Kinetic-inductance Parametric Amplifier Achieves 40 dB Gain and 6.9MHz Bandwidth for Quantum Measurement

Parametric amplification represents a crucial technology for enhancing the detection of incredibly faint microwave signals, a necessity for advancing quantum measurement. Danial Davoudi, Abdul Mohamed, and Shabir Barzanjeh, all from the University of Calgary, have pioneered a new approach to this challenge, developing a parametric amplifier based on kinetic-inductance circuits. Their device overcomes limitations found in existing Josephson-junction amplifiers, such as susceptibility to magnetic interference and restricted operating temperatures, while achieving significantly higher amplification power. The team demonstrates gains approaching 40 dB and vastly improved gain-bandwidth products, establishing coupled kinetic-inductance resonators as a promising and scalable platform for future quantum technologies, including improved readout of spin ensembles and quantum dots.

Hybridized-Mode Amplifier for Quantum Signals

Researchers have developed a novel parametric amplifier utilizing hybridized modes within a kinetic-inductance circuit, offering a robust and compact solution for amplifying weak microwave signals. This amplifier employs a carefully engineered network of circuit elements to create resonant modes that interact to boost signal strength, demonstrating amplification exceeding 10 decibels at 7. 5 gigahertz with a low noise figure below 4 decibels. This hybridized-mode amplifier represents a significant advancement in quantum amplification technology, potentially improving compatibility with complex quantum circuits.

NbTiN Kerr Amplifier Characterisation and Design

Scientists have demonstrated a two-mode kinetic-inductance parametric amplifier constructed from niobium-titanium-nitride and niobium-nitride thin films, addressing limitations of conventional parametric amplifiers. This device leverages the materials’ inherent nonlinear properties to achieve amplification without relying on Josephson junctions, exhibiting a gain of 12 decibels at 6. 2 gigahertz with a noise temperature of 800 millikelvin. Detailed characterisation and simulations confirm the amplifier’s performance and provide insights into the underlying physics, demonstrating a dynamic range exceeding 30 decibels.

Superconducting Amplifiers Exploit Nonlinear Circuit Elements

This document details technologies and concepts related to building low-noise, high-performance amplifiers using superconducting circuits for quantum applications. Parametric amplification is central to these designs, exploiting nonlinear circuit elements to transfer energy from a pump signal to a weak signal, and can be designed for near-quantum-limited noise. Key components include Josephson junctions and materials with high kinetic inductance, such as titanium nitride and niobium-titanium-nitride, used in superconducting nanowires and resonators. Critical performance metrics include noise figure, saturation power, bandwidth, and impedance matching, while minimizing magnetic field sensitivity is also important. Researchers are exploring dispersion engineering and multi-parametric amplification to further enhance amplifier performance. Improving bandwidth, increasing saturation power, and seamlessly integrating superconducting amplifiers with quantum circuits are key areas of ongoing research.

High-Gain Amplification with Kinetic Inductors

Scientists have demonstrated a new type of parametric amplifier based on coupled kinetic-inductance resonators fabricated from niobium-titanium-nitride and niobium-nitride thin films, achieving significant gains approaching 40 decibels with gain-bandwidth products up to 6. 9 megahertz. This amplification relies on a four-wave mixing process within the coupled resonators, boosting weak microwave signals with minimal added noise. The niobium-nitride device exhibited a larger nonlinear response and superior gain-bandwidth performance, highlighting the benefits of materials with high kinetic inductance. A coupled-mode theoretical model accurately predicts the amplifier’s behaviour, confirming the understanding of pump-induced modifications to the resonator modes. These kinetic-inductance parametric amplifiers offer a promising pathway towards scalable, high-dynamic-range quantum signal processing for multiplexed readout and broadband sensing.