National Institute of Standards and Technology
@usgov.national_institute_of_standard_vhf_josephson_arbitrary_e6c3b193
These data will appear in [1]. The abstract for that paper is given below:We report on the design, fabrication, and measurement of a Very High Frequency band Josephson Arbitrary Waveform Synthesizer (VHF-JAWS) at frequencies from 1kHz to 50.05MHz. The VHF-JAWS chip is composed of a series array of 12,810 Josephson junctions (JJs) embedded in a superconducting coplanar waveguide. Each JJ responds to a pattern of current pulses by creating a corresponding pattern of voltage pulses, each with a time-integrated area related to fundamental constants as $ extit{ extbf{h/2e}}$. The pulse patterns are chosen to produce quantum-based single-tone voltage waveforms with an open-circuit voltage of 50mVrms (\mbox{-19.03dBm} output power into 50$\Omega$ load impedances) at frequencies up to 50.05MHz, which is more than twice the voltage that has been generated by previous RF-JAWS designs at 1GHz. The VHF-JAWS is "quantum-locked", that is, it generates one quantized output voltage pulse per input current pulse per JJ while varying the dc current through the JJ array by at least 0.4mA and the amplitude of the bias pulses by at least 10%. We use the large bias pulse quantum-locking range to investigate one source of error in detail: the direct feedthrough of the current bias pulses into the DUT at VHF frequencies. We reduce this error by high-pass filtering the current bias pulses and measure the error as a function of input pulse amplitude using two techniques: by measuring small changes over the quantum-locking range and by passively attenuating the input pulse amplitude so that the nonlinear JJs no longer generate voltage pulses while the error is only linearly scaled.
Organization: National Institute of Standards and Technology
Last updated: 2024-03-12T23:56:27.774396
Tags: digital-analog-conversion, josephson-junction-arrays, power-measurement-standards, signal-synthesis, superconducting-integrated-circuits, superconducting-microwave-devices
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