Broadband Josephson parametric amplifier

Abstract

The invention describes a Josephson parametric amplifier and a manufacturing method thereof. The broadband Josephson parametric amplifier comprises: a substrate; a coplanar waveguide disposed on the substrate, the coplanar waveguide having an impedance that varies in a length direction thereof, in which the coplanar waveguide includes a conductor separated from a first ground plane by a first gap and separated from a second ground plane by a second gap; and a non-linear resonator disposed on the substrate and coupled to the coplanar waveguide.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 426,204, filed on November 17, 2022. Technical Field

[0002] The present invention relates generally to semiconductor processing and, more particularly, to a broadband Josephson parametric amplifier. Background Art

[0003] The application of current Josephson parametric amplifiers (JPAs) in multi-qubit quantum circuits is limited by their narrowband gain. Therefore, a broadband Josephson parametric amplifier is needed. Summary of the Invention

[0004] In one embodiment of the present disclosure, a broadband Josephson parametric amplifier includes a substrate, a coplanar waveguide disposed on the substrate, and a nonlinear resonator disposed on the substrate and coupled to the coplanar waveguide. The coplanar waveguide has an impedance that varies over the length of the coplanar waveguide, and includes a conductor separated from a first ground plane by a first gap and a conductor separated from a second ground plane by a second gap.

[0005] In one aspect, the nonlinear resonator comprises: a capacitor disposed on a substrate and coupled to a coplanar waveguide, and one or more superconducting quantum interface devices disposed on the substrate and coupled to the capacitor. In another aspect, each superconducting quantum interface device comprises two parallel Josephson junctions. In another aspect, the one or more superconducting quantum interface devices comprise two or more superconducting quantum interface devices connected in series. In another aspect, the amplifier further comprises an input / output port disposed on the substrate and coupled to the coplanar waveguide, and one or more control ports disposed on the substrate and inductively coupled to the nonlinear resonator. In another aspect, the conductor, the first ground plane, and the second ground plane all comprise aluminum. In another aspect, the impedance of the waveguide is varied by: (1) increasing the width of the conductor in the length direction of the coplanar waveguide, or (2) coupling a plurality of dielectric bridges in the length direction of the coplanar waveguide. In another aspect, the impedance of the coplanar waveguide varies from approximately 50 ohms to approximately 15 ohms. In another aspect, each dielectric bridge comprises: a dielectric disposed within the first and second gaps, covering the first and second gaps, the conductor, and extending to first portions of the first and second ground planes; and a metal disposed on top of the dielectric and extending to second portions of the first and second ground planes. In another aspect, the metal comprises aluminum, and the dielectric comprises aluminum oxide. In another aspect, the amplifier exhibits one or more performance parameters including: a gain of approximately 15-25 dB; a bandwidth of approximately 500 MHz; a tunable amplification band center; or a noise temperature approaching the quantum limit within the bandwidth.

[0006] In another embodiment of the present disclosure, a method for fabricating a broadband Josephson parametric amplifier includes: forming a first ground plane, a second ground plane, a conductor separated from the first ground plane by a first gap, the second ground plane separated from the second ground plane by a second gap, a capacitor electrode, and a first resonator junction lead separated from a second resonator junction lead by a third gap on a substrate, wherein the conductor separated from the first ground plane by the first gap and from the second ground plane by the second gap forms a coplanar waveguide; forming a capacitor on the capacitor electrode; forming one or more superconducting electrodes by: A quantum interface device: (1) depositing metal on a substrate at a first angle, wherein a portion of the metal is deposited within a fourth gap adjacent to a first resonator junction lead, (2) oxidizing an exposed portion of the metal deposited within the fourth gap adjacent to the first resonator junction lead, and (3) depositing metal on the substrate at a second angle within the fourth gap adjacent to a second resonator junction lead, overlapping a portion of the oxidized metal adjacent to the first resonator junction lead; wherein the coplanar waveguide has an impedance that varies over a length of the coplanar waveguide; and wherein a capacitor is coupled between the coplanar waveguide and the one or more superconducting quantum interface devices.

[0007] In one aspect, the method is performed using a lift-off process, a selective etching process, or a combination thereof. In another aspect, the first angle comprises approximately 30 to 45 degrees, and the second angle comprises approximately -30 to -45 degrees. In another aspect, the first angle comprises approximately 31.5 degrees, and the second angle comprises approximately -31.5 to 31.5 degrees. In another aspect, one or more superconducting quantum interface devices are formed before forming the capacitor. In another aspect, each superconducting quantum interface device comprises two Josephson junctions in parallel. In another aspect, the one or more superconducting quantum interface devices comprise two or more superconducting quantum interface devices connected in series. In another aspect, the method further comprises forming an input / output port disposed on the substrate and coupled to the coplanar waveguide, and forming one or more control ports disposed on the substrate, which are inductively coupled to the one or more superconducting quantum interface devices. In another aspect, the conductor, the first ground plane, and the second ground plane comprise aluminum. In another aspect, the impedance of the waveguide is changed by: (1) increasing the width of the conductor over the length of the coplanar waveguide, or (2) coupling multiple dielectric bridges to the coplanar waveguide over the length of the coplanar waveguide. In another aspect, the impedance of the coplanar waveguide varies from about 50 ohms to about 15 ohms. In another aspect, the method further comprises forming a plurality of dielectric bridges by: depositing a first photoresist coating; exposing the first photoresist coating according to a first pattern; depositing a metal oxide according to the first pattern: (1) within the first gap and the second gap, (2) on top of the first gap, the conductor, and the second gap, and (3) extending over a first portion of the first ground plane and a first portion of the second ground plane; removing the first photoresist coating; depositing a second photoresist coating; exposing the second photoresist coating according to a second pattern; depositing a metal on top of the metal oxide and extending over a second portion of the first ground plane and a second portion of the second ground plane; and removing the second photoresist coating. In another aspect, the metal oxide comprises aluminum oxide. In another aspect, forming the capacitor comprises depositing the metal oxide on top of the capacitor electrode, and depositing the metal on top of the metal oxide. On the other hand, the capacitor electrodes include a first capacitor electrode separated from a second capacitor electrode by a fourth gap, and forming the capacitor includes: (1) depositing a metal oxide on a top of the first capacitor electrode, a side of the first capacitor electrode within the third gap, a top of the second capacitor electrode, and a side of the second capacitor electrode within the third gap, (2) depositing the metal within a remaining portion of the third gap and depositing a top of the metal oxide above the first capacitor electrode and the second capacitor electrode, and (3) depositing the metal on a portion of the first capacitor electrode, a side of the metal oxide, and a top of the metal oxide.In another aspect, the amplifier has one or more performance characteristics including: a gain of approximately 15-25 dB; a bandwidth of approximately 500 MHz; a tunable amplification band center; or a noise temperature near the quantum limit within the bandwidth.

[0008] In another embodiment of the present disclosure, a broadband Josephson parametric amplifier is manufactured according to the above method. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] For a more complete understanding of the features and advantages of the present invention, reference is now made to the detailed description of the present invention and the accompanying drawings:

[0010] Figures 1A to 1C is a schematic diagram of a broadband Josephson parametric amplifier according to one embodiment of the present disclosure;

[0011] Figures 2A to 2H A method for manufacturing a broadband Josephson parametric amplifier according to one embodiment of the present disclosure is shown;

[0012] Figures 3A to 3D is a schematic diagram of a broadband Josephson parametric amplifier according to another embodiment of the present disclosure;

[0013] Figures 4A to 4H A method for manufacturing a broadband Josephson parametric amplifier according to another embodiment of the present disclosure is shown;

[0014] Figure 5 is an image of a broadband Josephson parametric amplifier according to another embodiment of the present disclosure;

[0015] Figure 6 is an image of a broadband Josephson parametric amplifier according to another embodiment of the present disclosure;

[0016] Figure 7 is a wiring diagram for measuring the signal gain of a broadband Josephson parameter amplifier according to another embodiment of the present disclosure;

[0017] Figure 8A and Figure 8B is a graph of performance data of a broadband Josephson parameter amplifier according to another embodiment of the present disclosure;

[0018] Figure 9 A method for manufacturing a broadband Josephson parametric amplifier according to another embodiment of the present disclosure is shown;

[0019] Figure 10 is a graph of noise temperature of a broadband Josephson parametric amplifier system compared to the quantum noise limit according to another embodiment of the present disclosure;

[0020] Figure 11is a graph showing the relationship between signal gain and frequency of a broadband Josephson parametric amplifier compared with the quantum noise limit according to another embodiment of the present disclosure;

[0021] Figure 12 FIG. 4 is a graph showing the relationship between the actual gain and frequency of a broadband Josephson parameter amplifier compared with the quantum noise limit according to another embodiment of the present disclosure.

[0022] Component Description 100: Broadband Josephson Parametric Amplifier 102: Substrate / Silicon Substrate 104: Input / output port 106: Coplanar Waveguide 108:Capacitor 109: Nonlinear Resonator 110: Superconducting Quantum Interface Device 111a: Josephson junction 111b: Josephson junction 112: Control port 114: Conductor 116: First ground contact surface 118: First gap 120: Second ground plane 122: Second gap 200:Method 202: Alignment mark 204: Titanium 205: Additional capacitor electrode 206:Capacitor electrode 208: First resonator junction lead 210: Second resonator junction lead 212: Aluminum / Aluminum layer 214: Aluminum oxide layer / aluminum oxide 216: Aluminum layer 218: Aluminum 220: First Angle 222: Gap 224: Aluminum 226: Second Angle 228:Patch 300: Broadband Josephson Parametric Amplifier 302: Coplanar Waveguide 304: Conductor 306: first ground contact surface 308: First gap 310: Second ground plane 312: Second gap 314: Dielectric bridge 316: Dielectric 320: Metal 400:Method 402: Alignment mark 404: Titanium 406: first capacitor electrode 408: second capacitor electrode 410: First resonator junction lead 412: Second resonator junction lead 414: Aluminum 416: Aluminum 418: First Angle 420: Gap 424: Aluminum / Aluminum Oxide 426: Second Angle 427: The Third Gap 428:Metal oxide 430: Aluminum 432: Alumina / Metal Oxide 434: Aluminum 500: Broadband Josephson Parametric Amplifier 502: Shell 504:Port 2 506:Port 1 700: Wiring Diagram 702: Broadband Josephson Parametric Amplifier 704: Input signal 706: Vector Network Analyzer 708:20dB attenuator 710: Low-pass filter 712: Received weak input signal / signal / weak input signal 714:Circulator 716: output signal / output reflected amplified signal 718: Low-pass filter 720:HEMT amplifier 721: DC bias + pumping signal 722: Bias Tree 724:RF pumping signal 726:RF signal generator 728:20dB attenuator 730: Low-pass filter 732: DC bias signal 734:DC power supply 900: Method 902: Step 904: Step 906: Step DETAILED DESCRIPTION

[0023] An exemplary embodiment of the system described herein is described below. For the sake of clarity, this specification does not describe all features of an actual implementation. It is understood that in developing any such actual implementation, numerous implementation-specific decisions must be made to achieve the developer's specific goals, such as meeting system-related and business-related constraints, which may vary depending on the specific implementation. Furthermore, it is understood that such development work may be complex and time-consuming, but it is nevertheless a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.

[0024] Various embodiments of the present disclosure provide a simple manufacturing process because the resonator and the Josephson junction are integrated into one electron beam lithography process. In some embodiments, only one additional lithography step is added to fabricate the aluminum dielectric bridge to achieve broadband amplification performance. The aluminum dielectric bridge reduces the quality factor by reducing the external equivalent impedance, thereby achieving broadband response. In addition, the simplified manufacturing process also makes it possible to mass-produce the broadband Josephson parameter amplifier chip. Moreover, its broadband and low-noise amplification characteristics make the chip a very promising component for commercializing multi-qubit quantum processors. According to various embodiments of the present disclosure, the broadband Josephson parameter amplifier has the following characteristics: (1) advanced level of gain among amplifiers close to the quantum limit, about 15–25 dB; (2) broadband quantum limit amplification capability of about 500 MHz; (3) high yield, simple and robust nanofabrication process; (4) tunable amplification band center; and / or (5) noise temperature close to the quantum limit within the bandwidth.

[0025] Now refer to Figures 1A-1C, shows a schematic diagram of a broadband Josephson parametric amplifier 100 according to one embodiment of the present disclosure. Broadband Josephson parametric amplifier 100 includes a substrate 102, an input / output port 104 disposed on substrate 102, a coplanar waveguide 106 disposed on substrate 102 and coupled to input / output port 104, a nonlinear resonator 109 disposed on substrate 102 and coupled to coplanar waveguide 106, and one or more control ports 112 disposed on substrate 102 and inductively coupled to nonlinear resonator 109. The impedance of coplanar waveguide 106 varies along its length. In the illustrated embodiment, coplanar waveguide 106 includes a conductor 114 separated from a first ground plane 116 by a first gap 118 and separated from a second ground plane 120 by a second gap 122. In this example, the impedance of coplanar waveguide 106 is varied by increasing the width of the conductor along its length. In one non-limiting example, the impedance of the coplanar waveguide 106 varies from approximately 50 ohms to approximately 15 ohms. It should be noted that the size, shape, and length of the coplanar waveguide 106 can be set to any suitable value as needed by a person skilled in the art. The conductor 114, the first ground plane 116, and the second ground plane 120 can be made of aluminum or other conductive materials suitable for amplifiers. The one or more control ports 112 are used to tune the center frequency of the amplification band and tune the amplifier to its operating point.

[0026] like Figure 1B As shown, the nonlinear resonator 109 may include a capacitor 108 disposed on the substrate 102 and coupled to the coplanar waveguide 106, and one or more superconducting quantum interface devices (SQUIDs) 110 disposed on the substrate 102 and coupled to the capacitor 108. In addition, the one or more superconducting quantum interface devices 110 may be two or more superconducting quantum interface devices 110 connected in series (i.e., a SQUID array) to obtain a larger nonlinear inductance. Each superconducting quantum interface device 110 may include two parallel Josephson junctions 111a and 111b, as shown in FIG. Figure 1C As shown, the superconducting quantum interface device 110 is a tunable nonlinear inductor whose inductance can be adjusted by the magnetic flux passing through the region between the two parallel Josephson junctions 111a and 111b. The one or more superconducting quantum interface devices 110 are inductively coupled to one or more control ports 112. Furthermore, the size and shape of the nonlinear resonator 109 can be selected by those skilled in the art to any suitable size and shape as needed.

[0027] Now refer to Figures 2A-2H , shows a method 200 for manufacturing a broadband Josephson parameter amplifier according to an embodiment of the present disclosure. The method 200 may use a stripping process, a selective etching process, or a combination thereof. In step 1 ( Figure 2A), the wafer (eg, silicon substrate 102) is cleaned by using a Piranha solution and a diluted hydrofluoric acid (HF) solution. In step 2 ( Figure 2B ), alignment mark 202 is formed by applying a photoresist coating, exposing the photoresist coating with ultraviolet light according to a first pattern, developing the pattern, depositing titanium 204, and stripping the photoresist coating using a solvent such as N-methylpyrrolidone (NMP). In step 3 ( Figure 2C ), the first ground plane 116, the conductor 114 and the second ground plane 120 (components of the coplanar waveguide), the capacitor electrode 206, the first resonator junction lead 208 and the second resonator junction lead 210 are formed using aluminum 212 in the following manner: a layer of aluminum 212 is deposited on the substrate 102, a photoresist coating is applied, and it is exposed to ultraviolet light according to a second pattern, which is used to form the ground plane, conductor, capacitor and resonator parts, and after development, the aluminum layer 212 is etched using reactive ion etching, and finally the photoresist is stripped. In some embodiments, additional capacitor electrodes 205 may be used depending on the structure of the capacitor. Note that the impedance of the coplanar waveguide is changed by increasing the conductor width along its length. In step 4 ( Figure 2D ), the formation of the capacitor includes: applying a photoresist coating, exposing the photoresist according to a third pattern (the pattern is used to form the capacitor), developing, depositing an aluminum oxide layer 214 on the capacitor electrode 206, then depositing an aluminum layer 216 on the aluminum oxide layer 214, and stripping the photoresist coating. In step 5 ( Figure 2E ), one or more superconducting quantum interface devices and Josephson junctions are formed by applying a photoresist coating, exposing with an electron beam according to a fourth pattern, and developing the photoresist coating at a first angle of 220 ( Figure 2G ) deposits aluminum 218 in the pattern, wherein part of the aluminum 218 is deposited on Figure 2C In step 3, the exposed aluminum 218 in the gap 222 next to the first resonator junction lead 208 is oxidized, and then the exposed aluminum 218 is oxidized at a second angle 226 ( Figure 2H ) Aluminum 224 is deposited into the gap and covers the area between the aluminum oxide 214 and the first resonator junction lead 208, and finally the photoresist is stripped using a solvent (such as NMP). The first angle 220 can be about 30 to 45 degrees, and the second angle 226 can be about -30 to -45 degrees, or any angle therebetween. In some embodiments, the first angle 220 is about 31.5 degrees, and the second angle 226 is about -31.5 degrees. In step 6 ( Figure 2F), a patch 228 (bandaids) is formed by applying a photoresist, exposing and developing according to the fifth pattern, then ion etching and aluminum deposition on the pattern to form the patch 228 on the top of the second resonator junction lead 210 and the portion of the internal area covered with aluminum 224, and finally stripping the photoresist using a solvent (such as NMP).

[0028] Now refer to Figure 3A Figure 3D shows a diagram of a broadband Josephson parametric amplifier 300 according to one embodiment of the present disclosure. The broadband Josephson parametric amplifier 300 includes a substrate 102, an input / output port 104 disposed on the substrate 102, a coplanar waveguide 302 disposed on the substrate 102 and coupled to the input / output port 104, a nonlinear resonator 109 disposed on the substrate 102 and coupled to the coplanar waveguide 302, and one or more control ports 112 disposed on the substrate 102 and inductively coupled to the nonlinear resonator 109. The nonlinear resonator 109 includes a capacitor 108 disposed on the substrate 102 and coupled to the coplanar waveguide 302, and one or more superconducting quantum interface devices 110 disposed on the substrate 102 and coupled to the capacitor 108.

[0029] The impedance of the coplanar waveguide 106 varies along its length. Figure 3B In the embodiment shown, the coplanar waveguide 302 includes a conductor 304 separated from a first ground plane 306 by a first gap 308 and separated from a second ground plane 310 by a second gap 312. In this example, the impedance of the coplanar waveguide 302 is changed by coupling a plurality of dielectric bridges 314 along its length. Figure 3C As shown in the cross-section of FIG, each dielectric bridge 314 includes: (1) a dielectric 316 disposed within the first gap 308 and the second gap 312, on top of the first gap 308 and the second gap 312, on top of the conductor 304, and extending to the first portion of the first ground plane 306 and the second ground plane 310; and (2) a metal 320 disposed on top of the dielectric 316 and extending to the second portion of the first ground plane 306 and the second ground plane 310. In one non-limiting example, the impedance of the coplanar waveguide 106 is changed from about 50 ohms to about 15 ohms. This impedance change is achieved by reducing the spacing of the dielectric bridge 314 between the input / output port 104 and the capacitor 108. Please note that the size, shape, and length of the coplanar waveguide 302 and the dielectric bridge 314 can be selected by a person skilled in the art according to the specific application. It should be noted that other types of bridges, such as air bridges, can also be used.

[0030] In addition, each superconducting quantum interface device 110 may include Figure 1C In addition, the one or more superconducting quantum interface devices 110 may be composed of multiple (eg Figure 3D The amplifier comprises four (as shown) superconducting quantum interface devices 110 connected in series. Furthermore, the size and shape of the one or more superconducting quantum interface devices 110 can be selected by those skilled in the art based on specific needs. Conductor 304, first ground plane 306, second ground plane 310, and metal 320 can be aluminum or other conductor materials suitable for amplifiers; dielectric 316 can be alumina or other dielectric materials suitable for amplifiers. In another aspect, the amplifier has one or more performance characteristics including: a gain of approximately 15–25 dB; a bandwidth of approximately 500 MHz; or a tunable amplification band center.

[0031] Now refer to Figure 4A -4H, shows a method 400 for manufacturing a broadband Josephson parametric amplifier according to an embodiment of the present disclosure. The method 400 may adopt a stripping process, a selective etching process or a combination thereof. In step 1 ( Figure 4A ), the wafer (eg, silicon substrate 102) is cleaned using a Piranha solution and a diluted hydrofluoric acid (HF) solution. In step 2 ( Figure 4B ), the alignment mark 402 is formed by coating a photoresist, UV-exposing the photoresist according to a first pattern, developing the first pattern, depositing titanium 404, and stripping the photoresist using a solvent such as acetone. In step 3 ( Figure 4C ), aluminum 414 is used to form the first ground plane 306, the conductor 304 and the second ground plane 310 (both for the coplanar waveguide), the first capacitor electrode 406, the second capacitor electrode 408, the first resonator junction lead 410 and the second resonator junction lead 412, which is completed by the following steps: coating a photoresist on the substrate 102, exposing the photoresist by electron beam according to a second pattern, developing the second pattern, and depositing aluminum 414 to form the above structure; then, at a first angle 418 ( Figure 4G ) deposits aluminum 416, wherein a portion of the aluminum 416 is deposited in the gap 420 next to the first resonator junction lead 410; oxidizes the exposed portion of the aluminum 416 to form an aluminum oxide layer 424; and then deposits the aluminum 416 at a second angle 426 ( Figure 4H ) Aluminum 424 is deposited in the gap 420, and the aluminum 424 covers a portion of the aluminum oxide layer 424, completing the formation of the Josephson junction; finally, the photoresist is stripped using a solvent such as acetone. The first angle 418 can be about 30 to 45 degrees, and the second angle 426 can be about -30 to -45 degrees, or any desired interval. In some embodiments, the first angle is about 31.5 degrees and the second angle is about -31.5 degrees. In step 4( Figure 4D), a capacitor is formed by applying a photoresist, UV-exposing the photoresist according to a third pattern, developing the third pattern, and depositing a metal oxide 428 on the top of the first capacitor electrode 406, the sidewalls of the first capacitor electrode 406 in the third gap 427, the top of the second capacitor electrode 408, and the sidewalls of the second capacitor electrode 408 in the third gap 427; then, aluminum 430 is deposited on the remaining portion of the third gap 427 and the metal oxide 428 to form a top electrode. Alternatively, the third gap 427 may be completely filled with aluminum 430. In step 5( Figure 4E ), the dielectric layer of the plurality of dielectric bridges 314 is patterned by the following steps: depositing photoresist; performing electron beam exposure according to a fourth pattern; developing the fourth pattern; depositing aluminum oxide 432 according to the fourth pattern: (1) inside the first gap 308 and the second gap 312; (2) on top of the first gap 308, the conductor 304, and the second gap 312; and (3) extending to the first portion of the first ground plane 306 and the second ground plane 310; and stripping the photoresist using a solvent such as acetone. In step 6 ( Figure 4F ), the aluminum layer of the dielectric bridge 314 is patterned by the following steps: depositing photoresist; performing electron beam exposure according to the fifth pattern; developing the fifth pattern; depositing aluminum 434 on top of the metal oxide 432 and extending to the first ground plane 306 and the second portion of the second ground plane 310; and finally stripping the photoresist using a solvent such as acetone.

[0032] Now see Figures 5 and 6 , shows an image of a broadband Josephson parametric amplifier 500 according to one embodiment of the present disclosure. The broadband Josephson parametric amplifier 500 is mounted in a housing 502 and connected to port 2504 (DC bias + pumping) and port 1506 (signal input and signal output). In this embodiment, the SMA port (port 2504) is used for radio frequency (RF) parametric pumping signals to drive parametric amplification of the signal and also provides DC flux bias for the nonlinear resonator to achieve amplification at the operating point; while the other SMA port (port 1506) is used to input weak signals and output amplified signals.

[0033] Now see Figure 7, shows a wiring diagram 700 for measuring the signal gain of a broadband Josephson parametric amplifier 702 according to another embodiment of the present disclosure. An input signal 704 is generated by a vector network analyzer 706 and attenuated by a set of 20 dB attenuators 708 and a low-pass filter 710. The resulting weak input signal 712 is directed through a circulator 714 into port 1506 of the broadband Josephson parametric amplifier 702. The weak input signal 712 then enters a coplanar waveguide (implemented by using coplanar waveguides of varying width or dielectric bridges with varying spacing) and subsequently interacts with a nonlinear resonator driven by a DC bias + pump signal 721 injected through port 2504. The weak input signal 712 is then parametrically amplified and reflected from the nonlinear resonator back to the on-chip impedance transformation line and back to port 1506. The output signal 716 is then amplified, and the circulator 714 directs the reflected and amplified output signal 716 to the vector network analyzer 706, through a low-pass filter 718, and to a HEMT amplifier 720. It should be noted that the input signal 712 and the output signal 716 can be isolated, thereby omitting the circulator 714. The DC bias + pump signal 721 is generated by a bias tree 722, which combines: (1) the RF pump signal 724 from the RF signal generator 726, through a set of 20dB attenuators 728 and low-pass filters 730; and (2) the DC bias signal 732 from the DC power supply 734. Figure 7 The performance data of the broadband Josephson parameter amplifier 702 obtained from the wiring diagram in FIG. Figure 8A and Figure 8B middle.

[0034] Now see Figure 9 , shows a method 900 for manufacturing a broadband Josephson parametric amplifier according to an embodiment of the present disclosure. In step 902, a first ground plane, a second ground plane, a conductor separated from the first ground plane by a first gap and separated from the second ground plane by a second gap, a capacitor electrode, and a first and a second resonator junction lead separated by a third gap are formed on a substrate. The conductor separated from the first ground plane by the first gap and separated from the second ground plane by the second gap forms a coplanar waveguide. In step 904, a capacitor is formed on the capacitor electrode. In step 906, one or more superconducting quantum interface devices are formed, specifically including: (1) depositing metal on the substrate at a first angle, wherein a portion of the metal is deposited in the fourth gap, adjacent to the first resonator junction lead; (2) oxidizing the exposed metal portion deposited in the fourth gap; (3) depositing metal on the substrate at a second angle, depositing it in the fourth gap next to the second resonator junction lead, and overlapping with the oxidized metal portion next to the first resonator junction lead. The coplanar waveguide has a varying impedance along its length, and the capacitor is connected between the coplanar waveguide and the nonlinear resonator.

[0035] In one aspect, the method may employ a stripping process, a selective etching process, or a combination of the two. In another aspect, the first angle is approximately 30 to 45 degrees and the second angle is approximately -30 to -45 degrees. In another aspect, the first angle is approximately 31.5 degrees and the second angle is approximately -31.5 degrees. In another aspect, one or more superconducting quantum interface devices are formed before forming the capacitor. In another aspect, each superconducting quantum interface device includes two parallel Josephson junctions. In another aspect, one or more superconducting quantum interface devices are composed of two or more devices connected in series. In another aspect, the method further includes forming an input / output port on the substrate, which is connected to the coplanar waveguide, and forming one or more control ports, which are inductively coupled to the one or more superconducting quantum interface devices. In another aspect, the conductor, the first ground plane, and the second ground plane include aluminum. In another aspect, the change in waveguide impedance is achieved by: (1) increasing the conductor width along the length of the coplanar waveguide, or (2) connecting multiple dielectric bridges along the length of the coplanar waveguide. In another aspect, the impedance of the coplanar waveguide varies from about 50 ohms to about 15 ohms. In another aspect, the method further comprises forming a plurality of dielectric bridges by: depositing a first photoresist coating; exposing the first photoresist coating according to a first pattern; depositing a metal oxide according to the first pattern: (1) deposited in the first gap and the second gap, (2) covering the top of the first gap, the conductor, and the top of the second gap, and (3) extending to a first portion of the first ground plane and the second ground plane; removing the first photoresist coating; depositing a second photoresist coating; exposing the second photoresist coating according to a second pattern; depositing a metal on top of the metal oxide and extending to a second portion of the first ground plane and the second ground plane; removing the second photoresist coating. In another aspect, the metal oxide is aluminum oxide. In another aspect, forming a capacitor comprises depositing the metal oxide on top of a capacitor electrode and depositing the metal over the metal oxide. In another aspect, the capacitor electrode comprises a first capacitor electrode and a second capacitor electrode, which are separated by a fourth gap, and forming a capacitor includes: (1) depositing metal oxide on the top of the first capacitor electrode, the sidewalls of the first capacitor electrode within the third gap, and the top and sidewalls of the second capacitor electrode; (2) depositing metal in the remaining area of the third gap and on the top of the metal oxide, covering the first capacitor electrode and the second capacitor electrode. In another aspect, the amplifier has one or more performance characteristics including: a gain of approximately 15-25 dB; a bandwidth of approximately 500 MHz; a tunable amplification band center; or a noise temperature close to the quantum limit within the bandwidth.

[0036] Figures 10 to 12 is a graph showing various performance characteristics of a broadband Josephson parameter amplifier according to an embodiment of the present disclosure. More specifically, Figure 10A plot showing the system noise temperature of a broadband Josephson parametric amplifier compared to the quantum noise limit is shown. The measured noise temperature indicates that this broadband Josephson parametric amplifier reaches or approaches the so-called quantum noise limit, which is the minimum noise level achievable by any amplifier in this frequency band (the best noise performance allowed by physics). Figure 11 A plot of the signal gain versus frequency for a broadband Josephson parametric amplifier is shown and compared to the quantum noise limit. Figure 12 The actual gain versus frequency plot of a broadband Josephson parameter amplifier is shown, also compared with the quantum noise limit.

[0037] In addition, the performance of the broadband Josephson parameter amplifier of a certain embodiment described in the present disclosure has been tested and detailed in the paper published by B. Qing, L. Nguyen, X. Liu, H. Ren, W. Livingston, N. Goss, A. Hajr, T. Chistolini, Z. Pedramrazi, D. Santiago, J. Luo, I. Siddigi, “Broadband CPW-based impedance-transformed Josephson parameter amplifier”, arXiv:2310.17084v1[quant-ph], October 26, 2023. More specifically, the article states: “It is noteworthy that, despite its simple structure, the performance of the CIMPA (CPW-based broadband impedance transformation parametric amplifier) is comparable to that of other IMPAs (broadband impedance transformation Josephson parametric amplifiers). The amplifier exhibits an instantaneous bandwidth of 700 (200) MHz at a gain of 15 (20) dB, a flux-tunable bandwidth of 1.4 GHz, a saturated input power of approximately -110 dBm, and no significant backlash on the qubit.” (pp. 1-2) In addition, the article states that “the amplifier fills the technological gap between Josephson parametric amplifiers (JPAs) and traveling-wave parametric amplifiers (TWPAs), and has potential applications ranging from qubit readout to axion dark matter detection.” (p. 5)

[0038] The circuits of the present invention may be implemented using, but are not limited to, single or combined discrete electrical and electronic components, integrated circuits, semiconductor devices, analog devices, digital devices, and the like. The components may be coupled to each other by any suitable direct or indirect connection method, including but not limited to wires, channels, lines, through-holes, electromagnetic induction, electrostatic coupling, optical connections, wireless communication connections, and the like.

[0039] It should be understood that the specific embodiments described herein are intended to be illustrative only and are not intended to limit the present invention. The core features of the present invention may be employed in a variety of different embodiments without departing from the scope of the present invention. Those skilled in the art will be able to identify or derive, without undue experimentation, a variety of equivalents to the specific methods described herein, and such equivalents are deemed to fall within the scope of the present invention and are protected by the claims.

[0040] All publications and patent applications mentioned in this specification reflect the expertise of those skilled in the art to which the invention pertains. All publications and patent applications are hereby incorporated by reference in their entirety into this specification, as if each individual publication or patent application were individually and specifically identified as such.

[0041] In the specification, reference may be made to the spatial relationships between components and the spatial orientation of aspects of the components, as shown in the accompanying drawings. However, those skilled in the art will recognize, after reading this application in its entirety, that the devices, elements, and apparatus described herein can be positioned in any desired orientation. Therefore, terms such as "above," "below," "upper," "lower," or other similar terms used to describe the spatial relationships between components or the spatial orientation of aspects of components should be understood to refer to the relative relationships between these components or the spatial orientation relationships of these components, and the devices described herein can be positioned in any desired orientation.

[0042] In the claims and / or the specification, when "a" and "an" are used with the terms "comprising" or "including," they can mean "one," but can also be interpreted as "one or more," "at least one," or "more than one." The use of "or" in a claim generally means "and / or" unless it is explicitly stated that only alternatives are being referred to or that the alternatives are mutually exclusive. Throughout this application, the word "about" or "approximately" is used to indicate that a value includes the inherent error of the device, the error of the method used to determine the value, or the range of variation that exists between the subjects of study.

[0043] In this specification and claims, the terms "comprising" or "including" are inclusive or open words, indicating that additional, unlisted elements or method steps are not excluded. In any composition and method embodiments provided in this specification, "comprising" or "including" can also be replaced by "essentially consisting of" or "only consisting of". The content required by "essentially consisting of" includes the specified elements or steps, as well as other elements or steps that do not substantially affect the nature or function of the invention. The term "consisting of" is used to indicate that only a single element (such as a feature, component, characteristic, attribute, method / process step or limitation) or a group of elements is present.

[0044] The term "or combinations thereof" refers to all permutations and combinations of the items listed before the term. For example, "A, B, C, or combinations thereof" is intended to include any of the following: A, B, C, AB, AC, BC, ABC; and, if order is important in the particular context, combinations such as BA, CA, CB, CBA, BCA, ACB, BAC, CAB, etc. Furthermore, combinations containing repeated items, such as BB, AAA, AB, BBC, AAABCCCC, CBBAAA, CABABB, etc., are expressly included. Those skilled in the art will understand that, unless the context indicates otherwise, there is generally no limit to the number of items in any combination.

[0045] In this specification, when approximate terms such as "about," "approximately," "substantially," or "substantially" are used to describe a condition, it should be understood that the condition does not need to be absolutely precise or perfect, but is sufficient for a person skilled in the art to believe that the condition has been met. The degree of possible variation in the description depends on the extent to which the magnitude of the variation still allows a person skilled in the art to believe that the feature still has its desired properties and functions. Generally speaking (but subject to the foregoing), if a value is modified by "about," the value can vary within the range of ±1%, 2%, 3%, 4%, 5%, 6%, 7%, 10%, 12%, or 15% of the stated value.

[0046] All devices and / or methods disclosed and claimed in this specification can be made and implemented without undue experimentation in accordance with the contents of this specification. Although the devices and / or methods of the present invention have been described with reference to specific embodiments, it will be clear to those skilled in the art that variations may be made in their composition and / or methods, as well as in the steps or sequence of steps of said methods, without departing from the core concept, spirit, and scope of the present invention. All similar alternatives and modifications that may be conceived by those skilled in the art are deemed to fall within the spirit, scope, and concept of the present invention and are protected by the appended claims.

[0047] Furthermore, no limitations are intended to the details of construction or design herein shown, except as described in the claims below. It is therefore apparent that the specific embodiments described above may be altered or modified, and all such variations are considered within the scope and spirit of this disclosure. The scope of protection sought herein is, therefore, as set forth in the claims hereinafter appended.

[0048] The systems and devices described herein may be modified, supplemented, or omitted without departing from the scope of the present invention. The components of the systems and devices may be integrated or separated. Furthermore, the operations of the systems and devices may be performed by more, fewer, or other components. The methods may also include more, fewer, or other steps, and the steps may be performed in any suitable order.

Claims

1. A broadband Josephson parametric amplifier, comprising: substrate; a coplanar waveguide disposed on the substrate, the coplanar waveguide having an impedance that varies along its length and comprising a conductor separated from a first ground plane by a first gap and separated from a second ground plane by a second gap; as well as A nonlinear resonator is disposed on the substrate and coupled to the coplanar waveguide.

2. The broadband Josephson parametric amplifier according to claim 1, wherein the nonlinear resonator comprises: a capacitor disposed on the substrate and coupled to the coplanar waveguide; as well as One or more superconducting quantum interface devices are disposed on the substrate and coupled to the capacitor.

3. The broadband Josephson parametric amplifier according to claim 2, wherein each superconducting quantum interface device comprises two parallel-connected Josephson junctions.

4. The broadband Josephson parametric amplifier according to claim 2, wherein the one or more superconducting quantum interface devices comprise two or more superconducting quantum interface devices connected in series.

5. The broadband Josephson parametric amplifier according to claim 1 , further comprising: an input / output port disposed on the substrate and coupled to the coplanar waveguide; as well as The nonlinear resonator is disposed on the substrate and inductively coupled to one or more control ports of the nonlinear resonator.

6. The broadband Josephson parametric amplifier of claim 1, wherein the conductor, the first ground plane, and the second ground plane comprise aluminum.

7. The broadband Josephson parametric amplifier according to claim 1, wherein the impedance of the waveguide is changed by: (1) increasing the conductor width of the coplanar waveguide along the length direction, or (2) coupling a plurality of dielectric bridges along the length direction of the coplanar waveguide.

8. The broadband Josephson parametric amplifier of claim 7, wherein the impedance of the coplanar waveguide varies from about 50 ohms to about 15 ohms.

9. The broadband Josephson parametric amplifier according to claim 7, wherein each dielectric bridge comprises: a dielectric disposed within the first gap and the second gap, on top of the first gap and the second gap, on top of the conductor, and on the first portion of the conductor extending over the first ground plane and the second ground plane; as well as A metal is disposed on top of the dielectric and extends over the first ground plane and the second portion of the second ground plane.

10. The broadband Josephson parametric amplifier according to claim 9, wherein: The metal includes aluminum; the dielectric includes aluminum oxide.

11. The broadband Josephson parametric amplifier of claim 1 , wherein the amplifier has one or more performance characteristics comprising: About 15-25dB of gain; Bandwidth of approximately 500MHz; Adjustable amplification center frequency band; or Noise temperature close to the quantum limit over the bandwidth.

12. A method for manufacturing a broadband Josephson parametric amplifier, comprising: forming a first ground plane, a second ground plane, a conductor separated from the first ground plane by a first gap and separated from the second ground plane by a second gap, a capacitor electrode, and first and second resonant junction leads separated by a third gap on a substrate, wherein the conductor separated from the first ground plane by the first gap and separated from the second ground plane by the second gap forms a coplanar waveguide; forming a capacitor on the capacitor electrode; Forming one or more superconducting quantum interface devices, the forming comprising: (1) depositing metal on a substrate at a first angle, wherein a portion of the metal is deposited adjacent to a first resonant junction lead in a fourth gap; (2) oxidizing an exposed portion of the deposited metal; and (3) depositing metal adjacent to a second resonant junction lead in the fourth gap at a second angle, overlapping the exposed portion of the oxidized metal. Wherein the coplanar waveguide has a varying impedance along its length; The capacitor is coupled between the coplanar waveguide and the one or more superconducting quantum interface devices.

13. The method according to claim 12, wherein the method is performed using a stripping process, a selective etching process, or a combination thereof.

14. The method according to claim 12, wherein: The first angle is about 30 to 45 degrees; the second angle is about -30 to -45 degrees.

15. The method of claim 12, wherein: The first angle is about 31.5 degrees; the second angle is about -31.5 Spend.

16. The method according to claim 12, wherein The one or more superconducting quantum interface devices are formed before forming the capacitor.

17. The method of claim 12, wherein the one or more superconducting quantum interface devices comprise two or more superconducting quantum interface devices connected in series.

18. The method of claim 12, wherein each superconducting quantum interface device comprises two parallel Josephson junctions.

19. The method of claim 12, wherein the one or more superconducting quantum interface devices comprise two or more superconducting quantum interface devices connected in series.

20. The method of claim 12, further comprising: forming an input / output port disposed on the substrate and coupled to the coplanar waveguide; as well as One or more control ports are formed on the substrate and inductively coupled to the one or more superconducting quantum interface devices.

21. The method of claim 12, wherein the conductor, first ground plane, and second ground plane comprise aluminum.

22. The method of claim 12, wherein the impedance of the waveguide is changed by: (1) increasing the conductor width of the coplanar waveguide along its length, or (2) coupling a plurality of dielectric bridges along its length.

23. The method of claim 22, wherein the impedance of the coplanar waveguide varies from about 50 ohms to about 15 ohms.

24. The method of claim 22, further comprising forming the plurality of dielectric bridges by: depositing a first photoresist coating; exposing the first photoresist according to a first pattern; Depositing metal oxide according to a first pattern: (1) within the first gap and the second gap, (2) on top of the first gap, the conductor, and the second gap, and (3) extending over first portions of the first and second ground planes; removing the first photoresist; depositing a second photoresist; exposing a second photoresist according to a second pattern; depositing a metal on top of the metal oxide and extending over the second portions of the first and second ground planes; The second photoresist is removed.

25. The method of claim 24, wherein the metal oxide comprises aluminum oxide.

26. The method of claim 12, wherein forming a capacitor comprises: depositing a metal oxide on top of the capacitor electrode; as well as A metal is deposited over the metal oxide.

27. The method of claim 12, wherein: The capacitor electrodes include a first capacitor electrode and a second capacitor electrode separated by a fourth gap; The forming of the capacitor includes: (1) depositing metal oxide on the top of the first capacitor electrode, the side within the third gap, the top of the second capacitor electrode and its side; (2) depositing metal on the remaining portion of the third gap and on the top of the metal oxide.

28. The method of claim 12, wherein the amplifier has one or more performance characteristics comprising: About 15-25dB of gain; Bandwidth of approximately 500MHz; Adjustable amplification center frequency band; or Noise temperature close to the quantum limit over the bandwidth.

29. A broadband Josephson parametric amplifier manufactured according to the method of claim 12.

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