Beam Dynamics in a Double-Channel Waveguide with Gain and Loss
  A double-channel waveguide with gain and loss is addressed and the corresponding coupled-mode equations are established by employing the coupled mode approach. Based on the coupled-mode equations, the beam dynamics in the double-channel waveguide with gain and loss is investigated, and the results show that there exist three distinct dynamical behaviors, which are amplification, attenuation to zero and tending to a steady value (or equilibrium state), respectively. Finally, it is shown that the theoretical results suggested by the coupled-mode equations agree well with the numerical simulations. 
Pengfei Li, Rujiang Li, Lu Li
physics.optics