Nonlinear distortions in amplitude detection of microwave signals by a Josephson junction

Н. И. Иванов, I. I. Iurchenko

Олег Викторович Карпов, Victor Matveevich Buchstaber, M. A. Tertychnaya +2 more

The theory and preliminary results of the experimental tests of a method for synthesizing ac-voltage signals through the use of pulse-width modulation of the microwave power biasing a Josephson junction are presented. It is shown that it is possible to synthesize sinusoidal ac-voltage signals with an amplitude of 1 V and a nonlinear distortion factor of <0.003%.

Hamed Mehrara, Farshid Raissi, Alireza Erfanian +2 more

Josephson Fluxonic Diode (JFD) provides a very nonlinear characteristic in comparison with a long Josephson junction at microwave frequencies. This nonlinearity is highly accentuated by creation and dynamics of vortex-antivortex pairs in two disparate modes of operation; forward and reverse-bias. Experimental detection of microwave frequencies through this device is not solely dependent on the geometry and seems to change drastically with the different operating condition. This paper attempts to understand the microwave characteristic of this device with respect to its bias and control current and rf-exposed boundary conditions defined in RCSJ model of JFD. Based on the simulation results, for a finite length of a JFD excited by a low-amplitude microwave signal below its plasma frequency, control current increases the rate of vortex-antivortex pair generation and fine-tunes the microwave resistance (Rω) up to an order of magnitude more than its zero magnetic field resistance (R0). Under this circumstance, adding the bias current which can move generated vortex-antivortex pairs causes a substantial increase up to three orders of magnitude compared to R0either in forward or reverse-bias, while damping coefficient 1/√βc(βcis Stewart-McCumber parameter of Josephson junction) can limit this increase. It has also been shown that the variation of polarity, frequency, or amplitude of incoming microwave signal can impact on the impedance due to its relation with pair generation rate and so causes variations in observed impedance both in linear and nonlinear form. According to the results, low-microwave impedance of a JFD can be multiplied externally using biasing sets to match with high-impedance sources, which justifies its detection mechanism at microwave frequency.

I. I. Yurchenko, V. S. Kartavtsev, V. I. Matveev +1 more

I. M. Dmitrenko, Н. И. Иванов, I. I. Iurchenko

G. Oelsner, Christian Kraglund Andersen, Marian Rehak +6 more

Quantum information processing based on light has invigorated research on the production and detection of single photons. The authors present an innovative detection scheme for weak microwave signals, based on a superconducting current-biased Josephson junction. In contrast to detectors that absorb photons, this system is optimized such that the amplitude of the classical photon field triggers detection.