  We theoretically investigate the possibility of realizing a nonlinear
all-optical diode by using the unique features of quasiperiodic 1D photonic
crystals. The interplay between the intrinsic spatial asymmetry in odd-order
Thue-Morse lattices and Kerr nonlinearity, combined with the unconventional
field localization properties of this class of quasiperiodic sequences, gives
rise to sharp resonances that can be used to give a polarization-insensitive,
nonreciprocal propagation with a contrast close to unity for low optical
intensities.
