Noise properties of a Josephson parametric oscillator

TL;DR

This study investigates the noise characteristics of a Josephson parametric oscillator using microwave homodyne interferometry, revealing phase noise behavior and how pump strength influences noise suppression.

Contribution

It introduces a novel noise spectroscopy method for JPOs and demonstrates how pump strength affects phase noise suppression.

Findings

Phase noise exhibits a $1/f^2$ spectrum.

Increasing pump strength suppresses phase noise fluctuations.

Long-term single shot measurements reveal detailed noise dynamics.

Abstract

We perform the noise spectroscopy of a Josephson parametric oscillator (JPO) by implementing a microwave homodyne interferometric measurement scheme. We observe the fluctuations in the self-oscillating output field of the JPO for a long 10 s time interval in a single shot measurement and characterize the phase and amplitude noise. Furthermore, we investigate the effects of the pump strength on the output noise power spectra of the JPO. We found strong fluctuations in the phase with a $1/f^2$ characteristics in the phase noise power spectrum, which is suppressed by increasing the pump strength.