, ultimately achieving the generation of a broadband quantum entangled light source. The broadband band containing the quantum entangled light source and the target band corresponding to each heating resistor can be predetermined.

[0064] Furthermore, considering that multiple heating resistors are simultaneously operating when using waveguide components to generate broadband quantum entangled light sources, in some embodiments, the controller is also used to:

[0065] The current connected to the heating resistor with the determined rated current is kept constant. A new target heating resistor is determined from the remaining heating resistors with undetermined rated currents, and the process returns to the step: control the target heating resistor to be connected to different currents until the intensity of the optical signal output terminal of the waveguide body corresponding to the target heating resistor reaches a preset intensity threshold. Based on the current connected to the target heating resistor when the preset intensity threshold is reached, the rated current of the target heating resistor is determined.

[0066] In this embodiment of the present disclosure, for a heating resistor that has already completed rated current calibration, the controller can control it to continue to be connected to the rated current and be in a state of heating the waveguide body. For the target heating resistor currently being calibrated, the controller controls it to gradually connect to different currents until the intensity of the optical signal output terminal of the waveguide body corresponding to the target heating resistor reaches a preset intensity threshold. Based on the current connected to the target heating resistor when the preset intensity threshold is reached, the rated current of the target heating resistor currently being calibrated is determined.

[0067] By adopting the technical solution of this disclosure embodiment, by controlling the current connected to the heating resistor with a determined rated current to remain unchanged, the calibration process of the rated current of the heating resistor can be closer to the actual use scenario of the waveguide component. This can further improve the heating accuracy of the heating resistor, so as to accurately generate a quantum entangled light source in a specified band.

[0068] In some implementations, when determining the rated current of the target heating resistor, the optical signal output terminal of the waveguide body is connected to the signal input terminal of the target bandpass filter corresponding to the target heating resistor, the signal output terminal of the target bandpass filter is connected to the power meter, the transmission wavelength of the target bandpass filter is the center wavelength of the target band, and the wavelength bandwidth of the transmission wavelength of the target bandpass filter is less than or equal to the wavelength bandwidth of the target band; in this case, the controller is also used to determine the intensity of the optical signal of the target band corresponding to the target heating resistor based on the data collected by the power meter.

[0069] In this embodiment, the intensity of the optical signal can be detected using a combination of a bandpass filter and a power meter. To accurately determine the intensity of the optical signal in the target wavelength band corresponding to the target heating resistor during calibration, a bandpass filter with a transmission wavelength equal to the center wavelength of the target wavelength band and a bandwidth less than or equal to the bandwidth of the target wavelength band can be used to filter the optical signal in the target wavelength band. This bandpass filter can be called a target bandpass filter. Furthermore, the controller can determine the intensity of the optical signal in the target wavelength band corresponding to the target heating resistor based on data collected by the power meter connected to the signal output terminal of the target bandpass filter, so as to compare it with a preset intensity threshold.

[0070] In some implementations, the preset strength threshold can be the signal strength corresponding to when the power meter reaches its maximum count value.

[0071] It should be noted that in the embodiments of this disclosure, during the stage of calibrating the rated current of the heating resistor, the optical signal output terminal of the waveguide body is connected to different bandpass filters respectively, while in the application of the waveguide component, the optical signal output terminal of the waveguide body is connected to the quantum entanglement light source application terminal.

[0072] The manufacturing process of the waveguide component of this disclosure will now be described with reference to a complete embodiment.

[0073] 1. The structural parameters of the waveguide body are scanned by numerical simulation, and the effective refractive index of each mode corresponding to each structural parameter is obtained. Then, the dispersion is calculated based on the refractive index, and the structural parameters with dispersion less than a preset dispersion threshold are selected. In traditional dispersion design methods, the dispersion is required to be very close to zero in this step. However, the method of this disclosure does not impose a hard requirement on dispersion, but selects structural parameters with relatively low dispersion from the perspective of improving performance, such as the structural parameters with the minimum dispersion.

[0074] 2. Based on the effective refractive index calculation results in step 1, and combined with the center wavelength of the candidate band to be subjected to spontaneous parametric down-conversion, based on the formula... Calculate the polarization period ,in, , , Both can be calculated based on the center wavelength of the candidate band. Similarly, in traditional design schemes, the polarization period... The accuracy requirements are high, and the method of this disclosure embodiment has high requirements for polarization period. The requirements are low; even if there is some error, it will not affect the performance of the waveguide component.

[0075] 3. After steps 1 and 2, the structural parameters of the waveguide body can be determined. Then, the polarization electrode can be fabricated. Optionally, the polarization electrode can be made of gold.

[0076] 4. Periodic polarization reversal is achieved by applying a strong electric field between the positive and negative electrodes of the polarization electrode using a probe.

[0077] 5. Remove the polarization electrode and fabricate the waveguide body. Optionally, the waveguide body can be a lithium niobate ridge waveguide. Optionally, in some embodiments, the waveguide body can be fabricated first and then polarized.

[0078] 6. Deposit cladding material; optionally, the cladding material may be silicon dioxide.

[0079] 7. Divide the waveguide body into N waveguide regions along the direction of optical signal propagation. Above each waveguide region, prepare a thermoelectric electrode consisting of a positive electrode, a negative electrode, and a heating resistor (the electrode material is preferably gold, and the heating resistor layer material is preferably titanium nitride). Let these N thermoelectric electrodes be H1, H2...Hn.

[0080] 8. The completed waveguide body can be referenced. Figure 2As shown, the candidate band is divided into N sub-bands, each of which is called a target band. N bandpass filters are required for each target band. The transmission wavelength of each bandpass filter is the center wavelength of the target band, and the transmission bandwidth cannot exceed the wavelength bandwidth of the target band. Let these N bandpass filters be F1, F2, ..., Fn.

[0081] 9. Pass the pump light (the pump light frequency should be twice the center wavelength of the target band) into the waveguide body through the optical signal input terminal, connect the bandpass filter F1 at the optical signal output terminal, and then connect the power meter.

[0082] 10. Apply current to the thermoelectrode H1 through the probe, adjust the current of H1 until the power meter reaches its maximum power, and record the corresponding current.

[0083] 11. Keep the power supply on H1, power on H2 using the same method, and replace filter F1 with F2. Adjust the power supply until the power meter reaches its maximum power.

[0084] 12. For the remaining thermoelectrodes, repeat step 11 until all N thermoelectrodes are adjusted and N currents are obtained. At this time, all thermoelectrodes are in a charged state, and the bandwidth of the corresponding spontaneous parametric downconversion will also cover the candidate band, realizing a broadband quantum entangled light source.

[0085] like Figure 3 As shown, the spectrum obtained by the spontaneous parametric down-conversion of the waveguide component in this embodiment is significantly broadened compared to the spectrum obtained by the spontaneous parametric down-conversion of a conventional waveguide, thus realizing the generation of a broadband quantum entangled light source.

[0086] Understandably, waveguide components fabricated using the above process do not achieve quasi-phase matching by altering the parameters of the waveguide component itself. Instead, they achieve quasi-phase matching over a wide bandwidth by employing segmented thermal tuning, selecting appropriate temperatures for each small segment of the waveguide. This allows the entire waveguide component to achieve quasi-phase matching over a broad bandwidth, enabling broadband quantum entangled light sources and thus offering greater design flexibility. Furthermore, broadband phase matching is not achieved during the design phase. Instead, after sample fabrication, the waveguide refractive index is tuned based on feedback from test results to achieve broadband phase matching, thereby overcoming the influence of process errors.

[0087] Figure 4 This is a flowchart of a control method for a waveguide assembly according to an embodiment of the present invention. This method can be applied to the waveguide assembly including a heating resistor in the foregoing embodiments, and can specifically be executed by a controller within the waveguide assembly. Figure 4 As shown, the control method for this waveguide component may include:

[0088] S410, The control light source output device outputs pump photons to the optical signal input terminal of the waveguide body;

[0089] S420. Obtain the rated current corresponding to each of the heating resistors;

[0090] S430. Based on the rated current of each heating resistor, control the current connected to the corresponding heating resistor so that the waveguide body in the region corresponding to the different heating resistors performs spontaneous parametric down-conversion on the passing optical signal to generate quantum entangled light sources in different bands.

[0091] Using the method of this invention, the current connected to multiple heating resistors can be controlled according to a pre-calibrated rated current, thereby enabling the entire waveguide assembly to meet quasi-phase matching within the required broadband range through segmented thermal tuning, thus realizing a broadband quantum entangled light source. Furthermore, since the waveguide assembly of this embodiment does not achieve broadband phase matching during the design stage, but tunes the waveguide refractive index to meet broadband phase matching by heating with a heating device after sample preparation, the influence of process errors can be overcome, thereby reducing the difficulty of waveguide manufacturing.

[0092] In some implementations, the waveguide component control method may further include the following steps:

[0093] The control light source output device outputs pump photons to the optical signal input terminal of the waveguide body;

[0094] Different currents are applied to the target heating resistor until the intensity of the optical signal output from the optical signal output terminal of the waveguide body, corresponding to the target band of the target heating resistor, reaches a preset intensity threshold. Based on the current applied to the target heating resistor when the preset intensity threshold is reached, the rated current of the target heating resistor is determined.

[0095] From the remaining heating resistors with undetermined rated currents, determine a new target heating resistor and return to the step: control the target heating resistor to be connected to different currents until the intensity of the optical signal output terminal of the waveguide body corresponding to the target band of the target heating resistor reaches a preset intensity threshold. Based on the current connected to the target heating resistor when the preset intensity threshold is reached, determine the rated current of the target heating resistor.

[0096] In some implementations, determining a new target heating resistor from the remaining heating resistors with undetermined rated current may include the following steps:

[0097] The current connected to the heating resistor with a known rated current is kept constant. A new target heating resistor is determined from the remaining heating resistors with undetermined rated currents. The process returns to the step of controlling the target heating resistor to be connected to different currents until the intensity of the optical signal output terminal of the waveguide body corresponding to the target heating resistor reaches a preset intensity threshold. Based on the current connected to the target heating resistor when the preset intensity threshold is reached, the rated current of the target heating resistor is determined.

[0098] In some embodiments, when determining the rated current of the target heating resistor, the optical signal output terminal of the waveguide body is connected to the signal input terminal of the target bandpass filter corresponding to the target heating resistor, the signal output terminal of the target bandpass filter is connected to a power meter, the transmission wavelength of the target bandpass filter is the center wavelength of the target band, and the wavelength bandwidth of the transmission wavelength of the target bandpass filter is less than or equal to the wavelength bandwidth of the target band. In this case, the control method of the waveguide assembly may further include the step of determining the intensity of the optical signal of the target band corresponding to the target heating resistor.

[0099] For a detailed description of the control method of the waveguide component in the above embodiments, please refer to the foregoing embodiments, and it will not be repeated here.

[0100] Based on the same technical concept, an embodiment of the present invention also provides an optical chip, including the waveguide component in the foregoing embodiment.

[0101] Optical chips may include optical components such as optical fibers, waveguide components as described in the foregoing embodiments, beam splitters, phase modulators, and mirrors to achieve optical transmission and logic operations (such as Hadamard gates and CNOT gates).

[0102] Based on the same technical concept, an embodiment of the present invention also provides an optical quantum computer, which includes the optical chip in the foregoing embodiment.

[0103] In optical quantum computers, optical chips (also known as optical quantum chips) are the core components that constitute the quantum information processing link; optical chips are the "processors of quantum computing".

[0104] Optical chips are the core carriers of quantum information processing. Their function is to programmably manipulate the quantum state of a single photon, enabling core functions such as quantum logic operations, quantum entanglement generation, and quantum state storage. Specific functions include:

[0105] Quantum bit manipulation: Through integrated waveguides, modulators, quantum gates and other components, phase modulation of single photons (single-bit gate) and interference of two photons (double-bit gate, such as CNOT gate) can be achieved.

[0106] Quantum entanglement preparation: using linear optical elements (such as beam splitters, phase shifters) or nonlinear processes (such as SPDC) to entangle multiple single photons into multiphoton quantum states (such as Greenberger-Horne-Zeilinger states).

[0107] Reconfigurable optical path: The optical path is dynamically switched by an electro-optic / thermo-optic modulator, enabling flexible deployment of quantum algorithms (similar to the "programmability" of traditional chips).

[0108] For example, a photonic quantum chip based on thin-film lithium niobate (TFLN) can integrate hundreds of quantum gates and achieve nanosecond-level single-photon phase modulation through electro-optic modulation, achieving a fidelity of over 98% for two-photon CNOT gates.

[0109] For details on the specific processing procedures of optical quantum computers, please refer to the relevant technical descriptions, which will not be elaborated here.

[0110] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0111] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0112] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0113] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0114] In addition, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0115] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program verification codes, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0116] Furthermore, it should be noted that the combination of the various technical features in this case is not limited to the combination methods described in the claims of this case or the combination methods described in the specific embodiments. All technical features described in this case can be freely combined or combined in any way, unless they contradict each other.

[0117] It should be noted that the above examples are merely specific embodiments of the present invention, and the present invention is obviously not limited to the above embodiments, with many similar variations. All modifications that can be directly derived or conceived by those skilled in the art from the content disclosed in this invention should fall within the protection scope of this invention.

[0118] It should be understood that the limiting terms such as "first" and "second" mentioned in the embodiments of the present invention are only for the purpose of more clearly describing the use of the technical solutions of the embodiments of the present invention, and cannot be used to limit the scope of protection of the present invention.

[0119] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications or equivalent substitutions made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A waveguide assembly, comprising: The application relates to a quantum entanglement light source, comprising: a waveguide body, which has a preset polarization period in a light signal propagation direction; a plurality of heating devices for heating different regions of the waveguide body, wherein the heating devices comprise heating resistors; a controller for controlling the heating resistors in the plurality of heating devices to heat the waveguide body in the corresponding regions to different temperatures according to corresponding rated currents, so that the waveguide body is subjected to spontaneous parametric down-conversion at different frequencies to generate quantum entanglement light sources of different wavebands; the controller is further configured to: control a light source output device to output pump photons to a light signal input end of the waveguide body; control a target heating resistor to be connected to different currents until the intensity of light signals of a target waveband corresponding to the target heating resistor and output from a light signal output end of the waveguide body reaches a preset intensity threshold, determine the rated current of the target heating resistor based on the current connected to the target heating resistor when the preset intensity threshold is reached; determine a new target heating resistor from the remaining heating resistors whose rated currents have not been determined, and return to the step of controlling the target heating resistor to be connected to different currents until the intensity of light signals of a target waveband corresponding to the target heating resistor and output from a light signal output end of the waveguide body reaches a preset intensity threshold, and determining the rated current of the target heating resistor based on the current connected to the target heating resistor when the preset intensity threshold is reached.

2. The waveguide assembly of claim 1, wherein, The plurality of heating devices are arranged on the waveguide body at intervals in the light signal propagation direction.

3. The waveguide assembly of claim 1, wherein, The controller is further configured to: control the currents connected to the heating resistors according to the rated currents of the heating resistors, so that the waveguide body in the regions corresponding to the different heating resistors is subjected to spontaneous parametric down-conversion on the passing light signals to generate quantum entanglement light sources of different wavebands.

4. The waveguide assembly of claim 1, wherein, The controller is further configured to: control the currents connected to the heating resistors whose rated currents have been determined to remain unchanged, determine a new target heating resistor from the remaining heating resistors whose rated currents have not been determined, and return to the step of controlling the target heating resistor to be connected to different currents until the intensity of light signals of a target waveband corresponding to the target heating resistor and output from a light signal output end of the waveguide body reaches a preset intensity threshold, and determining the rated current of the target heating resistor based on the current connected to the target heating resistor when the preset intensity threshold is reached.

5. The waveguide assembly of claim 1, wherein, When the rated current of the target heating resistor is determined, a signal input end of a target band-pass filter corresponding to the target heating resistor is connected to the light signal output end of the waveguide body, a signal output end of the target band-pass filter is connected to a power meter, the light transmission wavelength of the target band-pass filter is the central wavelength of the target waveband, and the wavelength bandwidth of the light transmission wavelength of the target band-pass filter is less than or equal to the wavelength bandwidth of the target waveband; the controller is further configured to determine the intensity of the light signals of the target waveband corresponding to the target heating resistor according to the data collected by the power meter.

6. The waveguide assembly of claim 1, wherein, The heating device further comprises a positive electrode end and a negative electrode end connected to the heating resistor.

7. A method of controlling a waveguide assembly, the method comprising: The heating device applied to the waveguide assembly of claim 1 comprises a heating resistor, and the method comprises: controlling the light source output device to output pump photons to the light signal input end of the waveguide body; acquiring the rated current corresponding to each heating resistor; controlling the current input to the corresponding heating resistor according to the rated current corresponding to each heating resistor, so that the waveguide body in the region corresponding to different heating resistors spontaneously parametrically down-converts the passing light signal to generate quantum entangled light sources of different wavebands; The method further comprises: controlling the target heating resistor to input different currents until the intensity of the light signal of the target waveband corresponding to the target heating resistor output by the light signal output end of the waveguide body reaches a preset intensity threshold, determining the rated current of the target heating resistor based on the current input to the target heating resistor when the preset intensity threshold is reached; determining a new target heating resistor from the remaining heating resistors whose rated current has not been determined, and returning to the step of controlling the target heating resistor to input different currents until the intensity of the light signal of the target waveband corresponding to the target heating resistor output by the light signal output end of the waveguide body reaches a preset intensity threshold, determining the rated current of the target heating resistor based on the current input to the target heating resistor when the preset intensity threshold is reached.

8. An optical chip, characterized by The waveguide assembly of any one of claims 1-6.

9. A photonic quantum computer, characterized by The optical quantum computer comprises the optical chip of claim 8.

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