Soliton interactions in one-dimensional photonic lattices with alternating couplings and saturable defocusing nonlinearity

Abstract

Westudy numerically the interactions of strongly localized modes in a discrete system characterized with two coupling constants and a self-defocusing saturable nonlinearity. Such a discrete system was proposed for media exhibiting a Kerr nonlinearity in Ref. [1]. A possible optical realization of this complex setup are onedimensional lithium niobate waveguide arrays in which individual channels of identical width are colinearly aligned and where the spacing between adjacent channels alternates between two distinguishable values. In such lattices an extra periodicity opens an additional mini-gap. In this gap light propagation is forbidden, enabling extended nonlinear light-matter interaction and occurrence of novel, spatially localized structureslattice solitons. The existence andstability of bothbrightanddarklatticesolitonsindefocusing, saturablephotonic lattices were recently investigated experimentally and theoretically [2,3]. In this contribution, we further enlighten the dynamics of observed bright optical solitons by a systematic study of their mutual interactions [4], which might be useful for the development of future all-optical photonic devices.