  Bistability induced by nonlinear Kerr effect in arrays of coupled waveguides
is studied and shown to be a means to conceive light detectors that switch
under excitation by a weak signal. The detector is obtained by coupling two
single 1D waveguide to an array of coupled waveguides with adjusted indices and
coupling. The process is understood by analytical description in the
conservative and continuous case and illustrated by numerical simulations of
the model with attenuation.
