Realization of an on-chip superconducting microwave switch

As state-of-the-art superconducting quantum devices get increasingly complex, they require a growing number of control and detection channels. On-chip routing and multiplexing of signals presents a way to realize these without requiring an unrealistically large number of microwave lines. The ability to route signals on a chip will also be a useful tool for fast in-situ characterization of superconducting devices. Here, we describe and experimentally demonstrate a superconducting on-chip microwave switch which can be integrated with current superconducting quantum circuits. The device is based on interference effects and is in principle lossless, making it well-suited for operation in dilution cryostats and for routing of signals at the single quantum level with near-unity efficiency. The first proof-of-principle device has a bandwidth of $150\,\mathrm{MHz}$, a $1\,\mathrm{dB}$ compression point of $-80\,\mathrm{dBm}$ and turn-on/off times on the order of $5\,\mathrm{ns}$. On/off power ratios reach values of approximately $30\,\mathrm{dB}$. We expect that our device will find use in (de)multiplexing of control and readout in superconducting circuits and routing of microwave fields in quantum optical experiments and quantum communication applications.