Dewar-to-Dewar Data Transfer at 2 Gigabits per Second

Abstract-Digital circuits have been developed to interface
superconductive electronic chips with high speed 50-O
transmission lines. Digital data at 2 Gigabits per second was
transferred fioin a Josephson chip in a first crvostat to another
Josephson chip in a second crvostat. The chips were connected
by moie than 3 meters of 50-O transmission line. No
semiconductor amplifiers were used in this data path. A
Hewlett Packard data source proided the original data to the
first chip, which converted it to SFQ data. Output interface
circuits were diiven by a 2-GHz external clock to latch selies
strings of 10 junctions and drive 2-Gbps data into a 50-O
cable. In the second cyrostat, a latching three-junction
inteiferometer vitli a two-turn control line converted the input
signal to latched data and switched an MVTL OR-gate output.
This demonstration showed that low-power Josephsoii digital
circuits can be integrated into inultichip digital subsystems
that can pass data at high rates without the use of power-
hungry semiconductor amplifiers.