Abstract
A long Josephson junction containing regions with a phase shift of is considered. By exploiting the defect modes due to the discontinuities present in the system, it is shown that Josephson junctions with phase shift can be an ideal setting for studying localized mode interactions. A phase-shift configuration acting as a double-well potential is considered and shown to admit mode tunnelings between the wells. When the phase-shift configuration is periodic, it is shown that localized excitations forming bright and dark solitons can be created. Multimode approximations are derived confirming the numerical results.