Simulation of Quantum Parametric Amplifiers

L. S. Kuzmin, K. K. Likharev, V. V. Migulin

Likai Yang, Yufeng Wu, Chaofan Wang +4 more

Kinetic inductance parametric amplifiers (KIPAs) have been widely studied for small-signal detection in superconducting quantum circuits. In this work, we demonstrate the modeling of a niobium nitride nanowire based KIPA using electromagnetic (EM) and circuit co-simulation, and compare the outcomes with experimental results. EM analysis is first performed on the device layout, taking into account the linear part of the kinetic inductance. The results are then integrated into a harmonic balance circuit simulator, in which the currentdependent inductance is modeled by representing the nanowire as a nonlinear inductor. Both linear and nonlinear responses of the device, including temperature-dependent resonance spectra and parametric gain, are extracted and show good agreement with experiments. We further show that when the KIPA operates as a degenerate amplifier, its phase-sensitive behavior can be accurately reproduced by the simulation. Our technique can serve as a valuable enabler for the simulation and design of quantum parametric amplifiers and superconducting kinetic inductance devices.

Keith Krause, Michael C. Hamilton

We have designed a traveling-wave parametric amplifier based on quantum phase-slip junctions. This amplifier has a LC-ladder nonlinear transmission line structure, and acts as a dual to the Josephson traveling-wave parametric amplifier. We use WRspice simulations to design and analyze the quantum phase-slip junction-based traveling-wave parametric amplifier. Our simulations capture parametric amplification by demonstrating frequency mixing, signal gain, and generation of an idler tone. In additional simulations, we control various circuit parameters: the quantum phase-slip junctions, critical voltage, quantum phase-slip junction count, and bias voltage. We report and discuss these parameters' effects on the amplifier's signal gain. We compare these performance metrics with those from simulations of a typical Josephson traveling-wave parametric amplifier.

Nikita S. Klimovich

Likai Yang, Jennifer Wang, Daryoush Shiri +6 more

The development of large-scale superconducting quantum computers critically depends on the accurate readout of qubit states. To enable this, cryogenic parametric amplifiers have been proposed and developed, and have since found widespread use in small-signal detection applications. Among various amplifier architectures, Josephson traveling-wave parametric amplifiers (JTWPAs) are widely adopted due to their broad bandwidth, high saturation power, and compatibility with superconducting qubits. In this work, we present a design workflow of JTWPAs based on a co-simulation approach combining electromagnetic (EM) and circuit-level simulation. We apply this method to a uniform JTWPA, comparing our simulation results with experimental data. To mitigate the challenge of constructing lumped element circuit models usually used in conventional simulation method, we directly perform full EM analysis of the device to accurately determine its linear response. The extracted S parameters are then fed into a nonlinear harmonic balance simulator with Josephson junctions modeled as circuit elements. By doing so, the linear and gain properties of the JTWPA are extracted. Different factors that impact device performance including gain compression, phase matching, and fabrication imperfections are further investigated and modeled. A good agreement between simulation and measurements is identified, establishing the effectiveness of our approach in designing quantum parametric amplifiers.

A. Metelmann, Archana Kamal