Heterodyne Mixing and Direct Detection with High Temperature Josephson Junctions

M. Malnou, C. Feuillet-Palma, Luo, Alan +5 more

Donald McDonald, Allan S. Risley, J. D. Cupp +1 more

M. Malnou, Thomas Wolf, C. Feuillet-Palma +4 more

A. I. Akimenko, I. K. Ianson, В. С. Соловьев

Oliver Harnack, Marian Darula, S. Beuven +1 more

We report on the mixing properties of high-T, superconductor (HTS) Josephson junctions. Direct radiation and heterodyne mixing experiments in the frequency range 78 GHz-119 GHz have been performed using YBa 2Cu30 7_ x (YBCO) step-edge junctions (SEJ) and bicrystal junctions (BO) on LaA10 3 and MgO substrates. Under external radiation our junctions showed harmonic phase synchronization (Shapiro steps) up to 1.88 THz. Junctions with current voltage characteristics (PVC) dose to predictions of the resistively shunted junction model (RSJ) were mounted into a heterodyne mixing setup. Under the radiation of two monochromatic signals we obtained conversion efficiencies around -14 dB in the 11 GHz intermediate frequency (IF) band. In the fundamental mixing regime we observed response at IF at working temperatures up to 72K. We demonstrated the operation of HTS Josephson junctions in the self-mixing mode. The experimental results are in good agreement with simulations using the RSJ model.

R. A. Panhuyzen, Gerard ter Horst, Th. de Graauw +4 more

Planar Nb-Nb Josephson Junctions (JJ's) have been developed to be used in submillimeter heterodyne mixers. Experimental mixing results show a System Noise Temperature around 1000 K with a best result of 800 K at an operating temperature of 1.5 K. Preliminary results at 900 GHz are reported. A strong temperature dependence of the mixer noise temperature has been observed.