609 research outputs found
Oscillating tails of dispersion-managed soliton
Oscillating tails of dispersion-managed optical fiber system are studied for
strong dispersion map in the framework of path-averaged Gabitov-Turitsyn
equation. The small parameter of the analytical theory is the inverse time. An
exponential decay in time of soliton tails envelope is consistent with nonlocal
nonlinearity of Gabitov-Turitsyn equation, and the fast oscillations are
described by a quadratic law. The pre-exponential modification factor is the
linear function of time for zero average dispersion and cubic function for
nonzero average dispersion.Comment: 6 pages, 4 figures; submitted to Jounal of the Optical Society of
America
Non-Gaussian Statistics of Multiple Filamentation
We consider the statistics of light amplitude fluctuations for the
propagation of a laser beam subjected to multiple filamentation in an amplified
Kerr media, with both linear and nonlinear dissipation. Dissipation arrests the
catastrophic collapse of filaments, causing their disintegration into almost
linear waves. These waves form a nearly-Gaussian random field which seeds new
filaments. For small amplitudes the probability density function (PDF) of light
amplitude is close to Gaussian, while for large amplitudes the PDF has a long
power-like tail which corresponds to strong non-Gaussian fluctuations, i.e.
intermittency of strong optical turbulence. This tail is determined by the
universal form of near singular filaments and the PDF for the maximum
amplitudes of the filaments
Diffusion of optical pulses in dispersion-shifted randomly birefringent optical fibers
An effect of polarization-mode dispersion, nonlinearity and random variation
of dispersion along an optical fiber on a pulse propagation in a randomly
birefringent dispersion-shifted optical fiber with zero average dispersion is
studied. An averaged pulse width is shown analytically to diffuse with
propagation distance for arbitrary strong pulse amplitude. It is found that
optical fiber nonlinearity can not change qualitatively a diffusion of pulse
width but can only modify a diffusion law which means that a root mean square
pulse width grows at least as a linear function of the propagation distance.Comment: 11 pages, submitted to Optics Communication
Nonlinear combining of laser beams
We propose to combine multiple laser beams into a single diffraction-limited
beam by the beam self-focusing (collapse) in the Kerr medium. The beams with
the total power above critical are first combined in the near field and then
propagated in the optical fiber/waveguide with the Kerr nonlinearity. Random
fluctuations during propagation eventually trigger strong self-focusing event
and produce diffraction-limited beam carrying the critical power.Comment: 5 pages, 5 figure
Quantum Chains with U_q(SL(2)) Symmetry and Unrestricted Representations
We consider two-state (q^2=-1) and three-state (q^3=1) one-dimensional
quantum spin chains with U_q(SL(2)) symmetry. Taking unrestricted
representations (periodic, semi-periodic and nilpotent), we show which are the
necessary conditions to obtain a Hermitian Hamiltonian.Comment: 9 pages, minor TeXnical revision to allow automatic TeXin
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