Crystal symmetry effects on nonlinear optical processes in optical waveguides

A general three-wave nonlinear (NL) optical interaction can be phase matched using the dispersion of optical waveguide modes. The phase-match condition can be fine tuned by varying the direction of propagation in a two-dimensional waveguide and using a birefringent NL material with an orientation that preserves TE and TM mode propagation. Two general cases are found where this technique is possible. The effects of crystal symmetry and orientation on the size of the NL interaction are calculated for all birefringent crystal classes and cubic crystal classes.