Using Integrated Photodiodes Towards Scalable Superconducting Quantum I/O

Abstract: Routing and thermalizing microwave signals into dilution refrigerator environments can be technically challenging when working at scale. Recent efforts to accommodate this challenge include the use of “super cables” [1], high density ribbon cables [2], and overall engineering of the refrigerator for larger cooling power or connected vacuum chambers. Alternatively, microwave tones for superconducting qubit control and readout can be generated directly inside cryogenic environments using bulk photodiodes [3]. In this work, we discuss results using an integrated photodiode as a source for superconducting transmon qubit readout tones at millikelvin temperatures, and possible paths forward for improving this technology to better mitigate issues associated with scaling superconducting quantum systems.

Acknowledgments: Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of AFRL.

[1] https://www.iarpa.gov/research-programs/supercables

[2] J. P. Smith et al. arXiv:2306.13574 (2023)

[3] Lecocq, F. et al. Nature 591, 575–579 (2021)