A Josephson parametric amplifier

Abstract

The present application discloses a Josephson parametric amplifier, which uses only two independent Josephson oscillators, thereby ensuring that the Josephson parametric amplifier has a simple structure and is easy to prepare, reducing the difficulty of the process. Moreover, by adopting flux pumping, compared with current pumping, no additional coupling structure and filtering structure are required, further ensuring that the Josephson parametric amplifier has a simple structure. Therefore, the Josephson parametric amplifier provided in the embodiment of the present application is conducive to realizing the integration of superconducting quantum bit readout amplification links.

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 Josephson parametric amplifier. Background Art

[0002] In quantum circuits, low-noise amplification of weak microwave signals is essential, and the Josephson Parametric Amplifier (JPA) is the most widely used device.

[0003] In the superconducting quantum bit test system, the signal needs to be amplified by multiple amplifiers before it can be effectively measured by instruments at room temperature. As the number of quantum bits continues to increase, the low-temperature multi-stage amplification part in the test link needs to be integrated, otherwise it will pose a great challenge to the space and heat load of the refrigerator. In related technologies, the first-stage amplifier uses a reflective Josephson parametric amplifier, which provides suitable gain and bandwidth while the noise is close to the standard quantum limit, making single-shot readout and feedback control of quantum bits possible. However, the reflective Josephson parametric amplifier needs to be used with a circulator when working to separate the input signal from the amplified output signal, which will bring the following problems to the integration of the superconducting quantum bit readout amplifier link: due to the complex structure of the circulator and the need for multiple control signals, this will increase the difficulty of integrating the superconducting quantum bit readout amplifier link; secondly, the overall bandwidth, dynamic range, noise and other performance of the superconducting quantum bit readout amplifier link will be affected by the circulator; in addition, direct inter-stage matching cannot be performed between multi-stage amplifiers, and they always need to pass through a circulator, which will be detrimental to improving the overall performance of the superconducting quantum bit readout amplifier link.

[0004] In summary, the reflective Josephson parametric amplifier is not conducive to the integration of superconducting quantum bit readout amplification links. Summary of the invention

[0005] The present application provides a Josephson parametric amplifier with a simple structure, which is conducive to the integration of superconducting quantum bit readout amplification links.

[0006] An embodiment of the present invention provides a Josephson parametric amplifier, wherein the Josephson parametric amplifier is provided with an input port and an output port, wherein a signal to be amplified enters the Josephson parametric amplifier from the input port, and the amplified signal is output from the output port; the Josephson parametric amplifier comprises: one or more signal distribution and coupling structures, a first Josephson oscillator, a second Josephson oscillator, and one or more flux bias and pump input lines; wherein,

[0007] The signal distribution and coupling structure is connected to the first Josephson oscillator, the second Josephson oscillator, the input port and the output port respectively; the signal distribution and coupling structure is used to: perform phase shift processing on the signal to be amplified to obtain a first signal to be amplified and a second signal to be amplified, the first signal to be amplified is transmitted to the first Josephson oscillator, and the second signal to be amplified is transmitted to the second Josephson oscillator; process the first amplified signal from the first Josephson oscillator and the second amplified signal from the second Josephson oscillator to achieve interference destructive phase between the first amplified signal and the second amplified signal reflected from the first Josephson oscillator and the second Josephson oscillator to the input port, and the first amplified signal and the second amplified signal amplified by the first Josephson oscillator and the second Josephson oscillator output to the output port after amplification are interfered constructively;

[0008] The first Josephson oscillator and the second Josephson oscillator are mutually inductively connected to the magnetic flux bias and pump input line respectively; the pump signal on the magnetic flux bias and pump input line is magnetic flux pumping, and the frequency is a microwave pump signal in the microwave frequency band;

[0009] The first Josephson resonator is used to mix and amplify the first signal to be amplified and the microwave pump signal to obtain the first amplified signal and transmit it to the signal distribution and coupling structure;

[0010] The second Josephson oscillator is used to mix and amplify the second signal to be amplified and the microwave pump signal to obtain the second amplified signal and transmit it to the signal distribution and coupling structure.

[0011] In an exemplary embodiment, it also includes: more than two matching networks; the matching networks are connected between the signal distribution and coupling structure and the first Josephson oscillator and the second Josephson oscillator to increase the bandwidth of the Josephson parametric amplifier.

[0012] In an exemplary embodiment, the matching network is a distributed matching network, or a lumped matching network, or a distributed and lumped hybrid matching network;

[0013] When the matching network is a distributed matching network, the distributed matching network is composed of microwave transmission lines;

[0014] When the matching network is a lumped matching network, the lumped matching network is composed of on-chip or independent capacitors, inductors, and resistors;

[0015] When the matching network is a distributed and lumped mixed matching network, the distributed and lumped mixed matching network is a combination of the distributed matching network and the lumped matching network.

[0016] In an exemplary embodiment, when the matching network is a lumped matching network, the inductor in the lumped matching network is an equivalent inductor formed by a Josephson junction or a superconducting quantum interference device (SQUID).

[0017] In an exemplary embodiment, the magnetic flux bias and pump input line comprises one magnetic flux bias and pump input line, and the first Josephson oscillator and the second Josephson oscillator are mutually inductively connected to the same magnetic flux bias and pump input line;

[0018] Alternatively, the flux bias and pump input line includes two flux bias and pump input lines, and the first Josephson oscillator and the second Josephson oscillator are mutually inductively connected to an independent flux bias and pump input line respectively.

[0019] In an exemplary embodiment, the flux bias and pump input line includes a DC bias signal and a microwave pump signal, wherein the DC bias signal is used to adjust the working point of the mutually inductively connected Josephson oscillator, and the microwave pump signal is used to realize the mixing amplification;

[0020] The DC bias signal and the microwave pump signal are combined together through a bias device BiasTee element and then input into the flux bias and pump input line.

[0021] In an exemplary embodiment, the phase shifting process of the signal to be amplified in the signal distribution and coupling structure to obtain the first signal to be amplified and the second signal to be amplified includes:

[0022] The power of the signal to be amplified is evenly divided into two equal parts and one of the parts is phase-shifted by 90° to obtain a first signal to be amplified and a second signal to be amplified, wherein the second signal to be amplified has a phase shift of 90° relative to the first signal to be amplified, the first signal to be amplified is output to the first Josephson oscillator, and the second signal to be amplified is output to the second Josephson oscillator.

[0023] In an exemplary embodiment, the processing of the first amplified signal from the first Josephson oscillator and the second amplified signal from the second Josephson oscillator in the signal distribution and coupling structure includes:

[0024] The second amplified signal reflected back to the input port by the second Josephson oscillator is phase-shifted by 90°, so that the second amplified signal has a phase shift of 180° more than the first amplified signal, and the first amplified signal and the second amplified signal reflected back to the input port have opposite phases, and interference destructively occurs; the first amplified signal output to the output port by the first Josephson oscillator is phase-shifted by 90°, so that the first amplified signal has a phase shift of 90° more than the second amplified signal, and the first amplified signal and the second amplified signal output to the output port have the same phase, and interference constructively occurs.

[0025] In an exemplary embodiment, the signal distribution and coupling structure is one, and the flux bias and pump input line is one;

[0026] The first Josephson oscillator and the second Josephson oscillator are in a reflection working state;

[0027] The signal distribution and coupling structure is composed of an orthogonal hybrid network, including four ports, wherein port 1 is the input port, port 4 is the output port, port 2 is connected to the first Josephson oscillator via the first matching network, and port 3 is connected to the second Josephson oscillator via the second matching network; the first Josephson oscillator and the second Josephson oscillator are mutually inductively connected to one of the flux bias and pump input lines;

[0028] The signal to be amplified enters the orthogonal hybrid network through the port 1, and the power of the signal to be amplified is evenly divided into the first signal to be amplified and the second signal to be amplified, wherein the first signal to be amplified is transmitted to the port 2, and the second signal to be amplified is transmitted to the port 3, and the second signal to be amplified transmitted to the port 3 has a phase shift of 90° more than the first signal to be amplified transmitted to the port 2;

[0029] The first signal to be amplified enters the first Josephson oscillator through the first matching network for amplification to obtain the first amplified signal, and the first amplified signal is reflected back to the port 2; the second signal to be amplified enters the second Josephson oscillator through the second matching network for amplification to obtain the second amplified signal, and the second amplified signal is reflected back to the port 3; the first amplified signal and the second amplified signal enter the orthogonal hybrid network from port 2 and port 3 respectively and are transmitted to the input port and the output port;

[0030] The second amplified signal reflected back to the port 3 is phase-shifted by 90° and then transmitted to the port 1, and the first amplified signal reflected back to the port 2 is phase-shifted by 0° and then transmitted to the port 1, so that there is a phase difference of 180° between the first amplified signal reflected back to the port 1 and the second amplified signal, and destructive interference occurs; the first amplified signal reflected back to the port 2 is phase-shifted by 90° and then transmitted to the port 4, and the second amplified signal reflected back to the port 3 is phase-shifted by 0° and then transmitted to the port 4, so that the first amplified signal and the second amplified signal transmitted to the port 4 have the same phase, and are output from the output port after constructive interference occurs.

[0031] In an exemplary embodiment, the signal distribution and coupling structure is a first signal distribution and coupling structure and a second signal distribution and coupling structure, the flux bias and pump input line includes a first flux bias and pump input line and a second flux bias and pump input line; the matching network includes a first matching network, a second matching network, a third matching network and a fourth matching network;

[0032] The first Josephson oscillator and the second Josephson oscillator are in a transmission working state;

[0033] The first signal distribution and coupling structure is composed of a first orthogonal hybrid network, including four ports, wherein port 11 is the input port, port 12 is connected to the first Josephson oscillator via the first matching network, and port 13 is connected to the second Josephson oscillator via the second matching network; port 14 is connected to an impedance matching load; the second signal distribution and coupling structure is composed of a second orthogonal hybrid network, including four ports, wherein port 23 is the output port, port 22 is connected to an impedance matching load, port 21 is connected to the first Josephson oscillator via the third matching network, and port 24 is connected to the second Josephson oscillator via the fourth matching network; the first Josephson oscillator is mutually inductively connected to the first magnetic flux bias and pump input line, and the second Josephson oscillator is mutually inductively connected to the second magnetic flux bias and pump input line;

[0034] The signal to be amplified enters the first orthogonal hybrid network through the port 11, and the power of the signal to be amplified will be evenly divided into the first signal to be amplified transmitted to the port 12 and the second signal to be amplified transmitted to the port 13, and the second signal to be amplified has a 90° phase shift more than the first signal to be amplified; the first signal to be amplified enters the first Josephson oscillator through the first matching network, and the second signal to be amplified enters the second Josephson oscillator through the second matching network; the first amplified signal amplified by the first Josephson oscillator is reflected back to the port 12, and output to the port 21 through the third matching network; the second amplified signal amplified by the second Josephson oscillator is reflected back to the port 13, and output to the port 24 through the fourth matching network;

[0035] The first amplified signal reflected back to the port 12 is phase-shifted by 0° and then transmitted to the port 11, and the second amplified signal reflected back to the port 13 is phase-shifted by 90° and then transmitted to the port 11, so that there is a phase difference of 180° between the first amplified signal reflected back to the port 11 and the second amplified signal, and interference destructive phase occurs; the first amplified signal reflected back to the port 12 is phase-shifted by 90° and then transmitted to the port 14, and the second amplified signal reflected back to the port 13 is phase-shifted by 0° and then transmitted to the port 14, and the first amplified signal and the second amplified signal reflected back to the port 14 are consumed by the impedance matching load;

[0036] The first amplified signal transmitted to the port 21 is phase-shifted by 90° and then transmitted to the port 23, and the second amplified signal transmitted to the port 24 is phase-shifted by 0° and then transmitted to the port 23, so that the first amplified signal transmitted to the port 23 and the second amplified signal have the same phase, and are output from the output port after constructive interference occurs; the first amplified signal transmitted to the port 21 is phase-shifted by 0° and then transmitted to the port 22, and the second amplified signal transmitted to the port 24 is phase-shifted by 90° and then transmitted to the port 22, so that the first amplified signal transmitted to the port 22 has a phase difference of 180° and the second amplified signal is interfered destructively.

[0037] The Josephson parametric amplifier provided in the embodiment of the present application is a transmission-type flux-pumped Josephson parametric amplifier based on the principle of multi-path signal interference. It only uses two independent Josephson oscillators, which ensures that the Josephson parametric amplifier has a simple structure and is easy to prepare, reducing the difficulty of the process. Moreover, by using flux pumping, compared with current pumping, no additional coupling structure and filtering structure are required, further ensuring the simplicity of the Josephson parametric amplifier structure. Therefore, the Josephson parametric amplifier provided in the embodiment of the present application is conducive to realizing the integration of superconducting quantum bit readout amplification links.

[0038] In one embodiment, when the Josephson parametric amplifier provided in the embodiment of the present application constitutes a multi-stage amplifier, the multi-stage amplifiers can be directly connected without passing through a circulator, which is conducive to the integration of the superconducting quantum bit readout amplifier link and will not cause additional inter-stage interference, thereby improving the overall performance of the superconducting quantum bit readout amplifier link.

[0039] 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

[0040] 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.

[0041] Figure 1 This is a schematic diagram of the composition principle of the Josephson parametric amplifier in the embodiment of the present application;

[0042] Figure 2 This is a schematic diagram of the composition structure of the first embodiment of the Josephson parametric amplifier in the embodiments of the present application;

[0043] Figure 3 Schematic diagram of the structure of the second embodiment of the Josephson parametric amplifier in the embodiments of the present application. DETAILED DESCRIPTION

[0044] 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 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] Figure 1 The figure is a schematic diagram of the composition principle of the Josephson parametric amplifier in the embodiment of the present application. The Josephson parametric amplifier in the present application is a dual-port amplifier. The Josephson parametric amplifier is provided with an input port and an output port. The signal to be amplified enters the Josephson parametric amplifier from the input port of the Josephson parametric amplifier, and the signal amplified by the Josephson parametric amplifier is output from the output port of the Josephson parametric amplifier. Figure 1 As shown, the Josephson parametric amplifier comprises at least: one or more signal distribution and coupling structures 101, a first Josephson oscillator 1021, a second Josephson oscillator 1022, and one or more flux bias and pump input lines 103; wherein,

[0051] The signal distribution and coupling structure 101 is respectively connected to the first Josephson oscillator 1021, the second Josephson oscillator 1022, the input port of the Josephson parametric amplifier and the output port of the Josephson parametric amplifier, and is used to perform phase shift processing on the signal to be amplified to obtain the first signal to be amplified and the second signal to be amplified, the first signal to be amplified is transmitted to the first Josephson oscillator 1021, and the second signal to be amplified is transmitted to the second Josephson oscillator 1022; the first amplified signal from the first Josephson oscillator 1021 and the second amplified signal from the second Josephson oscillator 1022 are processed to achieve the first amplified signal and the second amplified signal reflected from the first Josephson oscillator 1021 and the second Josephson oscillator 1022 to interfere with each other, and the first amplified signal and the second amplified signal output to the output port after amplification by the first Josephson oscillator 1021 and the second Josephson oscillator 1022 interfere with each other;

[0052] The first Josephson oscillator 1021 and the second Josephson oscillator 1022 are mutually inductively connected to the magnetic flux bias and pump input line 103 respectively; the pump signal on the magnetic flux bias and pump input line 103 is magnetic flux pumping, and is a microwave pump signal with a frequency in the microwave frequency band;

[0053] The first Josephson oscillator 1021 is used for mixing and amplifying the first signal to be amplified from the signal distribution and coupling structure 101 and the microwave pump signal applied in the magnetic flux bias and pump input line 103 to obtain a first amplified signal, and the first amplified signal obtained after amplification is transmitted to the signal distribution and coupling structure 101; the second Josephson oscillator 1022 is used for mixing and amplifying the second signal to be amplified from the signal distribution and coupling structure 101 and the microwave pump signal applied in the magnetic flux bias and pump input line 103 to obtain a second amplified signal, and the second amplified signal obtained after amplification is transmitted to the signal distribution and coupling structure 101.

[0054] The Josephson parametric amplifier provided in the embodiment of the present application is a transmission-type flux-pumped Josephson parametric amplifier based on the principle of multi-path signal interference. It only uses two independent Josephson oscillators, which ensures that the Josephson parametric amplifier has a simple structure and is easy to prepare, reducing the process difficulty. Moreover, by using flux pumping, compared with current pumping, no additional coupling structure and filtering structure are required, which further ensures that the Josephson parametric amplifier has a simple structure. Therefore, the Josephson parametric amplifier provided in the embodiment of the present application is conducive to realizing the integration of the superconducting quantum bit readout amplifier link. In one embodiment, when the Josephson parametric amplifier provided in the embodiment of the present application constitutes a multi-stage amplifier, the multi-stage amplifiers can be directly connected without passing through a circulator, which is conducive to realizing the integration of the superconducting quantum bit readout amplifier link, and will not cause additional inter-stage interference, thereby improving the overall performance of the superconducting quantum bit readout amplifier link.

[0055] In an exemplary embodiment, the Josephson parametric amplifier provided by the embodiment of the present application may also include: two or more matching networks 104, the matching network 104 is connected between the signal distribution and coupling structure 101 and the first Josephson oscillator 1021 and the second Josephson oscillator 1022, and is used to increase the bandwidth of the Josephson parametric amplifier. In one embodiment, the matching network 104 can be composed of a simple 50-ohm transmission line. In one embodiment, the signal distribution and coupling structure 101 can be combined with the matching network 104 to simultaneously achieve signal interference and impedance matching to achieve broadband amplification.

[0056] In one embodiment, if Figure 1 As shown, the matching network 104 includes a first matching network 1041 and a second matching network 1042 . The first matching network 1041 is connected between the signal distribution and coupling structure 101 and the first Josephson oscillator 1021 , and the second matching network 1042 is connected between the signal distribution and coupling structure 101 and the second Josephson oscillator 1022 .

[0057] In an exemplary embodiment, the first matching network 1041 may be formed by a simple 50-ohm transmission line, and is used to connect the first Josephson oscillator 1021 and the signal distribution and coupling structure 101. The second matching network 1042 may be formed by a simple 50-ohm transmission line, and is used to connect the second Josephson oscillator 1022 and the signal distribution and coupling structure 101.

[0058] In an exemplary embodiment, the first matching network 1041 or the second matching network 1042 may be formed by a Klopfenstein transmission line or two distributed resonant cavities. In this way, based on the Josephson parametric coupling network synthesis technology, higher-order broadband amplification may be achieved.

[0059] In an exemplary embodiment, the matching network 104 can be a distributed matching network, a lumped matching network, or a distributed and lumped mixed matching network. In one embodiment, the distributed matching network can be composed of microwave transmission lines. In one embodiment, the lumped matching network can be composed of on-chip or independent capacitors, inductors, and resistors. In one embodiment, the distributed and lumped mixed matching network can be a combination of a distributed matching network and a lumped matching network. In one embodiment, the inductor in the lumped matching network can be an equivalent inductor composed of a Josephson junction or a SQUID.

[0060] In an exemplary embodiment, the first Josephson oscillator 1021 includes a superconducting quantum interference device (SQUID) and a capacitor connected in parallel, and the second Josephson oscillator 1022 includes a SQUID and a capacitor connected in parallel. The first Josephson oscillator 1021 and the second Josephson oscillator 1022 may be the same. In one embodiment, the capacitor connected in parallel with the SQUID may be a parallel plate capacitor or a finger capacitor. In one embodiment, the SQUID may include one or more SQUIDs connected in series, and different bandwidths and dynamic ranges are achieved according to the number of SQUIDs connected in series.

[0061] In an exemplary embodiment, the first Josephson oscillator 1021 / the second Josephson oscillator 1022 includes two working states: reflection mode and transmission mode.

[0062] In an exemplary embodiment, the flux bias and pump input line 103 may include one flux bias and pump input line, that is, the first Josephson vibrator 1021 and the second Josephson vibrator 1022 are mutually inductively connected to the same flux bias and pump input line. In this embodiment, the first Josephson vibrator 1021 and the second Josephson vibrator 1022 share the same flux bias and pump input line, further saving chip area and flux bias and pump ports.

[0063] In an exemplary embodiment, the flux bias and pump input line 103 may include two flux bias and pump input lines, that is, the first Josephson oscillator 1021 and the second Josephson oscillator 1022 are mutually inductively connected to an independent flux bias and pump input line respectively.

[0064] In one embodiment, the flux bias and pump input line 103 includes a DC bias signal and a microwave pump signal, wherein the DC bias signal is used to adjust the working point of the Josephson oscillator connected to the flux bias and pump input line 103 by mutual inductance, and the microwave pump signal is used to achieve mixing amplification. In the embodiment of the present application, the pump signal on the flux bias and pump input line 103 is flux pumping, and the signal with a frequency in the microwave frequency band is referred to as a microwave pump signal in this article. In practical applications, one end of the flux bias and pump input line 103 is connected to a microwave source to input a microwave signal, so that a microwave frequency band current will appear on the flux bias and pump input line 103, thereby inducing a microwave frequency band magnetic flux.

[0065] In one embodiment, the DC bias signal and the microwave pump signal can be combined through a bias tee element and then input into the flux bias and pump input line 103. The BiasTee can be composed of ultra-wideband, near-idealized, high-frequency inductors and capacitors without resonance points. The DC signal is used to adjust the critical current of the SQUID and the corresponding equivalent inductance to achieve the tuning of the working point of the Josephson oscillator (such as the first Josephson oscillator 1021 and / or the second Josephson oscillator 1022) connected to the flux bias and pump input line by mutual inductance; the microwave pump signal is used to mix with the input signal to be amplified (such as the first signal to be amplified and the second signal to be amplified) through the SQUID, and the energy is transmitted to the input signal to be amplified to achieve the amplification of the signal to be amplified.

[0066] In the embodiment of the present application, on the one hand, since the microwave pump signal has an independent port and does not share a port with the input signal to be amplified, when the microwave pump signal is applied, there is no need to use an additional coupler to couple the signal to be amplified and the microwave pump signal, which is conducive to the simplification of the design of the Josephson parametric amplifier; on the other hand, since the microwave pump signal works in the three-wave mixing state, the microwave pump signal frequency ω p Equal to the frequency of the signal to be amplified ω s The pump frequency ω generated during the mixing process i The sum of p =ω s +ω i ≈2ω s , microwave pump signal frequency ω p Keep away from the signal frequency to be amplified ω s Therefore, there is no need to use an additional filtering structure to filter out the microwave pump signal, thereby avoiding its influence on the signal to be amplified, which is beneficial to the simplification of the design of the Josephson parametric amplifier; on the other hand, since the pumping method is flux pumping, when the Josephson parametric amplifier provided in the embodiment of the present application constitutes a multi-stage amplifier, the microwave pump signal will not bring about inter-stage influence between the Josephson parametric amplifiers at each stage, which is beneficial to the simplification of the design of the Josephson parametric amplifier and the improvement of the performance of the Josephson parametric amplifier.

[0067] In an exemplary embodiment, the signal distribution and coupling structure 101 performs phase shift processing on the signal to be amplified to obtain the first signal to be amplified and the second signal to be amplified, including:

[0068] The power of the signal to be amplified is evenly divided into two equal parts and one of the parts is phase-shifted by 90° to obtain a first signal to be amplified and a second signal to be amplified. The second signal to be amplified has a 90° more phase shift than the first signal to be amplified. The first signal to be amplified is output to the first Josephson oscillator 1021, and the second signal to be amplified is output to the second Josephson oscillator 1022.

[0069] In an exemplary embodiment, the signal distribution and coupling structure 101 processes the first amplified signal from the first Josephson oscillator 1021 and the second amplified signal from the second Josephson oscillator 1022, including:

[0070] The second amplified signal reflected by the second Josephson oscillator 1022 to the input port of the Josephson parametric amplifier is phase-shifted by 90°, so that the second amplified signal has an additional phase shift of 180° relative to the first amplified signal, that is, the first amplified signal reflected by the first Josephson oscillator 1021 and the second amplified signal reflected by the second Josephson oscillator 1022 are in opposite phases, and the two amplified signals interfere with each other; the first amplified signal output by the first Josephson oscillator 102 to the output port of the Josephson parametric amplifier is phase-shifted by 90°, so that the first amplified signal has an additional phase shift of 90° relative to the second amplified signal, that is, the first amplified signal and the second amplified signal output by the first Josephson oscillator 1021 and the second Josephson oscillator 1022 to the output port are in the same phase, and interfere with each other constructively. In this way, the amplified signal only appears at the output port of the Josephson parametric amplifier, and the signal reflected back to the input port of the Josephson parametric amplifier is suppressed.

[0071] In an exemplary embodiment, the signal distribution and coupling structure 101 may be composed of distributed elements, or composed of lumped elements, or a mixture of distributed elements and lumped elements to achieve a narrowband or broadband structure.

[0072] The Josephson parametric amplifier with transmission-type flux pumping based on the principle of multi-path signal interference provided by the embodiment of the present application maintains a low reflection signal while realizing transmission-type amplification, thereby avoiding additional interference to the quantum bit system being measured. The Josephson parametric amplifier provided by the embodiment of the present application only uses two independent Josephson oscillators, which ensures that the amplifier structure is simple and easy to prepare, and reduces the process difficulty. The Josephson parametric amplifier provided by the embodiment of the present application adopts flux pumping, which does not require additional coupling structure and filtering structure compared to current pumping, thereby reducing the circuit complexity. Moreover, when the Josephson parametric amplifier provided by the embodiment of the present application constitutes a multi-stage amplifier, no additional inter-stage interference is introduced. The Josephson parametric amplifier with transmission-type flux pumping provided by the embodiment of the present application can be directly connected between multi-stage amplifiers without passing through a circulator, which is conducive to the integration of the amplification link. Moreover, inter-stage matching can be directly performed between multi-stage amplifiers, which is conducive to improving the overall performance of the amplification link.

[0073] In one embodiment, the first Josephson oscillator 1021 and the second Josephson oscillator 1022 are in a reflective working state, such as Figure 2 As shown, the Josephson parametric amplifier at least includes: a signal distribution and coupling structure 101, a first Josephson oscillator 1021, a second Josephson oscillator 1022, a first matching network 1041, a second matching network 1042 and a flux bias and pump input line 103.

[0074] Figure 2 In the first embodiment shown, the signal distribution and coupling structure 101 is composed of an orthogonal hybrid network 101, including four ports, wherein port 1 (such as Figure 2 The input port of the Josephson parametric amplifier is shown in Figure ①, and port 4 (as shown in Figure ①) is the input port of the Josephson parametric amplifier. Figure 2 The output port of the Josephson parametric amplifier is connected to port 2 (as shown in the figure ④). Figure 2 ② in the figure) is connected to the first Josephson oscillator 1021 and the port 3 (as shown in FIG. Figure 2The first Josephson oscillator 1021 and the second Josephson oscillator 1022 share a flux bias and pump input line 103, that is, the first Josephson oscillator 1021 and the second Josephson oscillator 1022 are mutually inductively connected to the same flux bias and pump input line 103. In this embodiment, the first Josephson oscillator 1021 includes a parallel SQUID1 (abbreviated as SQ1 in the figure) and a capacitor Cp1, wherein SQUID1 is composed of two parallel-connected Josephson junctions, and the second Josephson oscillator 1022 includes a parallel SQUID2 (abbreviated as SQ2 in the figure) and a capacitor Cp2, wherein SQUID2 is composed of two parallel-connected Josephson junctions.

[0075] like Figure 2 As shown, the first end of the first matching network 1041 is used to receive the first signal to be amplified from the port 2 of the orthogonal hybrid network 101, and output the first amplified signal amplified from the first Josephson oscillator 1021 to the port 2 of the orthogonal hybrid network 101; the second end of the first matching network 1041 is connected to the first end of the capacitor Cp1 and the first end of the SQUID1; the first end of the flux bias and pump input line 103 is used to receive the DC bias signal and the microwave pump signal, and the second end of the capacitor Cp1, the second end of the SQUID1 and the second end of the flux bias and pump input line 103 are all grounded; wherein the SQUID1 is mutually inductively connected to the flux bias and pump input line 103. The first signal to be amplified is input from the first end of the first matching network 1041, and enters the capacitor Cp1 and the SQUID1 through the first matching network 1041. The DC bias signal and the microwave pump signal are inputted into the flux bias and pump input line 103 from the first end of the flux bias and pump input line 103, wherein the DC bias signal is used to bias SQUID1, adjust the equivalent inductance of SQUID1, and make the Josephson parameter amplifier work at the microwave frequency required to be amplified, and the microwave pump signal is used to provide energy to SQUID1. The amplified first amplified signal is outputted to the port 2 of the orthogonal hybrid network 101 via the first end of the first matching network 1041.

[0076] like Figure 2As shown, the first end of the second matching network 1042 is used to receive the second signal to be amplified from the port 3 of the orthogonal hybrid network 101, and output the second amplified signal amplified from the second Josephson oscillator 1022 to the port 3 of the orthogonal hybrid network 101; the second end of the second matching network 1042 is connected to the first end of the capacitor Cp2 and the first end of the SQUID2; the first end of the flux bias and pump input line 103 is used to receive the DC bias signal and the microwave pump signal, and the second end of the capacitor Cp2, the second end of the SQUID2 and the second end of the flux bias and pump input line 103 are all grounded; wherein the SQUID2 is mutually inductively connected to the flux bias and pump input line 103. The second signal to be amplified is input from the first end of the second matching network 1042, and enters the capacitor Cp2 and SQUID2 through the second matching network 1042. The DC bias signal and the microwave pump signal are inputted into the flux bias and pump input line 103 from the first end of the flux bias and pump input line 103, wherein the DC bias signal is used to bias SQUID 2, adjust the equivalent inductance of SQUID 2, and make the Josephson parameter amplifier work at the microwave frequency required to be amplified, and the microwave pump signal is used to provide energy to SQUID 2. The amplified second amplified signal is outputted to the port 3 of the orthogonal hybrid network 101 via the first end of the second matching network 1042.

[0077] It should be noted that Figure 2 In the first embodiment shown, the flux bias and pump input line 103 may also include two flux bias and pump input lines, one of which is individually connected to SQUID1 and the other is individually connected to SQUID2.

[0078] Figure 2In the first embodiment shown, two reflective Josephson oscillators (i.e., the first Josephson oscillator 1021 and the second Josephson oscillator 1022) and the flux bias and pump input line 103 constitute two independent reflective Josephson parametric quantum amplifiers. SQUID1 / SQUID2 is equivalent to a flux-regulated nonlinear inductor, and the capacitor Cp1 / capacitor Cp2 connected in parallel therewith constitutes a resonator with parametric modulation of the resonant frequency. By changing the DC bias current flowing through the flux bias and pump input line 103, the bias flux passing through the SQUID1 / SQUID2 loop changes, so that the resonant frequency of the first Josephson oscillator 1021 / the second Josephson oscillator 1022 also changes accordingly. If a microwave pump signal is added on the basis of the DC bias current, then the resonant frequency of the first Josephson oscillator 1021 / the second Josephson oscillator 1022 will oscillate at the frequency of the microwave pump signal, so that the Josephson parametric amplifier is in a working state. At this time, the first signal to be amplified / the second signal to be amplified input into the orthogonal hybrid network 101 enters the first Josephson oscillator 1021 / the second Josephson oscillator 1022 via the first matching network 1041 / the second matching network 1042, and is mixed with the microwave pump signal, and energy is transferred from the microwave pump signal to the first signal to be amplified / the second signal to be amplified; then, the first signal to be amplified / the second signal to be amplified is amplified, and the amplified first amplified signal / the second amplified signal is reflected back to the orthogonal hybrid network 101 along the original path (i.e., the first Josephson oscillator 1021 / the second Josephson oscillator 1022→the first matching network 1041 / the second matching network 1042→the port 2 of the orthogonal hybrid network 101 / the port 3 of the orthogonal hybrid network 101).

[0079] like Figure 2As shown, in the first embodiment, the input signal (i.e., the signal to be amplified) first enters an orthogonal hybrid network 101 through port 1, and the power of the signal to be amplified entering port 1 is evenly divided into two parts, one of which is the first signal to be amplified (0° phase shift) transmitted to port 2 directly opposite to port 1, and the other is the second signal to be amplified (90° phase shift) transmitted to port 3 diagonally opposite to port 1, and the second signal to be amplified transmitted to port 3 has an additional phase shift of 90° compared to the first signal to be amplified transmitted to port 2, so as to realize orthogonal coupling of the signals. That is to say, in the first embodiment, after the input signal passes through the orthogonal hybrid network 101, it is evenly divided into two parts and transmitted to port 2 and port 3 of the orthogonal hybrid network 101, and there is a phase difference of 90° between the two. Afterwards, the first signal to be amplified enters the first Josephson oscillator 1021 through the first matching network 1041 for amplification, and the first amplified signal is reflected back to port 2 of the orthogonal hybrid network 101 along the original path (i.e., the first Josephson oscillator 1021→the first matching network 1041→the orthogonal hybrid network 101), and the second signal to be amplified enters the second Josephson oscillator 1022 through the second matching network 1042 for amplification, and the second amplified signal is reflected back to port 3 of the orthogonal hybrid network 101 along the original path (i.e., the second Josephson oscillator 1022→the second matching network 1042→the orthogonal hybrid network 101). After the first amplified signal and the second amplified signal enter the orthogonal hybrid network 101 from port 2 and port 3 respectively, the first amplified signal and the second amplified signal are both transmitted to the input port (i.e., port 1) and the output port (i.e., port 4) of the Josephson parametric amplifier. The second amplified signal reflected back to port 3 is phase-shifted by 90° and then transmitted to port 1, and the first amplified signal reflected back to port 2 is phase-shifted by 0° and then transmitted to port 1, so that there is a 180° phase difference between the first amplified signal reflected back to port 1 and the second amplified signal, that is, the first amplified signal reflected back to port 1 and the second amplified signal are in opposite phases, and interference destructive phase occurs; the first amplified signal reflected back to port 2 is phase-shifted by 90° and then transmitted to port 4, and the second amplified signal reflected back to port 3 is phase-shifted by 0° and then transmitted to port 4, so that the first amplified signal transmitted to port 4 and the second amplified signal are in the same phase, and interference constructive phase occurs and is output from the output port, that is, the amplified signal only appears at the output port (i.e., port 4) of the Josephson parametric amplifier, and the signal reflected back to port 1 of the Josephson parametric amplifier is suppressed. In the first embodiment, the Josephson parametric amplifier realizes transmission amplification through mutual interference between two signals.

[0080] In one embodiment, the first Josephson oscillator 1021 and the second Josephson oscillator 1022 are in a transmission working state, such as Figure 3 As shown, the Josephson parametric amplifier comprises at least: two signal distribution and coupling structures 101 (such as Figure 3The first signal distribution and coupling structure 1011, the second signal distribution and coupling structure 1012 shown in FIG. 1 ), the first Josephson oscillator 1021, the second Josephson oscillator 1022, and the four matching networks 104 (such as Figure 3 The first matching network 1041, the second matching network 1042, the third matching network 1043 and the fourth matching network 1044 shown in FIG. 1 and the two flux bias and pump input lines 103 (as shown in FIG. Figure 3 The first magnetic flux bias and pump input line 1031 and the second magnetic flux bias and pump input line 1032 shown in FIG.

[0081] Figure 3 In the second embodiment shown in FIG. 1 , although the Josephson parametric amplifier includes four ports, it is equivalent to a two-port amplifier. The port 11 of the first signal distribution and coupling structure 1011 is the input port of the Josephson parametric amplifier (eg, Figure 3 Port 1 in the figure), port 23 of the second signal distribution and coupling structure 1012 is the output port of the Josephson parameter amplifier (such as Figure 3 The first signal distribution and coupling structure 1011 has a port 14 and a port 22, respectively, of the second signal distribution and coupling structure 1012. The port 14 and the port 22 of the first signal distribution and coupling structure 1011 and the port 22 of the second signal distribution and coupling structure 1012 are impedance matched loads, respectively connected to resistors of preset resistance values, such as 50 ohms (Ω). The signal to be amplified is input from the input port (such as the port 11 of the first signal distribution and coupling structure 1011), and after amplification, it is transmitted to the output port (such as the port 23 of the second signal distribution and coupling structure 1012) for output, thereby realizing transmission-type amplification.

[0082] Figure 3In the second embodiment shown, the signal distribution and coupling structure 1011 is composed of an orthogonal hybrid network 1011, including four ports, wherein port 11 is the input port of the Josephson parameter amplifier, port 14 is connected to an impedance-matched 50Ω load, port 12 is connected to a first Josephson oscillator 1021 via a first matching network 1041, and port 13 is connected to a second Josephson oscillator 1022 via a second matching network 1042; the second signal distribution and coupling structure 1012 is composed of an orthogonal hybrid network 1012, including The device includes four ports, wherein port 23 is the output port of the Josephson parametric amplifier, port 22 is connected to an impedance-matched 50Ω load, port 21 is connected to the first Josephson oscillator 1021 via a third matching network 1043, and port 24 is connected to the second Josephson oscillator 1022 via a fourth matching network 1044; the first Josephson oscillator 1021 is mutually inductively connected to the first magnetic flux bias and pump input line 1031, and the second Josephson oscillator 1022 is mutually inductively connected to the second magnetic flux bias and pump input line 1032. In this embodiment, the first Josephson oscillator 1021 includes a parallel SQUID1 (abbreviated as SQ1 in the figure) and a capacitor Cp1, wherein SQUID1 is composed of two parallel-connected Josephson junctions, and the second Josephson oscillator 1022 includes a parallel SQUID2 (abbreviated as SQ2 in the figure) and a capacitor Cp2, wherein SQUID2 is composed of two parallel-connected Josephson junctions.

[0083] like Figure 3As shown, the first end of the first matching network 1041 is used to receive the first signal to be amplified from the port 12 of the orthogonal hybrid network 1011, and to reflect the first amplified signal amplified by the first Josephson oscillator 1021 back to the port 12 of the first orthogonal hybrid network 1011; the second end of the first matching network 1041 is connected to the first end of the capacitor Cp1 and the first end of the SQUID1; the first end of the flux bias and pump input line 1031 is used to receive the first DC bias signal and the first microwave pump signal, and the second end of the capacitor Cp1, the second end of the SQUID1 and the second end of the flux bias and pump input line 1031 are all grounded; wherein, the SQUID1 is mutually inductively connected to the flux bias and pump input line 1031. The first signal to be amplified is input from the first end of the first matching network 1041, and enters the capacitor Cp1 and SQUID1 through the first matching network 1041. The first amplified signal after amplification by the first Josephson oscillator 1021 is reflected back to the port 12 of the first orthogonal hybrid network 1011 through the first end of the first matching network 1041. The first DC bias signal and the first microwave pump signal are input from the first end of the flux bias and pump input line 1031 to the flux bias and pump input line 1031, wherein the first DC bias signal is used to bias SQUID1, adjust the equivalent inductance of SQUID1, and make the first Josephson oscillator 1021 work at the microwave frequency that needs to be amplified, and the first microwave pump signal is used to provide energy to SQUID1. A first end of the third matching network 1043 is connected to a first end of the capacitor Cp1 and a first end of the SQUID1 , and a second end of the third matching network 1043 is used to output the first amplified signal amplified by the first Josephson oscillator 1021 to the port 21 of the orthogonal hybrid network 1012 .

[0084] like Figure 3As shown, the first end of the second matching network 1042 is used to receive the second signal to be amplified after 90° phase shift from the port 13 of the first orthogonal hybrid network 1011, and reflect the second amplified signal from the second Josephson oscillator 1022 back to the port 13 of the first orthogonal hybrid network 1011; the second end of the second matching network 1042 is connected to the first end of the capacitor Cp2 and the first end of the SQUID2; the first end of the flux bias and pump input line 1032 is used to receive the second DC bias signal and the second microwave pump signal, and the second end of the capacitor Cp2, the second end of the SQUID2 and the second end of the flux bias and pump input line 1032 are all grounded; wherein, the SQUID2 is mutually inductively connected to the flux bias and pump input line 1032. The second signal to be amplified is input from the first end of the second matching network 1042, enters the capacitor Cp2 and SQUID2 through the second matching network 1042, and the second amplified signal amplified by the second Josephson oscillator 1022 is reflected back to the port 13 of the first orthogonal hybrid network 1011 through the first end of the second matching network 1042. The second DC bias signal and the second microwave pump signal are input from the first end of the flux bias and pump input line 1032 to the flux bias and pump input line 1032, wherein the second DC bias signal is used to bias SQUID2, adjust the equivalent inductance of SQUID2, and make the second Josephson oscillator 1022 work at the microwave frequency that needs to be amplified, and the second microwave pump signal is used to provide energy to SQUID2. A first end of the fourth matching network 1044 is connected to a first end of the capacitor Cp2 and a first end of the SQUID2 , and a second end of the fourth matching network 1044 is used to output the second amplified signal amplified by the second Josephson oscillator 1022 to the port 24 of the orthogonal hybrid network 1012 .

[0085] Figure 3In the second embodiment shown, two transmission-type Josephson oscillators (i.e., the first Josephson oscillator 1021 and the second Josephson oscillator 1022) respectively form two independent transmission-type Josephson parametric quantum amplifiers with two flux bias and pump input lines (i.e., the first flux bias and pump input line 1031 and the second flux bias and pump input line 1032). The first Josephson oscillator 1021 / the second Josephson oscillator 1022 is the same as that in the first embodiment, and is equivalent to a resonator with a resonant frequency parameter modulation, and amplification is achieved by mixing the microwave pump signal with the input signal to be amplified. The second embodiment is different from the first embodiment in that the first amplified signal / the second amplified signal amplified by the first Josephson oscillator 1021 / the second Josephson oscillator 1022 is not only reflected back to the first orthogonal hybrid network 1011 along the input path (i.e., the first Josephson oscillator 1021 / the second Josephson oscillator 1022→the first matching network 1041 / the second matching network 1042→the port 12 of the first orthogonal hybrid network 1011 / the port 13 of the first orthogonal hybrid network 1011), but is also transmitted to the port 21 of the second orthogonal hybrid network 1012 / the port 24 of the second orthogonal hybrid network 1012 via the third matching network 1043 / the fourth matching network 1044.

[0086] like Figure 3 As shown, in the second embodiment, the input signal (i.e., the signal to be amplified) first enters the first orthogonal hybrid network 1011 through port 11 (i.e., port 1 of the Josephson parametric amplifier), and the power of the signal to be amplified entering port 11 will be evenly divided into two parts, one of which is the first signal to be amplified (0° phase shift) transmitted to port 12 directly opposite to port 11, and the other is the second signal to be amplified (90° phase shift) transmitted to port 13 diagonally opposite to port 11, and the second signal to be amplified transmitted to port 13 has an additional phase shift of 90° compared to the first signal to be amplified transmitted to port 12, so as to realize orthogonal coupling of the signals. That is to say, in the second embodiment, after the input signal to be amplified passes through the first orthogonal hybrid network 1011, it is evenly divided into two parts and transmitted to port 12 and port 13 of the first orthogonal hybrid network 1011, and there is a 90° phase difference between the two; then, the first signal to be amplified enters the first Josephson oscillator 1021 through the first matching network 1041, and the second signal to be amplified enters the second Josephson oscillator 1022 through the second matching network 1042, wherein the second signal to be amplified arriving at the second Josephson oscillator 1022 has a 90° more phase than the first signal to be amplified arriving at the first Josephson oscillator 1021.

[0087] Afterwards, the first amplified signal after being amplified by the first Josephson oscillator 1021, on the one hand, is reflected back to the port 12 of the first orthogonal hybrid network 1011 along the original path (i.e., the first Josephson oscillator 1021→the first matching network 1041→the first orthogonal hybrid network 1011), and on the other hand, is output to the port 21 of the second orthogonal hybrid network 1012 through the third matching network 1043; the second amplified signal after being amplified by the second Josephson oscillator 1022, on the one hand, is reflected back to the port 13 of the first orthogonal hybrid network 1011 along the original path (i.e., the second Josephson oscillator 1022→the second matching network 1042→the first orthogonal hybrid network 1011), and on the other hand, is output to the port 24 of the second orthogonal hybrid network 1012 through the fourth matching network 1044. The first amplified signal reflected back to port 12 is phase-shifted by 0° and then transmitted to port 11, and the second amplified signal reflected back to port 13 is phase-shifted by 90° and then transmitted to port 11, so that there is a phase difference of 180° between the first amplified signal reflected back to port 11 and the second amplified signal; the first amplified signal reflected back to port 12 is phase-shifted by 90° and then transmitted to port 14, and the second amplified signal reflected back to port 13 is phase-shifted by 0° and then transmitted to port 14, so that the first amplified signal reflected back to port 14 and the second amplified signal are in phase with each other, that is, the first amplified signal reflected back to port 11 and the second amplified signal are in phase with each other, and interference destructively occurs, and the first amplified signal reflected back to port 14 and the second amplified signal are in phase with each other, and interference constructively occurs, but are consumed by the load. The first amplified signal transmitted to port 21 is phase-shifted by 90° and then transmitted to port 23, and the second amplified signal transmitted to port 24 is phase-shifted by 0° and then transmitted to port 23, so that the first amplified signal transmitted to port 23 and the second amplified signal are in phase with each other, and are output from the output port (i.e., port 3 of the Josephson parametric amplifier) ​​after constructive interference occurs; the first amplified signal transmitted to port 21 is phase-shifted by 0° and then transmitted to port 22, and the second amplified signal transmitted to port 24 is phase-shifted by 90° and then transmitted to port 22, so that there is a phase difference of 180° between the first amplified signal transmitted to port 22 and the second amplified signal, and destructive interference occurs. In other words, the amplified signal only appears at port 3 of the Josephson parametric amplifier, and the signal reflected back to port 1 of the Josephson parametric amplifier is suppressed. When the Josephson parametric amplifier is in working state, ports 2 and 4 of the Josephson parametric amplifier are connected to a 50-ohm matching load, and the signals transmitted to ports 2 and 4 are consumed on the load. Therefore, in the second embodiment, the signal to be amplified is input from the input port (i.e., port 1) of the Josephson parametric amplifier, is amplified by two Josephson oscillators, and is output from the output port (i.e., port 3) of the Josephson parametric amplifier, thereby realizing transmission amplification from port 1 to port 3.

[0088] It should be noted that in the above implementation, the signal distribution and coupling structure 101 is only described as an orthogonal hybrid network, but it is not used to limit the implementation form of the signal distribution and coupling structure 101, nor is it used to limit the protection scope of this application.

[0089] 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 Josephson parametric amplifier, characterized in that: The Josephson parametric amplifier is provided with an input port and an output port, the signal to be amplified enters the Josephson parametric amplifier from the input port, and the amplified signal is output from the output port; The Josephson parametric amplifier comprises: one or more signal distribution and coupling structures, a first Josephson oscillator, a second Josephson oscillator, a matching network, and one or more flux bias and pump input lines; wherein, The matching network includes a first matching network and a second matching network, and the matching network is connected between the signal distribution and coupling structure and the first Josephson oscillator and the second Josephson oscillator, and is used to increase the bandwidth of the Josephson parametric amplifier; The signal distribution and coupling structure is composed of an orthogonal hybrid network, including four ports, which are respectively connected to the first Josephson oscillator, the second Josephson oscillator, the input port and the output port; the signal distribution and coupling structure is used to: receive the signal to be amplified inputted from the input port; divide the power of the signal to be amplified into two equal parts and perform a 90° phase shift on one of the parts to obtain a first signal to be amplified and a second signal to be amplified, wherein the second signal to be amplified has a 90° phase shift relative to the first signal to be amplified, the first signal to be amplified is transmitted to the first Josephson oscillator via the first matching network, and the second signal to be amplified is transmitted to the second Josephson oscillator via the second matching network; process the first amplified signal from the first Josephson oscillator and the second amplified signal from the second Josephson oscillator to achieve interference destructive phase between the first amplified signal and the second amplified signal reflected from the first Josephson oscillator and the second Josephson oscillator to the input port, and the first amplified signal and the second amplified signal amplified by the first Josephson oscillator and the second Josephson oscillator output to the output port after amplification by the first Josephson oscillator and the second Josephson oscillator interfere constructively; The first Josephson oscillator and the second Josephson oscillator are mutually inductively connected to the magnetic flux bias and pump input line respectively; the pump signal on the magnetic flux bias and pump input line is magnetic flux pumping, and the frequency is a microwave pump signal in the microwave frequency band; The first Josephson oscillator is used to mix and amplify the first signal to be amplified and the microwave pump signal to obtain the first amplified signal, and transmit the first amplified signal to the port connected to the first Josephson oscillator in the signal distribution and coupling structure; The second Josephson oscillator is used to mix and amplify the second signal to be amplified and the microwave pump signal to obtain the second amplified signal, and transmit the second amplified signal to the port connected to the second Josephson oscillator in the signal distribution and coupling structure.

2. The Josephson parametric amplifier according to claim 1, wherein: The matching network is a distributed matching network, or a lumped matching network, or a distributed and lumped mixed matching network; When the matching network is a distributed matching network, the distributed matching network is composed of microwave transmission lines; When the matching network is a lumped matching network, the lumped matching network is composed of on-chip or independent capacitors, inductors, and resistors; When the matching network is a distributed and lumped mixed matching network, the distributed and lumped mixed matching network is a combination of the distributed matching network and the lumped matching network.

3. The Josephson parametric amplifier according to claim 2, wherein: When the matching network is a lumped matching network, the inductor in the lumped matching network is an equivalent inductor formed by a Josephson junction or a superconducting quantum interference device (SQUID).

4. The Josephson parametric amplifier according to claim 1, wherein: The magnetic flux bias and pump input line comprises a magnetic flux bias and pump input line, and the first Josephson oscillator and the second Josephson oscillator are mutually inductively connected to the same magnetic flux bias and pump input line; Alternatively, the flux bias and pump input line includes two flux bias and pump input lines, and the first Josephson oscillator and the second Josephson oscillator are mutually inductively connected to an independent flux bias and pump input line respectively.

5. The Josephson parametric amplifier according to claim 4, wherein: The flux bias and pump input line includes a DC bias signal and a microwave pump signal, wherein the DC bias signal is used to adjust the working point of the mutually inductively connected Josephson oscillator, and the microwave pump signal is used to realize the mixing amplification; The DC bias signal and the microwave pump signal are combined together through a bias device BiasTee element and then input into the flux bias and pump input line.

6. The Josephson parametric amplifier according to claim 1, wherein: The processing of the first amplified signal from the first Josephson oscillator and the second amplified signal from the second Josephson oscillator in the signal distribution and coupling structure includes: The second amplified signal reflected back to the input port by the second Josephson oscillator is phase-shifted by 90°, so that the second amplified signal has a phase shift of 180° more than the first amplified signal, and the first amplified signal and the second amplified signal reflected back to the input port have opposite phases, and interference destructively occurs; the first amplified signal output to the output port by the first Josephson oscillator is phase-shifted by 90°, so that the first amplified signal has a phase shift of 90° more than the second amplified signal, and the first amplified signal and the second amplified signal output to the output port have the same phase, and interference constructively occurs.

7. The Josephson parametric amplifier according to claim 1, wherein: The signal distribution and coupling structure is one, and the magnetic flux bias and pump input line is one; The first Josephson oscillator and the second Josephson oscillator are in a reflection working state; The signal distribution and coupling structure is composed of an orthogonal hybrid network, including four ports, wherein port 1 is the input port, port 4 is the output port, port 2 is connected to the first Josephson oscillator via the first matching network, and port 3 is connected to the second Josephson oscillator via the second matching network; the first Josephson oscillator and the second Josephson oscillator are mutually inductively connected to one of the flux bias and pump input lines; The signal to be amplified enters the orthogonal hybrid network through the port 1, and the power of the signal to be amplified is evenly divided into the first signal to be amplified and the second signal to be amplified, wherein the first signal to be amplified is transmitted to the port 2, and the second signal to be amplified is transmitted to the port 3, and the second signal to be amplified transmitted to the port 3 has a phase shift of 90° more than the first signal to be amplified transmitted to the port 2; The first signal to be amplified enters the first Josephson oscillator through the first matching network for amplification to obtain the first amplified signal, and the first amplified signal is reflected back to the port 2; the second signal to be amplified enters the second Josephson oscillator through the second matching network for amplification to obtain the second amplified signal, and the second amplified signal is reflected back to the port 3; the first amplified signal and the second amplified signal enter the orthogonal hybrid network from port 2 and port 3 respectively and are transmitted to the input port and the output port; The second amplified signal reflected back to the port 3 is phase-shifted by 90° and then transmitted to the port 1, and the first amplified signal reflected back to the port 2 is phase-shifted by 0° and then transmitted to the port 1, so that there is a phase difference of 180° between the first amplified signal reflected back to the port 1 and the second amplified signal, and destructive interference occurs; the first amplified signal reflected back to the port 2 is phase-shifted by 90° and then transmitted to the port 4, and the second amplified signal reflected back to the port 3 is phase-shifted by 0° and then transmitted to the port 4, so that the first amplified signal and the second amplified signal transmitted to the port 4 have the same phase, and are output from the output port after constructive interference occurs.

8. The Josephson parametric amplifier according to claim 1, wherein: The signal distribution and coupling structure is a first signal distribution and coupling structure and a second signal distribution and coupling structure, the magnetic flux bias and pump input line includes a first magnetic flux bias and pump input line and a second magnetic flux bias and pump input line; the matching network also includes a third matching network and a fourth matching network; The first Josephson oscillator and the second Josephson oscillator are in a transmission working state; The first signal distribution and coupling structure is composed of a first orthogonal hybrid network, including four ports, wherein port 11 is the input port, port 12 is connected to the first Josephson oscillator via the first matching network, and port 13 is connected to the second Josephson oscillator via the second matching network; port 14 is connected to an impedance matching load; the second signal distribution and coupling structure is composed of a second orthogonal hybrid network, including four ports, wherein port 23 is the output port, port 22 is connected to an impedance matching load, port 21 is connected to the first Josephson oscillator via the third matching network, and port 24 is connected to the second Josephson oscillator via the fourth matching network; the first Josephson oscillator is mutually inductively connected to the first magnetic flux bias and pump input line, and the second Josephson oscillator is mutually inductively connected to the second magnetic flux bias and pump input line; The signal to be amplified enters the first orthogonal hybrid network through the port 11, and the power of the signal to be amplified will be evenly divided into the first signal to be amplified transmitted to the port 12 and the second signal to be amplified transmitted to the port 13, and the second signal to be amplified has a 90° phase shift more than the first signal to be amplified; the first signal to be amplified enters the first Josephson oscillator through the first matching network, and the second signal to be amplified enters the second Josephson oscillator through the second matching network; the first amplified signal amplified by the first Josephson oscillator is reflected back to the port 12, and output to the port 21 through the third matching network; the second amplified signal amplified by the second Josephson oscillator is reflected back to the port 13, and output to the port 24 through the fourth matching network; The first amplified signal reflected back to the port 12 is phase-shifted by 0° and then transmitted to the port 11, and the second amplified signal reflected back to the port 13 is phase-shifted by 90° and then transmitted to the port 11, so that there is a phase difference of 180° between the first amplified signal reflected back to the port 11 and the second amplified signal, and interference destructive phase occurs; the first amplified signal reflected back to the port 12 is phase-shifted by 90° and then transmitted to the port 14, and the second amplified signal reflected back to the port 13 is phase-shifted by 0° and then transmitted to the port 14, and the first amplified signal and the second amplified signal reflected back to the port 14 are consumed by the impedance matching load; The first amplified signal transmitted to the port 21 is phase-shifted by 90° and then transmitted to the port 23, and the second amplified signal transmitted to the port 24 is phase-shifted by 0° and then transmitted to the port 23, so that the first amplified signal transmitted to the port 23 and the second amplified signal have the same phase, and are output from the output port after constructive interference occurs; the first amplified signal transmitted to the port 21 is phase-shifted by 0° and then transmitted to the port 22, and the second amplified signal transmitted to the port 24 is phase-shifted by 90° and then transmitted to the port 22, so that the first amplified signal transmitted to the port 22 has a phase difference of 180° and the second amplified signal is interfered destructively.

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