arXiv subjects

Flavius Schackert

Publications and source records attributed to Flavius Schackert.

3 recordsLinked to original sources

arXiv2013

Three-wave mixing with three incoming waves: Signal-Idler Coherent Cancellation and Gain Enhancement in a Parametric Amplifier

Coherent, purely-dispersive three-wave mixing systems in optics and superconducting microwave circuits can be operated as parametric amplifiers, generating from a pump wave at one frequency amplified signal and idler waves at lower frequencies. Here we demonstrate the reciprocal process using a Josephson amplifier in which coherently imposed signal and idler beams up-convert to the pump frequency. For signal and idler beams strong enough to significantly deplete the pump, we show that this reciprocal process ("coherent cancellation") leads to large, phase-sensitive modulation and even enhancement of the amplifier gain, in good agreement with theoretical predictions.

physics.optics↗

arXiv2012

Full coherent frequency conversion between two microwave propagating modes

We demonstrate full frequency conversion in the microwave domain using a Josephson three-wave mixing device pumped at the difference between the frequencies of its fundamental eigenmodes. By measuring the signal output as a function of the intensity and phase of the three input signal, idler and pump tones, we show that the device functions as a controllable three-wave beam-splitter/combiner for propagating microwave modes, in accordance with theory. Losses at the full conversion point are found to be less than 10^-2. Potential applications of the device include quantum information transduction and realization of an ultra-sensitive interferometer with controllable feedback.

cond-mat.supr-con↗

arXiv2011

Josephson Amplifier for Qubit Readout

We report on measurements of a Josephson amplifier (J-amp) suitable for quantum-state qubit readout in the microwave domain. It consists of two microstrip resonators which intersect at a Josephson ring modulator. A maximum gain of about 20 dB, a bandwidth of 9 MHz, and a center-frequency tunability of about 60 MHz with gain in excess of 10 dB have been attained for idler and signal of frequencies 6.4 GHz and 8.1 GHz, in accordance with theory. Maximum input power measurements of the J-amp show a relatively good agreement with theoretical prediction. We discuss how the amplifier characteristics can be improved.

cond-mat.supr-con↗