Self-Equalization of Energies of Solitons in Transmission Systems by Guiding Filters

In this paper, the regulating effect of guiding filters on the energies of solitons in wave-length division multiplexing (WDM) transmission systems is rigorously studied. More precisely, it is shown that guiding filters prevent the energies of solitons from decaying to zero in long distances. This goal is achieved by studying a mathematical model of the evolution of energies of solitons in transmission systems. The approach is mathematical and does not use numerical or experimental results available in the literature; nevertheless, it reaffirms such results.Comment: 20 page

Dispersion-managed soliton in optical fibers with zero average dispersion

The dispersion-managed (DM) optical system with step-wise periodical variation of dispersion is studied in the framework of path-averaged Gabitov-Turitsyn equation. The soliton solution is obtained by iterating the path-averaged equation. The dependence of soliton parameters on dispersion map strength is investigated together with the oscillating tails of soliton.Comment: 5 pages, 2 figures, to appear in Optics Letters 25, #16 (2000

Restoration Of Dual-Frequency Signals With Nonlinear Propagation In Fibers With Positive Group-Velocity Dispersion

It is shown experimentally and theoretically that a sinusoidally modulated pulse evolves with time into a train of dark soliton-like pulses and then returns to its initial sinusoidal shape on propagation through a nonlinear single-mode fiber with positive group velocity dispersion. The experimental results are in agreement with predictions from the nonlinear Schrodinger equation

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

Helical vs. fundamental solitons in optical fibers

We consider solitons in a nonlinear optical fiber with a single polarization in a region of parameters where it carries exactly two distinct modes, the fundamental one and the first-order helical mode. From the viewpoint of applications to dense-WDM communication systems, this opens way to double the number of channels carried by the fiber. Aside from that, experimental observation of helical (spinning) solitons and collisions between them and with fundamental solitons are issues of fundamental interest. We introduce a system of coupled nonlinear Schroedinger equations for fundamental and helical modes, which have nonstandard values of the cross-phase-modulation coupling constants, and investigate, analytically and numerically, results of "complete" and "incomplete" collisions between solitons carried by the two modes. We conclude that the collision-induced crosstalk is partly attenuated in comparison with the usual WDM system, which sometimes may be crucially important, preventing merger of the colliding solitons into a breather. The interaction between the two modes is found to be additionally strongly suppressed in comparison with that in the WDM system in the case when a dispersion-shifted or dispersion-compensated fiber is used.Comment: a plain latex file with the text and two ps files with figures. Physica Scripta, in pres

Periodic waves in bimodal optical fibers

We consider coupled nonlinear Schrodinger equations (CNLSE) which govern the propagation of nonlinear waves in bimodal optical fibers. The nonlinear transform of a dual-frequency signal is used to generate an ultra-short-pulse train. To predict the energy and width of pulses in the train, we derive three new types of travelling periodic-wave solutions, using the Hirota bilinear method. We also show that all the previously reported periodic wave solutions of CNLSE can be derived in a systematic way, using the Hirota method.Comment: 10 pages with 2 figures. "Optics Communications, in press

Time-Domain All-Optical Demultiplexing With A Semiconductor Directional Coupler

We report the demonstration of demultiplexing of 150 fs pulses, without pulse breakup, in an AlGaAs nonlinear directional coupler operated at photon energies below half the band gap energy of AlGaAs

Pedestal free pulse compression of chirped optical solitons

Peer reviewedPostprin

Ultrafast Deflection of Spatial Solitons in AlGaAs Slab Waveguides

We demonstrate ultrafast all-optical deflection of spatial solitons in an AlGaAs slab waveguide using 190 fs, 1550 nm pulses which are used to generate and deflect the spatial soliton. The steering beam is focused onto the top of the waveguide near the soliton pathway and the soliton is steered due to refractive index changes induced by optical Kerr, or free carrier (Drude) effects. Angular deflections up to 8 mR are observed.Comment: accept. for publ. in Optics Letter

On the boundary of the dispersion-managed soliton existence

A breathing soliton-like structure in dispersion-managed (DM) optical fiber system is studied. It is proven that for negative average dispersion the breathing soliton is forbidden provided that a modulus of average dispersion exceed a threshold which depends on the soliton amplitude.Comment: LaTeX, 8 pages, to appear in JETP Lett. 72, #3 (2000