  We report an Aubrey-Andre-Harper (AAH) model based quasi-periodic lossless
evanescently coupled waveguide lattice to study the unconventional physics of
light localization. We present an exclusive methodical analysis of the
band-topology of a tight-binding discrete lattice and accordingly study the
modal characteristics to reveal the fact that a higher value of quasi-periodic
modulation strength is imperative for observing a signature of fully localized
light states having higher eigenenergy. This analytical concept has numerically
been implemented in the proposed topological lattice to achieve light
localization, where we have shown that the supported states not only depend on
topological parameters, but also on the specific location of excitation which
is supported by the violation of bulk-edge correspondence due to
quasi-periodicity. Furthermore, we have investigated a unique effect of the
presence of disorder on light localization phenomenon, where it has been
reported that the presence of off-diagonal disorder, which is otherwise
detrimental, favours light localization in the proposed structure due to
topological protection. The findings indeed have the potential to open up a
fertile platform to manipulate light in topologically aided passive photonic
devices.
