title: Stability of in-phase quadruple and vortex solitons in the parity-time-symmetric periodic potentials.
abstract: We report the stability of in-phase quadruple and off-site vortex solitons in the parity-time-symmetric periodic potentials with defocusing Kerr nonlinearity. All solitons can exist in the first gap and can be stable in a certain range. It is shown that the power of vortex solitons decreases and the stable region shrinks with increase of the topological charge. Especially the stable region is very small for double charge vortex solitons. The power evolutions of vortex solitons along the propagation distance are also analysed. Increasing the lattice depth or decreasing the gain-loss component can stabilize vortex solitons. For both lattice depth and gain-loss component there exists a critical value, below or above which all vortex solitons will become unstable.
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Ren
authors.forename: Hong
authors.initials: H
authors.lastname: Wang
authors.forename: Hongcheng
authors.initials: H
authors.lastname: Wang
authors.forename: Yingji
authors.initials: Y
authors.lastname: He