Abstract: A superconducting non-linear device comprising a superconducting conductor, a current source associated with the conductor for applying to the conductor a bias current, and a control device associated with the current source for selectably varying the bias current between a first value below the critical current for the conductor means and a second value above the critical current. The non-linear device is a switching device comprising a switching element in the form of a superconducting film, a terminal for inputting a signal to the switching element, a terminal for outputting a signal from the switching element, and a circuit for applying a DC bias current to the switching element and for causing the DC bias current to vary between a first value below the critical current for the superconducting film and a second value above the critical current.

Abstract: A superconducting non-linear device comprising a superconducting conductor, a current source associated with the conductor for applying to the conductor a bias current, and a control device associated with the current source for selectably controlling the magnitude of the bias current. The non-linear device according to the invention may be used in a number of circuit configurations, including current limiting, switching, mixing and detecting circuits.

Abstract: A primary current path (10) is defined by a thin film that spirals in a helix (14) around a central axis (16). A control path (12) extends peripherally around the helix to define a peripheral control coil (18). In this manner, the primary path and the control path each generate a magnetic flux parallel to the central axis. The primary and control paths are configured such that the magnetic flux density (B.sub.1) generated by the primary path is below a critical flux density (B.sub.c) of the superconducting material of the primary path. However, the sum of the magnetic flux densities from the primary and control paths exceeds the critical flux density (B.sub.1 +B.sub.2 >B.sub.c) quenching the superconductivity of the primary path. In the preferred embodiment, the superconducting film is anisotropic in that its critical flux density is smaller perpendicular to a plane of the film than parallel to the plane of the film.

Abstract: An edge defined geometry is used to produce very small area tunnel junctions (30) in a structure with niobium nitride superconducting electrodes (14, 28) and a magnesium oxide tunnel barrier (24). The incorporation of an MgO tunnel barrier with two NbN electrodes results in improved current-voltage characteristics, and may lead to better junction noise characteristics. The NbN electrodes are preferably sputter-deposited, with the first NbN electrode deposited on an insulating substrate maintained at about 250.degree. to 500.degree. C. for improved quality of the electrode.

Abstract: A combination of optical interconnect technology with superconducting matal to form a superconducting neural network array. Superconducting material in a matrix has the superconducting current decreased in one filament of the matrix by interaction of the Cooper pairs with radiation controlled by a spatial light modulator. This decrease in current results in a switch of current, in a relative sense, to another filament in the matrix. This "switching" mechanism can be used in a digital or analog fashion in a superconducting computer application.