Abstract: An effective high frequency oscillator is made of a plurality of Josephson devices. A high frequency converter as a high frequency circuit is made of the high frequency oscillator, nonlinear superconductor devices, and transmission line. Josephson devices are connected in parallel to make a superconductor module. Then superconductive modules are connected in series for high frequency via a phase locking circuit such as a thin film type capacitor to make the high frequency oscillator. Consequently, the high frequency oscillator is used as a local oscillator for a frequency converter. The high frequency system comprises a high frequency package housing a high frequency circuit, a cooling unit including a low temperature stage in thermal contact with the high frequency package, and a shielding case for housing the high frequency circuit and the low temperature stage. The high frequency system of the present invention provides a small-sized and power-saving high frequency circuit having operational stability.

Abstract: An oxide is formed which will form an oxide superconductor containing a Cu-O atomic layer. The oxide is hydrogenated. The oxide is oxidized after it is hydrogenated. The hydrogenation and the oxidization are executed simultaneously with or after the oxide is formed. The hydrogenation and the oxidization improve the superconducting characteristics of the oxide superconductor.

Abstract: An optical modulation device includes a substrate, and a dielectric member having first and second surfaces opposite to each other. An optical waveguide extends on the first surface of the dielectric member and exhibits an electro-optical effect. First and second parallel lines are electromagnetically coupled with each other, and are of a microstrip line structure. The first line has a first line member and a ground plane, and the second line has a second line member and the ground plane. The first line member and the second line member extend on the first surface of the dielectric member and extend at opposite sides of the optical waveguide respectively. The ground plane extends between the substrate and the second surface of the dielectric member.

Abstract: An optical modulation device includes a split ring resonator having a slit. An optical waveguide exhibiting an electro-optical effect has a portion located near the slit of the resonator. A light beam can travel in the optical waveguide. A voltage can be induced in the resonator in response to a modulating signal. The induced voltage causes an electric field at the slit of the resonator. The electric field depends on the modulating signal. The electro-optical effect enables the light beam to be changed in response to the electric field. Thus, the light beam is modulated in accordance with the modulating signal. The resonator may be replaced by a split ring electrode.

Abstract: An optical modulation device includes a substrate. An optical waveguide is formed on the substrate. The optical waveguide exhibits an electro-optical effect. Parallel lines electromagnetically coupled with each other are formed on the substrate. The parallel lines extend at opposite sides of the optical waveguide respectively. The parallel lines are of a microstrip line structure. The parallel lines may alternatively be of a strip line structure or a coplanar line structure.

Abstract: A manufacturing method for the thin film superconductor is disclosed in which photons having energies larger than ultraviolet rays are irradiated to the thin film superconductor on or after formation of the thin film. Further, manufacturing methods for superconductive magnetic memory, Josephson device and superconductive transistor are disclosed.

Abstract: A Josephson device, comprising a junction formed by forming the first layer-shaped oxide superconductor thin film including a plurality of Cu-O layers on a substrate, a barrier layer thereon and the second layer-shaped oxide superconductor thin film on the barrier layer. The Josephson device according to the present invention is manufactured by forming the first layer-shaped oxide superconductor thin film on a substrate, forming a barrier layer in the same vacuum chamber, defining patterns to said barrier layer and said first layer-shaped oxide superconductor thin film, forming an interlayer insulating film on said barrier layer, removing said interlayer insulating film in a region serving as a junction, effecting exposure to oxygen plasma, forming the second layer-shaped oxide superconductor thin film in contact with a part of the surface of said barrier layer and defining patterns to said second layer-shaped oxide superconductor thin film.