  We study nonlinear wave phenomena in coupled ring resonator optical
waveguides in the tight coupling regime. A discrete model for the system
dynamics is put forward and its steady state nonlinear Bloch modes are derived.
The switching behavior of the transmission system is addressed numerically and
the results are explained in the light of this analytical result. We also
present a numerical study on the spontaneous generation of Bragg solitons from
a continuous-wave input.
