A guided-wave TE to TM mode converter was demonstrated in LiTaO (3). The input mode is Bragg scattered from a collinear electrooptically induced wave of off-diagonal polarizability which couples the TE and TM modes. Compared with LiNbO(3), LiTaO(3) provides a smaller birefringence and thus a larger phase match period and larger optical bandwidth. A novel electrode structure allowed a four-phase drive of the polarizability wave with only two applied voltages. TE-TM mode conversion efficiency of 95% was demonstrated with a 103-A optical bandwidth. Operation as a frequency shifter was confined to low conversion efficiencies due to fringing fields.
