Qubit Readout with Integrated Traveling Wave Parametric Devices

Josephson junction-based traveling wave parametric amplifiers (JTWPAs) are widely used in cQED experiments for high-fidelity readout of superconducting qubits. These amplifiers naturally possess non-reciprocity and broadband gain. However, this non-reciprocity is not enough to protect sensitive quantum devices in readout chains from downstream noise sources. Moreover, microwave connectors and components needed to connect JTWPAs to superconducting qubit chips place additional limits on the quantum efficiency of readout systems.

We present an architecture for integrating a qubit with on-chip traveling wave devices that eliminates the need for many components in the readout chain. We show how integrating a multi-component readout system with amplifiers, frequency-converters, and add-drop filters together with qubits results in passive in-band reverse isolation and broadband amplification on a research-level qubit chip. We further explore how integrating a JTWPA on-chip affects qubit lifetimes and sources of decoherence compared to systems with separate components. We conclude by discussing how this architecture enables favorable scaling of superconducting qubit systems together with readout chains.