Processing and applications of electric field periodic poled LiNbO/sub 3/

Summary form only given. Efficient conversion in nonlinear optical crystals requires phase matching, typically achieved by use of the crystal birefringence to compensate for wavelength dispersion. Quasi-phase matching (QPM) in a nonlinear material is an attractive way to overcome many limitations of birefringent phase matching. The sign of the nonlinear optical susceptibility is reversed periodically so that the waves constructively interfere. Any three-wave interaction can be phase matched noncritically, irrespective of the birefringence. The highest nonlinear coefficient can be utilized in LiNbO/sub 3/. A periodic structure is lithographically defined on the substrate surface, and domain inversion is induced by selective re-poling.