Experimental demonstration of the Fermi-Pasta-Ulam recurrence in a modulationally unstable optical wave.

Through a detailed spectral analysis of the propagation of square-shaped laser pulses in optical fibers, we provide the experimental demonstration of the Fermi-Pasta-Ulam recurrence phenomenon in modulationally unstable optical waves ruled by the nonlinear Schrödinger equation.

Gordon-Haus effect on dark solitons.

The theory of the Gordon-Haus effect with application to dark solitons is presented. It is proved analytically that a random frequency shift of a fundamental dark soliton results in a time jitter radical2 times lower than that for bright solitons.

Selective mode excitation in graded-index multimode fiber by a computer-generated optical mask.

We report on the generation of optical masks that permit the spatial shaping of a laser beam so that one can selectively excite single modes of a multimode parabolic graded-index optical fiber. The amplitude masks are determined by the analytical radial function of the fiber mode in the weakly guiding approximation. Phase reversal is encoded on the transparency through a shifted-grating technique. Effective injection and propagation of a single mode in a largely multimode fiber are shown as examples.

Dark-soliton jitter in amplified optical transmission systems.

The transmission of dark solitons in ultralong transmission systems with optical amplification is numerically investigated. We show that amplifier noise is responsible for a random frequency shift with a resulting time jitter radical2 times lower than that observed for bright solitons.

Spectrotemporal measurement of picosecond pulses propagating in nonlinear single-mode fibers.

The combined effects of positive group-velocity dispersion, self-phase modulation, and stimulated Raman scattering experienced by 85-psec pulses propagating along a 960-m-long single-mode fiber are experimentally studied. The use of a spectrograph followed by a streak camera provides measurements in the spectrotemporal domain of the induced frequency modulation of a pump pulse. As a result, optical wave breaking, depletion of the leading edge with symmetrical spectral broadening, and complex instantaneous frequency structures are observed when the peak power of the input pulse is gradually increased to 435 W. The experimental method is also adapted for single-shot event analysis.