Direct observation of fluxon reflection in a Josephson transmission line

We have directly observed the reflection of fluxons in a Josephson transmission line (JTL) with an open end using a Josephson sampler. Depending on the bias current at the end of the JTL, a reflected single fluxon, an antifluxon, and multi-antifluxons are observed with the measurements of the propagating time delay for the reflection process. The observed reflection properties, including the interaction between reflected antifluxons, are in fairly good agreement with numerical simulations taking account of the nonlinear shunting loss and the surface loss.