  A long Josephson junction containing regions with a phase shift of pi 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. Multi-mode approximations are derived confirming the
numerical results.
