Two-stage SQUID amplifier with bias current re-use

TL;DR

This paper presents a novel two-stage SQUID amplifier design that reuses bias current, reducing the number of required bias and flux lines, and demonstrates its functionality at 4.2 K.

Contribution

The paper introduces a two-stage SQUID amplifier with bias current re-use, simplifying the biasing scheme and demonstrating its feasibility at cryogenic temperatures.

Findings

Successful fabrication and operation at 4.2 K

Reduced bias line requirements

Cascaded signal propagation in two-stage design

Abstract

We have designed and fabricated an integrated two-stage SQUID amplifier, requiring only one bias line and one flux setpoint line. From the biasing viewpoint the two stages are connected in series while from the signal propagation viewpoint the stages are cascaded. A proof-of principle demonstration at T = 4.2 K is presented.