Light-induced breaking of symmetry in photonic crystal waveguides with   nonlinear defects as a key for all-optical switching circuits
  We consider light transmission in 2D photonic crystal waveguide coupled with two identical nonlinear defects positioned symmetrically aside the waveguide. We show that with growth of injected light power there is a breaking of symmetry by two ways. In the first way the symmetry is broken because of different light intensities at the defects. In the second way the intensities at the defects are equaled but phases of complex amplitudes are different. That results in a vortical power flow between the defects similar to the DC Josephson effect if the input power over the waveguide is applied and the defects are coupled. As application of these phenomena we consider the symmetry breaking for the light transmission in a T-shaped photonic waveguide with two nonlinear defects. We demonstrate as this phenomenon can be explored for all-optical switching of light transmission from the left output waveguide to the right one by application of input pulses. Finally we consider the symmetry breaking in the waveguide coupled with single defect presented however by two dipole modes. 
Evgeny N. Bulgakov, Almas F. Sadreev, and Konstantin N. Pichugin
nlin.PS cond-mat.mes-hall