Through the final years of the previous decade, research supported by the MITI-funded Josephson Computer Project established Japan in a commanding leadership position in LTS digital circuit technology. Although the competition for resources with HTS has resulted in scaled-back LTS digital programs in both Japan and the United States, a sufficient investment was maintained in the United States to stimulate substantial circuit innovation, particularly in non-latching logic designs. Those design conceptions, coupled with accessible fabrication facilities, have sustained a critical level of circuit demonstrations in the United States and even permitted the successful demonstration of a completely packaged (electrically and cryogenically) packet switch. Innovations were not properly stimulated in Japan during the 1990s. At the same time, should the efforts of the "Big Three" in the United States succeed quickly enough in reducing the device spreads of HTS Josephson junctions by the few remaining percentage points needed to produce serious digital circuits, or should a compelling application for LTS digital emerge, the United States is well positioned to capitalize on the opportunities. On the other hand, Japanese funding agencies have recently made commitments to rebuild a portion of their LTS digital activities, and ISTEC and ETL have stated aggressive goals for HTS digital circuit fabrication technology, just as support in the United States for superconducting electronics is waning. Hence, the commanding U.S. position in digital superconducting electronics could dissipate in the absence of near-term military or commercial market opportunities that could sustain the field.

Published: July 1998; WTEC Hyper- Librarian