Fluxon propagation in Josephson junction transmission lines coupled by resistive networks

The transmission, reflection, and absorption characteristics for fluxons propagating in long Josephson junction transmission lines which are connected by resistive networks have been studied by means of computer simulation. Although fluxon scattering behavior is qualitatively similar to that expected for electromagnetic waves, the existence of threshold resistances which depend upon applied bias current and junction loss is observed. For the case of two long junctions coupled by a serious resistor, it is found that variations in bias current, junction loss, and resistor value determine whether a fluxon incident on the resistor is either absorbed, or produces a reflected fluxon, a transmitted fluxon, or both a reflected and a transmitted fluxon. It is found that three junction segments can be connected in a configuration which functions as a fluxon multiplexer. Finally, the time delay (that is, the time required for a fluxon to attain steady state energy) in a typical low-loss tunnel junction line is found to be comparable to the delay in lines having a linear shunt conductance.