A multi-mode traveling-wave Josephson converter for on-chip circulation: part I

Circulators are key components of circuitQED setups. However, commercially available devices are bulky, lossy and rely on ferrite cores which cannot be integrated in superconducting devices. A reliable on-chip circulator would allow integration of amplification chains in superconducting processors, thereby boosting measurement efficiency and reducing devices footprint. Moreover, it would pave the way for the simulation of non-trivial phases of matter. Unfortunately, existing implementations of on-chip non-reciprocal components face limitations in terms of bandwidth, tunability, and isolation.

In this two-part talk, we introduce a novel method that utilizes a two-mode transmission line doped with Josephson junctions. A traveling-wave pump applied on one mode activates a directional photon conversion process on the second mode, ultimately leading to circulation within the circuit. Our approach offers the advantage of broad tunability, high isolation, and is compatible with traveling-wave amplification. In this first part, I will present the working principle of our device.