Bipolar Waveform Synthesis With an Optically Driven Josephson Arbitrary Waveform Synthesizer

An array of Josephson junctions (JJs) was driven with photonically generated current pulses to synthesize a high-fidelity 1 kHz bipolar voltage waveform with a quantum-based amplitude that can be directly related to fundamental constants. A photodiode capable of producing high average photocurrent was used to generate large-amplitude current pulses that were ac-coupled to a JJ array. The resulting bipolar current pulses have enabled the first demonstration of quantum-based bipolar waveform synthesis with an optical drive. We measured the quantum locking range with respect to several operating parameters, including 1.2 mA with respect to a dc bias current applied to the array, confirming the robust synthesis of bipolar waveforms.