Towards a broadband quantum-limited amplifier at 20 GHz

Superconducting quantum systems have recently been implemented in millimeter-wave frequency bands [1]. A benefit derived from increased operating frequency is suppression of undesired thermal population of modes, hence lifting the requirement for costly refrigeration to millikelvin temperatures. This motivates building quantum-limited amplifiers offering high broadband gain and wide dynamic range in the K-band (18-26.5 GHz) and beyond.

In this work, we show progress towards physical realization of a 20 GHz amplifier using thin-film NbN nanowires embedded in a waveguide package. We will discuss the design, packaging, and measurement setup, while presenting preliminary results on typical amplifier metrics like gain, bandwidth, linearity, and added noise.

[1] Anferov, A., Harvey, S. P., Wan, F., Simon, J., & Schuster, D. I. (2024). Superconducting qubits above 20 GHz operating over 200 mK. PRX Quantum, 5(3), 030347.