Nonreciprocal transmission of microwaves through a long Josephson   junction
  Nonreciprocal microwave transmission through a long Josephson junction in the flux-flow regime is studied analytically and numerically within the framework of the perturbed sine-Gordon model. We demonstrate that the maximum attenuation of the transmitted power occurs when the direction of the flux flow is opposite to the direction of the microwave propagation. This attenuation is nonreciprocal with respect to the flux-flow direction and can be enhanced by increasing the system length and proper impedance matching of the junction ends to external transmission line. 
A.L. Pankratov, K.G. Fedorov, M. Salerno, S.V. Shitov, and A.V.   Ustinov
cond-mat.supr-con