Broadband SNAIL parametric amplifier with microstrip impedance transformer

What is it about?

This work addresses the Josephson parametric amplifiers are an important part of a modern superconducting quantum computing platform and squeezed quantum states generation devices. Here, we present a quantum-limited 3-wave-mixing parametric amplifier based on superconducting nonlinear asymmetric inductive elements (SNAILs), whose useful bandwidth is enhanced with an on-chip two-section impedance-matching circuit based on microstrip transmission lines. The amplifier dynamic range is increased using an array of 67 SNAILs with 268 Josephson junctions, forming a nonlinear quarter-wave resonator. Operating in a current-pumped mode, we experimentally demonstrate an average gain of 17 dB across 300 MHz bandwidth, along with an average saturation power of –100 dBm, which can go as high as −97 dBm with quantum-limited noise performance. Moreover, the amplifier can be fabricated using a simple technology with just one e-beam lithography step.

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Photo by Михаил Павленко on Unsplash

Photo by Михаил Павленко on Unsplash

Why is it important?

Parametric amplifiers have become key components in quantum information processing due to their near quantum-limited noise performance. Those devices are used as the first stage of the low-noise amplification schemes defining primarily the overall system noise and signal-to-noise ratio. Broadband Josephson parametric amplifiers are the only tools to perform single-photon power measurements of both microwave and optical signals, quantum metrology, and dark matter search. In quantum computing, it has been used for high-fidelity single-shot readout of superconducting qubits, real-time quantum feedback control, and generating squeezed quantum states.