Performance of a Kinetic-Inductance Traveling-Wave Parametric Amplifier at 4 Kelvin: Toward an Alternative to Semiconductor Amplifiers

  1. M. Malnou,
  2. J. Aumentado,
  3. M. R. Vissers,
  4. J. D. Wheeler,
  5. J. Hubmayr,
  6. J. N. Ullom,
  7. and J. Gao
Most microwave readout architectures in quantum computing or sensing rely on a semiconductor amplifier at 4 K, typically a high-electron mobility transistor (HEMT). Despite its remarkable noise performance, a conventional HEMT dissipates several milliwatts of power, posing a practical challenge to scale up the number of qubits or sensors addressed in these architectures. As an alternative, we present an amplification chain consisting of a kinetic-inductance traveling-wave parametric amplifier (KI-TWPA) placed at 4 K, followed by a HEMT placed at 70 K, and demonstrate a chain-added noise TΣ=6.3±0.5 K between 3.5 and 5.5 GHz. While, in principle, any parametric amplifier can be quantum limited even at 4 K, in practice we find the KI-TWPA’s performance limited by the temperature of its inputs, and by an excess of noise Tex=1.9 K. The dissipation of the KI-TWPA’s rf pump constitutes the main power load at 4 K and is about one percent that of a HEMT. These combined noise and power dissipation values pave the way for the KI-TWPA’s use as a replacement for semiconductor amplifiers.

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