Four wave-mixing in a microstrip kinetic inductance travelling wave parametric amplifier

Abstract

Superconducting quantum circuits are typically operated at low temperatures (mK), necessitating cryogenic low-noise, wideband amplifiers for signal readout ultimately also compatible with room temperature electronics. While existing implementations partly meet these criteria, they suffer from certain limitations, such as rippled transmission spectra or limited dynamic range, some of which are caused by the lack of proper impedance matching. We develop a microstrip kinetic inductance traveling wave amplifier, exploiting the nonlinear kinetic inductance of tungsten-silicide for wave-mixing of the signal and a pump, and engineer the impedance to 50 Ω, while decreasing the phase velocity, with benefit for the amplification. Despite losses, pumping on our device amplifies the signal by 15 dB over a 2 GHz bandwidth.

Compact Itinerant Microwave Photonics with Superconducting High-Kinetic Inductance Microstrips

“…in the amplifier in Ref. [23] and in the first two devices shown in this letter) is that the photons are decelerated to spend several nanoseconds in our device, permitting us to shorten the traces significantly and still maintain sufficient wave-mixing or appreciable routing to other coupled waveguides. In the case of resonant struc-tures, waveguide lengths L can be reduced according to L = λ/2 ∼ v ph /2f where f is the desired frequency, cf.…”

“…This fulfils the linear networking properties considered above. In addition, the nonlinearity [21,22] of such HKI microstrips provides a route to amplification at the quantum limit [23] due to wave-mixing phenomena. This can now be extended to a multi-mode network for more complex photonic tasks.…”

Compact itinerant microwave photonics with superconducting high-kinetic inductance microstrips

“…In the devices presented in this paper v ph 4 × 10 6 m s −1 . The immediate consequence for traveling waves (cf in the amplifier in [43] and in the first two devices shown here) is that the photons are decelerated to spend several nanoseconds in our device, permitting us to shorten the traces significantly and still maintain sufficient wave-mixing or appreciable routing to other coupled waveguides.…”

A three-wave mixing kinetic inductance traveling-wave amplifier with near-quantum-limited noise performance

“…The combined gain, bandwidth, and power handling performances are promising, provided that the KIT also presents a competitive noise performance. Measuring this noise is a topic of current interest [27,35], and we execute the task using a self-calibrated shot-noise thermometer (SNT) [28,29]. We perform a direct measurement of the output spectral density, which incorporates the true chain's microwave loss.…”