Improving high-TC dc SQUID performance by means of junction asymmetry

Abstract

We study noise and noise energy of a high- TC dc SQUID (superconducting quantum interference device) fabricated on a high- epsilonR substrate whose conduction properties are given by transmission line physics. We show that transmission line resonances greatly enhance the noise. Remarkably, resistance asymmetry enhances these resonances even more. However, as the transfer function (\frac {\rmd

v_{\mathrm {dc}}}{\rmd \phi } ) scales the same way, the noise energy is reduced by asymmetry, greatly enhancing the flexibility and performance of the SQUID.