A multi-port frequency division multiplexing filter
By designing a multi-port frequency division multiplexing filter, selective transmission of frequency signals is achieved using coupling modules and resonant cavities. This solves the port multiplexing problem in superconducting quantum processors, improves port resource utilization efficiency, and promotes the large-scale expansion of quantum processors.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- TSINGHUA UNIVERSITY
- Filing Date
- 2025-01-09
- Publication Date
- 2026-06-23
AI Technical Summary
In superconducting quantum processors, the increase in the number of measurement and control ports leads to a sharp increase in the complexity of room temperature interface processing and resource consumption. Existing technologies cannot effectively reuse room temperature and low temperature control circuits and readout circuit ports.
Design a multi-port frequency division multiplexing filter that achieves selective transmission of frequency signals through coupling modules and resonant cavities, supports the control and readout of multiple superconducting qubits, and employs coupling capacitors and superconducting coplanar waveguide structures to suppress high-order frequency harmonic modes, broaden the fundamental mode bandwidth, and improve port resource utilization efficiency.
It realizes the single-cavity bandpass filtering function with adjustable frequency band, solves the problem of XY control line port multiplexing in the field of superconducting quantum computing, improves the port resource utilization efficiency, and promotes the large-scale expansion of quantum processors.
Smart Images
Figure CN119833915B_ABST
Abstract
Description
Technical Field
[0001] This application relates to, but is not limited to, the field of quantum computing technology, and in particular to a multi-port frequency division multiplexing filter. Background Technology
[0002] In the rapid development of quantum computing technology, various qubit systems are in a critical stage of continuous integration and optimization. With the rapid advancement of superconducting quantum processors towards large-scale and highly integrated designs, the number of control and measurement ports is also increasing dramatically. This trend significantly increases the processing complexity and resource consumption of room-temperature interfaces. Therefore, the ability to provide technologies that can effectively reuse room-temperature control and readout circuit ports has become particularly urgent. Summary of the Invention
[0003] This application provides a multi-port frequency division multiplexing filter that can realize single-cavity bandpass filtering function with adjustable frequency band.
[0004] This invention provides a multi-port frequency division multiplexing filter, comprising: one or more frequency selective filtering modules, each of which has an input port and one or more output ports;
[0005] Each of the frequency selective filtering modules includes: one or more coupling modules, and one or more resonant cavities of different frequencies;
[0006] The coupling module is used to couple a frequency signal input via the input port to a resonant cavity of different frequencies;
[0007] A resonant cavity is used to selectively transmit signals of a corresponding frequency and output them from the corresponding output port.
[0008] In one exemplary instance, the input port receives XY control signals for operating on a plurality of superconducting qubits;
[0009] The resonant cavity is used to select the corresponding frequency signal that matches the resonant frequency of the corresponding qubit and output it from the corresponding output port. The resonant frequency of the resonant cavity is consistent with the resonant frequency of the corresponding qubit.
[0010] In one exemplary instance, the coupling module is a first coupling capacitor; for one of the frequency selective filtering modules:
[0011] Each XY control signal input port corresponds to one XY control signal input channel; each resonant cavity corresponds to one frequency selective filtering channel.
[0012] The XY control signal input channel is coupled to the frequency-selective filtering channel corresponding to the resonant cavity of different frequencies through the first coupling capacitor.
[0013] The frequency selective filtering module enables the control of one or more superconducting qubits; wherein the number of superconducting qubits is less than or equal to the number of frequency selective filtering channels.
[0014] In one exemplary instance, the one or more frequency-selective filtering modules include N in One XY control line input channel corresponding to the XY control signal input port;
[0015] The N in The number of XY control line input channels is equal to the number of control microwave signal input ports at room temperature.
[0016] In one exemplary instance, the XY control signal is applied from the room temperature port, attenuated and filtered to reach the low temperature port, and then driven to one or more superconducting qubits through the first coupling capacitor, so that the state of one or more superconducting qubits rotates around the X-axis or Y-axis on the Bloch sphere.
[0017] In one exemplary instance, each of the frequency-selective filtering channels corresponds to the resonant frequency of one or more qubits.
[0018] In one exemplary instance, it further includes: one or more readout resonant cavities and one or more readout lines;
[0019] The one or more superconducting qubits transmit information sequentially to the corresponding readout resonant cavity and readout line through the second coupling capacitor;
[0020] The number of readout lines is equal to the number of signal output ports at room temperature.
[0021] In one exemplary instance, the readout line transmits the signal within the readout resonant cavity to a room temperature end for detection and readout after filtering and amplification, and measures the state of one or more superconducting qubits based on the dispersion characteristics of the readout resonant cavity.
[0022] In one exemplary instance, the frequency-selective filtering channel is implemented on a superconducting circuit chip via a superconducting coplanar waveguide using one of the following structures:
[0023] A standard half-wavelength cavity, a quarter-wavelength cavity, or a standard half-wavelength cavity with an auxiliary grounding branch structure at the center.
[0024] In one exemplary instance, the readout resonant cavity is implemented on a superconducting circuit chip via a superconducting coplanar waveguide by one of the following structures:
[0025] A standard half-wavelength cavity, a quarter-wavelength cavity, or a standard half-wavelength cavity with an auxiliary grounding branch structure at the center.
[0026] The multi-port frequency division multiplexing filter provided in this application embodiment realizes single-cavity bandpass filtering function with adjustable frequency bands. It not only solves the problem of XY control line port multiplexing in the field of superconducting quantum computing, but also has the potential to realize multi-segment frequency division multiplexing functions in other application fields. This breakthrough is of great significance for promoting the large-scale expansion of quantum processors.
[0027] Furthermore, by combining the field distribution characteristics of the basic half-wavelength cavity with the auxiliary grounding branch structure, high-order harmonic modes within the half-wavelength resonant cavity are effectively suppressed, and the fundamental mode bandwidth is significantly broadened, thereby enhancing the practicality and frequency selectivity of the single-cavity filter. In one embodiment, by integrating multiple unit structures of different design sizes, a filter with multi-port functionality is constructed, significantly improving the utilization efficiency of port resources. The multi-port frequency division multiplexing filter provided in this application embodiment is suitable for the pre-amplifier unit of XY control line signals and is integrated with a superconducting quantum processor.
[0028] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims, and drawings. Attached Figure Description
[0029] The accompanying drawings are used to provide a further understanding of the technical solutions of this application and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of this application and do not constitute a limitation on the technical solutions of this application.
[0030] Figure 1 This is a schematic diagram of the composition structure of the multi-port frequency division multiplexing filter in the embodiments of this application;
[0031] Figure 2(a) is a schematic diagram of the composition structure of the first embodiment of the multi-port frequency division multiplexing filter in this application;
[0032] Figure 2(b) is a schematic diagram of the composition structure of the second embodiment of the multi-port frequency division multiplexing filter in this application;
[0033] Figure 2(c) is a schematic diagram of the composition structure of the third embodiment of the multi-port frequency division multiplexing filter in this application;
[0034] Figure 3(a) is a schematic diagram of the working principle of the resonant cavity shown in Figure 2(a) in an embodiment of this application;
[0035] Figure 3(b) is a schematic diagram of the working principle of the resonant cavity shown in Figure 2(b) in the embodiment of this application;
[0036] Figure 3(c) is a schematic diagram of the simulation results of the two cavities shown in Figure 3(a) and Figure 3(b) in the embodiments of this application;
[0037] Figure 4(a) is a schematic diagram of the output result of the four-port resonant cavity of the multi-port frequency selective filter according to an embodiment of this application;
[0038] Figure 4(b) is a schematic diagram of the output result of the six-port resonant cavity of the multi-port frequency selective filter according to an embodiment of this application;
[0039] Figure 4(c) is a schematic diagram of the output result of the eight-port resonant cavity of the multi-port frequency selective filter according to an embodiment of this application;
[0040] Figure 4(d) is a schematic diagram of the output result of the sixteen-port resonant cavity of the multi-port frequency selective filter according to an embodiment of this application. Detailed Implementation
[0041] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be arbitrarily combined with each other.
[0042] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.
[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.
[0044] It is understood that the terms "first" and "second" used in this application are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.
[0045] It is understood that the term "connection" in the following embodiments should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have electrical signal or data transmission with each other.
[0046] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Meanwhile, the term “and / or” as used in this specification includes any and all combinations of the associated listed items.
[0047] As superconducting quantum processors move towards large-scale integration, the number of measurement and control ports is increasing dramatically, significantly burdening the room-temperature interface. Therefore, a technology capable of effectively reusing the ports of room-temperature and cryogenic control circuits and readout circuits becomes crucial.
[0048] To address this challenge, this application proposes a multi-port frequency division multiplexing filter, which is not only intended for use in quantum computing chips within the field of superconducting quantum computing to achieve efficient multiplexing of room-temperature ports corresponding to the XY control lines, but also has the potential to realize single-cavity bandpass filtering with tunable frequency bands in a wider range of information processing fields. The multi-port frequency division multiplexing filter provided in this application is of great significance for solving interface bottleneck problems encountered by quantum processors during large-scale expansion, and also lays an innovative technical foundation for the continuous progress and long-term development of quantum information technology.
[0049] Figure 1 This is a schematic diagram of the composition structure of the multi-port frequency division multiplexing filter in the embodiments of this application, as shown below. Figure 1 As shown, it includes: one or more frequency selective filtering modules, each frequency selective filtering module is provided with one input port and one or more output ports;
[0050] Each frequency-selective filtering module includes: one or more coupling modules, and one or more resonant cavities of different frequencies;
[0051] The coupling module is used to couple a frequency signal input via the input port to a resonant cavity of different frequencies;
[0052] A resonant cavity is used to selectively transmit signals of a corresponding frequency and output them from the corresponding output port.
[0053] The multi-port frequency division multiplexing filter provided in this application embodiment realizes the single-cavity bandpass filtering function with adjustable frequency band.
[0054] The multi-port frequency division multiplexing filter provided in this application not only solves the problem of XY control line port multiplexing in the field of superconducting quantum computing, but also has the potential to realize multi-segment frequency division multiplexing function in other application fields. This breakthrough is of great significance for promoting the large-scale expansion of quantum processors.
[0055] In one exemplary instance, the input port receives XY control signals for operating multiple superconducting qubits, and the resonant cavity selects a corresponding frequency signal to match the resonant frequency of the corresponding qubit, and outputs it from the corresponding output port. The resonant frequency of the resonant cavity is consistent with the resonant frequency of the corresponding qubit. In one embodiment, the coupling module is a first coupling capacitor, such as... Figure 1 As shown, a multi-port frequency division multiplexing filter includes: N in N XY control signal input ports (i.e., N) in (Several XY control signal input channels), each XY control signal input channel is coupled to N through a first coupling capacitor. f Each frequency-selective filter module consists of N resonant cavities at different frequencies. f N resonant cavities (i.e., N) f (Single frequency-selective filtering channel), each XY signal input channel and N f The frequency-selective filter channels are coupled to each other through a first coupling capacitor, and each frequency-selective filter module realizes N q Control of N superconducting qubits, where N f ≥N q ≥1,N in ≥1,N out ≥1. Thus, each frequency-selective filtering module, through N... q The control of each superconducting quantum bit is determined by N out A single readout line enables the measurement of the state of a superconducting quantum bit, N. out =N in The total number of control qubits is N in *N q .
[0056] In one exemplary instance, for N f A frequency-selective filter module with a value of 2 has a resonant cavity called a four-port resonant cavity. In one exemplary instance, for N... f A frequency-selective filter module with a value of 3 has a resonant cavity called a six-port resonant cavity. In one exemplary instance, for N... f A frequency-selective filter module with N=4 has a resonant cavity called an eight-port resonant cavity. In one exemplary instance, for N... f The frequency selective filter module with a resolution of 8 has a resonant cavity called a sixteen-port resonant cavity.
[0057] In one exemplary instance, Nin The number of XY control line input channels corresponds to the number of control microwave signal input ports at room temperature, i.e., N. in The number of XY control line input channels is equal to the number of control microwave signal input ports at room temperature.
[0058] In one exemplary instance, the XY control line is relative to N. q The microwave control lines required to operate the state of a superconducting qubit to rotate around the X or Y axis on the Bloch sphere.
[0059] In one exemplary instance, N f Each frequency-selective channel is coupled to its corresponding XY control input channel via a first coupling capacitor.
[0060] In one exemplary instance, the XY control signals corresponding to different frequencies output by the frequency selective filtering module drive N respectively through the first coupling capacitor. q One superconducting quantum bit. In one embodiment, each frequency-selective filter channel may correspond to the resonant frequency of one or more quantum bits.
[0061] In one exemplary instance, N q Each superconducting quantum bit can transmit information to the corresponding readout resonant cavity through a second coupling capacitor (also known as a readout coupling capacitor).
[0062] In one exemplary instance, N q Each readout resonant cavity is capacitively coupled to its corresponding readout line.
[0063] In one exemplary instance, N out Each readout line corresponds to the number of signal output ports at room temperature, i.e., N. out The number of readout lines is equal to the number of signal output ports at room temperature.
[0064] In one exemplary instance, signals of various frequencies can be simultaneously input to the input port of the frequency selective filtering module provided in this application embodiment through a single main signal line. The frequency selective filtering module is used to couple and transmit the required frequency band signals, achieving the purpose of frequency division multiplexing, and then transmitting them to the corresponding superconducting quantum bits so that they can change state according to the signal.
[0065] In one exemplary instance, the XY control signal input channel is N. in (N in ≥1), the number of frequency-selective filtering channels in the frequency-selective filtering module is N. f (N f≥1), In one embodiment, taking one XY control signal input channel and eight frequency-selective filtering channels as an example, each superconducting quantum bit is coupled to the XY control line and coupled to one readout line through eight readout resonant cavities.
[0066] In one exemplary instance, taking an XY control signal input channel of 1 and a frequency-selective filtering module with 8 channels, coupled through a first coupling capacitor, the XY control line is the microwave control line required for rotating the state of the superconducting qubit around the X or Y axis on the Bloch sphere. On the superconducting circuit chip, it is implemented by a superconducting coplanar waveguide. The 8 superconducting qubits are driven by the XY control signal output from the frequency-selective filtering module through the first coupling capacitor, and are implemented on the superconducting circuit chip by a superconducting coplanar waveguide and coupling capacitors. The 8 superconducting qubits transmit information to their corresponding readout resonant cavities through a second coupling capacitor, which is implemented on the superconducting chip by a superconducting coplanar waveguide and a second coupling capacitor. The 8 readout resonant cavities are coupled to their corresponding readout lines through the second capacitor. In this embodiment, one readout line is a microwave line coupled to a half-wavelength resonant cavity of the 8 superconducting qubits, providing microwave signals for qubit measurement. The state of the superconducting qubit is obtained by measuring the dispersion characteristics of the readout resonant cavity.
[0067] In one exemplary instance, the XY control signal input channel is N. in (N in ≥1), the number of frequency-selective filtering channels in the frequency-selective filtering module is N. f (N f ≥1), each superconducting qubit is coupled to the XY control line and connected through N q One readout resonant cavity and N out The readout lines are coupled.
[0068] In one exemplary instance, the XY control signal input channel is N. in The frequency selective filtering module has N channels. f Taking the coupling between the two via a first coupling capacitor as an example, the XY control line is the microwave control line required for rotating the state of the superconducting quantum bit around the X-axis or Y-axis on the Bloch sphere, and is implemented by a superconducting coplanar waveguide on the superconducting circuit chip. q Each superconducting qubit is driven by an XY control signal output from a frequency-selective filtering module via a first coupling capacitor. This is implemented on the superconducting circuit chip by a superconducting coplanar waveguide and the first coupling capacitor. In other words, the XY control signal is applied from the room temperature port, attenuated, filtered, and then reaches the low temperature port. It is then driven to one or more superconducting qubits via the first coupling capacitor, causing the state of one or more superconducting qubits to rotate around the X-axis or Y-axis on the Bloch sphere.
[0069] In one exemplary instance, it further includes: one or more second coupling capacitors, one or more readout resonant cavities, and one or more readout lines, N q Each superconducting quantum bit transmits information to its corresponding readout resonant cavity via a second coupling capacitor. This is achieved on the superconducting chip using a superconducting coplanar waveguide and a second coupling capacitor. q Each readout resonant cavity is coupled to its corresponding readout line via a second coupling capacitor. out The readout line is coupled to N q The microwave line of the half-wavelength resonant cavity of each superconducting qubit provides the microwave signal for qubit measurement. The state of the superconducting qubit is obtained by measuring the dispersion characteristics of the readout resonant cavity. That is, one or more superconducting qubits transmit information sequentially to the corresponding readout resonant cavity and readout line through a second coupling capacitor. The readout line transmits the signal in the readout resonant cavity to the room temperature end for detection and readout, and the state of one or more superconducting qubits is obtained by measuring the dispersion characteristics of the readout resonant cavity.
[0070] In one exemplary instance, N f Each frequency-selective filter channel is coupled to its corresponding XY control input channel through a first coupling capacitor. Each frequency-selective filter channel is implemented on the superconducting circuit chip through a superconducting coplanar waveguide by one of the following structures: a standard half-wavelength cavity, a quarter-wavelength cavity, or a standard half-wavelength cavity with an auxiliary grounding branch structure set at the center.
[0071] In one exemplary instance, N q Each superconducting quantum bit is driven by the XY control signal output by the frequency selection module through the first coupling capacitor. The XY control signal corresponds to the operating frequency of the superconducting quantum bit. It is applied from the room temperature port, and after attenuation and filtering, it reaches the low temperature port and is then transmitted to the superconducting quantum bit through the superconducting coplanar waveguide and coupling capacitor.
[0072] In one exemplary instance, N q Each superconducting quantum bit transmits information to its corresponding N-bit via a second coupling capacitor. q Within a readout resonant cavity, the readout resonant cavity is implemented on the superconducting circuit chip via a superconducting coplanar waveguide by one of the following structures: a standard half-wavelength cavity, a quarter-wavelength cavity, or a standard half-wavelength cavity with an auxiliary grounding branch structure at the center.
[0073] In one exemplary instance, N q Each readout resonant cavity is coupled to the corresponding readout line through capacitors and inductors, providing microwave signals for quantum bit measurement. The state of the superconducting quantum bit is obtained by measuring the dispersion characteristics of the readout resonant cavity. It is implemented on the superconducting circuit chip by superconducting coplanar waveguides and coupling capacitors.
[0074] In one exemplary instance, the readout line transmits the signal from the readout resonant cavity to the room temperature end after filtering and amplification, where N out The number of readout lines is equal to the number of signal output ports at room temperature.
[0075] Taking each frequency selective filtering module as an example, which includes one XY control signal input channel and eight frequency selective filtering channels, then N in = 1 XY control signal input channel, N f =8 frequency selective filter channels, N q =8 superconducting qubits, such as Figures 2(a)-2(c) As shown, one XY control signal input channel and eight frequency-selective filter channels are capacitively coupled. The resonant cavities of different lengths corresponding to the eight frequency-selective filter channels are represented by different grayscale values. Various control frequency signals are input through the XY control signal input channel and then enter the corresponding port of the resonant filter single cavity through the first coupling capacitor. In this embodiment, the resonant cavities corresponding to the eight frequency-selective filter channels are in... Figures 2(a)-2(c) The three frequency-selective filtering modules shown have different forms. The first type has eight standard half-wavelength resonant cavities, as shown in Figure 2(a). This structure is simple, easy to manufacture, and has good fundamental mode performance. The second type adds grounding structures at the point where the central fundamental mode field strength is zero, as shown in Figure 2(b). Its transmission result suppresses the harmonic mode and widens the fundamental mode bandwidth, which is an optimization of the first type. The third type short-circuit the center positions of several resonant cavities of different sizes based on the second type, as shown in Figure 2(c). This maintains the transmission result of the second optimization method and improves the integration of the multi-port frequency division multiplexing filter composed of the frequency-selective filtering modules provided in this application embodiment.
[0076] Figure 3(a) is a schematic diagram of the working principle of the resonant cavity shown in Figure 2(a) in the embodiment of this application. As shown in Figure 3(a), a standard half-wavelength cavity (i.e., N) is displayed. in The structure and field strength distribution of the standard half-wavelength resonant cavity (one frequency-selective filter channel) are as follows: the half-wavelength cavity length L = λ / 2, and the field strength of its basic mode is zero at both ends and reaches its maximum value at the center. In one embodiment, the standard half-wavelength cavity length can be 12mm, and the first coupling capacitor can be 150fF. The field strength distribution of the second harmonic mode (2f) also reaches its maximum value at the center. That is, the field strength of the second harmonic mode in the standard half-wavelength resonant cavity reaches its maximum value at the center point, but this is prone to interference from the harmonic mode.
[0077] Figure 3(b) is a schematic diagram of the working principle of the resonant cavity shown in Figure 2(b) in an embodiment of this application. As shown in Figure 3(b), the optimized resonant cavity is displayed. An auxiliary grounding branch is set at the center position (the position where the field strength is zero). In one embodiment, the auxiliary grounding branch may include branch 1 and branch 2, with lengths of 0.3 mm and 3.8 mm, respectively. The purpose is to disrupt the field strength distribution of the harmonic mode, thereby suppressing the harmonic mode. In the optimized resonant cavity, the fundamental mode field strength distribution remains normal, and the main function of the resonant cavity is also guaranteed. It should be noted that there may be one or three auxiliary grounding branches, etc. This embodiment is used as an example for simulation with two auxiliary grounding branches. This embodiment is not intended to limit the protection scope of this application.
[0078] Figure 3(c) is a schematic diagram of the simulation results of the two cavities shown in Figures 3(a) and 3(b) in the embodiments of this application. In Figure 3(c), the horizontal axis represents frequency (GHz), and the vertical axis represents amplitude (dB). As shown in Figure 3(c), the scattering parameters S of the two resonant cavities shown in Figures 3(a) and 3(b) are displayed. 21 In one embodiment, the scattering parameters between the two ports were calculated using circuit simulation software. In Figure 3(c), curve 31 shows the result for the standard half-wavelength cavity, and curve 32 shows the result for the cavity optimized by introducing an auxiliary grounding branch. As shown in curve 31, the fundamental mode bandwidth of the standard half-wavelength cavity is 290MHz. As shown in curve 32, the fundamental mode bandwidth of the optimized cavity is broadened to 455MHz, approximately doubling. Moreover, the suppression level of the harmonic mode intensity near 8GHz reaches below -20dB. Simulation results demonstrate that the optimized scheme significantly improves anti-interference capability while maintaining fundamental mode resonance performance.
[0079] In this embodiment, by combining the field distribution characteristics of the basic half-wavelength cavity with an auxiliary branch structure, high-order harmonic modes within the half-wavelength resonant cavity are effectively suppressed, and the fundamental mode bandwidth is significantly broadened, thereby enhancing the practicality and frequency selectivity of the single-cavity filter. In one embodiment, by integrating multiple unit structures of different design sizes, a filter with multi-port functionality is constructed, significantly improving the utilization efficiency of port resources. The multi-port frequency division multiplexing filter provided in this embodiment is suitable for the pre-amplifier unit of XY control line signals and is integrated with a superconducting quantum processor.
[0080] Figures 4(a)-4(d) These are schematic diagrams showing the output results of resonant cavities with several typical port numbers for multi-port frequency-selective filters according to embodiments of this disclosure. The horizontal axis represents frequency in GHz, and the vertical axis represents amplitude in decibels (dB). Figure 4(a) shows the N corresponding to a four-port resonant cavity. f= 2 frequency-selective filtering channels. Figure 4(b) shows the N corresponding to the six-port resonator. f = 3 frequency-selective filtering channels. Figure 4(c) shows the N corresponding to the eight-port resonator. f = 4 frequency-selective filtering channels. Figure 4(d) shows the N corresponding to the sixteen-port resonant cavity. f =8 frequency selective filtering channels.
[0081] As shown in Figure 4(a), the left and right curves correspond to two frequency selection channels, respectively. The center frequency of the left curve is 113MHz, and the center frequency of the right curve is 148MHz. That is to say, in this embodiment, N f The two frequency-selective filtering channels have bandpass transmission characteristics of 113MHz and 148MHz, with obvious bandpass characteristics, low reflection loss, strong side-mode suppression, and significant signal amplitude attenuation in non-center frequency regions. In this embodiment, the first coupling capacitor is 50fF, the branch lengths corresponding to the four ports are 6mm, 6mm, 5mm, and 5mm, respectively, and the cavity length of the auxiliary grounding branch is 0.1mm.
[0082] As shown in Figure 4(b), the three curves from left to right correspond to the three frequency selection channels. The center frequency of the left curve is 108MHz, the center frequency of the middle curve is 139MHz, and the center frequency of the right curve is 157MHz. That is to say, in this embodiment, N f The three frequency-selective filtering channels possess bandpass transmission characteristics of 108MHz, 139MHz, and 157MHz. Each channel has a different bandwidth, exhibiting good bandpass transmission characteristics, good side-mode suppression, and improved isolation between channels. In this embodiment, the first coupling capacitor is 50fF, and the corresponding branch lengths for the six ports are 6mm, 6mm, 5mm, 5mm, 4.3mm, and 4.3mm, respectively. The auxiliary grounding branch cavity length is 0.1mm for each channel.
[0083] As shown in Figure 4(c), the four curves from left to right correspond to the four frequency selection channels. The center frequency of the leftmost curve is 108MHz, the center frequency of the middle left curve is 139MHz, the center frequency of the middle right curve is 177MHz, and the center frequency of the rightmost curve is 180MHz. That is to say, in this embodiment, N f The four frequency-selective filtering channels possess bandpass transmission characteristics of 108MHz, 139MHz, 177MHz, and 180MHz, with more uniform bandpass characteristics, wider bandwidth (some reaching up to 180MHz), reasonable frequency spacing, and minimal interference between channels. In this embodiment, the first coupling capacitor is 50fF, and the branch lengths corresponding to the eight ports are 6mm, 6mm, 5mm, 5mm, 4.3mm, 4.3mm, 3.8mm, and 3.8mm, respectively. The auxiliary grounding branch cavity length is 0.1mm for each channel.
[0084] As shown in Figure 4(d), the sixteen curves from left to right correspond to sixteen frequency selection channels, each with a bandpass characteristic of approximately 60MHz. In other words, in this embodiment, N... f =Each of the 8 frequency-selective filtering channels has a bandpass transmission characteristic of approximately 60MHz. Each channel has a narrow bandwidth, a uniformly distributed center frequency, and excellent isolation. Compared to N, the bandwidth is significantly higher. f The capacitance decreases slightly when the value is 2, 3, or 4, but the side-mode suppression effect is excellent. In this embodiment, the first coupling capacitor is 50fF, and the corresponding branch lengths of the sixteen ports are 6mm, 6mm, 5.7mm, 5.7mm, 5.4mm, 5.4mm, 5.15mm, 5.15mm, 4.9mm, 4.9mm, 4.65mm, 4.65mm, 4.45mm, 4.45mm, 4.25mm, and 4.25mm, respectively. The auxiliary grounding branch cavity lengths are 0.1mm and 0.02mm, respectively.
[0085] Figures 4(a)-4(d) In the embodiment shown, key parameters such as the center frequency, bandwidth, reflection loss, and side-mode rejection ratio of the frequency selection channel can be adjusted within a certain range by means of coupling capacitors and auxiliary grounding branch dimensions.
[0086] Simulation results show that the performance of the multi-port frequency-selective filter provided in this application embodiment improves with the increase of the number of ports, specifically manifested in more bandpass channels, better frequency distribution, and stronger side-mode suppression capability. By optimizing design parameters (such as coupling capacitors, auxiliary grounding branch cavity length, branch length, etc.), the center frequency and bandwidth of the frequency-selective channels can be flexibly adjusted to meet different application requirements.
[0087] Although the embodiments disclosed in this application are as described above, the content described is merely for the purpose of understanding this application and is not intended to limit this application. Any person skilled in the art to which this application pertains may make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in this application; however, the scope of patent protection of this application shall still be determined by the scope defined in the appended claims.
Claims
1. A multi-port frequency division multiplexing filter, characterized in that, include: One or more frequency selective filtering modules, each of which is provided with one input port and one or more output ports; Each of the frequency-selective filtering modules includes: one or more coupling modules and one or more resonant cavities of different frequencies; The coupling module is used to couple a frequency signal input via the input port to a resonant cavity of different frequencies; A resonant cavity is used to selectively transmit signals of a corresponding frequency and output them from the corresponding output port. The input port receives XY control signals for operating multiple superconducting qubits; the resonant cavity selects and outputs a corresponding frequency signal that matches the resonant frequency of the corresponding qubit from the corresponding output port, and the resonant frequency of the resonant cavity is consistent with the resonant frequency of the corresponding qubit. The coupling module is a first coupling capacitor; for one of the frequency selective filtering modules: Each XY control signal input port corresponds to one XY control signal input channel; each resonant cavity corresponds to one frequency selective filtering channel. The XY control signal input channel is coupled to the frequency selective filter channel corresponding to the resonant cavity of different frequencies through the first coupling capacitor; The frequency-selective filtering module enables the control of one or more superconducting qubits; wherein the number of superconducting qubits is less than or equal to the number of frequency-selective filtering channels.
2. The multi-port frequency division multiplexing filter according to claim 1, wherein, The one or more frequency selective filtering modules include One XY control line input channel corresponding to the XY control signal input port; The The number of XY control line input channels is equal to the number of control microwave signal input ports at room temperature.
3. The multi-port frequency division multiplexing filter according to claim 1, wherein, The XY control signal is applied from the room temperature port, and after attenuation and filtering, it reaches the low temperature port. Then, it is driven to the one or more superconducting qubits through the first coupling capacitor, so that the state of the one or more superconducting qubits rotates around the X-axis or Y-axis on the Bloch sphere.
4. The multi-port frequency division multiplexing filter according to claim 3, wherein, Each of the frequency-selective filtering channels corresponds to the resonant frequency of one or more qubits.
5. The multi-port frequency division multiplexing filter according to claim 1, further comprising: One or more second coupling capacitors, one or more readout resonant cavities, and one or more readout lines; The one or more superconducting qubits respectively transmit information to the corresponding readout resonant cavity and readout line through the second coupling capacitor; The number of readout lines is equal to the number of signal output ports at room temperature.
6. The multi-port frequency division multiplexing filter according to claim 5, wherein, The readout line transmits the signal in the readout resonant cavity to the room temperature end for detection and readout after filtering and amplification, and measures the state of one or more superconducting qubits based on the dispersion characteristics of the readout resonant cavity.
7. The multi-port frequency division multiplexing filter according to claim 1, wherein, The frequency-selective filtering channel is implemented on the superconducting circuit chip via a superconducting coplanar waveguide using a standard half-wavelength cavity or a quarter-wavelength cavity.
8. The multi-port frequency division multiplexing filter according to claim 5, wherein, The readout resonant cavity is implemented on the superconducting circuit chip via a superconducting coplanar waveguide, and is either a standard half-wavelength cavity or a quarter-wavelength cavity.
9. The multi-port frequency division multiplexing filter according to claim 1 or 5, wherein, The frequency-selective filtering channel is implemented on the superconducting circuit chip via a superconducting coplanar waveguide and a standard half-wavelength cavity with an auxiliary grounding branch structure at the center.