Radio frequency mixing modules for superconducting qubit room temperature control systems.

Area of Science:

• Quantum Computing
• Electrical Engineering
• RF Circuit Design

Background:

• Increasing qubit counts in quantum processors lead to complex RF analog circuits.
• Existing control systems face limitations in size, cost, and reliability due to complexity.

Purpose of the Study:

• To develop compact RF mixing boards for scalable quantum processor control.
• To integrate multiple RF functions onto a single, efficient printed circuit board.

Main Methods:

• Designed and fabricated a 40 × 80 mm² four-layer PCB with EMI shielding.
• Integrated I/Q quadrature mixing, IF/LO/RF power adjustments, and DC bias tuning.
• Tested RF performance (2.5-8.5 GHz), image rejection (~27 dBc), and channel isolation (~50 dB).

Main Results:

• Achieved high linearity: amplitude (5 ×10⁻⁴ Vpp/Vmean) and phase (1 ×10⁻³ radian pk-pk).
• Validated operation in a superconducting quantum processor's control system.
• Measured low single-qubit (9.3(3) × 10⁻⁴) and two-qubit (2.7(1) × 10⁻²) process infidelities.

Conclusions:

• The compact RF mixing boards effectively address control system complexity for quantum processors.
• The integrated design enables reliable and scalable quantum control systems.
• Demonstrated successful integration and performance validation through randomized benchmarking.