Josephson arbitrary waveform synthesizers (JAWS), which are driven with pulses, are used to realize the SI unit of volt for ac waveforms [1]. They and their Josephson pulse generator (JPG) counterparts can also be used to drive qubits [2]. Functional quantum computers need thousands of control lines, which conduct heat. To minimize the thermal leakage, one could use optical signal lines, where heat conduction is minimal and multiple signals can be packed into single line [3]. The optical signals can also be used to drive JAWS [4]. However, driving qubits with optically controlled JAWS is yet to be demonstrated. Multiple processes exist for JAWS fabrication including e.g. growing superconductor – normal metal – superconductor (SNS) trilayers [5]. Here we report on optically driven JAWS fabricated with sidewall passivated spacer (SWAPS) [6] technology. SWAPS is a scalable wafer level process that has been successfully used to fabricate e.g. Josephson parametric amplifiers (JPA) [7] and superconducting quantum interference devices (SQUIDs) [8].
[1] Appl. Phys. Lett. 68, 3171 (1996).
[2] Appl. Phys. Lett. 122, 192602 (2023).
[3] Nature 591, 575 (2021).
[4] Appl. Phys. Lett. 119, 032601 (2021).
[5] IEEE Transactions on Appl. Supercond. 19, 981 (2009)
[6] Supercond. Sci. Technol. 30, 125016 (2017)
[7] Supercond. Sci. Technol. 31, 105001 (2018)
[8] IEEE Transactions on Appl. Supercond. 28, 1600204 (2018)