ABSTRACT
We investigate theoretically and experimentally the modulation instability process in a dispersion oscillating fiber characterized by an amplitude modulation of its group velocity dispersion. We developed an analytical model that allows us to calculate the parametric gain in these fibers and to predict the position of the quasi-phase matched modulation instability sidelobes. The two fundamental frequencies characterizing the dispersion profile lead to the splitting of the original multiple sidelobes generated in basic sinusoidally varying dispersion oscillating fibers. These theoretical predictions are confirmed by experiments.
ABSTRACT
We investigate the role played by fourth-order dispersion on the modulation instability process in dispersion oscillating fibers. It not only leads to the appearance of instability sidebands in the normal dispersion regime (as in uniform fibers), but also to a new class of large detuned instability peaks that we ascribe to the variation of dispersion. All these theoretical predictions are experimentally confirmed.
ABSTRACT
We report the experimental demonstration of "discrete focusing" inside a 60-cm-long optical fiber made of a 2D square array of coupled waveguides. The suitable input amplitude and phase distributions are imposed by using a spatial light modulator. Thus we demonstrate that focusing in a single core at the output by discrete propagation is possible despite some amount of transverse heterogeneities of the waveguide array.
ABSTRACT
High second-order susceptibility has been created in a chalcogenide glass from Ge-Sb-S system. A thermal poling process was used to produce this non-linear effect and a second harmonic generation experiment allowed characterizing the phenomenon. A maximum chi(2) value of 8.0+/-0.5 pm/V was measured for the first time to our best knowledge in sulfide glasses.
ABSTRACT
The width of the depletion region in fused-silica samples thermally poled during various periods of time is investigated experimentally with four previously reported characterization techniques in an attempt to unify their findings. Although all measurements give a similar width of the depletion region, it is shown that the determination of the profile of chi(2) is also required for a good estimate of the nonlinearity induced by poling.
ABSTRACT
The second-order nonlinear profile induced within thermally poled Infrasil silica samples is characterized as a function of the duration of the poling process. For poling durations shorter than 5 min the spatial distribution of the chi(2) susceptibility exhibits a triangular shape. This observation, as well as the maximum value of the electric field recorded during poling (1.9 x 10(9) V/m), is in excellent agreement with charge migration models that involve a single charge carrier. It is shown that for higher poling durations the nonlinear profiles tend to flatten; in that case the charge injection mechanisms cannot be neglected. For another point of view, the experimental method introduced herein has allowed us to determine the mobility of the rapid charge carrier involved in the poling process: micro = 1.5 x 10(-15) m2 V(-1) s(-1) at 250 degrees C.
