High temperature superconducting GBit/s subbarmonically pumped modulator/demodulator

We have incorporated high temperature superconducting technology along with conventional semiconducting elements into a subharmonically-pumped digital phase modulator and demodulator. The appropriate bandpass filters, stopband filters, and matching networks are fabricated from post annealed double sided YBa2Cu307 films on 10 mil LaA103. The modulator/ demodulator pair is subharmonically pumped at 9.5 GHz. The local oscillator is upconverted and multiplied by the digital bit stream via an antiparallel Schottky diode pair to produce a phase encoded RF carrier at 19 GHz. This circuit showed clean eye diagrams of the recovered data trains up to 1.3 GBits/s with corresponding bit error rates of less than 1011. Work is in progress investigating this circuit with a superconducting resonator stabilized pump source on the same substrate as well as using superconducting bridges or junctions as the nonlinear mixing element.