High speed data link between digital superconductor chips

Abstract

Superconductor digital devices using single-flux-quantum (SFQ) data encoding offer higher speed at lower power than any other integrated circuit technology. For this very reason, interconnect is challenging. We report SFQ data transfer between chips flip chip mounted on a passive microstrip carrier. The flip-chip structure achieves bandwidths greater than 250 GHz. Unlike previous designs, our signal lines are terminated at both ends; this is accomplished using a driver that produces a double-flux-quantum signal. We measured the circuit for pseudorandom data in the range of 10–60 Gb/s. Bit error rates are measured down to 1E−10 and extrapolate to negligible values. The signal power on the microstrip is only 30 nW at 60 Gb ps.