Scattering of the discrete solitons on the PT-symmetric defects

We study the propagation of linear waves and solitons in an array of optical waveguides with an embedded defect created by a pair of waveguides with gain and loss satisfying the socalled parity-time (PT ) symmetry condition. We demonstrate that in the case of small soliton amplitudes, the linear theory describes the scattering of solitons with a good accuracy. We find that the incident high-amplitude solitons can excite the mode localized at the PT -symmetric defect. We also show that by exciting the localized mode of a large amplitude, it is possible to perform phase-sensitive control of soliton scattering and amplification or damping of the localized mode.