  Loss is a crucial problem in plasmonic integrated optical circuits and
metamaterials. The Er, Yb codoped gain material is introduced into a magnetic
plasmon waveguide composed of a chain of nanosandwiches in order to solve the
loss problem in such subwavelength waveguide. The magnetic plasmon mode and a
higher order mode are chosen as the signal and pump light to enhance the
radiation and pump efficiencies. The signal light propagating in the waveguide
is investigated with different Er3+ doping concentration and signal decay time.
It is shown that the gain effect can not only compensate the loss but also is
able to amplify the signal, when exceeding certain threshold values of doping
concentration and signal decay time.
