Superconducting qubit control with a system of an integrated microwave board and FPGA

As the number of qubits increases toward the realization of fault-tolerant superconducting quantum computers, current microwave control systems will be limiting factor for the scalability. To address this issue, it is necessary to integrate and miniaturize a large number of microwave control units. As microwave components in C-and X-bands are prone to crosstalk on a board, which is detrimental to the qubit control fidelity, they are often assembled with connectorized milling cases for individual channels, leading to an obstacle to scaling up the system size.

In this work, we integrate multiple microwave channels on a single board directly attached to an FPGA board. The differential microwave circuits achieve low crosstalk between channels over a wide bandwidth of 2 GHz.

In this talk, we discuss the performance and the scalability of the microwave control system. We also report experimental results on superconducting transmon qubits controlled by the system.