High-fidelity control of superconducting qubits requires the generation of microwave-frequency pulses precisely tailored on nanosecond timescales. These pulses are most commonly synthesized by up-converting and superimposing two narrow-band intermediate-frequency signals referred to as the in-phase (I) and quadrature (Q) components. While the calibration of their DC-offsets, relative amplitude and phase allows one to cancel unwanted sideband and carrier leakage, this IQ mixing approach suffers from the presence of additional spurious frequency components. Here, we experimentally study an alternative approach based on double frequency conversion, which overcomes this challenge and circumvents the need for IQ-calibration. We find a spurious-free dynamic range of more than 70dB and compare the quality of pulse generation against a state-of-the-art IQ mixing scheme by performing repeated single-qubit randomized benchmarking on a superconducting qubit.
@article{arxiv.2210.02513,
title = {Frequency Up-Conversion Schemes for Controlling Superconducting Qubits},
author = {Johannes Herrmann and Christoph Hellings and Stefania Lazar and Fabian Pfäffli and Florian Haupt and Tobias Thiele and Dante Colao Zanuz and Graham J. Norris and Flavio Heer and Christopher Eichler and Andreas Wallraff},
journal= {arXiv preprint arXiv:2210.02513},
year = {2022}
}