Maximizing conversion efficiency in second-order nonlinear process by optimizing periodic electrode width in periodic poling

The macroscopic distributions of an electric field and of an induced second-order nonlinearity in a waveguide are for the first time unveiled in case of metal-contact periodic poling. A basic field distribution between a set of electrodes with a generalized arbitrary width is first proposed and then, by using linear superposition and electrode periodicity, the net electric field generated in the whole waveguide is derived explicitly. On the basis of the total electric field, the mean distribution of the nonlinearity and the quasi-phase matching efficiency induced from the total field are defined to analyze the effectiveness in each type of the four periodic poling schemes classified by the configurations of electrode combinations.