Circuits for chip-to-chip transportation of bits from single flux quantum circuits

We have designed circuits to transmit and receive bits generated by Single-Flux-Quantum (SFQ) circuits. Our circuits were fabricated using shunted Nb-AlOx-Nb junctions. The transmitter is a series array of dc SQUIDs driven into the voltage state in response to an input SFQ pulse. The receiver circuit is inductively coupled to the transmitter. Current from the transmitter biases a junction race in the receiver such that a clock pulse either passes (a '1' bit) or does not (a '0' bit). We have measured a maximum peak-to-peak amplitude from the transmitter of 296 /spl mu/V at a clock rate of 2.5 GHz, and 187 /spl mu/V at 5 GHz.