We measured the performance of dc superconducting quantum interference devices (SQUIDs) fabricated from YBa2Cu3O7−δ films as a function of the SQUID inductance, L, and normal resistance, Rn, of step-edge Josephson junctions and compared it to theoretical expectations. A process for adjusting critical currents and obtaining high normal resistances of junctions has been developed. All measurements were performed in liquid nitrogen, i.e., at 77 K. We could obtain controllably normal resistances of 5–10 Ω per junction at critical currents of 20–50 μA. A spectral density of white flux noise of SΦ1/2=2.5μΦ0/√Hz was obtained with a dc SQUID having L=50 pH, Rn=7 Ω per junction, βL=0.5 and ∂V/∂Φ=110 μV/Φ0. The best magnetic field resolution at 1 kHz was 20 fT/√Hz, with L=150 pH.

We have developed a iiew concept for an optoelectronic froiztend receiver at 0.8511111 wciveletigth. A GaAs-PIN photodiode is coupled to a Perineable Junction Base Tsaiuistos (PJBT). The PJBT is a vertical Junction Field EjJect Tsunsistos with n honzoepitaxial, heavily p-doped gate whose n-doped GaAs clzarzriel is selectively grown. Ifs layer structure incosposates two p -i -i i doped layes structures, so it fits ideally to an integration with a PIN photodiode. The fabsication of the iritegsdori is described and results of the singlc devices, both DC aitcl KF iiieasurenicnts, ase psesented. The pefloroniiance of the jissf iiiiegsuted receives show (lie iisefulrzess of this corzcept fos Optoelectsonic Iiitegsated Ciscuits (OEIC) at bitsates of rnose ikaii 1 Gbids.