Signal generation device and method for quantum chip measurement and control system

Abstract

The invention provides a signal generation device and method for a quantum chip measurement and control system, and mainly relates to the technical field of quantum computing. The signal generation device comprises an optical frequency comb light source used for generating a frequency comb optical signal comprising a plurality of initial spectral lines with equal interval frequencies; the frequency spectrum beam splitter is used for performing spatial separation on a plurality of initial spectral lines included in the frequency comb optical signal to obtain respective discrete spectral lines of the plurality of initial spectral lines; the modulator array is used for performing amplitude and phase modulation on each discrete spectral line to obtain respective modulation spectral lines of the plurality of discrete spectral lines; the frequency spectrum combiner is used for carrying out beam combination on the plurality of modulation spectral lines to obtain a combined optical signal; the dispersion processing module is used for performing dispersion processing on the synthesized optical signal so as to generate a time domain optical signal through frequency-time mapping; and the photoelectric detector is used for converting the time domain optical signal into a radio frequency electric signal so as to obtain a target radio frequency signal.

Description

Technical Field

[0001] The present invention relates to the technical field of quantum computing, and more specifically, to a signal generation device and method. Background Art

[0002] In the field of quantum computing, during operations such as initializing, manipulating, reading, and error correcting a quantum chip, it is necessary to generate various desired complex radio frequency waveforms, such as high-frequency pulses and broadband modulation signals. Therefore, in a quantum measurement and control system, an arbitrary waveform generator as a signal generation device is often indispensable.

[0003] However, the signals generated by traditional radio frequency arbitrary waveform generators usually have a frequency range within 10 GHz (~10 GHz) and limited bandwidth. Therefore, the generated waveforms are not accurate and ideal enough, thereby reducing the fidelity of the operations. Summary of the Invention

[0004] In view of this, the present invention provides a signal generation device and method for a quantum chip measurement and control system.

[0005] One aspect of the present invention provides a signal generation device for a quantum chip measurement and control system. The signal generation device includes: an optical frequency comb light source for generating a frequency comb optical signal including a plurality of initial spectral lines with equal frequency intervals; a spectral beam splitter for spatially separating the plurality of initial spectral lines included in the frequency comb optical signal to obtain discrete spectral lines of each of the plurality of initial spectral lines; a modulator array for respectively performing amplitude and phase modulation on each of the discrete spectral lines to obtain modulated spectral lines of each of the discrete spectral lines; a spectral combiner for combining the plurality of modulated spectral lines to obtain a combined optical signal; a dispersion processing module for performing dispersion processing on the combined optical signal to generate a time-domain optical signal through frequency-time mapping; and a photodetector for converting the time-domain optical signal into a radio frequency electrical signal to obtain a target radio frequency signal.

[0006] According to an embodiment of the present invention, the signal generation device further includes an optical beam splitter and a plurality of the photodetectors. The optical beam splitter and the plurality of photodetectors are disposed inside a dilution refrigerator; the time-domain optical signal is transmitted to the optical beam splitter through an optical fiber; the optical beam splitter is used for splitting the time-domain optical signal into multiple paths of time-domain optical signals, wherein the waveform of each path of time-domain optical signal is the same as the waveform of the time-domain optical signal generated by the dispersion processing module; and the plurality of photodetectors are used for converting the multiple paths of time-domain optical signals into multiple paths of radio frequency electrical signals to generate multiple paths of radio frequency arbitrary waveforms.

[0007] According to an embodiment of the present invention, the above signal generation device further includes an optical amplifier, and the optical amplifier is used to amplify the above time-domain optical signal to obtain an amplified time-domain optical signal; the above optical splitter is further used to split the amplified time-domain optical signal into the above multiple time-domain optical signals.

[0008] According to an embodiment of the present invention, the above modulator array includes a spatial light modulator array, and the spatial light modulator array is used to independently perform amplitude and phase modulation on each of the above discrete spectral lines.

[0009] According to an embodiment of the present invention, the above modulator array includes an amplitude modulator array and a phase modulator array; the amplitude modulator array is used to independently perform amplitude modulation on each of the above discrete spectral lines; the phase modulator array is configured to be cascaded with the amplitude modulator array, and the phase modulator array is used to independently perform phase modulation on each of the above discrete spectral lines.

[0010] According to an embodiment of the present invention, the above spectral splitter, the above modulator array, and the above spectral combiner are integrated into a chip-type control array.

[0011] According to an embodiment of the present invention, the above spectral splitter includes an input waveguide array grating, and the input waveguide array grating is used to spatially separate each of the multiple above initial spectral lines included in the above frequency comb optical signal to obtain discrete spectral lines of each of the multiple above initial spectral lines; the above modulator array includes an amplitude modulator array and a phase modulator array, and the amplitude modulator array and the phase modulator array are integrated on the above chip-type control array to independently perform amplitude and phase modulation on each of the above discrete spectral lines; the above spectral combiner includes an output waveguide array grating, and the output waveguide array grating combines the multiple above modulated spectral lines to obtain the above combined optical signal.

[0012] According to an embodiment of the present invention, the above optical frequency comb light source includes an optical frequency comb module and an optical switch; wherein, the optical frequency comb module is used to generate multiple above frequency comb optical signals with different central wavelengths, and the optical switch is used to select different above frequency comb optical signals.

[0013] Another aspect of the present invention provides a signal generation method for a quantum chip measurement and control system, which is applied to the above-mentioned signal generation device. The signal generation method includes: spatially separating multiple initial spectral lines included in a frequency comb optical signal to obtain discrete spectral lines of each of the multiple initial spectral lines; performing amplitude and phase modulation on each of the discrete spectral lines to obtain modulated spectral lines of each of the multiple discrete spectral lines; combining the multiple modulated spectral lines to obtain a combined optical signal; performing dispersion processing on the combined optical signal to generate a time-domain optical signal through frequency-time mapping; and converting the time-domain optical signal into a radio frequency electrical signal to obtain a target radio frequency signal.

[0014] According to an embodiment of the present invention, the above method further includes: amplifying the time-domain optical signal to obtain an amplified time-domain optical signal; introducing the amplified time-domain optical signal into a dilution refrigerator through an optical fiber to split the amplified time-domain optical signal into multiple time-domain optical signals; and converting the multiple time-domain optical signals into multiple radio frequency signals to generate multiple radio frequency arbitrary waveforms.

[0015] According to an embodiment of the present invention, a light frequency comb light source is used to generate multiple spectral lines with equal frequency intervals, and an array of modulators is used to independently control the amplitude and phase of each spectral line to achieve Fourier domain spectral editing, so as to generate high-frequency and large-bandwidth radio frequency arbitrary waveforms to meet the requirements of quantum bit manipulation for high-frequency and high-precision microwave signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Through the following description of the embodiments of the present invention with reference to the drawings, the above and other objects, features, and advantages of the present invention will become clearer.

[0017] Figure 1 FIG. shows a schematic diagram of a signal generation device for a quantum chip measurement and control system according to an embodiment of the present invention.

[0018] Figure 2 FIG. shows a schematic diagram of a signal generation device according to a specific embodiment of the present invention.

[0019] Figure 3 FIG. shows a schematic diagram of a signal generation device according to another specific embodiment of the present invention.

[0020] Figure 4 FIG. shows a schematic diagram of a signal generation device including a spatial light modulator array according to a specific embodiment of the present invention.

[0021] Figure 5 FIG. shows a schematic diagram of a signal generation device including an amplitude modulator array and a phase modulator array according to a specific embodiment of the present invention.

[0022] Figure 6Shows a schematic diagram of a chip-integrated regulation array according to a specific embodiment of the present invention.

[0023] Figure 7 Shows a schematic diagram of a signal generation device including a specific chip-integrated regulation array structure according to a specific embodiment of the present invention.

[0024] Figure 8 Shows a schematic diagram of a signal generation device including an optical frequency comb module and an optical switch according to a specific embodiment of the present invention.

[0025] Figure 9 Shows a flowchart of a signal generation method for a quantum chip measurement and control system according to an embodiment of the present invention. Detailed implementation manners

[0026] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. In the following detailed description, for the sake of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present invention. However, it is obvious that one or more embodiments can also be implemented without these specific details. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present invention.

[0027] The terms used herein are merely for describing specific embodiments and are not intended to limit the present invention. The terms "including", "comprising", etc. used herein indicate the presence of the described features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0028] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0029] In the case of using expressions such as "at least one of A, B, and C", generally, it should be interpreted according to the meaning commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include, but not be limited to, a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.).

[0030] In the field of quantum computing, during processes such as initializing, manipulating, reading, and error correcting quantum chips, various desired complex radio frequency waveforms need to be generated, such as high-frequency pulses, broadband modulation signals, etc. Therefore, in a quantum measurement and control system, an arbitrary waveform generator as a signal generation device is often indispensable.

[0031] However, the signals generated by traditional radio frequency arbitrary waveform generators usually have a frequency range within 10 GHz (~10 GHz) and limited bandwidth. As a result, the generated waveforms are not accurate and ideal enough, thereby reducing the fidelity of the system.

[0032] At the same time, due to the certain size of the radio frequency coaxial cable used in conjunction with the arbitrary waveform generator, when the number of qubits is scaled up significantly, the volume occupied by the cable will increase significantly, restricting the expansion of the number of qubits. Moreover, the loss brought by the cable when transmitting high-frequency signals will also cause the temperature of the cryogenic refrigerator system to rise, reducing the ability of the system to provide a low-temperature working environment. In addition, since a single cable only transmits one signal path, when the number of bits is large, crosstalk between various signal paths also becomes a problem that needs to be overcome with emphasis.

[0033] In view of this, embodiments of the present invention utilize an optical frequency comb light source to generate multiple spectral lines with equal frequency intervals, and independently control the amplitude and phase of each spectral line through a modulator array to achieve Fourier domain spectral editing, so as to generate high-frequency and large-bandwidth radio frequency arbitrary waveforms to meet the requirements of qubit manipulation for high-frequency and high-precision microwave signals.

[0034] Specifically, embodiments of the present invention provide a signal generation device for a quantum chip measurement and control system, including: an optical frequency comb light source for generating a frequency comb optical signal including multiple initial spectral lines with equal frequency intervals; a spectral beam splitter for spatially separating the multiple initial spectral lines included in the frequency comb optical signal to obtain discrete spectral lines for each of the multiple initial spectral lines; a modulator array for performing amplitude and phase modulation on each discrete spectral line to obtain modulated spectral lines for each of the multiple discrete spectral lines; a spectral combiner for combining the multiple modulated spectral lines to obtain a combined optical signal; a dispersion processing module for performing dispersion processing on the combined optical signal to generate a time-domain optical signal through frequency-time mapping; and a photodetector for converting the time-domain optical signal into a radio frequency electrical signal to obtain a target radio frequency signal.

[0035] Figure 1 Shows a schematic diagram of a signal generation device for a quantum chip measurement and control system according to an embodiment of the present invention.

[0036] As Figure 1 shown, the signal generation device includes an optical frequency comb light source 1, a spectral beam splitter 2, a modulator array 3, a spectral combiner 4, a dispersion processing module 5, and a photodetector array 6.

[0037] As Figure 1 shown, the output end of the optical frequency comb light source 1 is connected to the input end of the spectral beam splitter 2 to transmit the generated frequency comb optical signal to the spectral beam splitter 2.

[0038] In this embodiment, the optical frequency comb light source 1 is used to generate a frequency comb optical signal, providing a fundamental frequency component for subsequent generation of complex waveforms. Among them, the spectrum of the frequency comb optical signal includes multiple initial spectral lines with equally spaced frequencies, and each initial spectral line corresponds to an exact frequency.

[0039] In a specific embodiment, this frequency can be expressed as , where f0 represents the starting frequency, that is, the frequency value of the first spectral line in the frequency comb; represents the frequency interval, that is, the frequency difference between adjacent two spectral lines, and this frequency interval has a relationship with the pulse repetition interval T as ; among them, , and N represents the number of spectral lines.

[0040] In a specific embodiment, the optical frequency comb light source 1 can be implemented by a mode-locked laser, a pumped microcavity system, a plasma, etc. In a specific implementation manner, the mode-locked laser can generate ultrashort optical pulses through periodic mode locking, and its frequency domain manifestation is an equally spaced frequency comb. In another specific implementation manner, the pumped microcavity system can include a pump laser and a microresonator. Among them, the pump laser can provide continuous light or pulsed light input to the microresonator, and the microresonator can convert the pump light into a broadband optical frequency comb. The plasma optical frequency comb generates a frequency comb optical signal by enhancing the nonlinear effects (such as high-order harmonics, four-wave mixing, etc.) in the metal-dielectric nanostructure through surface plasmon polaritons. In the embodiments of the present invention, the specific type of the optical frequency comb light source 1 is not specifically limited, and any device capable of generating an equally spaced multi-spectral line optical signal is within the protection scope of the present invention.

[0041] As Figure 1 shown, the output end of the spectral beam splitter 2 is connected to the input end of the modulator array 3 to split the frequency comb optical signal output by the optical frequency comb light source 1 into multiple independent spectral lines.

[0042] In this embodiment, the spectral beam splitter 2 is used to spatially separate the initial spectral lines with different frequencies in the frequency comb optical signal to form discrete spectral lines for each of the multiple initial spectral lines, so as to modulate each discrete spectral line separately.

[0043] In a specific embodiment, the spectral beam splitter 2 can be implemented by a wavelength-selective device such as a waveguide array grating, a diffraction grating, etc. According to the principle of light diffraction or interference, light of different frequencies or wavelengths can be separated by angle or path. For example, a diffraction grating, through the dispersion effect of light, causes light of different wavelengths to exit at different angles, and in combination with a spatial optical path or a waveguide structure, each discrete spectral line is guided to an independent channel. In the embodiments of the present invention, the spectral beam splitter 2 is not specifically limited.

[0044] As Figure 1 shown, the output end of the modulator array 3 is connected to the input end of the spectral combiner 4 to perform amplitude and phase modulation on each discrete spectral line respectively, obtaining the modulated spectral lines of each discrete spectral line.

[0045] In this embodiment, the modulator array 3 is used to perform independent amplitude and phase modulation on each discrete spectral line after spatial separation to generate multiple modulated spectral lines carrying target waveform information.

[0046] In a specific embodiment, before amplitude and phase modulation, the optical field expression is , where , respectively represent the initial amplitude and phase of the i-th discrete spectral line in terms of frequency. Among them, all discrete spectral lines are coherent. Each discrete spectral line corresponds to an independent modulation channel. By an electrical signal (such as a digital signal from a control computer), the modulator parameters are controlled in real time. The modulated optical field is , where , respectively characterize the amplitude and phase modulation of each frequency component by the modulator array 3. By precisely controlling the , of each discrete spectral line by the modulator array 3, the frequency-domain components of the synthesized target waveform can be customized.

[0047] As Figure 1 shown, the output end of the spectral combiner 4 is connected to the input end of the dispersion processing module 5 to combine multiple modulated spectral lines to obtain a synthesized optical signal.

[0048] In this embodiment, the spectral combiner 4 is used to recombine multiple modulated independent spectral lines into a single synthesized optical signal to achieve controllable coherent superposition of the optical field.

[0049] In a specific embodiment, the spectral combiner 4 can adopt a device complementary to the spectral beam splitter (such as a waveguide array grating, a reverse diffraction grating, etc.), and use the principle of light interference to converge light of different frequencies to the same output port along the original path or a symmetric path. In the embodiments of the present invention, the spectral combiner 4 is not specifically limited.

[0050] In this specific embodiment, the combined synthetic optical signal is the coherent superposition of each modulated spectral line, and its optical field can be expressed as , where and represent the amplitude and phase after modulation corresponding to the i-th spectral line. This signal appears as a comb spectrum carrying the target waveform information in the frequency domain, and can provide a frequency-domain input for time-domain waveform synthesis.

[0051] As Figure 1 shown, the output end of the dispersion processing module 5 is connected to the input end of the photodetector array 6 to perform dispersion processing on the synthetic optical signal and generate a time-domain optical signal.

[0052] In this embodiment, the dispersion processing module 5 processes the frequency-domain synthetic optical signal output by the spectral combiner 4 to utilize its dispersion characteristics and adapt to the bandwidth of the photodetector by adjusting the time-domain scale of the optical waveform.

[0053] In a specific embodiment, the dispersion processing module 5 can be implemented by using dispersion devices such as dispersion fibers, chirped fiber gratings, etc. In the embodiments of the present invention, the dispersion processing module 5 is not specifically limited.

[0054] In this specific embodiment, since the high-frequency optical signal propagates slower (normal dispersion) or faster (anomalous dispersion) in the dispersion medium, different frequency components have different time delays. Finally, each frequency component is arranged in frequency order in the time domain and superimposed to form the target waveform.

[0055] As Figure 1 shown, when the photodetector 6 receives the time-domain optical signal after dispersion processing, it converts the change in light intensity into a current signal through the photoelectric effect to obtain the radio-frequency electrical signal of the target waveform, and transmits the generated radio-frequency arbitrary waveform to multiple control ports of the quantum chip as the driving signal required for qubit manipulation.

[0056] Among them, the optical frequency comb light source 1, the spectral beam splitter 2, the modulator array 3, the spectral combiner 4, and the dispersion processing module 5 are configured in the normal-temperature space. The photodetector 6 is configured in a cryogenic dilution refrigerator, and the radio-frequency electrical signal output by the signal generation device is directly connected to the control interface of the quantum chip such as a superconducting quantum chip, a semiconductor chip, etc. to drive the qubit to complete quantum gate operations or state readings, etc.

[0057] Based on this, the embodiments of the present invention use an optical frequency comb light source to generate multiple spectral lines with equal frequency intervals, and independently regulate the amplitude and phase of each spectral line through the modulator array to achieve Fourier-domain spectral editing, so as to generate high-frequency and large-bandwidth arbitrary waveforms to meet the requirements of qubit manipulation for high-frequency and high-precision microwave signals.

[0058] Furthermore, in this embodiment, when the optical fiber transmits signals within a large frequency and temperature range, its phase change is small and the change relationship is simple, which is also very beneficial for the development of advanced dispersion reading technology. In addition, based on the anti-electromagnetic interference characteristics of the optical fiber, it does not radiate or absorb radio frequency signals, so the crosstalk between channels is small, which is also conducive to the high-precision and high-fidelity control of qubits.

[0059] Figure 2 The schematic diagram of the signal generation device according to a specific embodiment of the present invention is shown.

[0060] As Figure 2 shown, in this specific embodiment, the signal generation device further includes an optical splitter 7 and multiple photodetectors 6.

[0061] Among them, the optical splitter 7 and the multiple photodetectors 6 are both arranged inside the dilution refrigerator. The input end of the optical splitter 7 is connected to the output end of the dispersion processing module 5, and the output ends of the optical splitter 7 are respectively connected to the input ends of the multiple photodetectors 6. In this specific embodiment, the time-domain optical signal is transmitted to the optical splitter 7 located inside the dilution refrigerator through a single optical fiber. The optical splitter 7 evenly divides one path of time-domain optical signal into multiple paths of time-domain optical signals in a low-temperature environment to realize the conversion from a single-path optical signal to multiple paths of synchronous optical signals. Among them, after the time-domain optical signal after dispersion processing is split into multiple paths by the optical splitter 7, the frequency components, phase relationships, and time-domain waveforms of each path of time-domain optical signal are the same as the waveform of the time-domain optical signal generated by the dispersion processing module 5. The multiple photodetectors 6 are used to convert the multiple paths of time-domain optical signals into multiple paths of radio frequency electrical signals to generate radio frequency arbitrary waveforms and output them to the quantum chip.

[0062] As Figure 2 shown, in this specific embodiment, the signal generation device further includes an optical amplifier 8.

[0063] Among them, the input end of the optical amplifier 8 can be connected to the output end of the dispersion processing module 5, the output end of the optical amplifier 8 can be connected to the input end of the optical splitter 7 located inside the dilution refrigerator, and the optical amplifier 8 can be used to amplify the optical field of the time-domain optical signal output by the dispersion processing module 5 to obtain an amplified time-domain optical signal to pre-compensate for the optical intensity loss caused by subsequent beam splitting. The optical splitter 7 is further used to split the amplified time-domain optical signal into multiple paths of time-domain optical signals and transmit them to the multiple photodetectors 6.

[0064] In a specific embodiment of the present invention, the optical amplifier 8 can be configured as a tunable optical amplifier, and its gain can be dynamically adjusted according to the number of channels of the optical splitter 7 to compensate for the splitting loss. For example, when the number of channels of the optical splitter 7 increases, the gain of the optical amplifier 8 can be adjusted upward to ensure that the power of each optical signal meets the sensitivity requirements of the photodetector 6. Among them, the gain adjustment of the tunable optical amplifier can be completed in real time through an external control signal to adapt to the dynamic requirements of the quantum chip measurement and control system.

[0065] Figure 3 FIG. shows a schematic diagram of a signal generation device according to another specific embodiment of the present invention.

[0066] In this specific embodiment, the optical splitter 7 and the photodetector 6 can be integrated into the same packaging module, that is, the optoelectronic integration module 9 as shown in Figure 3 . The input end of the optoelectronic integration module 9 is connected to the output end of the optical amplifier 8, and the output end is connected to the control port of the quantum chip. Using this optoelectronic integration module 9 can reduce the volume of the signal generation device to facilitate high-density wiring inside the dilution refrigerator.

[0067] Based on this, in the embodiment of the present invention, the optical splitter is arranged inside the dilution refrigerator to evenly divide the single-channel time-domain optical signal after dispersion processing into multiple channels. The frequency components, phase relationships, and time-domain waveforms of each optical signal are the same, which is suitable for multi-port parallel manipulation of quantum chips and avoids manipulation errors caused by inconsistent transmission delays and amplitude attenuations of multiple signals.

[0068] Secondly, in the embodiment of the present invention, a single traditional coaxial cable can only transmit one electrical signal and has a diameter of several millimeters. Since a single optical fiber can transmit multiple optical signals through wavelength division multiplexing, and the diameter of the optical fiber ( ) is only one fortieth to one fiftieth of that of the coaxial cable, therefore, optical fibers can support high-density wiring. When the number of qubits expands to more than one hundred levels, the wiring volume of the optical fiber solution is significantly smaller than that of the cable solution, thereby greatly alleviating the problem of insufficient internal space in the refrigerator. In addition, since the weight per unit length of the optical fiber is only ~70 g / km, which is less than one ten-thousandth of that of the traditional coaxial cable (~600 kg / km), using optical fibers can avoid problems such as excessive load on the internal structure of the refrigerator caused by the weight of the cable. At the same time, due to the flexible and bendable characteristics of the optical fiber, it can be flexibly inserted among the complex pipelines inside the refrigerator, and the wiring can be carried out conveniently and flexibly without reserving turning space for rigid cables, thereby improving the wiring efficiency, especially suitable for the measurement and control of three-dimensional stacked quantum chip arrays.

[0069] Furthermore, when the traditional solution uses a cable to transmit radio frequency signals, its loss increases rapidly with the increase of frequency. Taking a 20GHz signal as an example, the cable loss can reach ~3dB / m, while the loss of optical fiber is only ~0.2dB / km, which is much lower than the cable loss. At the same time, since the phase of the optical fiber is not sensitive to temperature changes and is suitable for low-temperature environments, the embodiments of the present invention transmit the time-domain optical signal to the low-temperature environment of the dilution refrigerator through an optical fiber, which can reduce the thermal load of the dilution refrigerator.

[0070] Figure 4 FIG. shows a schematic diagram of a signal generation device including a spatial light modulator array according to a specific embodiment of the present invention.

[0071] As Figure 4 shown, in a specific embodiment, the modulator array 3 may use a spatial light modulator array as a modulation device, and each spatial light modulator corresponds to a separate spectral line to independently control its amplitude and phase. In a specific embodiment, the spatial light modulator may be implemented based on a liquid crystal modulator, an acousto-optic effect modulator, a microelectromechanical system (MEMS) modulator, a digital micromirror device (DMD), etc., to dynamically adjust the modulation parameters of each separate spectral line.

[0072] In the embodiments of the present invention, the spatial light modulator can allow real-time and independent control of the amplitude and phase of each separate spectral line through spatial optical routing or wavelength multiplexing technology, without time-sharing processing, improving the modulation efficiency and obtaining an accurate waveform.

[0073] Figure 5 FIG. shows a schematic diagram of a signal generation device including an amplitude modulator array and a phase modulator array according to a specific embodiment of the present invention.

[0074] As Figure 5 shown, in another specific embodiment, the modulator array 3 may also use an amplitude modulator array and a phase modulator array, wherein the amplitude modulator array and the phase modulator array may be cascaded to independently control the amplitude and phase of each spectral line. Among them, the cascaded modulation composed of the amplitude modulator array and the phase modulator array can independently and accurately control each spectral line to obtain the high-precision waveform required for quantum chip manipulation.

[0075] Figure 6 FIG. shows a schematic diagram of a signal generation device including a chip-integrated control array according to a specific embodiment of the present invention.

[0076] As Figure 6 shown, the signal generation device may include a chip-integrated control array 10, wherein the chip-integrated control array may be based on a photon integrated chip (PIC) technology, such as Figure 2Devices such as the spectral beam splitter 2, the modulator array 3, and the spectral combiner 4 shown in the figure are integrated on the same substrate (such as silicon or lithium niobate) to form a miniaturized and low-loss optical processing unit.

[0077] Figure 7 The figure shows a schematic diagram of a signal generation device including a specific chip-integrated control array structure according to a specific embodiment of the present invention.

[0078] As Figure 7 shown, the frequency comb optical signal enters the input waveguide array grating included in the chip-integrated control array 10 from the optical frequency comb light source 1. In the free input region, the frequency comb optical signal is separated into spectral lines of different wavelengths. After amplitude and phase modulation are sequentially performed by the chip-type amplitude modulator array and the chip-type phase modulator array, the modulated spectral lines are recombined into a beam in the free output region through the output waveguide array grating to obtain a combined optical signal, which is transmitted to the dispersion processing module 5.

[0079] In this specific embodiment, since the optical path connection loss of traditional discrete optical devices such as spatial beam splitters and free-space modulators is relatively large, in contrast, the optical path loss of waveguide integration in the chip is extremely small, and the phase change caused by temperature drift is small. Therefore, the chip-integrated control array 10 significantly improves signal stability, and has a simple structure and a small volume.

[0080] Figure 8 The figure shows a schematic diagram of a signal generation device including an optical frequency comb module and an optical switch according to a specific embodiment of the present invention.

[0081] As Figure 8 shown, the optical frequency comb light source 1 may include multiple optical frequency comb modules and an optical switch. The output end of the optical frequency comb module is connected to the input end of the optical switch, and the output end of the optical switch is connected to the input end of the spectral beam splitter 2. Among them, since the central wavelength or frequency range of each optical frequency comb module is different, the generated frequency comb spectral line intervals are the same but the overall frequency offsets are different. The optical switch can be used to quickly switch different optical frequency comb modules, enabling the system to dynamically select and output a frequency comb optical signal within a specific frequency range.

[0082] Specifically, each optical frequency comb module can generate a spectrum with the same frequency comb spectral line interval, and the frequency comb spectral line intervals generated between different optical frequency comb modules can be different. Therefore, by quickly switching the optical switch, the signal generation device can generate radio frequency waveforms within different frequency ranges after subsequent modulation, dispersion processing, etc.

[0083] For example, as Figure 8As shown, by switching the optical switch, the spectrum 1 with a Gaussian distribution is input into the spectrum beam splitter 2. After being processed by the modulator array 3, the spectrum combiner 4, the dispersion processing module 5, the optical amplifier 8, the optical beam splitter 7, and the photodetector 6, a radio frequency signal as shown in the output waveform 1 is generated. In another embodiment, by switching the optical switch, the spectrum k with equal intervals and equal amplitudes can also be input into the spectrum beam splitter 2. After being processed by the modulator array 3, the spectrum combiner 4, the dispersion processing module 5, the optical amplifier 8, the optical beam splitter 7, and the photodetector 6, a radio frequency signal as shown in the output waveform K is generated.

[0084] Based on this, in the embodiments of the present invention, since various complex radio frequency waveforms need to be generated in different operation stages of the quantum chip, such as initialization, manipulation, reading, operation, error correction, etc., different optical frequency comb signals can be generated by switching the optical frequency comb module and adjusting the modulation parameters. This enables the optical frequency comb light source to dynamically select the frequency range and reconstruct the radio frequency signal waveform without replacing the hardware, realizing the function of dynamically reconfigurable arbitrary waveform generation, thereby adapting to the measurement and control requirements of multiple types of qubits and improving the measurement and control efficiency.

[0085] According to an embodiment of the present invention, in the signal generation device as shown in Figures 1 to 8 it may further include a control module. Among them, the control module can adopt a field programmable gate array or a digital signal processor, etc., and can be used to coordinate the parameter configuration and dynamic control of each component.

[0086] Specifically, the control module can perform real-time adjustment on the amplitude modulation coefficient and phase offset of the modulator array 3 as shown in Figures 1 to 3 or on the modulation coefficient of the amplitude modulator array and the phase offset of the phase modulator array as shown in Figure 5 respectively, so as to generate a target radio frequency signal with an arbitrary waveform in real time.

[0087] In addition, the control module can also receive upper computer instructions or real-time feedback signals, generate an optical switch switching pulse signal, so as to realize the fast gating of multiple optical frequency comb modules as shown in Figure 8 This enables the optical frequency comb light source to dynamically generate multiple optical frequency comb signals on the same device without replacing the hardware, only by controlling the optical switch through the control module. On the basis of meeting the real-time frequency switching requirements in quantum measurement and control and supporting the generation of dynamic multi-frequency signals such as time division multiplexing multi-channel measurement and control, the system complexity and cost are reduced, and the compatibility is improved.

[0088] Figure 9 The flowchart of the signal generation method for the quantum chip measurement and control system according to an embodiment of the present invention is shown.

[0089] As shown in Figure 9As shown in the figure, an embodiment of the present invention further provides a signal generation method for a quantum chip measurement and control system, and this method includes operations S910 to S950.

[0090] In operation S910, multiple initial spectral lines included in a frequency comb optical signal are spatially separated respectively to obtain discrete spectral lines of each of the multiple initial spectral lines with equal frequency intervals.

[0091] In operation S920, amplitude and phase modulation are performed on each discrete spectral line respectively to obtain modulated spectral lines of each of the multiple discrete spectral lines.

[0092] In operation S930, the multiple modulated spectral lines are combined to obtain a combined optical signal.

[0093] In operation S940, dispersion processing is performed on the combined optical signal to generate a time-domain optical signal through frequency-time mapping.

[0094] In operation S950, the time-domain optical signal is converted into a radio frequency electrical signal to obtain a target radio frequency signal.

[0095] Among them, a signal generation method for a quantum chip measurement and control system further includes: performing amplification processing on the time-domain optical signal to obtain an amplified time-domain optical signal; introducing the amplified time-domain optical signal into the dilution refrigerator through an optical fiber to split the amplified time-domain optical signal into multiple paths of time-domain optical signals; converting the multiple paths of time-domain optical signals into multiple paths of radio frequency electrical signals to generate multiple paths of radio frequency arbitrary waveforms.

[0096] Based on this, the embodiment of the present invention uses an optical frequency comb light source to generate multiple spectral lines with equal frequency intervals, and independently controls the amplitude and phase of each spectral line through a modulator array to achieve Fourier domain spectrum editing, so as to generate arbitrary waveforms with high frequency and large bandwidth, meeting the requirements of quantum bit manipulation for high-frequency and high-precision microwave signals.

[0097] Furthermore, in this embodiment, since the phase change of the optical fiber is small and the change relationship is simple within a large frequency and temperature range when transmitting signals, this is also very beneficial for the development of advanced dispersion reading technology. In addition, based on the anti-electromagnetic interference characteristics of the optical fiber, it does not radiate nor absorb radio frequency signals, so the crosstalk between channels is small. Further combined with its wavelength division multiplexing characteristics, it is very beneficial for the high-precision and high-fidelity manipulation of quantum chips in the case of multi-channel signal transmission.

[0098] Secondly, in the embodiment of the present invention, an optical splitter is arranged inside the dilution refrigerator to evenly divide the single-path time-domain optical signal after dispersion processing into multiple paths. The frequency components, phase relationships, and time-domain waveforms of each path of optical signal are the same, which is suitable for the multi-port parallel manipulation of quantum chips and avoids manipulation errors caused by inconsistent transmission delays and amplitude attenuations of multiple paths of signals.

[0099] In addition, in the embodiments of the present invention, a single traditional coaxial cable can only transmit one electrical signal and has a diameter of several millimeters. Since a single optical fiber can transmit multiple optical signals through wavelength division multiplexing, and the diameter of the optical fiber ( is only one fortieth of that of the coaxial cable. Therefore, optical fibers can support high-density wiring. When the number of qubits expands to more than one hundred, the wiring volume of the optical fiber solution is significantly reduced compared to the cable solution, thus greatly alleviating the problem of insufficient internal space in the cryogenic refrigerator. Since the weight per unit length of the optical fiber is only ~70 g / km, less than one ten-thousandth of that of the traditional coaxial cable (~600 kg / km), using optical fibers can avoid problems such as excessive load on the internal structure of the cryogenic refrigerator caused by the weight of the cable. At the same time, due to the flexible and bendable characteristics of the optical fiber, it can be flexibly inserted among the complex pipelines inside the cryogenic refrigerator, facilitating convenient and flexible wiring without the need to reserve turning space for rigid cables, thereby improving the wiring efficiency, especially suitable for the measurement and control of three-dimensional stacked quantum chip arrays.

[0100] Furthermore, when the traditional solution uses a cable to transmit radio frequency signals, its loss increases rapidly with the increase in frequency. Taking a 20 GHz signal as an example, the cable loss can reach ~3 dB / m, while the loss of the optical fiber is only ~0.2 dB / km, which is much lower than the cable loss. At the same time, since the phase of the optical fiber is not sensitive to temperature changes and is suitable for low-temperature environments, in the embodiments of the present invention, the time-domain optical signal is transmitted to the low-temperature environment of the dilution refrigerator through the optical fiber, which can reduce the thermal load of the dilution refrigerator.

[0101] It should be noted that the signal generation method part in the embodiments of the present invention corresponds to the signal generation device part in the embodiments of the present invention. For the description of the signal generation method part, please refer specifically to the signal generation device part and will not be elaborated here.

[0102] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagram may represent a module, a segment of a program, or a portion of code, which contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions noted in the blocks may occur in a different order than that noted in the accompanying drawings. For example, two consecutive blocks shown may actually be executed substantially in parallel, or they may sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram or flowchart, and combinations of blocks in the block diagram or flowchart, can be implemented by a dedicated hardware-based system that performs the specified functions or operations, or can be implemented by a combination of dedicated hardware and computer instructions. Those skilled in the art will understand that the features described in the various embodiments of the present invention can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in the present invention. In particular, without departing from the spirit and teachings of the present invention, the features described in the various embodiments of the present invention can be combined and / or combined in various ways. All such combinations and / or combinations fall within the scope of the present invention.

[0103] The embodiments of the present invention have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention. Although the embodiments have been described separately above, this does not mean that the measures in each embodiment cannot be used advantageously in combination. Without departing from the scope of the present invention, those skilled in the art can make various substitutions and modifications, and all such substitutions and modifications should fall within the scope of the present invention.

Claims

1. A signal generation device for a quantum chip measurement and control system, characterized in that, The signal generation device includes: An optical frequency comb light source for generating a frequency comb optical signal including multiple initial spectral lines with equal frequency intervals; A spectral beam splitter for spatially separating the multiple initial spectral lines included in the frequency comb optical signal to obtain discrete spectral lines of each of the multiple initial spectral lines; A modulator array for performing amplitude and phase modulation on each of the discrete spectral lines to obtain modulated spectral lines of each of the discrete spectral lines; A spectral combiner for combining the multiple modulated spectral lines to obtain a combined optical signal; A dispersion processing module for performing dispersion processing on the combined optical signal to generate a time-domain optical signal through frequency-time mapping; A photodetector for converting the time-domain optical signal into a radio frequency electrical signal to obtain a target radio frequency signal.

2. The signal generating device according to claim 1, wherein The signal generation device further includes an optical beam splitter and multiple photodetectors. The optical beam splitter and the multiple photodetectors are disposed inside a dilution refrigerator, and the time-domain optical signal is transmitted to the optical beam splitter through an optical fiber; The optical beam splitter is used to split the time-domain optical signal into multiple paths of time-domain optical signals, wherein the waveform of each path of time-domain optical signal is consistent with the waveform of the time-domain optical signal generated by the dispersion processing module; The multiple photodetectors are used to convert the multiple paths of time-domain optical signals into multiple paths of radio frequency electrical signals to generate multiple paths of radio frequency arbitrary waveforms.

3. The signal generating device according to claim 2, characterized in that, The signal generation device further includes an optical amplifier for amplifying the time-domain optical signal to obtain an amplified time-domain optical signal; The optical beam splitter is further used to split the amplified time-domain optical signal into the multiple paths of time-domain optical signals.

4. The signal generation device according to claim 1, characterized in that, The modulator array includes a spatial light modulator array for independently performing amplitude and phase modulation on each of the discrete spectral lines.

5. The signal generation device according to claim 1, wherein The modulator array includes an amplitude modulator array and a phase modulator array; The amplitude modulator array is used to independently perform amplitude modulation on each of the discrete spectral lines; The phase modulator array is configured to be cascaded with the amplitude modulator array, and the phase modulator is used to independently perform phase modulation on each of the discrete spectral lines.

6. The signal generation device according to claim 1, characterized in that, The spectral beam splitter, the modulator array, and the spectral combiner are integrated into a chip-type regulation array.

7. The signal generation device according to claim 6, wherein The spectral beam splitter includes an input waveguide array grating for spatially separating the multiple initial spectral lines included in the frequency comb optical signal to obtain discrete spectral lines of each of the multiple initial spectral lines; The modulator array includes an amplitude modulator array and a phase modulator array. The amplitude modulator array and the phase modulator array are integrated on the chip-type regulation array to independently perform amplitude and phase modulation on each of the discrete spectral lines; The spectral combiner includes an output waveguide array grating for combining the multiple modulated spectral lines to obtain the combined optical signal.

8. The signal generation device according to any one of claims 2 to 7, characterized in that The optical frequency comb light source includes an optical frequency comb module and an optical switch; Among them, the optical frequency comb module is used to generate a plurality of frequency comb optical signals with different central wavelengths, and the optical switch is used to select different frequency comb optical signals.

9. A signal generation method for a quantum chip measurement and control system, applied to the signal generation device according to any one of claims 1 to 8, characterized in that, The signal generation method includes: spatially separating multiple initial spectral lines included in the frequency comb optical signal that are equally spaced in frequency to obtain discrete spectral lines of each of the multiple initial spectral lines; performing amplitude and phase modulation on each of the discrete spectral lines to obtain modulated spectral lines of each of the multiple discrete spectral lines; combining the multiple modulated spectral lines to obtain a combined optical signal; performing dispersion processing on the combined optical signal to generate a time-domain optical signal through frequency-time mapping; converting the time-domain optical signal into a radio frequency electrical signal to obtain a target radio frequency signal.

10. The signal generation method according to claim 9, wherein The method further includes: performing amplification processing on the time-domain optical signal to obtain an amplified time-domain optical signal; introducing the amplified time-domain optical signal into the dilution refrigerator through an optical fiber to split the amplified time-domain optical signal into multiple paths of time-domain optical signals; converting the multiple paths of time-domain optical signals into multiple paths of radio frequency electrical signals to generate multiple paths of radio frequency arbitrary waveforms.

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