Edgar Bonet

A Traveling Wave Parametric Amplifier Isolator

  1. Arpit Ranadive,
  2. Bekim Fazliji,
  3. Gwenael Le Gal,
  4. Giulio Cappelli,
  5. Guilliam Butseraen,
  6. Edgar Bonet,
  7. Eric Eyraud,
  8. Sina Böhling,
  9. Luca Planat,
  10. A. Metelmann,
  11. and Nicolas Roch
Superconducting traveling-wave parametric amplifiers have emerged as highly promising devices for near-quantum-limited broadband amplification of microwave signals and are essential
for high quantum-efficiency microwave readout lines. Built-in isolation, as well as gain, would address their primary limitation: lack of true directionality due to potential backward travel of electromagnetic radiation to their input port. Here, we demonstrate a Josephson-junction-based traveling-wave parametric amplifier isolator. It utilizes third-order nonlinearity for amplification and second-order nonlinearity for frequency upconversion of backward propagating modes to provide reverse isolation. These parametric processes, enhanced by a novel phase matching mechanism, exhibit gain of up to 20~dB and reverse isolation of up to 30~dB over a static 3~dB bandwidth greater than 500~MHz, while keeping near-quantum limited added noise. This demonstration of a broadband truly directional amplifier ultimately paves the way towards broadband quantum-limited microwave amplification lines without bulky magnetic isolators and with inhibited back-action.
arxiv pdf

A reversed Kerr traveling wave parametric amplifier

  1. Arpit Ranadive,
  2. Martina Esposito,
  3. Luca Planat,
  4. Edgar Bonet,
  5. Cécile Naud,
  6. Olivier Buisson,
  7. Wiebke Guichard,
  8. and Nicolas Roch
Traveling wave parametric amplification in a nonlinear medium provides broadband quantum-noise limited gain and is a remarkable resource for the detection of electromagnetic radiation.
This nonlinearity is at the same time the key to the amplification phenomenon but also the cause of a fundamental limitation: poor phase matching between the signal and the pump. Here we solve this issue with a new phase matching mechanism based on the sign reversal of the Kerr nonlinearity. We present a novel traveling wave parametric amplifier composed of a chain of superconducting nonlinear asymmetric inductive elements (SNAILs) which allows this sign reversal when biased with the proper magnetic flux. Compared to previous state of the art phase matching approaches, this reversed Kerr phase matching mechanism avoids the presence of gaps in transmission, reduces gain ripples, and allows in situ tunability of the amplification band over an unprecedented wide range. Besides such notable advancements in the amplification performance, with direct applications to superconducting quantum computing, the in-situ tunability of the nonlinearity in traveling wave structures, with no counterpart in optics to the best of our knowledge, opens exciting experimental possibilities in the general framework of microwave quantum optics and single-photon detection.
arxiv pdf