Anderson Localization in Optical Waveguide Arrays with Off-diagonal Coupling Disorder

We report on the observation of Anderson wave localization in one-dimensional waveguide arrays with off-diagonal disorder. The waveguide elements are inscribed in silica glass, and a uniform random distribution of coupling parameters is achieved by a precise variation of the relative waveguide positions. In the absence of disorder we observe ballistic transport as expected from discrete diffraction in periodic arrays. When off-diagonal disorder is deliberately introduced into the array we observe Anderson localization. The strength of the localization signature increases with higher levels of disorder.