High-saturation power Josephson ring modulators and fabrication of the same are provided. A Josephson ring modulator can comprise a plurality of matrix junctions. Matrix junctions of the plurality of matrix junctions can comprise respective superconducting parallel branches that can comprise a plurality of Josephson junctions operatively coupled in a series configuration. A method can comprise forming a first matrix junction comprising arranging a first group of Josephson junctions as first parallel branches. The method can also comprise forming a second matrix junction comprising arranging a second group of Josephson junctions as second parallel branches. Further, the method can comprise forming a third matrix junction comprising arranging a third group of Josephson junctions as third parallel branches. In addition, the method can comprise forming a fourth matrix junction comprising arranging a fourth group of Josephson junctions as fourth parallel branches.

An amplifier, e.g., a low-noise amplifier, includes a field-effect transistor having a one-dimensional channel. This channel includes a semiconductor material for conducting electrons along a main direction of the channel. This direction is perpendicular to a cross-section of the channel. Dimensions of this cross-section are, together with the semiconductor material, such that the channel exhibits quantized conduction of electrons along its main direction. The amplifier further includes an electrical circuit that is configured to operate the transistor at a value of gate-to-source voltage bias corresponding to a peak value of a peak of a transconductance of the channel with respect to gate-to-source voltage bias values.

A superconducting device that mixes surface acoustic waves and microwave signals and techniques for fabricating the same are provided. A superconducting device can comprise a superconducting surface acoustic wave resonator and a superconducting microwave resonator. The superconducting device can also comprise a Josephson ring modulator coupled to the superconducting surface acoustic wave resonator and the superconducting microwave resonator. The Josephson ring modulator can be a dispersive nonlinear three-wave mixing element.

A cryogenic integrated circuit or integrated module includes a travelling wave parametric amplifier or a Josephson parametric amplifier. The cryogenic integrated circuit or integrated module also includes an oscillator, a signal input, a biasing input, and a signal output. The oscillator is connected to an input of the amplifier and is configured to produce an oscillating drive signal. The signal input couples input signals into the amplifier. The biasing input couples biasing signals into the oscillator. The signal output conveys output signals from the amplifier out of the cryogenic integrated circuit or integrated module.

A cryogenic integrated circuit or integrated module includes a travelling wave parametric amplifier or a Josephson parametric amplifier. The cryogenic integrated circuit or integrated module also includes an oscillator, a signal input, a biasing input, and a signal output. The oscillator is connected to an input of the amplifier and is configured to produce an oscillating drive signal. The signal input couples input signals into the amplifier. The biasing input couples biasing signals into the oscillator. The signal output conveys output signals from the amplifier out of the cryogenic integrated circuit or integrated module.

A bandpass parametric amplifier circuit includes a plurality of unit cells. At least one unit cell includes a first inductor having a first node coupled to a center conductor and a second node coupled to ground. There is a first capacitor having a first node coupled to the center conductor and a second node coupled to ground. There is a second inductor having a first node coupled to the center conductor. A second capacitor has a first node coupled to a second node of the second inductor. The second capacitor and the second inductor are in series with the center conductor.

A bandpass parametric amplifier circuit includes a plurality of unit cells. At least one unit cell includes a first inductor having a first node coupled to a center conductor and a second node coupled to ground. There is a first capacitor having a first node coupled to the center conductor and a second node coupled to ground. There is a second inductor having a first node coupled to the center conductor. A second capacitor has a first node coupled to a second node of the second inductor. The second capacitor and the second inductor are in series with the center conductor.

The various embodiments described herein include methods, devices, and systems for fabricating and operating superconducting circuitry. In one aspect, an amplification circuit includes: (1) a superconducting component; (2) an amplifier coupled in parallel with the superconducting component such that the superconducting component is in a feedback loop of the amplifier; (3) a voltage source coupled to a first input of the amplifier; (4) one or more resistors coupled to a second input of the amplifier; and (5) an output terminal coupled to an output of the amplifier.

The various embodiments described herein include methods, devices, and systems for fabricating and operating superconducting circuitry. In one aspect, an amplification circuit includes: (1) a superconducting component; (2) an amplifier coupled in parallel with the superconducting component such that the superconducting component is in a feedback loop of the amplifier; (3) a voltage source coupled to a first input of the amplifier; (4) one or more resistors coupled to a second input of the amplifier; and (5) an output terminal coupled to an output of the amplifier.

A system and method are disclosed for a superconducting traveling-wave parametric amplifier (TWPA) with improved control and performance. In a preferred embodiment, the amplifier comprises an integrated array of symmetric rf-SQUIDs in a transmission line structure. A device was fabricated using niobium superconducting integrated circuits, and confirmed predicted performance, with a maximum gain up to 17 dB and a bandwidth of 4 GHz. A similar device can be applied as a low-noise, low-dissipation microwave amplifier for output from a superconducting quantum computer, or as a preamplifier, switch, or frequency converter for a sensitive microwave receiver, or as an output amplifier for a frequency-multiplexed superconducting detector array.