A novel Josephson device with many desirable properties/spl minus/fast switching speed, high operation frequency, and low power dissipation/spl minus/has been researched these several years: the Quantum Flux Parametron (QFP). This paper discusses the interconnection problem of QFP circuits, where wire inductance matching and high clock rate restrict the lengths of interconnection wires. A layout model of QFP interconnection wires is clarified, and the effects of wire inductance matching on interconnection area and wire length are analyzed. The limitation comes from the bound of the number of squares of wires, therefore similar effects will exist where wire resistance is bounded. This paper discusses a simple wiring and buffering algorithm for QFP circuits, in which wire inductance is adjusted and the maximum wire length is controlled, to prove that any logic is realizable as a QFP circuit.>

Flux transfer device theory is reviewed. In such devices, generalized magnetic flux, defined as the time integral of voltage, is used to describe the device characteristics. The Josephson junction and inductor are the main circuit elements in flux transfer devices, because they maintain a constant value for the time integral of voltage. Flux transfer devices are based on either an RF SQUID (superconducting quantum interference device) or a fluxon device. Four devices, including the parametric quantron and the quantum flux parametron, are reviewed as applications of the RF SQUID. The fluxon feedback oscillator and a soliton device are also reviewed as applications of fluxon devices. The quantum flux parametron is then described. The parametron principle and the fundamental properties of the quantum flux parametron such as gain, switching speed, and power dissipation are discussed. Logic circuits and a memory cell are also reviewed. A novel analog-to-digital converter is proposed as an application of the quantum flux parametron.>