Abstract: The present invention provides a modulation circuit that has excellent modulation characteristics and can be designed as an MMIC. Consequently, this modulation circuit is such that the modulating wave input means is composed of a capacitor 21 and an inductor 22, the carrier input means is composed of a capacitor 23 and a resistance element 24, the self-bias means is composed of a resistance element 26 and a capacitor 27, the carrier selection means is composed of an inductor 22 and a capacitor 28, and the modulated wave output means is composed of a capacitor 28.

Abstract: A bicrystal substrate is formed by joining end faces of a first single crystal substrate and a second single crystal substrate, the end faces having different crystal orientations. A high critical temperature superconducting thin film is then epitaxially formed on the bicrystal substrate. The superconducting thin film is etched so as to form a first superconducting electrode on the first single crystal substrate, a second superconducting electrode on the second single crystal substrate, and a superconducting bridge across a joint between the first and second single crystal substrates and connecting the first electrode and the second electrode. A conductive film is formed on the superconducting bridge by vapor deposition, and is then etched so as to form a weak link on a part of the superconducting bridge over the joint.

Abstract: A high critical temperature superconducting Josephson device includes a bicrystal substrate formed of a first single crystal substrate and a second single crystal substrate, with end faces of the first and second single crystal substrates having different crystal orientations and being joined to each other. A first superconducting electrode formed of a first film of a high critical temperature superconductor material is located on the first single crystal substrate, whereas a second superconducting electrode formed of a second film of a high critical temperature superconductor material is located on the second single crystal substrate. A bridge is formed of a third film of a high critical temperature superconductor material and located on the bicrystal substrate across a joint between said first and said second single crystal substrates.