Scalable Quantum i/o: Advances in Integrated Cryogenic Microwave Components in Flexible Stripline Structures Part 1/2

Conventional cryogenic coaxial cabling and filtering solutions for quantum computing have limited scaling potential towards and beyond the kQbit regime due to cost, connection-density, form-factor and heat-load. In this work, we present advances in monolithic flexible RF cabling, which directly connects room temperature electronics to the cryogenic interface of a quantum device.

In particular we focus on fully integrated low-pass filtering, metal-powder IR filtering and distributed attenuators with performances on-par with high-end coaxial solutions. We experimentally verify that the flat cabling is well-thermalized at cryogenic temperatures as low as 50mK. Finally we present the results of full two-port calibrated cryogenic microwave measurements performed on flexible superconducting RF hardware. In this first part of a two-part presentation, we introduce the flexible cabling concept and present fully integrated low-pass filtering, metal-powder IR filtering and distributed attenuators. As well as benchmarking measurements on state-of-the-art quantum devices.