Distributed optical feedback and nonlinear photonic crystals based on selective etching of periodically-poled lithium niobate

Selective etching technique is applied to a periodically poled crystal of lithium niobate and surface-relief grating is formed. The grating quality is analyzed in an optical diffraction experiment. The surface grating created can be used to provide distributed feedback in PPLN crystals doped with laser-active ions. In the same manner, the grating is itself both a photonic bandgap crystal of high index contrast and a nonlinear photonic crystal.