  Spontaneous emission of an excited atom in a featureless continuum of
electromagnetic modes is a fundamental process in quantum electrodynamics
associated with an exponential decay of the quantum emitter to its ground state
accompanied by an irreversible emission of a photon. However, such a simple
scenario is deeply modified when considering a $^{\prime}$giant$^{\prime}$
atom, i.e an atom whose dimension is larger than the wavelength of the emitted
photon. In such an unconventional regime, non-Markovian effects and strong
deviations from an exponential decay are observed owing to interference effects
arising from non-local light-atom coupling. Here we suggest a photonic
simulation of non-Markovian giant atom decay, based on light escape dynamics in
an optical waveguide non-locally-coupled to a waveguide lattice. Major effects
such as non-exponential decay, enhancement or slowing down of the decay, and
formation of atom-field dark states can be emulated in this system
