Phase-matched mode convertor in LiNbO3 using near-Z-axis propagation

Abstract

A phase-matched TE↔TM mode convertor, where the requirement for a birefringence tuning voltage is removed, is demonstrated in Y-cut LiNbO3. The direction of propagation is at 2° to the Z-axis where the sense of this angle is chosen not only to remove the residual waveguide birefringence but to improve the efficiency of the electro-optic interaction.