Modal analysis of the impact of the boundaries on transverse Anderson localization in a one-dimensional disordered optical lattice

• Investigated the impact of boundaries on modes of a 1D disordered optical lattice.
• The mode widths near the boundaries can be smaller.
• This is merely because of the near-truncation effect of cladding-waveguide index step.
• The density of the localized modes is lower near the boundaries.

Impact of the boundaries on transversely localized modes of a truncated one-dimensional disordered optical lattice is numerically studied. The results show lower modal number density near the boundaries compared with the bulk, while the average decay rate of the tail of localized modes is the same near the boundaries as in the bulk. It is suggested that the perceived suppressed localization near the boundaries is due to a lower mode density: on average, it is less probable to excite a localized mode near the boundaries; however, once it is excited, its localization is with the same exponential decay rate as any other localized mode.