https://doi.org/10.1140/epjd/e2012-30204-4
Regular Article
Dark lattice solitons in one-dimensional waveguide arrays with defocusing saturable nonlinearity and alternating couplings
1
Faculty of Electrical Engineering, Helmut Schmidt
University, 22043
Hamburg,
Germany
2
Grupo de Física No Lineal, Departamento de Física Aplicada I,
Universidad de Sevilla, Escuela Politécnica Superior, C/Virgen de África 7, 41011
Sevilla,
Spain
3
Department of Mathematics and Statistics, University of
Massachusetts, MA
01003-4515
Amherst,
USA
a e-mail: jcuevas@us.es
Received:
28
March
2012
Received in final form:
3
May
2012
Published online:
12
July
2012
In the present work, we examine “binary” waveguide arrays, where the coupling between adjacent sites alternates between two distinct values C1 and C2 and a saturable nonlinearity is present on each site. Motivated by experimental investigations of this type of system in fabricated LiNbO3 arrays, we proceed to analyze the nonlinear wave excitations arising in the self-defocusing nonlinear regime, examining, in particular, dark solitons and bubbles. We find that such solutions may, in fact, possess a reasonably wide, experimentally relevant parametric interval of stability, while they may also feature both prototypical types of instabilities, namely exponential and oscillatory ones, for the same configuration. The dynamical manifestation of the instabilities is also examined through direct numerical simulations.
Key words: Optical Phenomena and Photonics
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag 2012