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

Pulse confinement in optical fibers with random dispersion

Short range correlated uniform noise in the dispersion coefficient, inherent in many types of optical fibers, broadens and eventually destroys all initially ultra-short pulses. However, under the constraint that the integral of the random component of the dispersion coefficient is set to zero, or pinned, periodically or quasi-periodically along the fiber, the nature of the pulse propagation changes dramatically. For the case that randomness is added to constant positive dispersion, the pinning restriction significantly reduces pulse broadening. If the randomness is added to piecewise constant periodic dispersion, the pinning may even provide probability distributions of pulse parameters that are numerically indistinguishable from the statistically steady case. The pinning method can be used to both manufacture better fibers and upgrade existing fiber links.Comment: 4 pages, 2 figure

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

Maximum-Likelihood Detection of Soliton with Timing Jitter

Using the maximum-likelihood detector (MLD) of a soliton with timing jitter and noise, other than walk-out of the bit interval, timing jitter does not degrade the performance of MLD. When the MLD is simulated with important sampling method, even with a timing jitter standard deviation the same as the full-width-half-maximum (FWHM) of the soliton, the signal-to-noise (SNR) penalty is just about 0.2 dB. The MLD performs better than conventional scheme to lengthen the decision window with additive noise proportional to the window wide.Comment: 3 pages, 2 figures, submitted to Optics Letter

Intermittent dynamics, strong correlations, and bit-error-rate in multichannel optical fiber communication systems

We investigate the effects of delayed Raman response on pulse dynamics in massive multichannel optical fiber communication systems. Taking into account the stochastic nature of pulse sequences in different frequency channels and the Raman induced energy exchange in pulse collisions we show that the pulse parameters exhibit intermittent dynamic behavior, and that the pulse amplitudes exhibit relatively strong and long-range correlations. Moreover, we find that the Raman-induced cross frequency shift is the main intermittency-related mechanism leading to bit pattern deterioration and evaluate the bit-error-rate of the system.Comment: 17 pages, 4 figures. Submitted to Phys. Lett.

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

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

Exchange-coupled Chromium Ion Pairs in Ruby

Exchange-coupled chromium ion pairs in ruby, and application of piezospectroscopic effect to laser technolog

Dispersion-managed soliton in a strong dispersion map limit

A dispersion-managed optical system with step-wise periodical variation of dispersion is studied in a strong dispersion map limit in the framework of path-averaged Gabitov-Turitsyn equation. The soliton solution is obtained by iterating the path-averaged equation analytically and numerically. An efficient numerical algorithm for obtaining of DM soliton shape is developed. The envelope of soliton oscillating tails is found to decay exponentially in time while the oscillations are described by a quadratic law.Comment: 11 Pages, 3 Figures; Submitted to Optics Letter

Deterministic Raman crosstalk effects in amplified wavelength division multiplexing transmission

We study the deterministic effects of Raman-induced crosstalk in amplified wavelength division multiplexing (WDM) optical fiber transmission lines. We show that the dynamics of pulse amplitudes in an N-channel transmission system is described by an N-dimensional predator-prey model. We find the equilibrium states with non-zero amplitudes and prove their stability by obtaining the Lyapunov function. The stability is independent of the exact details of the approximation for the Raman gain curve. Furthermore, we investigate the impact of cross phase modulation and Raman self and cross frequency shifts on the dynamics and establish the stability of the equilibrium state with respect to these perturbations. Our results provide a quantitative explanation for the robustness of differential-phase-shift-keyed WDM transmission against Raman crosstalk effects.Comment: 34 pages and 12 figures. Revised paper. Submitted to Optics Communication