A technique relates to operating a multimode Josephson parametric converter as a multimode quantum limited amplifier. The multimode Josephson parametric converter receives multiple quantum signals in parallel at different resonance frequencies. The multimode Josephson parametric converter amplifies simultaneously the multiple quantum signals, according to pump signals applied to the multimode Josephson parametric converter. The multiple quantum signals having been amplified at the different resonance frequencies are reflected, according to the pump signals.

A technique relates to operating a multimode josephson parametric converter as a multimode quantum limited amplifier. The multimode. Josephson parametric converter receives multiple quantum signals in parallel at different resonance frequencies. The multimode Josephson parametric converter amplifies simultaneously the multiple quantum signals, according to pump signals applied to the multimode Josephson parametric converter. The multiple quantum signals having been amplified at the different resonance frequencies are reflected, according to the pump signals.

A wireless Josephson-junction-based parametric converter is described. The converter may be formed on a substrate with antennas that pump are configured to wirelessly receive pump, signal and idler frequencies and couple the received frequencies to the converter's circuitry. Capacitors may also be fabricated on the same substrate and sized to tune operation of the converter to desired frequencies. The converter may be coupled directly to microwave waveguides, and may be tuned to different signal frequencies by applying magnetic flux to the converter circuitry.

A technique relates to a microwave device. The microwave device includes a Josephson ring modulator, a first multimode resonator connected to the Josephson ring modulator, where the first multimode resonator is made of a first left-handed transmission line, and a second multimode resonator connected to the Josephson ring modulator, where the second multimode resonator is made of a second left-handed transmission line.

A superconducting multi-bit digital mixer, designed using rapid single flux quantum (RSFQ) logic, for multiplying two independent digital streams, at least one of these comprising a plurality of parallel bit lines, wherein the output is also a similar plurality of bit lines. In a preferred embodiment, one of the digital streams represents a local oscillator signal, and the other digital stream digital radio frequency input from an analog-to-digital converter. The multi-bit mixer comprises an array of bit-slices, with the local oscillator signal generated using shift registers. This multi-bit mixer is suitable for an integrated circuit with application to a broadband digital radio frequency receiver, a digital correlation receiver, or a digital radio frequency transmitter. A synchronous pulse distribution network is used to ensure proper operation at data rates of 20 GHz or above.

According to some aspects, a quantum circuit is provided including a plurality of non-linear circuit elements coupled together in series and in parallel, such that at least two of the circuit elements are coupled together in series and at least two of the circuit elements are coupled together in parallel, wherein the quantum circuit is configured to act as an amplifier.

A device for generating a qubit control signal includes: a first signal envelope generator circuit including a first multiple of signal sources, in which an output of each signal source of the first multiple of signal sources is combined to provide a first cumulative output; and a first mixer circuit coupled to the first signal envelope generator circuit, in which the first cumulative output is coupled to a first input of the first mixer circuit, and an output of the first mixer circuit includes a first qubit control signal.

A technique relates to a microwave device. The microwave device includes a Josephson ring modulator, a first multimode resonator connected to the Josephson ring modulator, where the first multimode resonator is made of a first left-handed transmission line, and a second multimode resonator connected to the Josephson ring modulator, where the second multimode resonator is made of a second left-handed transmission line.

A technique relates to operating a multimode Josephson parametric converter as a multimode quantum limited amplifier. The multimode Josephson parametric converter receives multiple quantum signals in parallel at different resonance frequencies. The multimode Josephson parametric converter amplifies simultaneously the multiple quantum signals, according to pump signals applied to the multimode Josephson parametric converter. The multiple quantum signals having been amplified at the different resonance frequencies are reflected, according to the pump signals.

A Josephson parametric converter is provided. The Josephson parametric converter includes a multi-Josephson junction ring modulator having arrays of N Josephson junctions arranged in a ring configuration with nodes inter-dispersed between the arrays. N is an integer having a value greater than one. The Josephson parametric converter includes a first and a second resonator formed from lumped-element capacitors that shunt the multi-Josephson junction ring modulator and respectively enable a first and a second mode of the Josephson parametric converter.