Broadband lumped-element Josephson parametric amplifier with single-step lithography

Abstract

We present a lumped-element Josephson parametric amplifier (JPA) utilizing a straightforward fabrication process involving a single electron beam lithography step followed by double-angle evaporation of aluminum and in-situ oxidation. The Josephson junctions forming the SQUID are fabricated using bridgeless shadow evaporation technique, which enables reliable fabrication of relatively large ($\sim 9\mu {\mathrm{m}}^2$) junctions. Our strongly coupled flux-pumped JPA achieves 20~dB gain with 95~MHz bandwidth around 5~GHz, while the center frequency is tunable by more than 1~GHz, with the additional possibility for rapid tuning by varying the pump frequency alone. Analytical calculations based on the input-output theory reproduce our measurement results closely.

pages 11, 5 figures

References in corpus (4)

• Amplification and squeezing of quantum noise with a tunable Josephson metamaterial
• High-gain weakly nonlinear flux-modulated Josephson parametric amplifier using a SQUID-array
• RF bifurcation of a Josephson junction: microwave embedding circuit requirements
• Advanced Concepts in Josephson Junction Reflection Amplifiers