Lithium niobate (LiNbO₃) is an extremely versatile nonlinear crystal material. The electro-optic and nonlinear optical coefficients of lithium niobate are used for various photonic applications. Titanium indiffused or annealed proton exchange (APE) waveguides can be fabricated in LiNbO₃ for integrated optical applications.
Lithium Niobate has nonlinear optical applications in harmonic generation, optical parametric oscillation and electro-optic modulation. LiNbO₃ offers excellent transmission properties coupled with a high extinction ratio and low half-wave voltage.
Fast (GHz) optical switches are commercially manufactured with lithium niobate wafers. Electro-optically-controlled multiplexers and demultiplexers can be fabricated into lithium niobate wafers. In addition, optical sources can be produced by doping or by indiffusion of rare-earth ions such as neodymium. Two-dimensional optical computing algorithms are also possible. Three-inch diameter wafers are typically produced for integrated photonic applications.
Integrated optics applications for optical-wafer grade LiNbO₃ include: switches, interconnects, multiplexers, waveguide lasers, and nonlinear optical waveguides. Periodic poling of Z-cut wafers can be used for quasi-phasematching to produce second-harmonic generation (SHG) or optical parametric conversion (OPO).