308 research outputs found
Giant anomalous self-steepening in photonic crystal waveguides
Self-steepening of optical pulses arises due the dispersive contribution of
the Kerr nonlinearity. In typical structures this response
is on the order of a few femtoseconds with a fixed frequency response. In
contrast, the effective Kerr nonlinearity in photonic crystal
waveguides (PhCWGs) is largely determined by the geometrical parameters of the
structure and is consequently tunable over a wide range. Here we show
self-steepening based on group-velocity (group-index) modulation for the first
time, giving rise to a new physical mechanism for generating this effect.
Further, we demonstrate that periodic media such as PhCWGS can exhibit
self-steepening coefficients two orders of magnitude larger than typical
systems. At these magnitudes the self-steepening strongly affects the nonlinear
pulse dynamics even for picosecond pulses. Due to interaction with additional
higher-order nonlinearities in the semiconductor materials under consideration,
we employ a generalized nonlinear Schr\"{o}dinger equation numerical model to
describe the impact of self-steepening on the temporal and spectral properties
of the optical pulses in practical systems, including new figures of merit.
These results provide a theoretical description for recent experimental results
presented in [Scientific Reports 3, 1100 (2013) and Phys. Rev. A 87, 041802
(2013)]. More generally, these observations apply to all periodic media due to
the rapid group-velocity variation characteristic of these structures.Comment: 7 pages, 4 figure
Research on two masterpieces of Liège's artistic heritage: the ivory of Notger and the baptismal fonts of Renier de Huy
History and Criticism. Third question. Reports on Miss Nadine de Rassenfosse's dissertation
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