Development of researches on nonlinear photonic crystals

Based on the concept of quasi-phase matching nonlinear interaction, and successful fabrication of nonlinear photonic crystal using high voltage electric field in 90´s, studies on nonlinear photonic crystal were made by different research teams. The related works sharply developed from single one-dimensional superlattice to various structures. On the other hand, further fabrications were made in these crystals, for example, the fabrication of optical waveguides etc. Fabrications of multiple optical waveguides in one two-dimensional photonic crystal were suggested in this paper. This will be helpful to the extension of laser wavelengths, compact optical elements and all-optical switches.