307 research outputs found
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
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