A LOW-POWER 12-BIT FLUX SHUTTLE SHIFT REGISTER WITH NB TECHNOLOGY

A 12 bit Flux Shuttle shift register with a new write and readout gate has been simulated and fabricated using Nb/Al2O3/Nb Josephson junctio ns. Write, shift and read operations have been tested successfully at 4.2 K. Drive currents are independent from input bit sequence. Althoug h measurements were disturbed by trapped flux, minimum margins are Del ta I = +/-10%. The power dissipation of a shift register cell is 9 nW/ GHz. Total power losses caused by terminating resistors are 70 mu W. T he minimum line width may be scaled down to 0.5 mu m, because power lo sses per unit area of long Flux Shuttle shift registers are extremely low.