IQUANTUM is launching a programmable Josephson voltage standard (PJVS) system consisting of a PJVS chip with a Josephson junction array and microwave circuit components made of NbN thin films, a compact cryocooler, a source of bias currents, and a source of a microwave (16GHz). The NbN films employed for the PJVS chips have a Tc above 15K. This allows for the chips to be operated above 10K, and permits a more compact and overall lower cost system than usual PJVS systems which employ PJVS chips made of Nb thin films (Tc = 9K). We plan to build the first prototype model of the product by May, 2005, incorporating its PJVS chips generating output voltages from -1V to 1V.

"All-NbN digital-to-analog converters for a programmable voltage standard",H. Yamamori, M. Itoh, H. Sasaki, A. Shoji, S.P. Benz, and P.D. Dresselhaus,Supercond. Sci. Technol., vol. 14, pp. 1048-1051 (2001).

Open Patent
"Operation of a NbN-based programmable Josephson standard chip with acompact refrigeration system", A. Shoji, H. Yamamori, M. Ishizaki, S.P.Benz, and P.D. Dresselhaus, IEEE Trans. Appl. Supercond., vol. 13, pp.919-921 (2003).

IQUANTUM is an AIST Venture Company.