Chaofan Wang

A K-band Kinetic Inductance Parametric Amplifier Near the Quantum Limit

  1. Chaofan Wang,
  2. Shihan Liu,
  3. Yufeng Wu,
  4. Danqing Wang,
  5. Manuel C. C. Pace,
  6. Xiangzheng Li,
  7. and Hong X. Tang
Advancing superconducting quantum devices to higher operating frequencies broadens their functionality and enables operation at elevated temperatures, but it also requires near-quantum-limited
amplifiers beyond the few-gigahertz regime. Here we present a junction-free, kinetic-inductance parametric amplifier based on thin-film niobium nitride (NbN) operating at 23 GHz in the microwave K-band, achieving a gain up to 40 dB, a 100 MHz gain-bandwidth product, a 1 dB saturation input power of -85 dBm with 23 dB gain, and added noise no greater than 1.4 quanta for phase-preserving amplification. Leveraging the large superconducting gap of NbN, this architecture can be extended to even higher frequencies, supporting applications such as high-fidelity readout of millimeter-wave superconducting qubits and axion searches over an expanded mass window.
arxiv pdf

Broad Spectrum Coherent Frequency Conversion with Kinetic Inductance Superconducting Metastructures

  1. Yufeng Wu,
  2. Chaofan Wang,
  3. Danqing Wang,
  4. Mingrui Xu,
  5. Yiyu Zhou,
  6. and Hong X. Tang
arametric frequency converters (PFCs) play a critical role in bridging the frequency gap between quantum information carriers. PFCs in the microwave band are particularly important
for superconducting quantum processors, but their operating bandwidth is often strongly limited. Here, we present a multimode kinetic metastructure for parametric frequency conversion between broadly spanning frequency modes. This device comprises a chain of asymmetric kinetic inductance grids designed to deliver efficient three-wave mixing nonlinearity. We demonstrate high efficient coherent conversion among broadly distributed modes, and the mode frequency is continuously tunable by controlling the external magnetic field strength, making it ideally suited for quantum computing and communication applications requiring flexible and efficient frequency conversion.
arxiv pdf