Josephson transmission lines with multilayer Josephson junctions

We present a new type of Josephson transmission line (JTL) in which discrete multilayer Josephson junctions are employed instead of the standard single tri-layer junction technology. It is shown via numerical simulation that such a structure supports the propagation of multiple flux quantum solitons, which are represented in this system by a 2πn kink in the phase difference across a multilayer junction of n superconductor-insulator-superconductor layers. As a practical aspect, parallel and series connected multilayer junctions in a JTL can significantly reduce the need for microstrip line inductance, thereby providing the optimal conditions for large scale integration of JTL-based logic and memory circuitry. In this article we investigate in detail through numerical simulation the properties of JTL designs with multilayer junctions, incorporating expected variations in junction characteristics. A brief description of the current fabrication of multilayer junctions for flux quantum circuitry will be provided.