Light propagation in quasi-periodic Fibonacci waveguide arrays

Abstract

We investigate light propagation along one-dimensional quasi-periodic Fibonacci waveguide array optically induced in Fe:LiNbO3 crystal. Two Fibonacci elements, A and B, are used as a separation between waveguides. We demonstrate numerically and experimentally that a beam expansion in such arrays is effectively reduced compared to the periodic ones, without changing beam expansion scaling law. The influence of refractive index variation on the beam expansion in such systems is discussed: more pronounced diffraction suppression is observed for a higher refractive index variation.