Interplay between Coherence and Incoherence in Multi-Soliton Complexes

We analyze photo-refractive incoherent soliton beams and their interactions in Kerr-like nonlinear media. The field in each of M incoherently interacting components is calculated using an integrable set of coupled nonlinear Schrodinger equations. In particular, we obtain a general N-soliton solution, describing propagation of multi-soliton complexes and their collisions. The analysis shows that the evolution of such higher-order soliton beams is determined by coherent and incoherent contributions from fundamental solitons. Common features and differences between these internal interactions are revealed and illustrated by numerical examples.Comment: 4 pages, 3 figures; submitted to Physical Revie

Multi-gap discrete vector solitons

We analyze nonlinear collective effects in periodic systems with multi-gap transmission spectra such as light in waveguide arrays or Bose-Einstein condensates in optical lattices. We demonstrate that the inter-band interactions in nonlinear periodic gratings can be efficiently managed by controlling their geometry, and predict novel types of discrete vector solitons supported by nonlinear coupling between different bandgaps and study their stability.Comment: 4 pages, 4 figure

Generation and stability of discrete gap solitons

We analyze stability and generation of discrete gap solitons in weakly coupled optical waveguides. We demonstrate how both stable and unstable solitons can be observed experimentally in the engineered binary waveguide arrays, and also reveal a connection between the gap-soliton instabilities and limitations on the mutual beam focusing in periodic photonic structures.Comment: 3 pages, 3 figure

Whispering gallery modes in optical fibers based on reflectionless potentials

We consider an optical fiber with nanoscale variation of the effective fiber radius supporting whispering gallery modes slowly propagating along the fiber, and reveal that the radius variation can be designed to support reflectionless propagation of these modes. We show that reflectionless modulations can realize control of transmission amplitude and temporal delay, while enabling close packing due to the absence of cross-talk, in contrast to conventional potentials.Comment: 4 pages, 3 figure

Nonlinear suppression of time-reversals in PT-symmetric optical couplers

We reveal a generic connection between the effect of time-reversals and nonlinear wave dynamics in systems with parity-time (PT) symmetry, considering a symmetric optical coupler with balanced gain and loss where these effects can be readily observed experimentally. We show that for intensities below a threshold level, the amplitudes oscillate between the waveguides, and the effects of gain and loss are exactly compensated after each period due to {periodic time-reversals}. For intensities above a threshold level, nonlinearity suppresses periodic time-reversals leading to the symmetry breaking and a sharp beam switching to the waveguide with gain. Another nontrivial consequence of linear PT-symmetry is that the threshold intensity remains the same when the input intensities at waveguides with loss and gain are exchanged.Comment: 5 pages, 4 figure