BEAM-PROPAGATION METHOD FOR 2ND-HARMONIC GENERATION IN WAVE-GUIDES WITH BIREFRINGENT MATERIALS

Finite difference equations are given for second-harmonic generation i n two-dimensional planar structures for coupling between TE polarizati ons at two frequencies as well as for TM polarizations at two frequenc ies, including the effect of birefringence in the latter case. Attenti on is given to obtaining accurate expressions for the finite differenc e operators for points close to interfaces, and it is shown how the eq uations for nonlinear coupling can be incorporated into the beam-propa gation method and the coupled-mode theory. Computational results of se cond-harmonic generation incorporating both the coupled mode theory an d the beam-propagation method are given and discussed. (C) 1997 Optica l Society of America.