On-Chip Superconducting Microwave Circulator from Synthetic Rotation

Abstract

We analyze the design of a potential replacement technology for the commercial ferrite circulators that are ubiquitous in contemporary quantum superconducting microwave experiments. The lossless, lumped element design is capable of being integrated on chip with other superconducting microwave devices, thus circumventing the many performance-limiting aspects of ferrite circulators. The design is based on the dynamic modulation of DC superconducting microwave quantum interference devices (SQUIDs) that function as nearly linear, tunable inductors. The connection to familiar ferrite-based circulators is a simple frame boost in the internal dynamics' equation of motion. In addition to the general, schematic analysis, we also give an overview of many considerations necessary to achieve a practical design with a tunable center frequency in the 4-8 GHz frequency band, a bandwidth of 240 MHz, reflections at the -20 dB level, and a maximum signal power of approximately order 100 microwave photons per inverse bandwidth.

Micromachined Integrated Quantum Circuit Containing a Superconducting Qubit

“…[22]. More sophisticated on-chip input/output circuitry, such as quantum limited amplifiers [23][24][25], circulators [26,27], and switching elements [28,29], will also be required for practical quantum information processing. This integration will likely be accompanied by through-wafer metalized vias to prevent cross-talk.…”

Magnetic Resonance with Squeezed Microwaves

“…To reduce the losses below 1 dB, more radical setup changes would probably be needed, such as integrating the squeezer, the circulator, the ESR resonator, and the amplifier on a single chip. While such a complex quantum integrated circuit has never been achieved so far, promising steps in that direction have already been taken, with, in particular, several recent demonstrations of on-chip superconducting circulators [44][45][46][47].…”

On-Chip Microwave Quantum Hall Circulator

“…Miniaturized, nonreciprocal devices are currently of broad interest for enabling new applications in acoustics [1], photonics [2,3], transceiver technology [4], and in the regime of near quantum-limited measurement [5][6][7][8][9], where they are needed to isolate qubits from their noisy readout circuits. Since the 1950s, passive circuit elements exhibiting nonreciprocity at microwave frequencies have been implemented using bulky magnetic devices that are comparable in scale to the centimeter wavelength of signals in their operating band.…”