Synthesis of sinusoidal signals with a Josephson arbitrary waveform synthesizer

Abstract

A Josephson arbitrary waveform synthesizer (JAWS) has been used for the synthesis of bipolar waveform voltage signals. The two major changes with respect to earlier work are the use of Josephson arrays consisting of more junctions and the use of a new type of pattern generator. With a multi-branch Josephson array from IPHT, the synthesized sinusoidal voltages have amplitudes up to 9.5 mV zero to peak and frequencies in the range from 100 Hz to 150 kHz. For instance, for a 9.5 mV sine wave of 122 kHz, the spectrum of the synthesized signal shows that higher harmonics are at least 86 dB below the fundamental. Comparable suppression was achieved with a single-branch Josephson array from PTB generating a 17 mV sine wave of 180 Hz. Additionally, with a PTB array, sinusoidal signals with amplitudes up to 57 mV zero to peak are generated with higher harmonics typically 60 dB to 70 dB below the fundamental at frequencies below a few hundred hertz.