Arrays of weakly coupled, periodically poled lithium niobate waveguides: beam propagation and discrete spatial quadratic solitons

Abstract

Discrete optical systems can be realized as arrays of parallel, weakly coupled, channel waveguides where light normally undergoes "discrete diffraction" via the weak coupling between adjacent channels. Here we describe how light can be forced to maintain a constant field profile on propagation in waveguide arrays, i.e., to localize into a discrete spatial soliton, by using the second order nonlinearity of periodically poled lithium niobate near phase-matching for second harmonic generation. Detailed sample characterization and experimental verification of the excitation of discrete quadratic solitons is reported. © 2005 COSiW SEP, Warsaw.