All-optical switch with two periodically curved nonlinear waveguides
  We propose a type of all-optical switch which consists of two periodically curved nonlinear optical waveguides placed in parallel. Compared to the all-optical switch based on the traditional nonlinear directional coupler with straight waveguides, this all-optical switch has much lower switching threshold power and sharper switching width. 
Qiongtao Xie, Xiaobing Luo, Biao Wu