  We propose an all-optical nonlinear router based on a double barrier gate
connected to periodically modulated guides. A semiconductor microcavity is
driven nonresonantly in-between the barriers to form an exciton-polariton
condensate on a discrete state that is subject to the exciton blueshift. The
subsequent coherent optical signal is allowed to propagate through a guide
provided that the condensate energy is resonant with a miniband or is blocked
if it faces a gap. While a symmetric sample operates as an optical switch, its
asymmetric counterpart embodies a router turned to be polarization selective
under applied magnetic field.
