A cryogenic on-chip microwave pulse generator for large-scale superconducting quantum computing

For superconducting quantum processors, microwave signals are delivered to each qubit from room-temperature electronics to the cryogenic environment through coaxial cables. Limited by the heat load of cabling and the massive cost of electronics, such an architecture is not viable for millions of qubits required for fault-tolerant quantum computing. Monolithic integration of the control electronics and the qubits provides a promising solution, but it requires a coherent cryogenic microwave pulse generator that is compatible with superconducting quantum circuits [1]. In this talk, we will introduce such a signal source driven by digital-like signals, generating pulsed microwave emission with well-controlled phase, intensity, and frequency directly at millikelvin temperatures [2]. We exhibit successful readouts of superconducting qubits using this microwave pulse generator. The device demonstrated here has a small footprint, negligible heat load, great flexibility to operate, and is fully compatible with today’s superconducting quantum circuits.

[1] Blais, A., Girvin, S. & Oliver, W. Nat. Phys. 16, 247–256 (2020).

[2] Bao, Z., Li, Y., Wang, Z. et al. Nat Commun. 15, 5958 (2024).