Multi-port frequency division multiplexing filter

Abstract

The invention discloses a multi-port frequency division multiplexing filter, which comprises one or more than one frequency selection filtering module, and each frequency selection filtering module is provided with an input port and one or more than one output port; each frequency-selecting filtering module comprises one or more than one coupling module and one or more than one resonant cavity with different frequencies; the coupling module is used for coupling a section of frequency signal input through the input port to the resonant cavities with different frequencies; and the resonant cavity is used for completing selective transmission of a corresponding frequency signal and outputting the signal from a corresponding output port. According to the embodiment of the invention, the frequency-adjustable single-cavity band-pass filtering function is realized. The problem of XY control line port multiplexing in the superconducting quantum computing field can be solved, the potential of achieving the multi-segment frequency division multiplexing function in other application fields is achieved, and the great significance is achieved for promoting large-scale expansion of quantum processors.

Description

Technical Field

[0001] The present 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 Art

[0002] In the rapid development of quantum computing technology, various quantum bit 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 development, the number of measurement and control ports has also increased dramatically. This trend has significantly increased the processing complexity and resource consumption of the room temperature interface. Therefore, it is particularly urgent to provide a technology that can effectively reuse the room temperature control circuit and readout circuit ports. Summary of the invention

[0003] The present application provides a multi-port frequency division multiplexing filter, which can realize a single-cavity bandpass filtering function with an adjustable frequency band.

[0004] The embodiment of the present invention provides a multi-port frequency division multiplexing filter, comprising: one or more frequency selection filter modules, each of which is provided with an input port and one or more output ports;

[0005] Each of the frequency-selective filtering modules comprises: one or more coupling modules, and one or more resonant cavities of different frequencies;

[0006] A coupling module, used for coupling a frequency signal inputted via an input port to a resonant cavity of a different frequency;

[0007] The resonant cavity is used to selectively transmit the corresponding frequency signal and output it from the corresponding output port.

[0008] In an exemplary embodiment, the input port inputs an XY control signal for operating 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 quantum bit and output it from the corresponding output port, and the resonant frequency of the resonant cavity is consistent with the resonant frequency of the corresponding quantum bit.

[0010] In an exemplary embodiment, the coupling module is a first coupling capacitor; for one of the frequency selection filtering modules:

[0011] The XY control signal input port corresponds to an XY control signal input channel; each of the resonant cavities corresponds to a frequency selection filter channel;

[0012] 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.

[0013] The frequency-selective filtering module realizes the control of one or more superconducting quantum bits; wherein the number of superconducting quantum bits is less than or equal to the number of frequency-selective filtering channels.

[0014] In an exemplary embodiment, the one or more frequency-selective filtering modules include N in an 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 an exemplary embodiment, the XY control signal is applied from the room temperature port, and after attenuation and filtering, reaches the low temperature end, it is driven to the one or more superconducting quantum bits through the first coupling capacitor, so that the state of the one or more superconducting quantum bits rotates around the X-axis or Y-axis on the Bloch sphere.

[0017] In an exemplary embodiment, each of the frequency-selective filtering channels corresponds to a resonant frequency of one or more quantum bits.

[0018] In an exemplary embodiment, the device further comprises: one or more readout resonant cavities, one or more readout lines;

[0019] The one or more superconducting quantum bits sequentially transmit information to the corresponding readout resonant cavity and readout line through the second coupling capacitor;

[0020] The number of the readout lines is equal to the number of signal output ports at room temperature.

[0021] In an exemplary embodiment, 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 the one or more superconducting quantum bits based on the dispersion characteristics of the readout resonant cavity.

[0022] In an exemplary embodiment, the frequency-selective filtering channel is implemented on a superconducting circuit chip through a superconducting coplanar waveguide by one of the following structures:

[0023] A standard half-wavelength cavity, a 1 / 4-wavelength cavity, or a standard half-wavelength cavity with an auxiliary ground branch structure at the center.

[0024] In an exemplary embodiment, the readout resonant cavity is implemented on a superconducting circuit chip by a superconducting coplanar waveguide and by one of the following structures:

[0025] A standard half-wavelength cavity, a 1 / 4-wavelength cavity, or a standard half-wavelength cavity with an auxiliary ground branch structure at the center.

[0026] The multi-port frequency division multiplexing filter provided in the embodiment of the present application realizes the single-cavity bandpass filtering function with adjustable frequency band. It can not only solve 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. The 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 ground branch structure, the high-order frequency-multiplication modes in the half-wavelength resonant cavity are effectively suppressed, and the fundamental mode bandwidth is significantly broadened, thereby enhancing the practicality and frequency selection performance of the single-cavity filter. In one embodiment, a filter with multi-port function is constructed by integrating multiple unit structures of designed sizes, which greatly improves the utilization efficiency of port resources. The multi-port frequency division multiplexing filter provided in the embodiment of the present application is suitable for the front unit of the XY control line signal, and is integrated with the superconducting quantum processor.

[0028] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings are used to provide further understanding of the technical solution of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present application and do not constitute a limitation on the technical solution of the present application.

[0030] Figure 1 This is a schematic diagram of the composition structure of a multi-port frequency division multiplexing filter in an embodiment of the present application;

[0031] FIG2( a ) is a schematic diagram of the composition structure of a first embodiment of a multi-port frequency division multiplexing filter in an embodiment of the present application;

[0032] FIG2( b ) is a schematic diagram of the composition structure of a second embodiment of a multi-port frequency division multiplexing filter in an embodiment of the present application;

[0033] FIG2( c ) is a schematic diagram of the composition structure of a third embodiment of a multi-port frequency division multiplexing filter in an embodiment of the present application;

[0034] FIG3( a ) is a schematic diagram of the working principle of the resonant cavity shown in FIG2( a ) in an embodiment of the present application;

[0035] FIG3( b ) is a schematic diagram of the working principle of the resonant cavity shown in FIG2( b ) in an embodiment of the present application;

[0036] FIG3(c) is a schematic diagram of simulation results of the two cavities shown in FIG3(a) and FIG3(b) in an embodiment of the present application;

[0037] FIG4( 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 the present application;

[0038] FIG4( 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 the present application;

[0039] FIG4( 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 the present application;

[0040] FIG4( d ) is a schematic diagram of the output results of the sixteen-port resonant cavity of the multi-port frequency-selective filter according to an embodiment of the present application. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and advantages of the present application more clear, the embodiments of the present application will be described in detail below with reference to the accompanying drawings. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other arbitrarily without conflict.

[0042] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0044] It is understood that the terms "first" and "second" used in this application are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0045] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if the connected circuits, modules, units, etc. have electrical signals or data transmission between each other.

[0046] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the relevant listed items.

[0047] As superconducting quantum processors develop towards large-scale integration, the number of measurement and control ports increases dramatically, which greatly increases the processing burden of the room temperature interface. Therefore, a technology that can effectively multiplex room temperature and low temperature control circuits and readout circuit ports becomes particularly critical.

[0048] In response to this challenge, this application proposes a multi-port frequency division multiplexing filter, which is not only intended to be used in the field of superconducting quantum computing, for quantum computing chips, to achieve efficient multiplexing of XY control lines corresponding to room temperature ports, but also has the potential to achieve single-cavity bandpass filtering functions with adjustable frequency bands in a wider range of information processing fields. The multi-port frequency division multiplexing filter provided in the embodiment of this application is of great significance for solving the interface bottleneck problem encountered by quantum processors during the large-scale expansion process, and also lays an innovative technical foundation for the continuous progress and long-term development of quantum information technology.

[0049] Figure 1 FIG. 1 is a schematic diagram of the composition structure of a multi-port frequency division multiplexing filter in an embodiment of the present application. Figure 1 As shown, it includes: one or more frequency selection and filtering modules, each frequency selection and filtering module is provided with an input port and one or more output ports;

[0050] Each frequency-selective filtering module includes: one or more coupling modules, one or more resonant cavities of different frequencies;

[0051] A coupling module, used for coupling a frequency signal inputted via an input port to a resonant cavity of a different frequency;

[0052] The resonant cavity is used to selectively transmit the corresponding frequency signal and output it from the corresponding output port.

[0053] The multi-port frequency division multiplexing filter provided in the embodiment of the present application realizes a single-cavity bandpass filtering function with an adjustable frequency band.

[0054] The multi-port frequency division multiplexing filter provided in the embodiment of the present application can not only solve 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. The breakthrough is of great significance for promoting the large-scale expansion of quantum processors.

[0055] In an exemplary embodiment, the input port inputs an XY control signal for operating multiple superconducting quantum bits, and the resonant cavity is used to select a corresponding frequency signal, that is, to match the resonant frequency of the corresponding quantum bit, and output it from the corresponding output port, wherein the resonant frequency of the resonant cavity is consistent with the resonant frequency of the corresponding quantum bit. 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 XY control signal input port (i.e. N in XY control signal input channels), each XY control signal input channel is coupled to N through a first coupling capacitor. f Resonant cavities of different frequencies, that is, each frequency-selective filter module includes N f resonant cavity (that is, N f Each XY signal input channel is connected to N f The frequency-selective filter channels are coupled to each other through the first coupling capacitor, and each frequency-selective filter module realizes N q The control of superconducting quantum bits, where N f ≥N q ≥1,N in ≥1,N out ≥1. In this way, each frequency selection filter module q The control of N superconducting quantum bits is out The readout lines realize the measurement of the superconducting quantum bit state, N out =N in , the total number of controlled quantum bits is N in *N q .

[0056] In an exemplary embodiment, for N f =2 frequency-selective filter module, whose resonant cavity is called a four-port resonant cavity. In an exemplary embodiment, for N f =3 frequency-selective filter module, whose resonant cavity is called a six-port resonant cavity. In an exemplary embodiment, for N f =4 frequency-selective filter module, whose resonant cavity is called an eight-port resonant cavity. In an exemplary embodiment, for N f =8 frequency selective filtering module, its resonant cavity is called a sixteen-port resonant cavity.

[0057] In one exemplary embodiment, Nin The XY control line input channels correspond to the number of control microwave signal input ports at room temperature, that is, 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 embodiment, the XY control line is a pair of N q The microwave control lines required to rotate the state of a superconducting quantum bit around the X or Y axis on the Bloch sphere.

[0059] In one exemplary embodiment, N f The frequency selection channels are coupled to the corresponding XY control input channels through the first coupling capacitors respectively.

[0060] In an exemplary embodiment, the XY control signals corresponding to different frequencies output by the frequency selection filter module drive N q In one embodiment, each frequency-selective filtering channel may correspond to the resonant frequency of one or more quantum bits.

[0061] In one exemplary embodiment, N q A superconducting quantum bit can transfer information to the corresponding readout resonant cavity through a second coupling capacitor (also called a readout coupling capacitor).

[0062] In one exemplary embodiment, N q Each readout resonant cavity is capacitively coupled to the corresponding readout line.

[0063] In one exemplary embodiment, N out The number of readout lines corresponds to the number of signal output ports at room temperature, that is, N out The number of readout lines is equal to the number of signal output ports at room temperature.

[0064] In an exemplary embodiment, signals of various frequencies can be simultaneously input into the input port of the frequency selective filtering module provided in the embodiment of the present application through a main signal line, and the frequency selective filtering module is used to complete the coupling and transmission of the required frequency band signal to achieve the purpose of frequency division multiplexing, and transmit it to the corresponding superconducting quantum bit to change its state according to the signal.

[0065] In an exemplary embodiment, the XY control signal input channel is N in (N in ≥1), the number of frequency selection filter channels in the frequency selection filter module is N f (N f≥1), in one embodiment, taking 1 XY control signal input channel and 8 frequency-selective filter channels as an example, each superconducting quantum bit is coupled to the XY control line and is coupled to 1 readout line through 8 readout resonant cavities.

[0066] In an exemplary embodiment, taking the XY control signal input channel as 1, the number of channels in the frequency selection filter module as 8, and the two being coupled through the first coupling capacitor as an example, the XY control line is the microwave control line required for the operation of 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. The 8 superconducting quantum bits are driven by the XY control signal output by the frequency selection filter module through the first coupling capacitor, and are implemented by superconducting coplanar waveguides and coupling capacitors on the superconducting circuit chip. The 8 superconducting quantum bits transmit information to the corresponding readout resonant cavity through the second coupling capacitor, which is implemented by the superconducting coplanar waveguide and the second coupling capacitor on the superconducting chip. The 8 readout resonant cavities are coupled to the corresponding readout lines through the second capacitor. In this embodiment, one readout line is a microwave line coupled to the half-wavelength resonant cavity of the 8 superconducting quantum bits, providing a microwave signal for measuring the quantum bit, and the state of the superconducting quantum bit is obtained by measuring the dispersion characteristics of the readout resonant cavity.

[0067] In an exemplary embodiment, the XY control signal input channel is N in (N in ≥1), the number of frequency selection filter channels in the frequency selection filter module is N f (N f ≥1), each superconducting qubit is coupled to the XY control line and connected to the N q readout resonant cavity and N out The readout lines are coupled.

[0068] In an exemplary embodiment, the XY control signal input channel is N in , the number of channels in the frequency selection filter module is N f , for example, the two are coupled through the first coupling capacitor, and the XY control line is the microwave control line required for the operation of rotating the state of the superconducting quantum bit around the X axis or Y axis on the Bloch sphere, which is realized by the superconducting coplanar waveguide on the superconducting circuit chip. q Each superconducting qubit is driven by the XY control signal output by the frequency selection filter module through the first coupling capacitor, which is implemented on the superconducting circuit chip by the superconducting coplanar waveguide and the first coupling capacitor. In other words, the XY control signal is applied from the room temperature port, and after attenuation and filtering, it reaches the low temperature end, and is 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.

[0069] In an exemplary embodiment, it further includes: one or more second coupling capacitors, one or more readout resonant cavities, one or more readout lines, N q Each superconducting quantum bit transmits information to the corresponding readout resonant cavity through the second coupling capacitor, which is realized on the superconducting chip by the superconducting coplanar waveguide and the second coupling capacitor. q Each readout resonant cavity is coupled to the corresponding readout line through a second coupling capacitor. out The readout lines are coupled to N q The microwave line of the half-wavelength resonant cavity of each superconducting quantum bit provides a microwave signal for measuring the quantum bit, and the state of the superconducting quantum bit is measured by reading out the dispersion characteristics of the resonant cavity. In other words, one or more superconducting quantum bits transmit information to the corresponding readout resonant cavity and readout line in sequence through the second coupling capacitor; 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 the state of one or more superconducting quantum bits is measured according to the dispersion characteristics of the readout resonant cavity.

[0070] In one exemplary embodiment, N f The frequency-selective filter channels are respectively coupled with the corresponding XY control input channels through the first coupling capacitors, and 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 1 / 4 wavelength cavity, or a standard half-wavelength cavity with an auxiliary ground branch structure arranged at the center.

[0071] In one exemplary embodiment, N q A 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, attenuated and filtered to reach the low temperature end, and then transmitted to the superconducting quantum bit through the superconducting coplanar waveguide and coupling capacitor.

[0072] In one exemplary embodiment, N q The superconducting quantum bits transmit information to the corresponding N q The readout resonant cavity is realized on a superconducting circuit chip through a superconducting coplanar waveguide by one of the following structures: a standard half-wavelength cavity, a 1 / 4-wavelength cavity, or a standard half-wavelength cavity with an auxiliary ground branch structure arranged at a central position.

[0073] In one exemplary embodiment, N q Each readout resonant cavity is coupled to the corresponding readout line through capacitance and inductance, providing a microwave signal for measuring the quantum bit. The state of the superconducting quantum bit is measured by measuring the dispersion characteristics of the readout resonant cavity, which is realized on the superconducting circuit chip by superconducting coplanar waveguides and coupling capacitors.

[0074] In an exemplary embodiment, the readout line transmits the signal in the readout resonant cavity to the room temperature end for detection and readout after filtering and amplification, wherein N out The number of readout lines is equal to the number of signal output ports at room temperature.

[0075] For example, each frequency-selective filter module includes 1 XY control signal input channel and 8 frequency-selective filter channels. Then, N in = 1 XY control signal input channel, N f =8 frequency-selective filter channels, N q = 8 superconducting qubits, such as Figure 2(a)-Figure 2(c) As shown, one XY control signal input channel and eight frequency-selective filter channels are coupled via capacitors, and the resonant cavities of different lengths corresponding to the eight frequency-selective filter channels are represented by different grayscales. Various control frequency signals are input via the XY control signal input channel, and then enter the port corresponding to the resonant filter cavity via the first coupling capacitor. In the embodiment of the present application, the resonant cavities corresponding to the eight frequency-selective filter channels are Figure 2(a)-Figure 2(c) The three types of frequency-selective filtering modules shown have different shapes. The first type is 8 standard half-wavelength resonant cavities, as shown in FIG2(a). This structure is simple, easy to manufacture, and has good fundamental mode working performance. The second type adds a grounding structure at the point where the central fundamental mode field strength is zero, as shown in FIG2(b). Its transmission result suppresses the frequency-doubled mode and broadens the fundamental mode bandwidth, which is an optimization of the first method. The third type short-circuits the center positions of several resonant cavities of different sizes on the basis of the second method, as shown in FIG2(c). This not only maintains the transmission result of the second optimization method, but also improves the integration of the multi-port frequency-division multiplexing filter composed of the frequency-selective filtering module provided in the embodiment of the present application.

[0076] FIG. 3( a ) is a schematic diagram of the working principle of the resonant cavity shown in FIG. 2( a ) in the embodiment of the present application. As shown in FIG. 3( a ), a standard half-wavelength cavity (i.e., N in =1 frequency-selective filter channel), the half-wavelength cavity length L=λ / 2, the field intensity of the basic mode is zero at both ends and reaches a maximum 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 intensity distribution of the double frequency mode (2f) also reaches a maximum at the center, that is, the double frequency mode in the standard half-wavelength resonant cavity reaches a maximum field intensity at the center point, but it is easy to cause interference with the double frequency mode.

[0077] FIG3(b) is a schematic diagram of the working principle of the resonant cavity shown in FIG2(b) in the embodiment of the present application. As shown in FIG3(b), the optimized resonant cavity is shown, and 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, in order to destroy the field strength distribution of the frequency doubling mode, thereby suppressing the frequency doubling mode. After the optimization of the 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 the auxiliary grounding branch can also be one, or three, etc., but this embodiment is simulated by setting two auxiliary grounding branches as an example, and this embodiment is not used to limit the scope of protection of the present application.

[0078] FIG3(c) is a schematic diagram of the simulation results of the two cavities shown in FIG3(a) and FIG3(b) in the embodiment of the present application. In FIG3(c), the horizontal axis represents the frequency (Frequency), the unit is GHz, and the vertical axis represents the amplitude (Magnitude), the unit is decibel (dB). As shown in FIG3(c), the scattering parameters S of the two resonant cavities shown in FIG3(a) and FIG3(b) are shown. 21 Simulation results, in one embodiment, the scattering parameters between the two ports are calculated by circuit simulation software. In Figure 3(c), curve 31 is the result of the standard half-wavelength cavity, and curve 32 is the result of the cavity after the auxiliary ground branch is introduced. 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 widened to 455MHz, which is about doubled. Moreover, at the frequency-doubled mode intensity near 8GHz, the suppression level of the optimized cavity reaches below -20dB. The simulation results show that the optimization scheme significantly improves the anti-interference ability while maintaining the fundamental mode resonance performance.

[0079] In the embodiment of the present application, by combining the field distribution characteristics of the basic half-wavelength cavity with the auxiliary branch structure, the high-order frequency-multiplication mode in the half-wavelength resonant cavity is effectively suppressed, and the fundamental mode bandwidth is significantly broadened, thereby enhancing the practicality and frequency selection performance of the single-cavity filter. In one embodiment, by integrating multiple unit structures of designed sizes, a filter with multi-port function is constructed, which greatly improves the utilization efficiency of port resources. The multi-port frequency division multiplexing filter provided in the embodiment of the present application is suitable for the front unit of the XY control line signal, and is integrated with the superconducting quantum processor.

[0080] Figure 4(a)-Figure 4(d) Schematic diagrams of the output results of the resonant cavity with several typical port numbers of the multi-port frequency-selective filter of the embodiment of the present disclosure, wherein the horizontal axis represents the frequency in GHz and the vertical axis represents the amplitude in decibel (dB). FIG4(a) shows the N corresponding to the four-port resonant cavity. f= 2 frequency-selective filter channels. Figure 4(b) shows the N corresponding to the six-port resonant cavity. f = 3 frequency-selective filter channels. Figure 4(c) shows the N corresponding to the eight-port resonant cavity. f = 4 frequency-selective filter channels. Figure 4(d) shows the N corresponding to the sixteen-port resonant cavity. f =8 frequency selective filter channels.

[0081] As shown in FIG4(a), the left curve and the right curve correspond to two frequency selection channels respectively. The center frequency of the left curve is 113 MHz, and the center frequency of the right curve is 148 MHz. That is, in this embodiment, N f = 2 frequency-selective filter channels have 113MHz and 148MHz bandpass transmission characteristics, with obvious bandpass characteristics, small reflection loss, strong side mode suppression, and significant attenuation of signal amplitude in non-center frequency areas. In this embodiment, the first coupling capacitor is 50fF, the corresponding branch lengths of the four ports are 6mm, 6mm, 5mm, and 5mm respectively, and the auxiliary ground branch cavity lengths are all 0.1mm.

[0082] As shown in FIG4(b), the three curves from left to right correspond to three frequency selection channels, the center frequency of the left curve is 108 MHz, the center frequency of the middle curve is 139 MHz, and the center frequency of the right curve is 157 MHz. That is, in this embodiment, N f =3 frequency-selective filter channels have bandpass transmission characteristics of 108MHz, 139MHz, and 157MHz. The bandwidth of each channel is different, with good bandpass transmission characteristics, good side mode suppression effect, and improved isolation between channels. In this embodiment, the first coupling capacitor is 50fF, and the corresponding branch lengths of the six ports are 6mm, 6mm, 5mm, 5mm, 4.3mm, and 4.3mm, respectively, and the auxiliary ground branch cavity length is 0.1mm.

[0083] As shown in FIG4(c), the four curves from left to right correspond to four frequency selection channels, the center frequency of the leftmost curve is 108 MHz, the center frequency of the middle left curve is 139 MHz, the center frequency of the middle right curve is 177 MHz, and the center frequency of the rightmost curve is 180 MHz. That is to say, in this embodiment, N f = 4 frequency-selective filter channels have bandpass transmission characteristics of 108MHz, 139MHz, 177MHz, and 180MHz, with more uniform bandpass characteristics, wider bandwidth (partially up to 180MHz), more reasonable frequency intervals, and minimal interference between channels. In this embodiment, the first coupling capacitor is 50fF, and the corresponding branch lengths of the eight ports are 6mm, 6mm, 5mm, 5mm, 4.3mm, 4.3mm, 3.8mm, and 3.8mm, respectively, and the auxiliary ground branch cavity lengths are all 0.1mm.

[0084] As shown in FIG4(d), the sixteen curves from left to right correspond to sixteen frequency selection channels, each of which has a passband characteristic of about 60 MHz. That is, in this embodiment, N f = 8 frequency-selective filter channels have a bandpass transmission characteristic of about 60MHz each. The bandwidth of each channel is narrow, and the center frequency is evenly distributed, with excellent isolation. The bandwidth is much higher than that of N f =2, 3 or 4, but the side mode suppression effect is excellent. In this embodiment, the first coupling capacitor is 50fF, and the branch lengths corresponding to 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, and the auxiliary ground branch cavity lengths are 0.1mm and 0.02mm, respectively.

[0085] Figure 4(a)-Figure 4(d) In the illustrated embodiment, key parameters such as the center frequency, bandwidth, reflection loss, and side mode suppression ratio of the frequency selection channel can be controlled within a certain range by means of coupling capacitance and auxiliary ground branch size.

[0086] Through simulation, it can be seen that the performance of the multi-port frequency-selective filter provided by the embodiment of the present application improves with the increase of the number of ports, which is specifically manifested in more bandpass channels, better frequency distribution and stronger side mode suppression capability. By optimizing the design parameters (such as coupling capacitance, auxiliary ground branch cavity length, branch length, etc.), the center frequency and bandwidth of the frequency-selective channel can be flexibly adjusted to meet the purpose of different application requirements.

[0087] Although the embodiments disclosed in this application are as above, the contents described are only embodiments adopted to facilitate understanding of this application and are not intended to limit this application. Any technician in the field to which this application belongs can make any modifications and changes in the form and details of implementation without departing from the spirit and scope disclosed in this application, but the scope of patent protection of this application shall still be based on the scope defined in the attached 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 comprises: one or more coupling modules, and one or more resonant cavities of different frequencies; A coupling module, used for coupling a frequency signal inputted via an input port to a resonant cavity of a different frequency; The resonant cavity is used to selectively transmit the corresponding frequency signal and output it from the corresponding output port.

2. The multi-port frequency division multiplexing filter according to claim 1, wherein: The input port inputs an XY control signal for operating a plurality of superconducting quantum bits; The resonant cavity is used to select the corresponding frequency signal that matches the resonant frequency of the corresponding quantum bit and output it from the corresponding output port, and the resonant frequency of the resonant cavity is consistent with the resonant frequency of the corresponding quantum bit.

3. The multi-port frequency division multiplexing filter according to claim 2, wherein: The coupling module is a first coupling capacitor; for one of the frequency selection and filtering modules: The XY control signal input port corresponds to an XY control signal input channel; each of the resonant cavities corresponds to a frequency selection filter channel; The XY control signal input channel is coupled to the frequency selection filter channel corresponding to the resonant cavity of different frequencies through the first coupling capacitor; The frequency-selective filtering module realizes the control of one or more superconducting quantum bits; wherein the number of superconducting quantum bits is less than or equal to the number of frequency-selective filtering channels.

4. The multi-port frequency division multiplexing filter according to claim 1, wherein: The one or more frequency selection filter modules include N in an XY control line input channel corresponding to the XY control signal input port; 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.

5. The multi-port frequency division multiplexing filter according to claim 3, wherein: The XY control signal is applied from the room temperature port, and after attenuation and filtering, reaches the low temperature end, it is driven to the one or more superconducting quantum bits through the first coupling capacitor, so that the state of the one or more superconducting quantum bits rotates around the X-axis or the Y-axis on the Bloch sphere.

6. The multi-port frequency division multiplexing filter according to claim 5, wherein: Each of the frequency-selective filtering channels corresponds to the resonant frequency of one or more quantum bits.

7. The multi-port frequency division multiplexing filter according to claim 3, further comprising: one or more second coupling capacitors, one or more readout resonant cavities, one or more readout lines; The one or more superconducting quantum bits transmit information to the corresponding readout resonant cavity and readout line in sequence through the second coupling capacitor; The number of the readout lines is equal to the number of signal output ports at room temperature.

8. The multi-port frequency division multiplexing filter according to claim 7, 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 obtains the state of the one or more superconducting quantum bits according to the dispersion characteristics of the readout resonant cavity.

9. The multi-port frequency division multiplexing filter according to claim 3, wherein: The frequency-selective filtering channel is implemented on a superconducting circuit chip through a superconducting coplanar waveguide by one of the following structures: A standard half-wavelength cavity, a 1 / 4-wavelength cavity, or a standard half-wavelength cavity with an auxiliary ground branch structure at the center.

10. The multi-port frequency division multiplexing filter according to claim 7, wherein: The readout resonant cavity is implemented on a superconducting circuit chip through a superconducting coplanar waveguide by one of the following structures: A standard half-wavelength cavity, a 1 / 4-wavelength cavity, or a standard half-wavelength cavity with an auxiliary ground branch structure at the center.

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