Fabrication of proton-exchange waveguide using stoichiometric LiTaO 3 for guided wave electrooptic modulators with polarization-reversed structure

Abstract

Optical waveguides were fabricated on z-cut stoichiometric LiTaO 3 (SLT) by using the proton-exchange method. The surface index change for the extraordinary ray on the SLT substrate resulting from the proton exchange was 0.017, which coincided well with congruent LiTaO 3 substrates. The proton exchange coefficient in the SLT was 0.25 × 10-12 cm 2/s. The application of the SLT waveguide to a quasi-velocity-matched travelling-wave electrooptic modulator with periodically polarization-reversed structure is also reported.